巴西橡胶树HbDRM的克隆与表达分析

Cloning and Expression of HbDRM from Hevea brasiliensis

运用PCR和RACE技术从巴西橡胶树中克隆出了一个域重排甲基转移酶(Domains rearranged methyltransferase,DRM)基因(HbDRM)。HbDRM全长为2 245 bp,含有1 917 bp的阅读框,145 bp的5′-UTR和176 bp 3′-UTR,编码638个氨基酸,分子量为71.39 ku,等电点为4.90。HbDRM的氨基酸序列与可可、葡萄、黄瓜、鹰嘴豆、番茄、拟南芥DRM家族成员的同源性分别为77%、74%、72%、67%、64%和52%。定量RT-PCR分析表明HbDRM在巴西橡胶树的根、树皮、叶、花、胶乳、胚和愈伤组织中均有表达,其中在花和愈伤组织中表达量较高,在胶乳中表达量最低,此外HbDRM在橡胶树自根幼态无性系的胶乳中表达比其供体胶乳中的表达低。HbDRM的克隆和表达分析为下一步研究HbDRM在巴西橡胶树自根幼态无性系高产中的作用打下基础。

The full-length cDNA encoding a domains rearranged methyltransferase,designated HbDRM,was isolated from rubber tree by using PCR and RACE techniques.HbDRM was 2 245 bp in length and contained an open reading frame of 1917 bp.Sequence analysis revealed that the ORF of HbDRM encoded 638 amino acid residues with apredicted molecular mass of 71.39 ku.The deduced amino acid sequences of HbDRM showed high identities of 77％,74％,72％,67％,64％ and 52％ to those of the DRM from Theobroma cacao,Cucumis sativus,Cicer arietinum,Solanum lycopersicum and Arabidopsis thaliana HbDRM expressed at different levels with the highest transcription in the flowers,followed by the callus and leaves.HbDRM transcript expressed at different levels with the lower in self-rooting juvenile clones than in their donor clones.The present study perhaps contributes towards an understanding of the molecular mechanism underlying high yielding in self-rooting juvenile clones.