Molecular Cloning and Expressional Analysis of HbGSK1 from Rubber Tree（Hevea brasiliensis Müll. Arg.）

Key words: 
• Hevea brasiliensis Müll.Arg. /
• HbGSK1 /
• gene cloning /
• expression analysis

Abstract: Recent studies have revealed that plant GSK3 proteins are actively implicated in hormonal signalling networks during development as well as in biotic and abiotic stress responses. The GSK in rubber tree function in stress tolerance is unknown. Rubber trees of clone CATAS7-33-97 were treated with mechanical wounding（ without latex flow）,tapping（ with latex flow） with the untreated as the control,and then tapped after 2 hr,6 hr and 1 d,3 d,5 d,7 d of treatment to extract the total RNA from the latex sampled,and the full length cDNA of HbGSK1（ GenBank: JN835185. 1） was amplified from the cDNA library in the latex. It was 1 506 base pairs（ bp）in length,containing a 1 230 bp open reading frame（ ORF）,encoding 409 amino acid residues with a predicted molecular mass of 46. 35 ku and a pI of 8. 69. Real-time PCR analysis showed that the expression of HbGSK1 was upregulated by mechanical wounding（ without latex flow）. However,the expression of HbGSK1 was downregulated by first tapping,upregulated by second tapping,and then recovered to the level of that of the untreated control. The tapping had higher influence on HbGSK1 expression than the mechanical wounding. Furthermore,the expression patterns of HbGSK1 in the latex was regulated by biological clock. The change of HbGSK1 transcript levels in the latex indicated that the HbGSK1 protein was involved in abiotic stress responses of rubber tree.