巴西橡胶树importin和exportin基因的克隆及其乙烯响应规律分析

Molecular Cloning of importin and exportin in Hevea brasiliensis and Gene Expression Induced by Ethylene

摘要:

为了解巴西橡胶树(Hevea brasiliensis)中importin和exportin基因的功能,采用RACE技术从巴西橡胶树中克隆了他们的cDNA全长,分别命名为HbIMP和HbXPO。结果表明,HbIMP全长4170 bp,编码1115个氨基酸;HbXPO全长4108 bp,编码1081个氨基酸。HbIMP和HbXPO分别与importin5和exportin1A亚家族的同源性最高。HbIMP包含18个外显子,17个内含子,而HbXPO包含30个外显子,29个内含子,且在上游调控序列中都存在乙烯响应元件ERELEE4和LECPLEACS2。在无乙烯刺激情况下,HbIMP和HbXPO在根、茎、叶、皮中有表达,但在胶乳中几乎检测不到表达;乙烯处理后HbIMP和HbXPO在胶乳中被明显诱导表达。因此,推测HbIMP和HbXPO参与了乙烯诱导蛋白出入细胞核的转运。

Abstract:

The aim was to understand the functions of importin and exportin genes in Hevea brasiliensis. The full-length cDNAs of importin and exportin gene were cloned from H. brasiliensis by rapid amplification of cDNA ends (RACE) technique, named as HbIMP and HbXPO, respectively. The results showed that HbIMP was 4170 bp in length, encoding 1115 amino acids, and HbXPO for 4108 bp in length, encoding 1081 amino acids. Multiple sequence alignment and phylogenetic analysis revealed that HbIMP belonged to importin5 subfamily, while HbXPO to exportin1A subfamily. The sequences analysis showed that HbIMP contained 18 exons and 17 introns, while HbXPO had 30 exons and 29 introns, and both of them containing ethylene response elements ERELEE4 and LECPLEACS2 in upstream sequences. Real time PCR analysis indicated that both HbIMP and HbXPO had expression in root, stream, leaf and bark, but not in latex, but their expression in latex were obviously induced by ethylene stimulation. Therefore, it was suggested that HbIMP and HbXPO might be involved in the transporting of macromolecules induced by ethylene.