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Latest Articles

Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes/issues, but are citable by Digital Object Identifier (DOI).
Plant Protection
The toxic effect of water extracts from five plants on the Bursaphelenchus xylophilus
ZHANG Yuhua, HE Ziting, LUO Dun, ZHONG Xianlong, LI Keyi, MENG Lihua, HU Ping
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240137
Abstract:
Pine wilt disease, caused by Bursaphelenchus xylophilus, has done significant damage to pine forests. The trunk injection method is a new way to prevent and control B. xylophilus. It is urgent to develop new prevention and control agents that can slow down B. xylophilus's resistance to existing insecticides. Plant-derived natural active substances are a promising option as they have a strong toxic effect on B. xylophilus. This study selected five common plants in the Guangxi Zhuang Autonomous Region—Mikania micrantha, Lantana camara, Camellia oleifera, Melia azedarach, and Polygonum hydropiper—to obtain their water extracts. The study investigated the toxic effects of these extracts on B. xylophilus using an immersion method and analyzed their impact on B. xylophilus 's activity and reproductive capabilities. The results showed that the water extracts from all five plants had some toxic effect on B. xylophilus. Specifically, Lantana camara achieved a corrected mortality rate of 95.05% after 72 hours of treatment at a concentration of 40 g·L−1. Lantana camara exhibited the strongest inhibition of B. xylophilus's activity, while Melia azedarach showed the strongest inhibition of B. xylophilus 's reproductive capability. This study demonstrates that Lantana camara and Melia azedarach can be used to serve as potential materials for developing green control agents against B. xylophilus.
Tropical Crop
Rice industry development bottlenecks in Hainan and their solution paths
ZHANG Luanjuan, JIAO Bin, LYU Baoqian, SUN Qiang, LU Hui, TANG Jihong, ZHANG Qikai, ZHAN Junping
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240111
Abstract:
As an important part of Hainan's agriculture, rice industry in Hainan has unique development advantages, high-quality tropical natural conditions and abundant light and heat resources. The current situation of rice industry in Hainan was analyzed in terms of planting area, production, rice varieties and branding. The analysis showed that there are major problems in rice production in Hainan, such as high cost, low yield and no premium. In order to solve these problems and promote the green and efficient development of Hainan's rice industry, a series of countermeasures are proposed, including promoting intelligent mechanised planting to reduce costs, relying on scientific and technological innovations to improve rice yield, implementing green production modes to improve the quality and efficiency of rice, as well as strengthening brand building and market promotion. The comprehensive application of these countermeasures aims to improve the market competitiveness of Hainan rice, achieve a win-win situation in terms of ecological and economic benefits, and promote the sustainable development of rice industry in Hainan.
Cloning and protein functional validation of MeDAWDLEgene
TAN Mengting, XU Haoran, ZENG Hongqiu
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240146
Abstract:
In order to investigate the protein function of MeDAWDLE, Cassava SC 124 was used as a variety of cassava to isolate and identify its MeDAWDLE through PCR amplification. The evolutionary tree revealed that MeDAWDLE shares high homology with the DAWDLE protein in apples at a homology rate of 76.3%. Analysis of the physicochemical properties of MeDAWDLE sequence revealed that the molecular weight of MeDAWDLE is 52 kD and that the theoretical isoelectric point of MeDAWDLE is 5.04. Expression analysis showed that MeDAWDLE is distributed in different tissues and organs of cassava, and the transcript of MeDAWDLE is upregulated under stress conditions. To explore the protein function of MeDAWDLE, the expression vector was constructed and the protein was induced. Further protein function analysis revealed that MeDAWDLE can significantly increase the reactive oxygen species (ROS) levels and the disease resistance of cassava. All these results indicated that MeDAWDLEmight play an important role in cassava stress response.
Tropical Horticulture
Physiological response and transcriptome differential changes of Nypa fruticans seedlings under low light environment
WANG Peng, HUAI Zhiwen, LIU Zihan, LEI Peng, GENG Xiaoxiao
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240114
Abstract:
An attempt was made to analyze the physiological changes and transcriptome expression differences in Nypa fruticans seedlings under low light levels (CK:100% of natural light intensity; Z1: 30% of natural light intensity; Z2: 20% of natural light intensity) through shading experiments to reveal the physiological responses and differential changes in the transcriptome of N. fruticans seedlings under low light levels, providing a scientific basis for the breeding of N. fruticans. The results indicated that at 40 days under low light conditions, the superoxide dismutase (SOD) activity in N. fruticans seedlings was 57.1% higher in Z1 and 62.1% higher in Z2 as compared to CK. Similarly, peroxidase (POD) activity was 41.2% higher in Z1 and 35.7% higher in Z2 compared to CK. Malondialdehyde (MDA) content was 42.6% lower in Z1 and 32.9% lower in Z2 compared to CK. However, chlorophyll (Chl) content was decreased by 61.1% in Z1 and 70.3% in Z2 compared to CK. Soluble protein (SP) content remained stable with no significant differences observed. The root-shoot ratio was 57.6% lower in Z1 and 48.1% lower in Z2 compared to CK. Under low light levels, N. fruticans seedlings were adapted to reduced light intensity within approximately 10 days by enhancing antioxidant enzyme activities, increasing leaf area, and promoting lateral root growth. Even in lower light availability, seedlings were further adapted to the environment by improving light absorption efficiency and regulating hormone levels.
Total Health
Fitness cost analysis of resistance to dimefluthrin in Aedes albopictus
ZHOU Xiangrong, JIANG Dingxin
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240152
Abstract:
The fitness cost of resistance to dimefluthrin in Aedes albopictus was analyzed by population life table comparison method using the resistant line (RR) of Ae. albopictus for experiment with the susceptible line SS as control. The results showed that the net reproduction rate (R0), mean generation time (T), intrinsic rate of increase (rm), finite rate of increase (λ), and population doubling time (D) were 41.13, 11.77 d, 0.32 d−1, 1.38 d−1, and 2.17 d, respectively, for the susceptible line population, and. 26.48, 14.27 d, 0.23 d−1, 1.26 d−1, and 3.01 d, respectively, for the resistant line. The resistant line of Ae. albopictus was longer in population doubling time than the susceptible line, indicating that its reproductive rate has slowed down. The pupation rate and emergence rate of the susceptible and resistant lines were all 100%, indicating there was no significant difference between them. The average development time from first instar larvae to pupae was (9.66±0.17)d for the susceptible line and (11.31±0.17)d for the resistant line; the average emergence time of pupae for both of the lines was (2.15±0.04)d and (2.90±0.03)d, respectively; the average survival time of female mosquitoes was (30.03±1.60)d and (21.83±1.12)d, respectively, for both of the lines, and there were all significant differences. The development time of larval and pupal stages and the life span of adult mosquitoes were prolonged, indicating that there is a certain fitness cost of resistance to dimefluthrin in Ae. albopictus.
Functional analysis of MeAPX2 gene in cassava resistance to cassava common mosaic disease
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250032
Abstract:
Ascorbate peroxidases (APXs) play a significant role in plant resistance to abiotic stress. An attempt was made to investigate the role of APXs in cassava resistance to cassava common mosaic virus (CsCMV). APX activity and the expression level of MeAPXs during infection of cassava with CsCMV were analyzed. The results showed that APX activity and MeAPX2 transcript level were reduced. Therefore, MeAPX2 was identified as a candidate gene for further analysis. MeAPX2 positively regulated cassava resistance to CsCMV, as determined by the disease index in MeAPX2-silenced plants. Further analysis revealed that MeAPX2 directly interacts with the coat protein (CP) of CsCMV. Moreover, CP was found to inhibit the activity of MeAPX2 both in vivo and in vitro. The results demonstrated that CsCMV suppresses APX activity during infection in cassava. Furthermore, MeAPX2 positively regulates cassava resistance to CsCMV by targeting CP.
Screening of the candidate interacting protein of RLK1 and validation of its interacting relationship with BSK by yeast two-hybrid in cassava
ZHENG Yu, CHENG Xiao, CHENG Ke, ZHAO Huiping
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240187
Abstract:
In order to screen proteins in cassava (Manihot esculenta) that jointly regulate cassava disease resistance with MeRLK1, 24 candidate interacting proteins of the MeRLK1 protein including heat shock protein (Hsp), ADP-ribosylation factor 1 (ARF1), aquaporin transported protein (AQP), etc were selected through screening from the yeast two-hybrid library. Further analysis of the spatiotemporal expression correlation between MeRLK1 and 24 candidate interacting genes revealed that genes including Pentatricopeptide repeat 2 (PPR2) and BR-signaling kinase (BSK) exhibited high correlations (R>0.7) with MeRLK1 expression across diverse tissues and under stress conditions. Based on the screening, the full-length sequence vector of MeBSK, a protein related to the brassinosteroid (BR) signaling pathway was constructed. Through the yeast two-hybrid experiment, it was found that there might be an interaction between MeRLK1 and MeBSK. Subsequently, bimolecular fluorescence complementation (BiFC) will be needed to further verify this interaction in vivo.
Foliar application of nematicides in the control of root-knot nematodes infecting tomato in pots
HUI Renjie, LIAO Yuqi, YU Zilin, DING Xiaofan
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250039
Abstract:
Root-knot nematodes (Meloidogyne spp.) are one of the most important plant parasitic nematodes worldwide, which seriously threatens agricultural production. Application of nematicides around the root-zone is still the main control method. Tomato plants in pots were foliar sprayed with nematicides to explore the pot control efficacy of the nematicides against root-knot nematodes in tomato and the inhibitory effects of root exudates (RE) and root metabolites (RM) on the second-stage juveniles (J2s) and egg hatching. The results showed that foliar application of fluopyram, fosthiazate, and abamectin had certain pot control efficacy against root-knot nematodes in tomato. On the whole, RE had better inhibitory effect on J2s and egg hatching than RM. RE obtained by foliar application of fosthiazate showed extremely high inhibitory effect on J2s, with a mortality rate of 84.10% on the first day after application. The results preliminarily proved the feasibility of foliar application of nematicides for the control of root-knot nematodes, which might provide an innovative strategy for reducing soil application and "reusing old nematicides" in tropical facility agriculture.
Genome-wide identification and prokaryotic expression analysis of TkBZR family genes in rubber dandelion (Taraxacum kok-saghyz)
DING Jiahui, ZHANG Qianyu, YUAN Hongmei
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250029
Abstract:
To further understand the role of the TkBZR family genes in the growth, development, and stress resistance of rubber dandelion (Taraxacum kok-saghyz), the TkBZR/BES family genes were identified and analyzed by examining the whole genome sequencing data of T. kok-saghyz. A total of 6 members of the TkBZR family were identified, named from TkBZR1 to TkBZR6, and their distribution on chromosomes, domain characteristics, tissue expression profiles and the spatial-temporal gene expression were analyzed. The results revealed that TkBZR/BES gene family members were distributed on 6 independent scaffolds. Phylogenetic trees indicate that TkBZR/BES gene family members are evolutionarily conserved, with rubber dandelion and lettuce genes clustering in the same subgroup, suggesting a possible close evolutionary relationship between the two. Gene structure and conserved domain analysis show that except for TkBZR5, all the other TkBZR genes contain two exons and one intron, and that all the family members exhibit a highly conserved BES1_N domain. Expression pattern analysis reveals that 5 members are expressed in all five tissues, while one member is almost unexpressed. Additionally, the TkBZR2 gene with the highest expression abundance was successfully cloned, encoding 307 amino acids. Homologous recombination of TkBZR2 was made into prokaryotic expression vector, and the recombinant plasmid was transferred into E. coli BL21(DE3) .The recombinant protein TkBZR2 was expressed in E. coli BL21 (DE3).
Faunal analysis of Heteroptera insects in the main peak region of Jianfengling Mountains, Hainan Island
LI Zili, WANG Jianyun, LUO Wen, LIN Ruixiu, SU Honghua, MO Shiliang
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240180
Abstract:
A faunal analysis was made of Heteroptera insects in the main peak region of Jianfengling, Mountans, Hainan Island to elucidate species composition and distribution patterns of Heteroptera insects in this region. This is of great significance for the biodiversity conservation of Jianfengling Mountains. The faunal characteristics of the Heteroptera insects in the main peak area of Jianfengling Mountains, Hainan Island was analyzed through line transect survey, species identification, data collation and analysis. The analysis results show that a total of 100 species of Heteroptera insects were recorded in the main peak area of Jianfengling Mountains, Hainan Island, belonging to 85 genera and 15 families. Among the families identified the Reduviidae and Pentatomidae are dominant. The Reduviidae has the higher number of species, with a total of 34 species, accounting for 34% of the total species; followed by the Pentatomidae, with a total of 25 species, accounting for 25% of the total species. Overall, there is no obvious dominant genus in this region. In terms of the composition of genera, monotypic genera contain the highest number of species, with a total of 74 species, accounting for 74% of the total species; oligotypic genera contain 26 species, accounting for 26% of the total species. The genus with the largest number of species is Physopelta, with a total of 5 species recorded, accounting for 5% of the total species. The Heteroptera insects in the main peak area of Jianfengling Mountains on Hainan Island are mainly composed of Oriental and Palearctic realms in the Zoological fauna of the world at the genus level, with the Oriental realm accounting for the highest proportion, followed by the Palearctic realm. In the zoogeographic fauna of China, the components at genus levels are mainly composed of those in South China region, Southwest District region and Central China region, exhibiting the distribution characteristics of multiple regions. Among them, the components from the South China region account for the highest proportion, followed by those from the Southwest District region and Central China region. Overall, the diversity of insect species in the Jianfengling Mountains area of Hainan Island is relatively complex. All these results provide basic information for the comprehensive investigation and research of insects in the Jianfengling Mountains area of Hainan Island, and at the same time also offer scientific reference for the prevention and control of Heteroptera pests and the protection and utilization of predatory Heteroptera insects.
Cloning and preliminary functional analysis of MeIAA19 in cassava
LIU Xiaoli, WEI Yunxie
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240145
Abstract:
Auxin is widely present in plants and plays an important role in mediating plant development and disease resistance. The Aux/IAA family are widely involved in the early response of auxin and regulate the entire process of auxin signal transduction. In order to study the characteristics of Aux/IAA and their roles in reponse to stresses, this study cloned and identified the MeIAA19 from cassava, which encodes 244 aa with a typical PB1 conserved domain of Aux/IAA proteins. Additionally, MeIAA19 protein, expressed and purified from DE3 strains, could significantly induced ROS burst and MePR1 and MePR2 expression. Moreover, the expression level of MeIAA19 significantly increased with time under Xam infection. These results will provide a certain theoretical basis for exploring the function and mechanism of action of the MeIAA19 in cassava.
Effect of natural enemy protection and utilization on maize pest control in Hainan Province
YANG Deyan, LU Hui, LYU Baoqian, CHEN Bin, TANG Jihong, ZHANG Qikai, JIAO Bin
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240108
Abstract:
The occurrence of fresh corn pests is serious in Hainan, which seriously threatens the safety of fresh corn production. In order to develop a technical model suitable for the green production of corn in Hainan, a survey was made of the occurrence of the main harmful populations and natural enemies of corn pests from 2019−2023, and the prevention and control experiments and demonstrations were also completed. The results showed that Spodoptera frugiperda infested corn during the whole growth period of corn and accounted for more than 40% of the pest population, which results in an infestation percentage of 25% to 43%. As a secondary pest, Ostrinia furnacalis accounted for more than 25% of the pest population, and the percentage of infestation caused thereby was 5% to 17%. With the invasion of S. frugiperda, the application frequency of chemical pesticides in a single corn growth period increased significantly in 2020, from 4.27−5.47 times in 2019 to 7.73−8.77 times in 2020, which may have a potential negative impact on the environment. Natural enemy insects play an important role in the biological control of corn pests, among which parasitic natural enemies are dominant and account for 75.89% of the population. The parasitism rates of Trichogramma sp. and Telenomus remus were 23.22% and 7.91%, respectively. In 2023, by applying the combined control strategy of natural enemy insects and pathogenic microorganisms, the control effect of S. frugiperda and O. furnacalis reached 81.41% and 78.77%, respectively, which were equivalent to the chemical control effect. The combined control mode of parasitic wasps and Metarhizium sp. has a significant effect on pest control, reduces the use of chemical pesticides, is safe for corn production, and can be applied to the pest control of fresh corn in Hainan.
Stomatal and photosynthetic characteristics of halophyte plant, seashore Paspalum
SUN Quanquan, ZHU Qing, HU Xu, XU Tao, WANG Zhiyong, LIAO Li, LI Xinhua
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240085
Abstract:
An attempt was made to analyze the relationship between stomatal and photosynthetic characteristics of different accessions of seashore paspalum (Paspalum vaginatum Sw.), and 25 seashore Paspalum germplasm were analyzed in terms of photosynthetic parameters, leaf length, leaf width and stomatal characteristics. The results showed that all traits of the paspalum germplasm were significantly different (P < 0.05), and were significantly (P < 0.05) positively or negatively correlated with each other. The net photosynthetic rate was significantly negatively correlated with the leaf length, stomatal density and stomatal area index (P < 0.01), and significantly negatively correlated with leaf width (P < 0.05). Stomatal conductance was significantly negatively correlated with stomatal density (P < 0.05), and positively with stomatal pore length (P < 0.01), while water utilization was negatively correlated with stomatal size (P < 0.05), but not with other stomatal characteristics (P > 0.05). The principal component analysis showed that the cumulative contribution rate of the four main components (net photosynthetic rate, stomatal conductance, stomatal size and guard cell length) was 75.80%. Twenty-five accessions of the paspalum germplasm were classified into three groups (A, B and C) by using four indexes. Group C includes 14 accessions that have the highest net photosynthetic rate with the largest stomatal size, the widest stomatal pore and low stomatal density. Group C are accessions of seashore Paspalum germplasm with better photosynthetic characteristics, with their photosynthetic capacity regulated through the function of stomatal accessory cells, and the stomatal traits are also key indicators for regulating net photosynthetic rate.
Proline imino-peptidases regulate the virulence of Xanthomonas campestris
XING Yun, ZHAN Zhaohong, WU Kejian, WEI Bingzheng, TAO Jun
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240079
Abstract:
To investigate if the proline aminopeptidase (PIPase) regulate the virulence of Xanthomonas campestris pv. campestris (Xcc), we first analyzed the putative PIPases in Xcc by bioinformatics; then expressed and purified these proteins, and detected their PIPase activities in vitro; finally studied the roles of these genes in Xcc virulence by analyzing the infective ability, growth rates, motility, and extracellular enzyme activities of the mutants and supplementary strains of these genes. The results indicate that Xcc encodes two PIPases, PipA and PipB. Mutation of either gene led to a decrease in Xcc virulence. Overexpression of pipA or pipB resulted in enhanced motility. In addition, pipA overexpression increased the activities of the extracellular proteases in Xcc, but pipB did not have this activity. Therefore, PipA and PipB may affect Xcc virulence by regulating its motility, and PipA may also regulate extracellular protease activity to affect Xcc infection.
Effect of biochar on the growth, nutrient accumulation and yield of maize in the tropics after three years of application
HOU Guangqing, CHENG Wenxiao, SHAO Xujie, SHI Dairen, JIA Ruihong, YE Jingang, LI Changzhen, LI Changjiang
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240057
Abstract:
In order to clarify the effect of biochar application on maize (Zea mays) in the tropics, two types of biochar, peanut hull biochar and rice hull biochar, were applied to the maize field at the rates of 10, 20, 40, and 60 t·hm−2), with no biochar as the control (CK), to observe their effects on the growth, development, nutrient accumulation and yield of the maize, and the soil properties in the maize field three years after biochar application. The results showed that the plant height and leaf SPAD values of maize were not significantly different among treatments throughout the reproductive period, while at the silking stage, the leaf SPAD values of maize in the 40 t·hm−2 treatment were significantly higher than those in the 60 t·hm−2 treatment. In addition, with the increase of biochar application rate, the soil pH and the contents of organic carbon, ammonium nitrogen, soil available phosphorus and soil available potassium in the 0~40 cm soil layer at the maturity stage of maize increased gradually. Except for the 40 t·hm−2 treatment, the 60 t·hm−2 treatment significantly increased the soil pH, and the contents of organic carbon, ammonium nitrogen, soil available phosphorus and soil available potassium as against the other treatments. At the same time, there was no significant difference in the contents of soil ammonium nitrogen and soil available phosphorus between the 40 t·hm−2 treatment and CK. The 40 t·hm−2 treatment had the highest accumulation in maize dry matter, nitrogen, phosphorus and potassium, and was highest in number of grains in ears and yield, which were significantly higher than those of the CK treatment. However, there was no significant difference in utilization efficiency of nitrogen, phosphorus and potassium between the 40 t·hm−2 treatment and CK. Correlation analysis found that yield was significantly positively correlated with soil pH, dry matter accumulation, plant N, P and K accumulation and number of grains in ears. Taken together, the 40 t·hm−2 biochar treatment could improve the soil and the growth and nutrient utilization and yield of maize, which could be optimal in the tropics, and rice hull biochar was superior to peanut hull biochar.
Analysis of the function of the CaMYB44 gene in Capsicum annuum
WU Shuhua, LIU Jiancheng, NING JiaHui, WANG Zhiwei
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240067
Abstract:
The MYB transcription factor family plays an important role in plant response to environmental stress. Capsicum annuum is the most widely cultivated species in the genus Capsicum. The transcriptome data obtained by our group were analyzed, based on which MYB44 transcription factor was selected for bioinformatics analysis of the cis-acting elements of the promoter, protein structure, evolutionary relationship. A preliminary experimental research was then conducted on subcellular localization and low temperature response. The open reading frame (ORF) of CaMYB44 gene is 981 bp in length, encoding an unstable hydrophilic protein with an amino acid of 326 aa. It is predicted that CaMYB44 protein has no signal peptide and transmembrane domain, is a non-secretory protein, and belongs to R2R3 MYB. Phylogenetic tree analysis showed that it had high homology with SmMYB73, NtMYB44-like, StMYB44-like and SlMYB44, followed by AtMYB70 and OsMYB77. Cis-acting element analysis showed that the promoter region contained a low temperature response element and multiple abscisic acid and light response elements. Subcellular localization results showed that CaMYB44 was localized in the nucleus. The RT-qPCR showed that the expression of CaMYB44 was down-regulated after 24 h of low temperature stress at 4°C, which was similar to the expression trend of other negative regulatory factors under low temperature stress. This paper provides basic data for further analysis of low temperature tolerance transcription factors in C. annuum.
Genetic diversity and genetic differentiation of Bursaphelenchus xylophilus in Guangxi based on mt COI sequences
MENG Lihua, HE Ziting, ZHANG Yuhua, LI Keyi, WU Jinfeng, WU Yitong, LUO Min, HU Ping
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240135
Abstract:
An attempt was made to investigate the genetic diversity and genetic differentiation of Bursaphelenchus xylophilus, the causative agent of pine wilt disease, which is posing a severe threat to the forest ecosystem and economic development in Guangxi Zhuang Autonomous Region. Sixty seven strains of B. xylophilus collected from eight different districts/counties within Guangxi were analyzed by using the mitochondrial cytochrome c oxidase subunit Ⅰ (mt COI) gene fragment. The results indicated that there were three polymorphic sites and one parsimony-informative site within a 647 bp region, with genetic diversity indices at extremely low levels. Four haplotypes of B. xylophilus were identified in Guangxi, with an overall haplotype diversity of 0.170, where Hap1 was the predominant haplotype. The B. xylophilus strains in Guangxi were clearly distinct from those found in other regions both domestically and internationally, forming an independent branch. In recent years, the spread of B. xylophilus in Guangxi occurred primarily through natural dispersion. All these findings might provide a theoretical basis for developing targeted prevention and control strategies for B. xylophilus in Guangxi.
A new species and a newly record species of genus Forcipomyia subgenus Euprojoannisia (Diptera: Ceratopogonidae) from Hainan Island
MENG Xiangrui, LI Jiahui, LIN Xiaodan
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240071
Abstract:
Euprojoannisia Brèthes is one of the 35 subgenera of genus Forcipomyia Meigen, known as the third largest subgenus in terms of the number of species just behind subgenus Forcipomyia s.str. and subgenus Lasiohelea Kieffer. The specimens of subgenus Euprojoannisia were collected from the mangrove forests in Hainan Province and identified by morphological characters and DNA barcodes. A new species, F. (E.) quadrata sp. nov., and a new record species of Hainan Province, F. (E.) psilonota Kieffer, 1911, were found and described. Besides, the characteristics of the females of F. (E.) appendicular Liu, Yan and Liu, 1996, were first reported.
Population dynamics of Bactrocera dorsalis and the impact of meteorological factors
MO Wu, GONG Zhi, YI Kexian
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240084
Abstract:
To clarify the population dynamics of Bactrocera dorsalis in Hainan region, surveys were conducted on the population of B. dorsalis in the main agricultural production areas of Hainan, and the correlation between the population and meteorological factors was explored. The results showed that B. dorsalis can occur throughout the year in Hainan, with the peak occurrence period from May to August, and the low occurrence period in winter from November to December. The monitoring data of B. dorsalis populations in some areas were positively correlated rwith average temperature, maximum temperature, and minimum temperature, but not significantly with precipitation, relative humidity, and rainy days was. This provides a good referece for formulating control strategies for B. dorsalis in Hainan.
Preparation of sodium butyrate-loaded chitosan nanoparticles and their anti-inflammatory activities
PENG Shulu, SHAO Jia, TANG Yanqiong, MA Xiang, LI Hong, CHI Xue, LIU Zhu, LI Juanjuan
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240069
Abstract:
Pathogenic bacterial infections release large amounts of lipopolysaccharides that disrupt the structure of intestinal tight junction proteins, leading to increased intestinal permeability, causing dysfunction of the intestinal epithelial barrier, and inducing severe intestinal inflammation. Sodium butyrate, as a type of short-chain fatty acid, has an important role in relieving intestinal inflammation. However, its properties such as volatility and low utilization rate seriously affect its application. Therefore, the design and development of sodium butyrate drug delivery system is important to improve the utilization and effect of sodium butyrate. In this context the nature of cross-linking of chitosan (CS) and hyaluronic acid in the presence of sodium tripolyphosphate was made full use of to form CS-SB nanoparticles by encapsulating sodium butyrate (SB) in the particles. CS-SB was characterized by transmission electron microscopy and laser particle size analysis, and was found to be irregularly spherical with a particle size of approximately 97.30 ± 4.20 nm. SB was able to release in PBS buffer, reaching a cumulative release of 116.27 ± 7.75 ng over 24 h. A lipopolysaccharide-induced intestinal cellular inflammation model was constructed, and it was found that CS-SB could effectively inhibit the expression of cellular pro-inflammatory factors and play a role in alleviating inflammation. The drug delivery system developed using natural products such as chitosan can effectively overcome the shortcomings of sodium butyrate, which is volatile, and provides a new idea for designing new bioactive oral drug delivery systems.
Cloning, bioinformatics analysis and expression pattern of CdMYC2 gene in Camellia drupifera Lour.
YANG Eyue, LI Yang, MO Mingzhu, YANG Dongmei, LIU Ya, WU Yougen, YU Jing
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250031
Abstract:
MYC2 is an important transcription factor that regulates the synthesis of terpenoid secondary metabolites in plants. However, little is known about the CdMYC2 transcription factor in C. drupifera. In this study, the related sequence information of CdMYC2 gene was obtained based on the transcriptome annotation data of C. drupifera. A CdMYC2 gene was successfully isolated and cloned from the leaves of C. drupifera for the first time. Its CDS sequence length was 1515 bp, encoding 504 amino acids, with typical bHLH-MYC _ N super family and bHLH _ SF super family conserved domains. This gene was predicted to be located in the nucleus. Multiple sequence alignment further confirmed that the amplified CdMYC2 belongs to the MYC2 family transcription factor. The phylogenetic tree analysis showed that CdMYC2 was clustered into a clade with Camellia sinensis, a plant belonging to the same family and genus, while it was far away from the clades of Quercus lobata and Quercus robur. RT-qPCR results showed that the expression level of CdMYC2 gene was higher in the leaves than in other tissues. Among the different developmental stages of the fruit, the expression of CdMYC2 in the fruit reached the highest in September. This study provides an important reference for the subsequent exploration of the function of MYC2 transcription factor in the regulation of triterpenoid saponin biosynthesis pathway in C. drupifera.
Spatiotemporal dynamics of butterfly diversity in Wuyuan River National Wetland Park, Haikou, Hainan
YANG Zixuan, ZHU Zunyan, LI Jiahui, LIN Xiaodan
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240164
Abstract:
Butterfly is an important indicator organism for environmental monitoring, its community composition and diversity are closely related to habitat type, and its diversity and distribution can well reflect local ecological and environmental quality to a certain extent. In order to explore the relationship between habitats and butterfly diversity, a systematic survey of butterflies in four habitats of Wuyuan River National Wetland Park, Haikou, Hainan Province was conducted from February 2023 to January 2024 by using line transects method, and the distribution of butterflies in different habitats of Wuyuan River National Wetland Park was analyzed. In the survey a total of 2107 individuals of butterfly belonging to 6 families 90 genera 128 species were recorded, most species were from Oriental Region, and Nymphalidae contain the most species and abundance. There were significant spatiotemporal differences in community diversity, and the monthly dynamics of adult insects indicate that the changes of species and individual numbers were bimodal with peaks in May and September, respectively. There were obvious differences in species composition and diversity index in different habitats. The diversity index, richness index and evenness index of butterfly community in laurifruticeta were the highest, and the diversity index and evenness index of butterfly community in emersiherbosa were the lowest. This survey improved the basic data of butterfly resources in Wuyuan River National Wetland Park, and provided references for the conservation and utilization of butterfly diversity and the ecological environment assessment.
Gene cloning and expression analysis of MRFs gene cDNA in the tissues of giant grouper Epinephelus lanceolatus
ZHANG Longting, ZHENG Zhi, WANG Yao, GAO Yujie
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250030
Abstract:
Myogenic regulatory factors (MRFs) are critical regulators of skeletal muscle growth and development in animals. The full-length cDNA sequences of five MRFs from the giant grouper (Epinephelus lanceolatus) were cloned using RT-PCR and RAC, including MyoD1 (1,962 bp), MyoD2 (1,466 bp), MyoG (926 bp), MRF4 (1,052 bp), and Myf5 (1,133 bp), encoding 297, 270, 251, 238, and 242 amino acids, respectively. Amino acid sequence alignment revealed that all five MRFs contain a conserved basic helix-loop-helix (bHLH) domain consisting of 60 amino acids. Phylogenetic analysis demonstrated that the MRF genes are clustered into two distinct branches: MyoD (MyoD1 and MyoD2) groups with Myf5 in one clade, while MRF4 and MyoG form the other. All genes showed closest evolutionary relationships with Perciformes homologs. Real-time quantitative PCR analysis revealed predominant expression of these MRFs in skeletal muscle, with significantly lower expression levels in the liver, heart, and intestine. These findings provide foundation for elucidating the regulatory mechanisms of MRFs in skeletal muscle development of the giant grouper.
In vitro induction of microrhizome in Curcuma wenyujin
WANG Kaixuan, GUO Jiaxin, CHEN Jianmiao, ZENG Jinsong, LIANG Jing, LI Ying
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250012
Abstract:
In order to improve the propagation efficiency of Curcuma wenyujin plants, tissue cultured plants of C. wenyujin was cultured on in vitro rooting medium (1/2MS + NAA 0.5 mg·L−1) supplemented with broad spectrum plant growth regulators, choline chloride (CC) and compound sodium nitrophenolate (CSN), at different concentrations and ratios to induce the differentiation of their microrhizomes, and the growth status of the tissue-cultured plants after transplantation was observed. The results showed that the tissue cultured plants cultured on the medium supplemented with a combination of CC at 1.0 mg·L−1 and CSN at 2.0 mg·L−1 were induced to form microrhizomes obviously, with an inducing rate of 62%. In the medium supplemented with a combination of CC at 3.0 mg·L−1 and CSN at 1.0 mg·L−1, the induction rate was 46%, but the swelling and thickening of microrhizomes were the most obvious, with a transverse diameter of about 6.8 mm. There was no significant difference in the length of microrhizomes between the two groups. All the tissue-cultured rooted plants with microrhizomes survived after transplantation, and their survival rate, growth rate, tiller number, number of new leaves, and the weights of tuberous roots and rhizomes increased by 36.4%, 112.5%, 83.0%, 103.9%, and 83.2%, respectively compared with the control tissue-cultured rooted plants.
Optimization of an in vitro identification system for rice resistance to bacterial blight
LING Yuxuan, LI Yiyong, LI Yao, XIA Zhihui
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240048
Abstract:
An attempt was made to establish an in vitro identification system for resistance of rice to bacterial blight. Detached rice leaves of varying lengths were treated with 6-Benzylaminopurine (6-BA), Kinetin (KT), and Thidiazuron (TDZ) at different concentrations to select an optimized system for maintaining leaf greenness in vitro, based on which in vitro identification systems for resistance of rice to bacterial blight were established. The results indicated that regardless of the type of hormone used as a greening agent, the efficacy of greening was closely correlated with the length of the detached leaves, with shorter leaves exhibiting better greening effects. Further analysis of the relative chlorophyll content data revealed that the optimal concentration for each hormone that yielded the best greening effects were 0.28 mg·L−1 for TDZ, 4 mg·L−1 for 6-BA, and 4 mg·L−1 for KT, with 0.28 mg·L−1 for TDZ being the most effective concentration for detached rice leaves, and 4 mg·L−1 for 6-BA and 4 mg·L−1 for KT being similarly effective. Using 0.28 mg·L−1 TDZ as the greening agent, the detached leaves from rice plants with five different levels of field disease resistance were inoculated with Xanthomonas oryzae via the "clipping method." The results demonstrated a positive correlation between the lesion lengths of the detached leaves and those from field inoculations after 7 days of inoculation, with the regression equation of y = −0.62 + 1.32x (R2 = 0.98). The findings of this study contribute to the molecular breeding efforts for rice resistance to bacterial blight.
The insecticidal activity and mechanism of 9-Phenylacridine on Aedes aegypti
LIU Huaxin, GAO Longxiang, HOU Dezhong, LUO Yanping, WANG Lanying
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240172
Abstract:
In order to develop insecticides with photoactivation activity, Aedes aegypti was used as the target organism to determine the insecticidal activity of 6 acridine derivatives and explore the activity mechanism of the highly active compound. The results showed that all the tested compounds were photosensitive and had no insecticidal activity under dark conditions. The insecticidal activity of all compounds increased significantly after UV irradiation, among which 9-phenylacridine had the highest activity (LC50 = 0.717 mg/L ). At the concentrations of LC50 and LC75, the 9-phenylacridine could significantly reduce the pupation rate and emergence rate and increase the mortality rate of pupae while inhibit chitinase activity; the ROS level was increased in the tested insects; the activities of SOD and CAT showed a trend of increasing first and then decreasing; the activity of POD increased. What’s more the AchE activity was inhibited by 9-phenylacridine with LC75 concentration. It is speculated that 9-phenylacridine can induce the organism to produce ROS and cause oxidative damage to the organism, thus exerting insecticidal activity. It is concluded that 9-phenylacridine has the potential to be developed into photoactivated insecticide.
Transcriptome differences resolve the phenomenon of bud jumping in Oncidium and its regulation
LAN Hanqiao, LIU Le, LI Weishi, HAO Daicheng, CHEN Taizhen, LU Ling, TANG Minqiang, LING Peng
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240197
Abstract:
To address the decreased cut flower yield caused by the bud jumping development phenomenon, where adventitious buds interrupt the normal growth cycle of flower bud differentiation in Oncidium cut flower production, flower buds and vegetative buds of Oncidium hybridum 'Boda NO1' were selected for high-throughput transcriptome sequencing. A total of 127,452,717 high-quality sequences (37.36 Gb) were obtained, and 7,671 differentially expressed genes (DEGs) were identified. COG functional classification revealed primary enrichment in signal transduction pathways and carbohydrate transport/metabolism pathways. KEGG analysis showed that DEGs were significantly enriched in starch and sucrose metabolism, phytohormone signaling, and other pathways. Among these, 78 DEGs were identified in the phytohormone signaling pathway, with the most pronounced differences involving auxin, cytokinins, salicylic acid, and gibberellins. Thirteen transcription factors and flowering-related genes, including MADS1, AP2, and FLK, were also screened. These results partially elucidate the effects of auxin, cytokinins, and flowering-related genes on the differentiation of flower buds and vegetative buds in Oncidium. This study provides a theoretical foundation for further research on the mechanism underlying the bud jumping development phenomenon during Oncidium production. Additionally, it supports subsequent improvement in production efficiency, quality enhancement, and optimization of cultivation and management. These findings hold significant practical value for advancing orchid breeding, seedling production, and industry development in China.
A new record genus of Pilotrichaceae plants in Hainan, China
SU Xin, QI Tianyun, ZHANG Lina, HAO Jiewei
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240203
Abstract:
In order to understand the distribution of moss resources and species diversity in Hainan Tropical Rainforest National Park, moss plant specimen collections were conducted several times on the main peak of Limu Mountain from 2022 to 2023, and the specimens collected were identified morphologically in combination of literature review. A new record genus of Pilotrichaceae plants for Hainan was confirmed: Actinodontium, along with the species Actinodontium rhaphidostegum (Müll. Hal.) Bosch & Sande Lac. The morphological characteristics of the newly recorded genus and species were described, and illustrated with characteristic plates. The habitat and geographical distribution of the genus and species was also introduced. This new record enriches the diversity of bryophytes in Hainan Island.
Functional analysis of the Pth11-like CFEM protein CgCFEM17 in Colletotrichum gloeosporioides from rubber tree
HE Erxiu, LUO Hongli
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250009
Abstract:
Colletotrichum gloeosporioides is the main pathogen causing anthracnose of rubber tree (Hevea brasiliensis). The common in fungal extracellular membrane (CFEM) domain is a unique motif of fungi, and the proteins containing CFEM and transmembrane domains are defined as Pth11-like CFEM protein, which plays important roles in regulating the development and pathogenicity of pathogenic fungi. In order to study the pathogenesis of C. gloeosporiorides, a gene encoding Pth11-like CFEM protein was screened from the transcriptome of C. gloeospriorides and named as CgCFEM17. The encoding region of the gene CgCFEM17 is 1341bp in length and encodes a peptide with 446 amino acids. Bioinformatics analysis showed that the N-terminus of CgCFEM17 has a signal peptide with 26 amino acids and a conserved CFEM domain, and the C-terminus contained six transmembrane domains. The knockout mutant strain (∆CgCFEM17) and complementary strain (∆CgCFEM17-C) of the gene CgCFEM17 were constructed to analyze the function of CgCFEM17. The results showed that the conidium germination and invasion structure of ∆CgCFEM17 were delayed compared with the wild type and complementary strain, but the colony growth rate, conidiation, appressorium formation rate, and morphogenesis were not changed. These results indicated that the gene CgCFEM17 could affect the pathogenicity of C. gloeosporioides on rubber tree by regulating the germination process of conidia and delaying the formation of infection structure, which lays a theoretical foundation for exploring of the pathogenic mechanism of C. gloeosporioides and establishing of a new control strategy for anthracnose of rubber trees.
Analysis and evaluation of nutritional components of Acanthophora muscoides and Gracilaria coronopifolia
CAI Hongyan, WANG Chen, ZENG Jun, LI Hang, WANG Rundong, TAN Huaqiang, WANG Liyun
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240160
Abstract:
Abstracts: Macroalgae, such as Acanthophora muscoides and Gracilaria coronopifolia, widely distributed in the water of Liusha Bay in the Leizhou Peninsula in Zhanjiang, Guangdong Province. The basic nutritional components of A. muscoides and G. coronopifolia were analyzed and their nutritional value was assessed in a view to exploring their potential value for development. The results showed that the fresh weight moisture contents of A. muscoides and G. coronopifolia were 93.10% and 88.60%, respectively. Additionally, A. muscoides had crude protein content of 9.4%, crude fat content of 2.89%, ash content of 55.07%, and crude fiber content of 5.7%, while G. coronopifolia contained 7.5% of crude protein, 1.78% of crude fat, 27.38% of ash, and 3.57% of crude fiber. In term of amino acid profile, A. muscoides and G. coronopifolia contained 13 types of amino acids, with a rational composition and high levels of essential and flavor amino acids. The DAA/TAA ratios of the two macroalgae were 56.74% and 48.14%, respectively, meeting the requirements of the FAO/WHO standard pattern. The first limiting amino acid for both species was leucine, while the second limiting amino acids were isoleucine and lysine for A. muscoides and G. coronopifolia, respectively. Moreover, these macroalgae had valuable minerals, such as calcium, iron, sodium, magnesium, zinc, and potassium, and had low content of heavy metals. All these results showed that A. muscoides and G. coronopifolia had diverse and patterned amino acids, and vital minerals, making them highly valuable for nutrition and offering broad prospects for development and application. This study provides some reference for further resource development and utilization of A. muscoides and G.coronopifolia.
Identification of interaction domains between cassava MeKIN10 and MeRAV1/2 proteins
HE Jiaoyan, CHEN Ao, YAN Yu
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250028
Abstract:
Cassava (Manihot esculenta), a crucial staple and bioenergy crop, faces significant yield and quality losses due to oxidative stress induced by environmental factors such as drought and high temperature. Previous studies have demonstrated that MeKIN10, a protein kinases associated with energy sensing in cassava, enhances oxidative stress tolerance by mediating the phosphorylation of MeRAV1/2. While protein-protein interaction is essential for kinase-mediated phosphorylation, the specific interaction regions between MeKIN10 and MeRAV1/2 remain elusive. In this context the interaction regions of MeKIN10 and MeRAV1/2 were identified through protein domain analysis, AlphaFold3 prediction and yeast two-hybrid experiment. The results demonstrate that the STKc-AMPK-alpha kinase domain of MeKIN10 is the key domain in its interaction with MeRAV1/2, which further indicates that the protein interaction between MeKIN10 and MeRAV1/2 is the key in mediating the phosphorylation of MeRAV1/2.
Community structure of macroalgae in the Marine Ranch of Wuzhizhou Island, Sanya
TIAN Hui, QIN Lezheng, HE Linwen
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240142
Abstract:
To explore the characteristics of macroalgae species and community structure in the Marine Ranch of Wuzhizhou Island, Sanya, sampling surveys were conducted from April 2023 to June 2023 at 12 different sites within the marine ranch area. A total of 29 species of macroalgae were collected, including 17 species from the Rhodophyta phylum, 9 species from the Chlorophyta phylum, and 3 species from the Phaeophyta phylum. The dominant species were Amphiroa fragilissima and Turbinaria ornata. The average biomass of macroalgae was 2.40±1.89 g·m−2. The average carbon content and nitrogen content of different species of macroalgae were 18.80% and 0.98%, respectively, with an average C/N ratio of 24.04±13.61. The mean values of species diversity index (H′), species richness index (D), and species evenness index (J) of the macroalgae community were 1.28±0.59, 5.60±4.61, and 0.87±0.70, respectively. Cluster and ordination analysis revealed that the 12 sites were grouped into 3 clusters. SIMPER and ANOSIM analyses indicated significant differences in the community structure of macroalgae among these three clusters, with basic separation of community structures. These results suggest that the Marine Ranch of Wuzhizhou Island, Sanya harbors a rich diversity of macroalgae, but significant differences in community structure exist among different clusters due to specific dominant species and habitat variations.
Screening of plant growth regulators for green-retaining of pitaya fruit scales and fruit-weight improvement
JIANG Senrong, KANG Shaoling, DING Yi, YANG Zhuangjia, WANG Meng, WANG Zhouwen, WEI Shuangshuang, TANG Hua
, Available online  , doi: 10.15886/j.cnki.rdswxb.20230135
Abstract:
Through field preliminary screening and re-screening experiments, pitaya was treated by spraying after pollination with nine plant growth regulators, including chlorpropham (CPPU), trans-abscisic acid (S-ABA), 6-benzylaminopurine (6-BA), ethephon (ETH), gibberellic acid (GA3), brassinolide (BR), diethyl aminoethyl hexanoate (DA-6), compound sodium nitrophenolate (CSN), and 1-naphthaleneacetic acid (NAA), to observe the effect of the growth regulators on scales green-retaining and fruit weight improvement of pitaya. The results indicate that appropriate plant growth regulators can promote scales green-retaining and fruit weight improvement in pitaya fruits. Treatments with CPPU diluted at 50 times, 200 times, and 100 times on the 13th and 23rd days after pollination were best in retention of green scales, and their green scale ratios were 74.84%, 74.26%, and 72.41%, respectively, with an increase ratio of 0.55, 0.53, and 0.5 times compared to the control group. The most effective treatments for promoting fruit weight were those of spraying GA3 at a dilution of 500 times on the 13th day after pollination, and spraying GA3 at dilutions of 500 times and 2000 times on the 13th and 23rd days after pollination, and their fruit weights were 411.32 g, 498.32 g, and 484.17 g, respectively, with an increase in weight ratio of 0.39, 0.32, and 0.31 times compared to the control group. The labor cost was considered in actual production in this experiment, and pitaya was thus sprayed with the plant growth regulators for only one round. The results showed that the treatment with GA3 diluted 500-folds on the 13th day after pollination was the best among the treatments in green retention of scales and fruit weight gain. Under this treatment the proportion of green parts of scales was 70.2%, showing a significant increase of 15.8% compared to the control group, and the average fruit weight was 411.3g, significantly higher by 116.2g compared to the control group, meeting the requirements for field production.
Identification and Bioinformatics Analysis of KNOX Gene Family in water lily (Nymphaea L.)
XU Huixian, LI Jie, LI meier, ZHANG ruxin, WANG Tongxin, LI Tingge, ZHAO Ying, WANG Jian
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250024
Abstract:
The KNOX gene family encodes homeobox proteins that function as transcription factors and are integral to regulating plant growth and development. To investigate the bioinformatic characteristics of the KNOX gene family and its potential roles during viviparous seedling development in water lily (Nymphaea), this study identified 15 KNOX genes from the Nymphaea genome using bioinformatics approaches. These genes were distributed across chromosomes 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, and 13. Detailed analyses were performed to assess their physicochemical properties, cis-regulatory elements, and interspecies collinearity. The physicochemical characterization revealed that the KNOX proteins ranged from 249 to 2270 amino acids in length, were hydrophilic, and had molecular weights between 2.84 and 24.95 kDa. Subcellular localization predictions indicated that most KNOX proteins localized in the nucleus. Furthermore, the majority of these proteins contained four conserved domains KNOX1, KNOX2, ELK, and Homeobox KN. Based on structural features and phylogenetic analysis, the KNOX gene family was classified into Class Ⅰ and Class Ⅱ, with Class Ⅱ-B potentially representing a specific clade unique to Nymphaea. Interspecies collinearity analysis revealed that 13 of the KNOX genes shared conserved synteny with KNOX genes from Arabidopsis thaliana, Solanum lycopersicum, Oryza sativa, and Zea mays, with the highest level of homology observed with tomato. Additionally, promoter analysis identified numerous cis-regulatory elements related to growth and development, hormone response, and stress response. Expression pattern analysis across different development stages of leaves suggested that Class Ⅰ genes likely played a pivotal role in the formation and development of leaf viviparous shoots in Nymphaea.
Identification and analysis of four pan-neuronal expression genes in Bactrocera dorsalis
LIU Jiaying, ZHANG Jie, WANG Qi, Wu Shaoying, WANG Guirong, Liu Wei
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240158
Abstract:
Research on the central nervous system function of pests forms the foundation for developing precise behavior control technologies. Despite the significant role of neuron-labeling techniques based on genetic manipulation in this field, such techniques remain relatively scarce for non-model insects, such as the oriental fruit fly, Bactrocera dorsalis. In this context an attempt was made to identify four pan-neuronal expression genes in B. dorsalis with a view to laying the groundwork for constructing a neuron-labeling system for this species. The genomic structures of the pan-neuronal expression genes in B. dorsalis were identified and analyzed by employing bioinformatics and molecular biology to verify their full-length sequences and peripheral expression patterns. The results indicate that, by referring to four pan-neuronal expression genes from Drosophila, four homologous genes were identified in the B. dorsalis, namely BdornSyb, BdorSyt1, Bdorelav, and BdorBrp. The full genomic lengths of these four genes are 19,337 bp (5 exons, 4 introns), 26,884 bp (8 exons, 7 introns), 1,341 bp (1 exon), and 49,692 bp (14 exons, 13 introns), respectively. The domains of BdornSyb, BdorSyt1, and Bdorelav are highly conserved among closely related species. PCR cloning results indicated that the CDS sequence lengths of these four genes are all over 500 bp, consistent with the bioinformatics analysis results. Evolutionary and genomic structure analyses demonstrated that the four genes are highly conserved among Diptera insects. Expression pattern analysis revealed that all the four genes are expressed in the peripheral sensory organs of B. dorsalis, with three genes, BdornSyb, BdorSyt1 and BdorBrp, showing higher expression levels in the primary olfactory organs, the antennae, and the maxillary palp. The four genes identified are candidate pan-neuronal expression genes in B. dorsalis, providing a foundation for constructing a pan-neuronal labeling system for this species in the future.
Correlation and path analysis between mineral elements and quality of Jinzhen durian fruit
WANG Yuanming, XU Danyong, WANG Yuyang, LI Huadong, ZHOU Junlei, LIN Dian
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240134
Abstract:
In order to explore the effect of mineral nutrient elements on fruit quality and screen the main mineral element factors affecting fruit quality, fruit of durian (Durio zibethinus Murr) Jinzhen planted in Hainan Province were selected for correlation and path coefficient analysis of the external morphology and internal quality indexes of the fruit as well as 11 mineral elements. The correlation analysis showed that there was a significantly negative correlation between soluble solids content and sulfur (S) content. The total acid content was significantly positively correlated with calcium (C) and boron (B) contents. There was a significantly positive correlation between vitamin C content and magnesium (Mg) and S contents. There was a significantly negative correlation between sugar-acid ratio and B content. The solid-acid ratio was significantly negatively correlated with Ca and B contents. The path analysis showed that there were some differences in the effects of mineral elements on fruit quality indexes. The main elements influencing soluble solids content were nitrogen (N), Mg, zinc (Zn) and manganese (Mn). The main factors influencing soluble sugar content were B, Mn, Zn and N, and the main elements affecting the total acid content of the fruit were potassium (K), N, Mg and Zn. The main elements affecting the content of vitamin C were S, iron (Fe), Mg and Zn. The main elements affecting the ratio of sugar to acid are K, Zn, Mn and B, and the main elements influencing solid acid ratio were Mg, Zn, Fe and Mn. In summary, K, N, Ca, Mg, Zn and B are the main elements affecting the quality of the durian fruit, and are the comprehensive results of the synergistic regulation of various mineral elements. Considering the local soil and fruit nutrient content in Hainan, the fruit yield and quality can be improved through application of K, Mg, Zn and B fertilizers at a slightly higher rate and a coordinated ratio.
Screening of internal reference genes of tomato under different plant parts and hormone treatments
MIAO Die, ZHANG Shuxin, WANG Peng
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240140
Abstract:
Solanum lycopersicum is a model plant for research in genetics and molecular biology. Recently selection of tomato internal reference genes has been reported but with less types of exogenous hormones used for treatment. An attempt was hence made to select internal reference genes with stable expression in different tissues of tomato and under treatment with plant hormones. DANJ, EF-1α, ACT, UBI, APT, CAC, TIP41 and RPL8 were used as candidate internal reference genes, and selected under the 8 experimental conditions: exogenous hormone treatment with auxin, gibberellin, abscisic acid, cytokinin, salicylic acid, brassinolide and ethylene and various plant parts. The stability of the candidate reference genes was comprehensively evaluated using algorithms such as geNorm, NormFinder, BestKeeper, Delta CT and RefFinder. The stability of the reference genes was validated using the auxin-responsive gene SlGH3.4. The results showed that APT is the most stable reference gene expressed in auxin, gibberellin, abscisic acid, brassinosteroid treatment and various plant parts, that UBI is the most stable reference gene expressed in all samples under cytokinin and salicylic acid treatment, and that TIP41 is the most stable reference gene expressed under ethylene treatment. Finally, when APT, which has a relatively stable comprehensive ranking, was used as an internal reference gene, it was found that the expression level of SlGH3.4 gene showed a similar trend under IAA treatment conditions, while the less stable RPL8 gene failed to accurately correct the expression level of the target gene. All these results may provide theoretical support for the analysis of gene expression networks and molecular regulatory mechanisms in the response of tomato to exogenous hormone treatment.
Survey of the species and damages of agromyzid leafminers and their natural enemy parasitoids in Ningxia Region
HUO Baowei, YUAN Shiwei, YE Fuyu, DU Sujie, WAN Weijie, GUO Jianyang, WAN fanghao, ZHOU Hongxu, LIU Wanxue
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240190
Abstract:
To clarify the occurrence and damage of leafminers on vegetables in Ningxia, China, and the species composition of their parasitoid wasps, sampling surveys on leafminers and their parasitoids on vegetables in Ningxia were conducted. The species were identified by morphological methods. From 2016 to 2019, there were five common species of leafminers observed in Ningxia, including Liriomyza sativae, Liriomyza huidobrensis, Phytomyza horticola, Liriomyza bryoniae and Liriomyza chinensis. Among these leafminers, L. huidobrensis was the highest in occurrence and number of host plants, particularly preferring Cucurbitaceae plants. L. bryoniae was only found on Brassica campestris and Lycopersicon esculentum, with low damage. The parasitoid wasp species attacking leafminers were found to have 27 species from 17 genera of 4 families. The dominant parasitoid species, based on population and parasitism rates, were Neochrysocharis formosa (1 129 individuals, 41.81% of the total) and Diglyphus isaea (458 individuals, 16.96% of the total). Leafminers in Ningxia have caused varying degrees of damage to crops, especially Fabaceae crops. It is crucial to strengthen field monitoring, early warning systems, and implement green control measures. Additionally, the region has abundant parasitoid wasp resources, and further efforts should be made to protect these natural enemies. Special attention should be given to exploring the potential biological control capabilities of dominant parasitoids such as N. formosa and D.isaea, in order to achieve sustainable and environmentally friendly pest management.
PcSec62 is involved in regulating the growth, development and virulence of Phytophthora capsici
HUANG Yuyuan, YE Qianqian, CHEN Qinhe, LIANG Qifu
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240170
Abstract:
The endoplasmic reticulum (ER) serves as a crucial site for protein processing in eukaryotic cells. Sec62, an essential component of the ER translocation complex, plays a significant role in growth, development, and stress regulation. An attempt was made to examine the transcription levels of the PcSec62 gene at various growth stages and during pathogenic processes. The PcSec62 gene was knocked out by using CRISPR/Cas9 gene editing to produce knockout mutants (ΔPcsec62) and a complementary strain (ΔPcsec62-C). The results showed that the transcriptional expression of PcSec62 significantly increased during the sporangia and infection stages. The ΔPcsec62 mutants exhibited notably reduced growth and sporulation abilities, alongside stunted hyphal growth. Additionally, the ΔPcsec62 strain showed significantly low tolerance to abiotic stress and reduced pathogenicity. These findings indicate that PcSec62 is involved in regulating the growth, development, abiotic stress responses, and pathogenicity of Phytophthora capsici.
Anaplasma spp. seroepidemiological research and related risk factor analysis of companion dogs in Haikou
KANG Shenchen, SUN Chenhao, YANG Xinyue, ZHAO Yuanjie, CHEN Yu, LIU Mengmeng
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240153
Abstract:
As two tick-borne pathogens that are widely prevalent in tropical and subtropical regions, Anaplasma platys (A. platys) and Anaplasma phagocytophilum (A. phagocytophilum) are of great zoonotic and public health significance. To date, seroepidemiological investigations and analysis of associated risk factors for A. phagocytophilum and A. platys in companion dogs in Hainan are not documented. In this study, 184 companion dogs in the Haikou area of Hainan Province were tested for antibodies to Anaplasma spp. by using a standard commercialized kit, and the associated risk factors were analyzed with 128 clinical questionnaires. The results showed that the seroprevalence of antibodies of companion dogs to A. phagocytophilum/A. platys in Haikou area was 7.1%. Modeling calculations revealed a significant correlation between tick bites and seropositive antibodies to Anaplasma spp. among all investigated risk factors, further clarifying the important role of ticks as a vector. This study lays the foundation for the Anaplasma spp. epidemiologic study of companion dogs in Hainan province, and provides an important scientific basis for the prevention and control of anaplasmosis.
Analysis of prokaryotic protein expression and disease resistance function of cassava gene RXam2
TANG Luzhi, WU Jingyuan, CHEN Yuanlai, ZHU Binbin, ZHAO huiping
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240147
Abstract:
Cassava (Manihot esculenta Crantz) has important economic value. Exploring the key genes of cassava is of great significance for improving cassava quality. To mine disease-resistant genes of cassava, a specific immune receptor-related gene resistant to Xam (MeRXam2) was cloned, and its protein structure was analyzed. The analysis was found that the coding sequence (CDS) region of this gene is 3561 bp, with the protein size of about 132.847 kD, Real-time fluorescent quantitative (Real-time quantitative reverse transcription PCR, qRT-PCR) analysis showed that the expression level of MeRXam2 increased with time under pathogen infection and reached the maximum at 24 h, indicating that MeRXam2 was involved in the resistance response to cassava disease. In addition, a MeRXam2-pET32a protein expression vector was constructed by homologous recombination, and the protein was induced and determined. After exogenous spraying of MeRXam2 protein on cassava leaf tissues, the number of bacteria was found significantly lower than that of the control strain, indicating that this protein could slow down bacterial infection. This founding might provide a theoretical basis and candidate protein for cassava molecular breeding.
Volatile components and antioxidant activity of the extract of longan flowers from Fujian
LIN Shuihua, HUANG Xiaoyi, YANG Binjun, ZHANG Lingling, LI Sihong, HUANG Youxia
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240116
Abstract:
To explore the volatile components and aroma composition of the flowers of longan (Dimocarpus longan), and to investigate the antioxidant activity of their extracts, the flowers of longan were collected from Fujian and extracted with different solvents, and their volatile components and the aroma of the components were analyzed by using the GC-MS technology. Meanwhile, DPPH and ABTS free radical scavenging assays were used to detect the antioxidant activity of the longan flower extracts. The results showed that 59 components were identified from the essential oil extracted from the longan flowers, accounting for approximately 82.2% of the total volatile components. In the essential oil 4 key aroma compounds, 3 potential aroma compounds and 1 modified aroma compound were found. The DPPH and ABTS free radical scavenging assay showed that different solvent extracts of longan flowers had a certain degree of antioxidant activity. Water extract, methanol extract and ethanol extract had significant antioxidant activity, while n-butyl alcohol extract and ethyl acetate extract had low antioxidant activity. All the results show that longan flowers have a great development potential in the fields of medicine, cosmetics, health products, functional foods and so on, which provides a scientific basis for the development and utilization of longan flowers.
Cloning and interaction protein screening of MeJAZ2.2 gene
ZHANG Bowen, XU Haoran, ZENG Hongqiu
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240169
Abstract:
Cassava is an important food crop in tropical regions, but the yield of cassava is affected by salt stress, which endangers food security. JAZ (jasmonate ZIM-domain, JAZ) proteins, as essential components in the jasmonate signaling pathway, are involved in regulating the tolerance to salt stress in a variety of crops. In order to investigate response of JAZ proteins in cassava to salt stress, as well as the underlying regulatory mechanisms two homologous genes MeJAZ2.1 and MeJAZ2.2 were identified from cassava variety SC124 through bioinformatics. The evolutionary tree and conserved domain analysis indicated that they both contain two conserved domains, ZIM and Jas, which belong to the JAZ gene family. Further research discovered that the expression level of MeJAZ2.2 changed more significantly in response to salt stress in cassava. MeJAZ2.2-silenced cassava plants were more susceptibility to salt stress compared to the wild type, indicating that MeJAZ2.2 may positively regulate cassava resistance to salt stress. The pGADT7-MeJAZ2.2 bait vector was constructed and no self-activating activity was found by yeast two-hybrid experiment. Moreover, three candidate interacting proteins of MeJAZ2.2 were screened, including glutamine synthetase (GS), ubiquitin 3 (Ub3), and FRIGIDA-LIKE PROTEIN (FRI-L), which provides a preliminary framework for analyzing the function and molecular mechanism of JAZ proteins to salt stress in cassava.
Drug sensitivity analysis of Escherichia coli based on fluorescence photoelectric detection
SHEN Yi, GUO Tianci, LAI ZHUO YUAN, YI BO, LIN Chuan, ZHU Heran, WAN Yi, MAO Haimei, QU Long
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240149
Abstract:
The bactericidal effects of different antibiotics on Escherichia coli were analyzed by using fluorescence photoelectric microbial detection devices. The results prove that the antimicrobial analysis using fluorescence photoelectric microbial detection devices is equivalent to the K-B disk diffusion method. Compared to the traditional methods, the fluorescence photoelectric microbial detection method can be used to quickly identify microbial resistance in clinical specimens, especially of fastidious bacteria and other slow-growing strains, providing timely reference for the clinical application of antibiotics and drug resistance analysis of pathogens. The detection of the drug resistance of E. coli to 9 antibiotics showed that E. coli had the highest resistance to nalidixic acid, with a minimal inhibitory concentration (MIC) of 100 μg.mL-1. E. coli had the lowest resistance to cefotaxime, with a minimal inhibitory concentration of 0.2 μg.mL-1. Combination of nalidixic acid with ciprofloxacin, cefotaxime, or chloramphenicol indicated that the combination of 0.5 MIC concentration of nalidixic acid with 0.5 MIC concentration of ciprofloxacin had the best bactericidal effect.
Pathogen identification and biological characteristics of leaf spot disease of Bidens pilosa
YANG Zhichao, XIAO Yang, WU Yanna, WANG Honggang, LUO kai, CHEN Yinhua, ZHANG Rui
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250033
Abstract:
Bidens pilosa, an invasive weed commonly found in South China, is considered as a companion weeds in various upland cropping systems and serves as an intermediate host for a range of phytopathogens. This study reports the occurrence of leaf spot lesions in a population of B. pilosa. To investigate the cause, pathogens were isolated from the infected leaves using a tissue isolation method, and pathogenicity was confirmed through detached-leaf inoculation assays. A combination of morphological characterization and phylogenetic analysis of concatenated rDNA-ITS and tef1 sequences enabled accurate identification of the pathogen. The pathogen was identified as Lasiodiplodia theobromae, which causes leaf wilt and rot in B. pilosa. Preliminary environmental studies indicated that the isolated strain exhibited optimal colony growth at 28 ℃, pH 6, on Potato Dextrose Agar(PDA) medium supplemented with sucrose and sodium nitrate, which served as the preferred carbon and nitrogen sources, respectively.
Effects of different Agricultural Jiaosu on the quality and yield of Passiflora edulis
CHEN Mei, ZHANG Rongping, GAO Ling, LIU Difa, XU Li, FENG Hongyu, ZHAO Yanan
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250008
Abstract:
In order to select an agricultural Jiaosu that can effectively improve the quality and yield of passion fruit (Passiflora edulis), passion fruit seedlings were treated with agricultural Jiaosu formulations prepared from four different substrates, namely passion fruit peel, passion fruit straw, cherry tomato straw and corn straw, and chemical fertilizer as control to observe the effects of the treatments on the quality and yield of passion fruits in pot culture under anti-insect net and field experiments. The results showed that the fruit size, single fruit weight and first-class fruit rate of passion fruit under the passion fruit peel Jiaosu treatment were similar to those of the chemical fertilizer treatment, with the yield being 6.38% higher, and that this Jiaosu treatment was better than other Jiaosu treatments. In terms of quality, the passion fruit peel Jiaosu treatment significantly increased the content of Ca and total sugar in juice, decreased the content of organic acid, and had the highest TSS-TA ratio and sugar-acid ratio, and this treatment was better than the passion fruit straw Jiaosu and corn straw Jiaosu treatments. The cherry tomato straw Jiaosu treatment significantly increased the contents of Fe, Zn, total organic acids, total amino acids and vitamin C in the fruit. However, the fruits in this treatment were low in TSS-TA ratio and sugar-acid ratio due to the high acid content, and hence were poor in comprehensive quality. Based on the data of 2 years of experiments, the passion fruit peel Jiaosu treatment had the best effects on improving the comprehensive quality and yield of passion fruits, and the fruits under this treatment had a higher commercial value, which was suggested to be the best treatment.
Screening of bacteriostatic agents for sugarcane open hydroponics
YANG Yuli, WU Yuanli, ZAN Limei, CHEN Yimeng, YANG Benpeng
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240047
Abstract:
In order to screen out bacteriostatic agents and their concentrations suitable for sugarcane open hydroponics, virus-free healthy seedlings of sugarcane cultivar Zhongtang No. 1 were treated with bacteriostatic agents including Diclofenac zinc, carbendazim, sodium hypochlorite, polyols and isothiazolinone at different concentrations and cultured in open hydroponics to observe their contamination rate, proliferation coefficient and rooting rate. The results showed that treatment with 0.14% isothiazolinone had the best effect on proliferation in open hydroponics of sugarcane, with a medium contamination rate of 7.04% and a plant proliferation coefficient of 2.71, whereas the treatment with 0.11% isothiazolinone had maximum effect on rooting in open hydroponics, with the medium contamination rate of 6.58%, and the rooting rate of 94.44%.
Bioinformatics analysis and functional study of cassava ERF gene family Ⅶ subfamily
ZHANG Zihe, ZHENG Linling, LI Ke, CHEN Yinhua, GAO Yu
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250035
Abstract:
In order to investigate the potential functions of the cassava (Manihot esculenta) Ⅶ subfamily of ERF gene family in response to biotic stress, we identified 161 ERF genes in the cassava genome, which were divided into 13 subfamilies. Analyses were performed on the conserved domains, cis-acting elements in promoter regions, interacting proteins, target genes, and expression patterns of the Ⅶ subfamily members. The results showed that all members of this subfamily contained a conserved AP2 domain, and their promoter regions included 13 types of cis-acting elements related to plant growth and development, and environmental stress responses. Expression pattern analysis revealed that the MeERF46, MeERF133, and MeERF92 genes responded actively to Xpm infection among them, the change of MeERF92 expression was the most significant. WGCNA and protein-protein interaction network analysis indicated that MeERF92 might be involved in the process of oxidative stress, while MeERF133 was widely involved in glycometabolism. These findings provide candidate genes for further research into the functions and mechanisms of ERFs in cassava's response to biotic stress.
Operational efficacy of ANAMMOX under different nitrogen loads and dynamic changes of the microbial communities
GUO Mengxia, FU Xiangzhuang, ZHOU Xinwei, XU Wen, WANG Dexin, YU Ming, BAI Xiao
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240053
Abstract:
Polyurethane sponge was used as a biofilm carrier for the enrichment of anaerobic ammonia oxidizing bacteria (AnAOB) to investigate the denitrification performance and microbial community changes of the biofilm system under different nitrogen loads of influent water. The results showed that the total nitrogen removal rate increased with the nitrogen load of influent water. The total nitrogen removal rate was as high as 85.79% in the stabilization period, the nitrogen load in effluent was 0.26 kg·N·m−3·d−1, and the total nitrogen removal reached the national standard. Meanwhile, the formation of cauliflower-shaped biofilm on the polyurethane sponge carrier was observed by using the scanning electron microscopy, and the sequencing of the biofilm samples showed that the biofilm system had been used to enrich the anaerobic ammonia oxidizing bacteria (AnAOB). Subsequently, the sequencing showed that the functional microorganisms in the system were Candiadatus brocadia, which accounted for 29.80% of the total number of microorganisms in the stable period. Finally, the changes of cross-feeding interactions between the genera of anaerobic ammonia oxidizing bacteria and other genera of microbiota under high load conditions were summarized, which will provide a comprehensive guideline for the future metabolism research and practical application of the anaerobic ammonia oxidizing bacterial flora in the engineering.
The total saponin content and antioxidant activity of Callerya speciosa roots at different ages
LIU Zhen, WANG Zhunian, WANG Maoyuan, TANG Huan
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240088
Abstract:
An attempt was made to determine the content of total saponins and antioxidant activity in the roots of Callerya speciosa (Champion ex Bentham) Schot at different ages, and provide reference for their rational development and utilization. The roots of C. speciosa were collected and extracted by using an ultrasonic-assisted extraction method, and the extraction process of total saponins from C. speciosa roots were optimized. Furthermore, the content of total saponins from the extracts of the C. speciosa roots at different ages (3-year-old, 6-year-old, 10-year-old and 15-year-old) was determined by using UV photometer.. The antioxidant activity of total saponins from the C. speciosa roots was determined by using the DPPH free radical method and hydroxyl free radical method. The results showed that the best extraction conditions for total saponins of the C. speciosa roots are 80% ethanol, 1∶ 40 solid-liquid ratio, 40 min ultrasound time, and 3 extraction times. Among the four materials, the 6-year-old C. speciosa roots had the highest total saponin content, while the 15-year-old C. speciosa had the lowest. The total saponin content of the C. speciosa roots tended to increase and then decrease with the ages of C. speciosa. The antioxidant activity test found that total saponins of the C. speciosa roots at different ages all possessed a certain level of antioxidant capacity in vitro, which can be developed and utilized as a potential natural antioxidant.
Response of soil physio-chemical properties and microbial community composition to extreme water stress based on a pot experiment of Cinnamomum camphora seedlings
CHEN Hong, DUAN Honglang, WU Jianping
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240119
Abstract:
Extreme climate-driven alterations in precipitation patterns lead to frequent heavy rainfall, drought, and dry-wet alternation events, and hence significantly impact plant growth and soil community stability. Cinnamomum camphora, a crucial economic species for greening, is particularly sensitive to these environmental changes. Understanding the influence of altered precipitation patterns on the growth of C. camphora and its associated soil systems holds significant implications for cultivation, management and planting strategies in the context of global extreme climate change. A pot experiment was designed to simulate precipitation patterns to cultivate C. camphora seedlings to determine the soil physicochemical properties (pH, soil organic carbon, and soil total nitrogen) and microbial biomass in the pot soil. The seedlings were treated with stress of flooding, drought, or wet-dry alternation, with no stress as a control. Results indicated that the three stress treatments notably increased soil total nitrogen content (P<0.001 as against the control. Soil total phospholipid fatty acids and bacterial biomass were significantly higher in the stress treatment of flooding or dry-wet alternation compared to the drought stress, whereas fungal biomass remained relatively stable under stress conditions. Additionally, the microbial Simpson index was significantly lower under the drought stress treatment compared to the other treatments. In conclusion under extreme stress events the growth of C. camphora was inhibited, and the soil microorganisms become more constrained by carbon substrates. The drought stress had a more pronounced impact on soil physiochemical properties and microbial communities compared to the stress treatments of flooding and dry-wet alternation. Under the extreme climate events the coupling of microorganisms and plants should be enhanced to improve the ability of plants to adapt to extreme climate, thereby preserving the stability and functionality of the soil ecosystem and benefiting plant recovery.
Growth and quality formation of the fruit of wax apple ‘Nanlu No. 1’
XU Danyong, WANG Yuanming, LIN Sihong, WANG Yuyang, LI Huadong, XING Jun, MA Yalong, LIN Dian
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240082
Abstract:
Four-year-old trees of wax apple 'Nanlu No.1' (Syzygium samarangense (BI.) Merr. et Perry) of similar growth vigor located in Yazhou District, Sanya City, Hainan Province were selected to observe the fruit growth and development and determine their fruit quality to elucidate the fruit growth development and quality formation patterns A comprehensive two-year tracking experiment was conducted from 2022 to 2024, starting from 10 days after flowering to the maturity of the fruit in both summer and winter seasons. Dynamic changes in fruit size and flesh quality indicators were systematically observed and evaluated. Results indicated significant differences in external quality indicators, such as fruit size and shape index from 10 days after flowering to maturity and in internal quality indicators from the fruit expansion stage to maturity. Single fruit weight and the contents of soluble sugar, ascorbic acid and soluble solids all showed a significant increasing trend. In contrast, total acid content and fruit shape index exhibited a less pronounced trend. Notable differences were observed in fruit quality indicators at maturity in different seasons, with the winter fruits scoring higher in principal component analysis compared to the summer fruits. The critical growth and development periods were identified as 30-70 days after flowering for the summer fruits and 20-50 days after flowering for the winter fruits. The critical quality formation periods were 60-80 days and 50-60 days after flowering for the winter and summer fruits, respectively. The optimal harvesting time was approximately 80 days after flowering for the winter fruits and 60 days after flowering for the summer fruits, at which time the overall indicators of the contents of soluble sugars, soluble solids and ascorbic acid, and sugar-acid ratio were the best. The primary factors influencing fruit quality at maturity included ascorbic acid content, transverse and longitudinal diameter, fresh weight, solids-acid ratio, sugar-acid ratio, and fruit shape index, with the winter fruits demonstrating superior overall quality over the summer fruits.
Establishment of nested PCR detection method for Verticillium dahliae and its application in pathogen detection of cotton seeds
FANG Yuxiao, LIU Lijuan, ZHANG Yufang, Miao Weiguo, CHEN Daipeng
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240022
Abstract:
Cotton verticillium wilt is a destructive disease that seriously affects the cotton industry. Verticillium dahliae is the main causing agent of cotton verticillium wilt in Chin. It is difficult to effectively controll this disease through conventional methods, and it hence is of great significance to establish a rapid and efficient detection method for early monitoring, diagnosis, and controlling of this disease. A highly conserved DNA sequence among strains of V. dahliae and a high divergence among different species were discovered by using NCBI BLAST. Based on this DNA segment, six pairs of PCR primers were designed and one set of primers that are highly specific and sensitive were eventually selected for detecting V. dahliae through nested PCR. And the optimal amplification conditions for these primers were determined. A set of nested PCR primers were identified, namely V.d-2 and V.d-5. The amplification conditions are as follows: 95 ℃ for 5 minutes, 95 ℃ for 30 seconds, 58 ℃ for 30 seconds, 72 ℃ for 1 minute, performed 35 cycles. The resulting bands are of sizes 512 bp and 375 bp, respectively. Resulting nested PCR can be used to detect the lowest amount of pathogenic DNA at 1×10−6 ng·μL−1, which is 3 orders of magnitude higher in sensitivity compared to the conventional PCR. The primer specifity was verified by using 15 species of pathogens such as Verticillium longisporum, etc. The lowest number of 10 spores each conton seed bearing pathogen of V. dahliae can be detected by using this method. And hence a rapid molecular detection method for determining the presence of Verticillium wilt pathogen on cotton seeds is developed.
Effects of magnesium and zinc deficiency on the growth and photosynthetic characteristics of Musa. AA seedlings
JIANG Chengjun, WANG Lixia, ZHAI Lina, ZHAO Yan, HE Yingdui
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250010
Abstract:
Banana 'Haigong' (Musa. AA) seedlings were treated with magnesium (Mg) and zinc (Zn) at gradient concentrations of 0%, 50%, and 100% of normal levels to observe the effects of magnesium and zinc deficiency on the growth and photosynthesis of the seedlings. The results show that after 120 days of treatment, the combined deficiency of Mg and Zn inhibited the growth and photosynthetic physiology of 'Haigong' seedlings. Under normal treatment, the plant height was 31.5 cm, stem diameter was 8.65 cm, and total root length was 1,051.47 cm; under deficiency treatment, plant height, stem diameter, and total root length were all reduced to varying degrees, with no significant difference in leaf morphology, and the relative growth rate of plant height varied among treatments. In terms of photosynthetic characteristics, there were significant differences in SPAD value, Pn value, Tr value, Ci value, and Gs value between normal and deficiency treatments, and under deficiency treatment the Y(Ⅱ) value and Fv/Fm value decreased, while the NPQ value fluctuated. This study monitored the growth and photosynthetic physiology of banana 'Haigong' seedlings under Mg and Zn deficiency, providing a reference for precise nutrient management.
The Study of Tissue Anatomy, Physiological and Biochemical Changes during the Grafting Healing of Bombax ceiba
FENG Jianhang, LIU Weiwei, YANG Siyi, CAI Zeping, LUO Can, YU Xudong
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240192
Abstract:
To investigate the grafting compatibility and healing mechanisms of Bombax ceiba, this study employed Ceiba speciosa as rootstocks and one-year-old B. ceiba branches as scions. Utilizing the cleft grafting technique, graft union tissues were collected at various post-grafting stages for histological observation via hard tissue sectioning to analyze structural changes during healing. Physiological activities of soluble sugars, soluble proteins, peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) were quantitatively assessed, while endogenous hormone levels at the graft interface were determined using enzyme-linked immunosorbent assay (ELISA).The healing process of the graft is divided into four distinct stages: (1) isolation layer formation stage (Day 0–3); (2) callus formation stage (Day 3–10); (3) callus differentiation and connection stage (Day 10–22); and (4) cambial connection and vascular tissue differentiation stage (Day 22–40). The first 22 days post-grafting are critical for determining whether a viable graft union can form, and the first 40 days are crucial for graft survival. The activities of POD, SOD, and CAT initially increased and then decreased during the healing process, with peak activity observed during the callus differentiation and connection stage. The hormones IAA, GA, and CTK promoted cell division and vascular tissue formation. The concentrations of IAA and CTK peaked during the callus differentiation and connection stage, while GA reached its highest concentration during the cambial connection and vascular tissue differentiation stage. ABA levels showed a decreasing trend followed by an increase, with ABA inhibiting the proliferation of callus cells.
Screening and comprehensive evaluation of low-nitrogen tolerance indices in Paspalum vaginatium
FU Chunchan, HU Xu, LIN Jiaqi, MA Mengxin, WANG Xiaochun, WANG Zhiyong, LIAO Li
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240191
Abstract:
To investigate the low-nitrogen tolerance characteristics of Paspalum vaginatum, this study selected 10 Paspalum vaginatum germplasm accessions as experimental materials. A hydroponic method was applied with two nitrogen concentration treatments: full nitrogen (5.0 mmol·L−1) and 1/100 nitrogen (0.05 mmol·L−1), for a duration of 30 days. Eighteen agronomic traits, including chlorophyll content, shoot fresh weight, and turfgrass height, were measured after treatment, and variance analysis was conducted to compare and explore the low-nitrogen tolerance characteristics of the 10 germplasm accessions. A comprehensive evaluation of low-nitrogen tolerance was performed. The results showed that, compared to normal nitrogen treatment, indicators such as shoot fresh weight, shoot dry weight, total tillers length and tillers number significantly decreased under low nitrogen treatment, while indicators such as fresh weight ratio of root shoot, dry weight ratio of root shoot, shoot dry matter content and root dry matter content significantly increased. Through correlation analysis, principal component analysis, and membership function analysis, two low-nitrogen-tolerant Paspalum vaginatum, 17USA-03 and 17HN-39, were selected.
Evolutionary analysis of the plastic-degrading hydroxylase gene CYP450 in Bradyrhizobium
LU Zhenzhang, MA Jiayue, LI Juanjuan, CHI Xue, MA Xiang, TANG Yanqiong, LI Hong
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240175
Abstract:
To explore the evolutionary history of the Bradyrhizobium and its plastic degradation-related gene the hydroxylase gene CYP450, and to understand the mechanisms by which the genus acquires its plastic degradation potential. In this study, 28 fully assembled strains of Bradyrhizobium were collected to investigate the evolution and dissemination of Bradyrhizobium and their hydroxylase genes CYP450 through comparative genomic and phylogenetic analyses. The results revealed that, compared to the core genes, the unique and accessory genes of Bradyrhizobium exhibited an increase in functions related to plastic degradation, such as membrane transport, xenobiotic biodegradation and metabolism, lipid metabolism, and signal transduction. Bradyrhizobium has an open pan-genome, enabling it to acquire genes from other species, adapt to new environments, and evolve new functions. Analysis of the flow of the hydroxylase gene CYP450 in bacteria and archaea revealed that Bradyrhizobium likely acquired hydroxylase gene CYP450 from the Actinobacteria phylum through horizontal gene transfer, thus gaining the potential for plastic degradation.
The pathogenicity of Xanthomonas oryzae pv. oryzae regulated by type Ⅲ effector protein XopG and its localization analysis in plant cells
YU Xi, LI Chunxia, TAO Jun
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240058
Abstract:
Xanthomonas oryzae pv. oryzae is the pathogen that causes bacterial leaf blight in rice, and Type Ⅲ Secretion Effectors (T3SEs) play an important role in the virulence of Xoo. An attempt was made to make a preliminary clear of the function of XopG in the virulence of Xoo and the localization of XopG in plant cells by using informatics analysis, gene knockout, expression regulation analysis, pathogenicity analysis and subcellular localization. The results showed that the xopG promoter sequence contained an atypical plant-induced promoter PIP-box, predicting that xopG expression was regulated by HrpX. The GUS activity test of hrpX deletion mutant showed that the expression level of xopG in hrpX mutant was significantly lower than that in the wild type, indicating that HrpX positively regulates the expression of xopG. Compared to the wild type T7174, the virulence of xopG mutant was significantly reduced, indicating that XopG is a necessary cellular component for Xoo to infect rice. Subcellular localization showed that XopG located in the nucleus, cell membrane and cytoplasm of plant cells. This study laid a foundation for exploring the molecular mechanism of XopG-Xoo interaction.
Identification and Characteristic Analysis of BBR-BPC Gene Family in Greater Yam (Dioscorea alata L.)
ZHAO Aote, LIN Huiting, ZHANG Yuting, HUANG Xiaolong, WU Wenqiang, XIA Wei, HUANG Dongyi
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250026
Abstract:
In order to understand the regulatory role of the BBR-BPC gene family in the growth and development of Dioscorea alata (greater yam), we analyzed the gene structure, phylogenetic evolution, conserved motifs, and physicochemical properties of the BBR-BPC gene family in greater yam. We also predicted the secondary and tertiary structures of BBR-BPC proteins and verified the interaction between the BBR-BPC gene and the DELLA gene. Through HMMsearch and BLAST analyses, we identified six members of the BBR-BPC family in the greater yam genome. These gene proteins exhibited significant differences and alternative splicing events, with a total of 10 splice variants detected. Subcellular localization analysis revealed that all members of the BBR-BPC family in greater yam are located in the nucleus.The yeast two-hybrid interaction results between Da4BBR-BPC2 and DaDELLA2 indicate that there is an interaction between Da4BBR-BPC2 and DaDELLA2, occurring at the N-terminus of the DaDELLA2 gene.
Expression analysis and prokaryotic expression purification of HbbZIP74 gene in rubber tree
LIU Ziquan, ZHU Jiahong, WANG Ying, LI Huiliang, LI Yuji, TANG Yanqiong, GUO Dong
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250015
Abstract:
In order to assess the role of the bZIP transcription factor in the biosynthesis of natural rubber in Hevea brasiliensis, HbbZIP74 gene was successfully cloned based on previous work in our laboratory. Bioinformatics analysis and expression pattern analysis were performed. The pET28-HbbZIP74 expression vector was constructed, and the recombinant protein was expressed in the strain E. coli BL21 (DE3) and then purified. The results showed that the open reading frame (ORF) of the gene HbbZIP74 is 486 bp, encoding 161 amino acids, with a bZIP domain, classifying it as a bZIP transcription factor S subgroup. The expression level of HbbZIP74 is higher in latex and leaves, and its expression can be induced by jasmonic acid, abscisic acid, ethylene, and salicylic acid in latex. The optimal condition for the heterologous expression of the HbbZIP74-His recombinant protein was induced at 1 mmol·L−1 IPTG and 37 ℃ for 3 h. The recombinant protein was mainly accumulated in inclusion bodies. The recombinant protein, approximately 22 kDa in size, was purified using Ni-NTA affinity chromatography, which was consistent with expectations. This study lays the foundation for further exploration of the role of HbbZIP74 in the biosynthesis of natural rubber.
Risk analysis of the invation of Metcalfa pruinosa into China
YAN Wenqian, MENG Rui, XI Yu, CAI Bo, LIU Fuxiu, WU Shaoying
, Available online  , doi: 10.15886/j.cnki.rdswxb.20230142
Abstract:
Metcalfa pruinosa (Say, 1830) is an invasive pest of the genus Solenopsis that originated in North America, spread rapidly after being accidentally introduced into Europe in the late 1970s, and has been found to invade East Asia in recent years. M. pruinosa is a highly polyphagous insect with low host specificity that colonizes a variety of trees, shrubs, fruit trees and crops in agricultural, forest and urban areas. Although not reported in China, the pest has the potential risk of invasion. A qualitative assessment and a semi-quantitative analysis of this pest were carried out by using the pest risk analysis program and multi-index comprehensive evaluation method according to the international and national standards of pest risk analysis. The semi-quantitative analysis showed that the comprehensive risk R value of this pest was 2.41. It is a highly dangerous pest in China, and it is a potential threat to important fruit trees such as citrus, plum and apple as well as soybean crops in China. It is hence suggested that quarantine departments strengthen the regulation and supervision of the products from the quarantined area, perform early monitoring and warning, and formulate effective quarantine and control methods for this pest in China.
Effects of treatment of tapping panel with aluminum solutions on latex yield and physiological parameters
WANG Mengyue, KANG Li, ZHAO Pingjuan, XIE Guishui, LIU Zhao, ZHANG Yingying, LIU Zifan, AN Feng
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240185
Abstract:
To clarify the effects of aluminum stress on latex yield, physiological parameters and tapping panel dryness (TPD) of mature rubber trees (Hevea brasiliensis), rubber trees of clone Reyan7-33-97 tapped for eight-years were treated with AlCl3 solution at different concentrations. Two control solutions with different pH values (T0 was treated with ultrapure water of pH7.0 and T1 was treated with ultrapure water solution of pH adjusted to 4.2 by hydrochloric acid) and four concentrations (i.e. 50, 100, 200 and 400 mmol·L−1) of AlCl3 solutions with pH4.2 were applied just above the tapping cut. The rubber trees were tapped regularly and the latex volume, dry rubber yield, latex physiological parameters, TPD incidence and grade were observed in the early, middle and late stage of the treatment. The results showed that the harvested latex volume and dry rubber yield increased in the early stage of aluminum treatment, decreased to the same level as the control in the middle stage, and was lower than the control in the late stage, while the total latex volume and dry rubber yield of the 10 tappings after Al treatment were not significantly different from those of the control. Aluminum treatment increased dry rubber content, lutoid bursting index of the early latex and thiols content of late latex, indicating that aluminum treatment led to the decrease of latex flow capacity. Meanwhile aluminum treatment decreased latex sucrose content, and Mg2+ content of latex at the middle and late stages, and increased the inorganic phosphor content of latex at the late stage, which indicates that aluminum treatment also led to the decrease of rubber regeneration ability. High concentration aluminum treatment increased the incidence and grade of TPD. In summary, aluminum solution with a high concentration of 50 mmol·L−1 can increase latex yield in the short term and maintain the stability of dry latex production in a certain period of time, but it leads to the decline of the latex flow and regeneration capacity, inducing the occurrence of TPD. High concentration of Al is not conducive to maintaining the long-term latex production stability.
A Study on Tropical Rural Waste Treatment and Economic Costs from the Perspective of Ecological Compensation
XU Zhaoji, DU Mingze, LIU Ruibin, LI Tang, YU Chaoqing
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250014
Abstract:
Cost accounting for rural waste treatment is vital for advancing the sustainability of agricultural and rural development. However, there is a severe lack of publicly accessible first-hand data on full-chain technological pathways and economic cost analyses in China’s tropical rural regions, which constrains the evaluation of integrated waste management strategies. This study, conducted in Sandao Town, Baoting Li-Miao Autonomous County, Hainan Province, applies life cycle assessment to quantify waste treatment costs across multiple technological scenarios. Findings reveal centralized municipal solid waste treatment costs of 9.4132 million yuan·a−1, household kitchen waste treatment costs of 4.7274 million yuan·a−1, crop residue treatment costs of 3.3028 million yuan·a−1, and orchard pruning waste treatment costs of 0.5147 million yuan·a−1. For domestic sewage, 39% is processed via centralized systems at 3.185 million yuan·a−1, 60% undergoes decentralized village-level treatment before discharge at 8.2713 million yuan·a−1, and only 1% is reused as fertilizer at 37,700 yuan·a−1. A holistic cost-benefit analysis recommends enhancing municipal waste management efficiency through staff optimization, workflow refinement, and new energy logistics, alongside prioritizing crop residue recycling and wastewater-to-fertilizer technologies as the most viable integrated solutions. This research not only offers a scientific foundation for global economic assessments of waste treatment technologies but also delivers quantitative insights to refine ecological compensation mechanisms, promoting rural sustainability through synergies between environmental preservation and economic growth.
Resources and Floristic Composition Characteristics of Vascular Plants in Wetlands of Dongfang City, Hainan Province
Chen Jueqi, He Rongxiao, Song Xiqiang, Duanmu Jialong, Yang Zexiu
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240195
Abstract:
Wetland plants are important components of wetland ecosystems, which not only can maintain ecological balance, but also can promote the ecological functions of wetlands. In this study, we investigated and analyzed the vascular Plant Resources in five types of wetlands, including rivers, artificial, lakes, offshore and coastal, in Dongfang City as the study area. The results of the study showed that (1) the Plant Resources of wetlands in Dongfang City are relatively rich, with 114 families, 426 genera and 626 species of vascular plants recorded, including 15 ferns, 1 gymnosperm and 610 angiosperms. (2) The flora and geographic distribution of wetlands in Dongfang City can be divided into 12 types and 12 variants. (3) The vegetation types can be categorized into 6 wetland vegetation type groups, 7 vegetation types and 11 clusters, including rainforests, evergreen broad-leaved scrubs, scrub-herbaceous scrubs, aquatic vegetation, fleshy prickly scrubs and mangroves. The vegetation types are mainly tropical. (4) The invasive plants had more Class Ⅰ (malicious invasion) and Class Ⅱ (serious invasion) plants, which posed a threat to the diversity of regional wetland ecosystems. The results of this study initially clarified the status of wetland Plant Resources in Dongfang City, enriched the Plant Resources information of wetlands in the tropical coastal semi-arid zone, and provided scientific basis and basic data for the protection, ecological restoration and rational utilization of wetland vascular plant resources.
Spatiotemporal distribution of safe seed production for two-line hybrid rice in spring in Hainan Island
LV Xiaoqin, CHEN Xiaomin, PAN Zhihua, LV Run
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240178
Abstract:
In order to explore the suitable period for safe production of rice seeds in spring in Hainan Island under the influence of climate change, daily meteorological data on two-line hybrid rice seed production from 18 cities/counties in Hainan Island from February 1961 to August 2020 were used to analyze the spatiotemporal distribution characteristics of major meteorological disasters during the key development period for two-line hybrid rice seed production. The results indicate that the south area is the preferred area for two-line hybrid rice seed production in spring in Hainan Island, and that rice varieties with lower threshold temperatures during the sensitive period of fertility should be selected; For the safe time of two-line hybrid seed production in spring in the south area, the sensitive period for fertility should be arranged in early May, the flowering and pollination period should be arranged in May, and the mature harvesting period should be before mid-June.
Screening and Evaluation of Reference Genes in Cassava unpon Infection by Xanthomonas phaseoli pv. manihotis
LI Ciyun, YANG Jing, LU Dongying, YANG Jianfei, YANG Qi, WANG Fei, Chen Yinhua, NIU Xiaolei
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240201
Abstract:
In order to screen for stable expression of cassava reference genes in cassava leaves infected with Xanthomonas phaseoli pv. manihotis(Xpm), we used Xpm resistant variety ‘G1301’ and susceptible variety ‘SC9’cassava leaves as research materials. Samples were collected from cassava leaves of ‘G1301’ and ‘SC9’ at 0 h, 6 h, 12 h, 24 h, 72 h, and 120 h after Xpm infection, and the stability of the commonly used reference genes Nascent, EF1a, ACT, GTPb, and TUB was determined. The results showed that there were differences in the expression levels of five reference genes after Xpm infection in the leaves of ‘G1301’ and ‘SC9’. Delta CT, GeNorm, NormFinder, BestKeeper and RefFinder software were used to rank the stability of these candidate reference genes. We found that the most stable reference gene expressed in Xpm-infected leaves is EF1α. This study identified the stable internal reference genes expressed during Xpm infection in cassava leaves, laying the foundation for studying gene expression in response to Xpm infection and exploring disease resistance genes.
Identification of Key Biodiversity Areas (KBAs) in Diaoluo Mountain, Hainan Tropical Rainforest National Park
ZHANG Ze, SHI Youhai, ZHANG Changda, DU Yanjun
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240194
Abstract:
To identify Key Biodiversity Areas (KBAs) within national parks and allocate limited conservation resources effectively, this study takes the Diaoluo Mountain core protection area of Hainan Tropical Rainforest National Park as a case study. A grid-based methodology was employed to conduct plant taxa surveys, and priority plant species within the study area were determined according to the Checklist of Priority Protected Species in Hainan Tropical Rainforest National Park. KBAs were identified based on the number of priority protected species present within the sample plots. The results revealed that a total of 67 priority protected plant species were recorded in the 195 surveyed sample plots, which accounted for 65.05% of all priority protected plant species listed in Hainan Tropical Rainforest National Park. When the number of priority protected species was no less than 4, the proportion of plots identified as KBAs was 57.44%. When the number of priority protected species was no less than 5, the proportion of KBA-identified plots was 40.00%. When the number of priority protected species was no less than 6, the proportion of KBA-identified plots was 25.64%. The Baishui、 Xin'an and Nanxi management jurisdictions have higher conservation value, contributing over 70% to the overall KBAs identification results. This study provides critical insights into plant conservation within Diaoluo Mountain National Park and offers specific guidance for biodiversity conservation actions in national parks. It also delivers vital technical support for systematic KBA identification in Hainan Tropical Rainforest National Park, serving as a model for similar efforts in China's national park system.
Preliminary Localization of a Rice Lesion Mimic Gene Based on BSA-seq
LU Dongying, CHEN jie, LI Ciyun, YANG Jianfei, NIU Xiaolei
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250022
Abstract:
Lesion mimic mutants (LMM) are important in plant immunity and growth and development studies. The aim of this study was to perform a preliminary localization of a rice lesion mimic gene by BSA-seq (Bulked Segregant Analysis sequencing) technique. First, we screened a mutant, LMM43, from the population of indica rice cultivar Huang Huazhan (HHZ) mutagenized by EMS for the appearance of lesion-like symptoms, and phenotyped the F2 segregant population obtained by crossing LMM43 with the wild-type parent to determine the mode of inheritance of the lesion-like trait. High-throughput sequencing was performed on mixed samples of DNA from individuals with disease-like spot phenotypes and normal individuals using BSA-seq technology. Through the association analysis of Single Nucleotide Polymorphism (SNP) and Insertion and Deletion (InDel) differences combined with phenotypic analysis, the target genes were preliminarily localized in a segment of rice chromosome 10, which is about 1.37 Mb in length and contains 199 genes. The length of this interval is about 1.37 Mb, which contains 199 genes, and five candidate genes were finally identified. The preliminary localization results laid the foundation for further gene cloning and functional verification, and helped to deeply understand the molecular mechanism of rice-like spot mutants, which is of great theoretical and applied value for the study of rice disease resistance breeding and plant immunity mechanism.
Ecosystem service functions of rubber plantations in Hainan Island and their value analysis
ZENG Huifen, FAN Xiaofeng, YANG Chuan, WU Zhixiang
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240121
Abstract:
Natural rubber has a vital position, and its safe supply is of great significance to the security of the national economy and even the security of the country. In recent years, the rapid expansion of rubber plantation area and potential ecological problems have attracted more attention. The assessment of the ecosystem service of rubber plantations in Hainan Island is conducive to determine the ecological value of rubber plantations, examine the important position of natural rubber industry from the perspective of ecological economics, and promote the sustainable development of natural rubber industry. In this context, the recognition algorithm of rubber plantations of different ages in Hainan Island was used to calculate the planting area of rubber plantations of different ages in Hainan Island, and the ecological service function value of the rubber plantations in different areas at different ages in Hainan Island was evaluated by substitute cost method and shadow engineering method. The results showed that the total value of ecosystem services in the rubber plantations in Hainan Island was 35.304 billion yuan, and the value of ecosystem services per unit area was 67 478.91 yuan/ha. The value of carbon sequestration and oxygen release was 23.571 billion yuan, the value of water purification and regulation was 3.390 billion yuan, the value of soil fixation and fertilizer conservation was 0.573 billion yuan, the value of air purification was 3.458 billion yuan, the value of farmland protection was 0.400 billion yuan, the value of forest tree nutrient accumulation was 1.543 billion yuan, and the value of biodiversity conservation was 0.314 billion yuan. Among them, the ecosystem service value of rubber plantatons at the ages of 16−20 years in Hainan Island was the highest. The spatial distribution pattern of ecosystem service value of the rubber plantations in Hainan Island is basically in the order of northwest >middle > southwest > southeast > northeast. The results show that rubber plantations have a strong ecosystem service function, which can not only bring economic and social benefits to human beings, but also produce greater ecological benefits.
Functional identification of soybean peroxidase GmPOD123 and screening of interacting proteins
LIU Xiaoyu, YAO Wenbo, ZHAO Yan, PEI Shuangkang, ZHANG Lijuan, ZHU Mengxue, WANG Xinrui, WANG Jiale, XU Hao, XU Keheng, ZHOU Yonggang, LI Haiyan
, Available online  , doi: 10.15886/j.cnki.rdswxb.20250007
Abstract:
To further explore the key genes regulating drought resistance in soybean, the peroxidase gene GmPOD123, which is significantly induced under drought stress, was screened based on previous transcriptomic analyses (RNA-Seq) of soybean leaves under drought stress. An expression analysis of the soybean GmPOD123 gene under drought stress was performed to identify whether GmPOD123 is involved in response to drought stress, and the results showed that GmPOD123 was significantly up-regulated after 3 h stress treatment. Moreover, phenotype identification of transgenic Arabidopsis plants of overexpressing GmPOD123 showed that overexpression of GmPOD123 in Arabidopsis could increase the drought tolerance, which was compared to wild type Arabidopsis. To further explore the drought-resistant molecular mechanism of GmPOD123, fructose-1,6-bisphosphate aldolase (GmFBA2), an interacting protein of GmPOD123, was screened from the soybean cDNA yeast library by Mating, and its interaction with GmPOD123 was identified by yeast two-hybrid system and luciferase complementation assay (LCA). In summary, GmFBA2 may influence ROS levels by interacting with GmPOD123, thereby regulating soybean drought resistance.
Screening and characterization of wild type yeast Torulaspora delbrueckii from Cantaloupe
CHEN Yixuan, ZHAI Jinling
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240161
Abstract:
Torulaspora delbrueckii is one of non-Saccharomyces yeasts mostly used for research, and is widely used for brewing of various fruit wines. It is co-fermented with Saccharomyces cerevisiae for improving fruit wine flavors. In this experiment, a wild-type yeast strain was selected from the peel of cantaloupe in Fulo Town, Ledong County, Hainan Province. Through phenotypic observation of the strain and constructing a phylogenetic tree based on 18S rDNA sequencing, the strain was identified as T. delbrueckii. Under the fermentation condition of fruit wine, T. delbrueckii grew normally in the range of alcohol content 4−20%, pH value 2.8−3.6 and sulfur dioxide concentration 100−500 mg·L−1, and the growth rate was the highest under the condition of alcohol content 4%, pH value 3.6 and sulfur dioxide concentration 300 mg·L−1. The results show that T. delbrueckii did not produce hydrogen sulfide, had no killing effect on S. cerevisiae, and improved the flavor of cantaloupe fruit wine, which can be used in the production of cantaloupe fruit wine.
Effect of combination of Syzygium infrarubiginosum extract and fungicides on disease control
BAI Yongxia, ZHANG Xi, FU Yingjie, WANG Shuai, LI Dong, SUN Ranfeng
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240173
Abstract:
An attempt was made to make full use of the advantages of plant extracts and chemical pesticides to reduce the dosage of chemical pesticides. Syzygium infrarubiginosum was extracted with methanol, and mixed with four chemical fungicides, including ethirimol, pyraclostrobin, thifluzamide and difenoconazole to screen the synergistic ratio of their mixtures against Rhizoctonia solani, the pathogen of rice sheath blight by indoor activity determination of mycelial growth rate of R. solani. The control effects of the synergistic mixtures on rice sheath blight and cowpea powdery mildew were determined by indoor pot experiment. The indoor activity determination showed that the mixtures at 11 ratios were found to have significant synergistic effects in the indoor activity determination of rice sheath blight, including the mixture of 5% (w/w) methanol extract microemulsion with 5% (w/w) pyraclostrobin suspension at the ratios of 4:1 and 5:1 ratio (the synergistic coefficient was 2.349 and 2.987, respectively), with 5% thifluzamide suspension at the respective ratios of 1:3, 1:4 and 1:5 (the synergistic coefficient values were 2.714, 2.455 and 2.167, respectively). The pot experiment showed that the mixtures screened could effectively control the occurrence of rice sheath blight and cowpea powdery mildew.
Prokaryotic expression and purification identification of lactate dehydrogenase from Phaeodactylum tricornutum Bohlin
ZHENG Yimeng, DUAN Jiawen, ZHANG Yi, LI Chenhui, XIE Zhenyu, HUANG Aiyou
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240176
Abstract:
An attempt was made to investigate the expression of lactate dehydrogenase (ptLDHA), a key enzyme in lactate metabolism, and to explore the acetylation modification sites on ptLDHA and their potential role in the interplay between lactylation and acetylation modifications in Phaeodactylum tricornutum Bohlin. The ptLDHA gene sequence was first cloned from P. tricornutum Bohlin cDNA, and then a prokaryotic expression vector, pMBP-C-LDHA, was constructed. The recombinant plasmid was then transferred into Escherichia coli BL21 (DE3) for induced expression. Under optimized conditions (16℃, 0.2 mmol·L−1 IPTG for 24 hours), ptLDHA protein was successfully expressed, predominantly in a soluble form. The fusion protein was purified using His-tag affinity chromatography and identified by Western blot with ptLDHA polyclonal antibodies. A single protein band at approximately 78 kDa was observed, confirming that the purified protein was ptLDHA. The expression and purification of ptLDHA in prokaryotic cells was successfully established, laying foundations for subsequent site-directed mutagenesis of acetylation modification sites and for investigation of the effects of modification and demodification on enzyme activity.
Contents of soil carbon, nitrogen and phosphorus and characteristics of their ecological stoichiometric ratios in Yunnan rubber plantations
ZANG Qinghui, WU Zhixiang, SUN Rui, YANG Chuan, FU Qingmao
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240138
Abstract:
In order to fully understand the reasonable nutrients of Yunnan rubber (Hevea brasiliensis) forest, soil ecological restoration of rubber forest provides data support. Using the soil of Yunnan (Jinghong, Hekou, Ruili), the typical samples of 20 m 20 m in different rubber forests, the soil samples were stratified (0−20, 20−40, 40−60, 60−80, 80−100 cm), and the spatial distribution characteristics of the soil of the rubber forest soil with the forest age and the dynamic changes were analyzed. The result show that the soil TC, TN, and TP contents in the rubber plantations generally increased and then decreased with the plantation age and soil depth. Significant differences were observed in the soil TC, TN, and TP contents among different ages of rubber plantations in Ruili and Jinghong, while the differences in Hekou were not significant. In Jinghong, the soil C∶N ratio increased and then decreased with soil depth, reaching its highest value at (40−60 cm). The soil C∶P ratio decreased with increasing soil depth, peaking at the surface layer (0−20 cm). The N∶P ratio initially decreased and then increased with soil depth. The C∶P and N∶P ratios showed a trend of decreasing and then increasing, with the highest values at 40−60 cm. In Ruili, the C∶N and C∶P ratios decreased and then increased with soil depth, also peaking at 40−60 cm, while the N∶P ratio continuously decreased. In Hekou, the C∶P ratio decreased and then increased with soil depth, while both C∶P and N∶P ratios showed a general decreasing trend. The contents of soil nutrients (C, N, P) and their ecological stoichiometric ratios in rubber plantations generally increased and then decreased with plantation age. Significant differences were found in the soil C, N, P contents and their stoichiometric ratios among different ages and soil layers in the rubber plantations (P<0.05), with highly significant differences observed between areas (P<0.01). It is suggested that during the rapid growth stage of rubber plantations, appropriate application of nitrogen and phosphorus fertilizers should be considered, as the soil N and P affect the growth of mature rubber plantations.
Genome-wide identification and expression analysis of jasmonate-induced oxygenases JOXs gene family in Manihot esculenta
HU Wencheng, ZHU Shousong, WANG Yixuan, YANG Da, CHEN Yinhua
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240199
Abstract:
To explore the role of jasmonate-induced oxygenases JOX family genes in the growth, development, and stress resistance of cassava (Manihot esculenta), MeJOXs family members were identified in cassava genome by bioinformatics methods, and their gene structure, promoter cis-acting elements, evolutionary relationships and expression patterns were analyzed. The results showed that there were four MeJOXs family genes in cassava genome, and each member had similar gene structure, conserved motifs, and protein domains. Each gene member exhibited at least 68% protein homology, with the highest similarity observed between MeJOX1 and MeJOX4, as well as between MeJOX2 and MeJOX3. Promoter cis-acting elements analysis showed that MeJOXs contained numerous light-responsive elements. Furthermore, each gene member possessed a varying number of hormone-responsive elements. Phylogenetic analysis showed that MeJOXs were more closely related to JOX genes in dicotyledonous plants. Transcriptome analysis revealed that all the genes were differentially expressed in stems, leaves, midveins, and fibrous roots, with the exception of MeJOX2 that was scarcely expressed in various cassava tissues. MeJOXs were induced by MeJA in different cassava germplasm, with MeJOX3 demonstrating the most significant expression by inducing. Upon infection by pathogen Xpm, MeJOX1/3/4 responded promptly, but their response patterns were distinctly different. MeJOX1/3 were upregulated, whereas MeJOX4 exhibited a trend of downregulation, and MeJOX2 exhibited negligible response. This study provides a theoretical foundation for further elucidating the functions of the MeJOXs gene family in cassava.
Isolation, identification and antibacterial activity of biocontrol Streptomyces Q2-02
XU Renwei, YANG Lin, HE Yanyan, WANG Lanying
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240177
Abstract:
In order to understand the anti-actinomycetes with biocontrol value isolated and screened from the soil in Hainan Island, actinomycetes were isolated from six soil samples from different regions of Hainan by using a gradient dilution method, and the actinomycete strains were screened by using the confrontation culture method and identified based on their morphology, physiological and biochemical characteristics and molecular biology methods. The potential application value of the active strains was determined by fruit soaking method and pot experiment. A total of 285 actinomycete strains were isolated from the soil samples, and the strain Q2-02 had the highest antibacterial activity. Its inhibition rates of Botryodiplodia theobromae, Colletotrichum gloeosporioides and Rhizoctonia solani were 92.8%, 90.0% and 88.2%, respectively, and the inhibition rates of the other six pathogens were also more than 60.0%. The identification of this strain showed that the strain Q2-02 was Streptomyces lunalinharesii. The pot experiments showed that the control effect of the 10-fold dilution of the fermented supernatant of the strain on mango stemend rot and rice sheath blight was significantly higher than that of the positive control 45% thiophandazim suspension diluted 800 times and 10% validacin aqueous solution diluted 1000 times, indicating that the strain Q2-02 has the value of further development and application.
Habitat suitability evaluation and overlap analysis of sympatric Red Junglefowl and Chinese Francolin
WU Guanmian, ZENG Qingling, DING Yishuo, XU Yuxin, RAO Xiaodong
, Available online  , doi: 10.15886/j.cnki.rdswxb.20240073
Abstract:
Exploring the spatial ecological niche delineation between co-distributed proximate species is crucial to understand their coexistence in the community. A survey of two species of pheasants, Red Junglefowl (Gallus gallus jabouillei) and Chinese Francolin (Francolinus pintadeanus), were made at 105 and 79 distribution sites in Datian National Nature Reserve, Hainan, from March 2023 to January 2024, respectively, using the line transect method and satellite tracking technology. A maximum entropy model was used to predict the suitable habitats for these two species of pheasants by combining 12 environmental variables, and analyze their overlap. The results showed that there are differences in the distribution patterns of suitable habitats for the two species of pheasants. The suitable habitat for the Red Junglefowl was located in the north-western and central parts of the reserve, which are dominated by deciduous broad-leaved and scrub forests, while the suitable habitat of the Chinese Francolin was located in the northern part of the reserve, and was mainly in the grass area. The potential suitable habitats of the two species of pheasants were 633.18 hm2 and 337.31 hm2, accounting for 48.61% and 25.89% of the area of the reserve, respectively. The ecological overlap indices of the Red Junglefowl and the Chinese Francolin were low, with D and I values being 0.421 and 0.711, respectively, and the overlapping area of suitable habitat was 41.31 hm2, which accounted for 17.64% and 17.22% of the area of the suitable habitats for the Red Junglefowl and the Chinese Francolin, respectively. There were similarities and differences in the selection of environmental factors by the two species. Differences lie in the fact that the variables with the greatest influence on the habitat distribution of the two species of pheasants were the distance from the ranger path and the normalized difference vegetation index (NDVI), which are mainly manifested in the fact that the Red Junglefowl preferred deciduous broad-leaved forests and scrubs near the ranger paths, whereas the Chinese Francolin was more influenced by the NDVI; similarities lie in the fact that the variable with the second highest influence on the habitat distribution of the two species of pheasants was the distance from the water source, which was manifested in the fact that the Red Junglefowl and the Chinese Francolin preferred to distribute within 400 m and 500~1000 m from water sources, respectively. This survey reveals a spatial sympatric niche relationship between the Red Junglefowl and the Chinese Francolin, and helps to further understand the interspecific competition and coexistence mechanisms of tropical pheasants.
Screening of effector protein CSEP00565 of Erysiphe quercicola and preliminary analysis of its mechanism
LIU Lijuan, LIU Yuhan, FANG Yuxiao, SHAN Jiaxin, ZUO Minghao, MIAO Weiguo, LI Xiao
, Available online  , doi: 10.15886/j.cnki.rdswxb.20230143
Abstract:
The rubber tree (Hevea brasiliensis) is an important economic crop in tropical areas of China, and its related industries play an important role in the local agricultural economy. The powdery mildew fungus Erysiphe quercicola is the most severe disease infecting H. brasiliensis. The effector proteins secreted by phytopahogenic microbes play important roles in the pathogenesis, but how effector proteins promote the infection by E. quercicola is less documented, which has limited disease resistance breeding programme and disease control strategies. The E. quercicola has 24 highly conserved candidate effector proteins, which has homologous in many other powdery mildews. It is possible that these proteins are required for the pathogenicity of powdery mildew. In order to find the important virulence factor among the 24 CSEPs, two conserved effector proteins were selected for functional analysis and found that only the effector CSEP00565 suppressed hypersensitive responses induced by Phytophthora infestans INF1 when these effectors were expressed in Nicotiana benthamiana. The effector CSEP00565 suppressed callose deposition induced by fungal chitin and bacteria flg22 when this effector was expressed in Arabidopsis thaliana, further supporting that CSEP00565 has a function to inhibit plant immunity. When CSEP00565 was further silenced by using spray-induced gene, the pathogenicity of the fungus significantly decreased. And the expression level of CSEP00565 was up-regulated at the haustorium formation stage (24 h) after inoculation with E. quercicola. Further research has discovered that the signal peptide of CSEP00565 possesses the activity of direct protein secretion. All these results indicate that CSEP00565 is a key virulence factor in promoting the infection by E. quercicola, which is conducive to understanding of the molecular mechanisms underlying H. brasiliensis-E. quercicola interaction.