巴西橡胶树HbCMT1的克隆与表达分析

Cloning and Expression Analysis of Hb CMT1 in Hevea brasiliensis

通过PCR和RACE技术克隆获得了巴西橡胶树染色质甲基化酶(CMT,chromomethylase)基因(Hb CMT1)。Hb CMT1全长2697 bp,含有2556 bp的阅读框,编码851个氨基酸。推测Hb CMT1分子量为95.67 k D,等电点为5.38,氨基酸序列与可可、烟草、葡萄、黄瓜、鹰嘴豆和拟南芥等CMT家族成员的同源性分别为66%、51%、50%、56%、53%和50%。定量PCR分析表明Hb CMT1在巴西橡胶树的根、树皮、叶、胶乳中均有表达,其中在叶中表达量最高,在胶乳中表达量最低。此外Hb CMT1在橡胶树自根幼态无性系胶乳中的表达量比老态无性系胶乳中的低。

The full-length c DNA encoding chromomethylase（ CMT）,designated as Hb CMT1,was isolated from Hevea brasiliensis using PCR and rapid amplification of c DNA ends（ RACE） techniques. Hb CMT1 was 2697 bp and contained an open reading frame of 2556 bp. Sequence analysis revealed that Hb CMT1 encoded 851 amino acid residues with a total predicted molecular mass of 95. 67 k D and isoelectric point（ p I） of 5. 37. The deduced amino acid sequences of Hb CMT1 showed high identities of 66%,51%,50%,56%,53% and 50% to those of the CMT from Theobroma cacao,Nicotiana benthamiana,Vitis vinifera,Cucumis sativus,Cicer arietinum,and Arabidopsis thaliana.Real time quantitative PCR analysis showed that Hb CMT1 transcripts accumulated in various examined tissues,with high expression levels in the leaf and low levels in the latex. Hb CMT1 transcript expressed at different levels with the lower in self-rooting juvenile clones than in their donor clones.