橡胶树HbBAM2基因的克隆与表达分析  

Molecular Cloning and Expression Analysis of HbBAM2 from Hevea brasiliensis

作　　者：阳江华[1] 邹智[1] 肖小虎 秦云霞[1] 

机构地区：[1]中国热带农业科学院,橡胶研究所/农业部橡胶树生物学重点开放实验室/省部共建国家重点实验室培育基地,海南省热带作物栽培生理学重点实验室,海南海口

出　　处：《植物学研究》2018年第6期583-591,共9页Botanical Research

摘　　要：在植物中,β-淀粉酶由一多基因家族编码,在不同组织的淀粉降解过程中起重要作用。目前有关种子和叶片的β-淀粉酶研究较多,而对花等其它异养组织则鲜有报道。本研究从橡胶树胶乳中克隆到了一个β-淀粉酶基因(命名为HbBAM2),其编码区长1752 bp,预测编码583个氨基酸。同源比较和亚细胞分析表明HbBAM2定位于叶绿体中。实时荧光定量PCR分析显示,HbBAM2主要在雌花、胶乳和雄花中表达;割胶条件下,HbBAM2的表达水平在新开割树的胶乳中随刀次的增加而明显下调,同时,乙烯利刺激也可部分下调HbBAM2在胶乳中的表达。HbBAM2重组蛋白热稳定性差,以可溶性淀粉和支链淀粉为底物,最适酶活性温度均为25℃,在45℃时已没有酶活性。根据HbBAM2的表达特点和酶学特性我们推测HbBAM2可能通过参与橡胶树花器官淀粉的降解,影响花器官的生长发育,HbBAM2还可能参与了橡胶树胶乳中淀粉的降解,为乳管细胞中的橡胶合成提供能量和碳源。β-amylase which is encoded by a multigene family in plants, plays an important role for starch degradation in different plant tissues. The β-amylase in seeds and leaves already had many re-ports, however, in other heterotrophic tissues such as flowers has seldom been studied. HbBAM2 was cloned from Hevea brasiliensis in this paper, its coding region is 1752 bp, encodes 583 amino acids. By means of homology analysis and subcellular prediction, HbBAM2 may locate in the chloroplast. qRT-PCR displayed the expression patterns of HbBAM2, which was mainly expressed in male flowers, latex and female flowers. HbBAM2 was reduced observably in latex of the virgin trees tapped, and down regulated partly by ethephon treatment. The recombinant protein HbBAM2 was thermal unstable with the optimum temperature 25?C of substrates, soluble starch or amylopectin, and undetectable activity at 45?C. It is presumed that HbBAM2 may influence the development of flowers by participating the starch degradation in flowers of Hevea brasiliensis, and HbBAM2 may degrade the starch in latex, providing energy and carbon source for rubber synthesis in laticifer.

关 键 词：橡胶树 Β-淀粉酶 HbBAM2 胶乳 花 

分 类 号：S5[农业科学—作物学]