巴西橡胶树HbICE2基因的克隆及表达分析

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

ICE(inducer of CBF expression)介导的非依赖ABA信号传导途径在植物应对低温胁迫反应中起重要的调节作用。采用RT-PCR技术从橡胶树无性系热研8-79的叶片中扩增到1条全长c DNA,共1 677 bp,包括1 593 bp的开放阅读框,编码530个氨基酸,含有bHLH结构域,其中包含19个特征性的保守KMDRASILGDAI(D/E)YLKELL氨基酸序列,命名为HbICE2(Gene Bank登陆号:KY406163)。该基因编码的蛋白分子质量为58.02 KDa,理论等电点为5.95。荧光定量PCR分析结果表明,HbICE2主要在叶片和树皮中表达,而且在原生皮中的表达量显著高于再生皮,在抗寒性较强的橡胶树无性系PR107的树皮中表达量显著高于抗寒性弱的橡胶树无性系热研8-79。HbICE2可能在橡胶树树皮应对低温胁迫的反应中起重要的调节作用。

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.