巴西橡胶树中碱性转化酶HbNINa基因的克隆和表达模式分析

摘要

检索橡胶树EST和基因组数据库,发现了1个在叶片中高丰度表达的中碱性转化酶基因.采用RT-PCR和RACE技术获得了该基因的cDNA和基因组序列,命名为Hb NINa.序列分析结果显示,HbNINa基因cDNA序列的编码区(CDS)序列长度为1 719 bp,对应的基因组序列为3 696 bp.序列分析表明,该基因编码571个氨基酸多肽,推测其分子量大小为65.7 ku,等电点为6.36.HbNINa蛋白包含植物中碱性转化酶的全部保守结构域.基因组结构分析显示Hb NINa基因包含4个外显子和3个内含子.QPCR分析结果表明,HbNINa基因在在胶乳中表达水平极低,而在其他组织如树皮、树叶和雌花中的表达丰度相对较高.在叶片发育过程中,Hb NINa在叶片发育的初期高丰度表达,推测HbNINa可能参与叶片蔗糖利用,进而在橡胶树叶片发育过程中起重要作用.%Based on the Hevea EST and genome sequence database,we cloned one alkaline/neutral invertase gene,HbNINa,which was highly expressed in the leaf of Hevea brasiliensis.Sequence analysis revealed that HbNINa coding sequence was 1 719 bp,and the deduced peptide was 571 amino acids in length,with an average molecular weight of 65.7 ku and a pIvalue of 6.36.The HbNINa protein contained all the conserved domains of typical plant alkaline/neutral invertases.Exon/intron structure analysis showed that the HbNINa gene contained four exons and three introns.The real-time RT-PCR results indicated that the HbNINa expression was mainly found in the bark,leaf and female flower,whereas barely detectable in the latex.HbNINa was also found highly expressed in bronze-stage leaf and down-regulated with leaf maturation,suggesting the important roles of this gene in the process of leaf maturation in rubber tree.