Molecular Cloning and Expression Analysis of HbICE2 in Rubber Tree（Hevea brasiliensis Muell. Arg.）

Key words: 
• Hevea brasiliensis Muell /
• Arg /
• HbICE2 /
• bark /
• cold tolerance

Abstract: ICE（inducer of CBF expression）-mediated ABA-independent signal transduction plays an important role in regulating the responses of plants to cold stress. A c DNA of HbICE2（ Gene Bank Accession No. :KY406163） was cloned from the leaf samples of rubber tree clone Reyan 8-79 by using RT-PCR. The HbICE2 was 1 677 base pairs（ bp） in length,containing a 1 593 bp open reading frame（ ORF）. The encoded protein,HbICE2,contained 530 amino acid residues with a predicted molecular mass of 58. 02 KDa and a pI of 5. 95.The HbICE2 had a b HLH domain with a specific highly conserved amino acid motif（ KMDRASILGDAI（ D/E）YLKELL）. Real-time quantitative PCR analysis showed that HbICE2 was mainly expressed in the leaf and bark among the samples tested. Its expression level was significantly higher in the original bark than in the regenerated bark,and significantly higher in the bark of the highly cold tolerant rubber clone PR107 that in that of the less cold tolerant clone Reyan 8-79. This suggests that HbICE2 may be crucial in regulating the cold tolerance of the bark of the rubber tree.