巴西橡胶树6个蔗糖转运蛋白基因的克隆与序列分析

Molecular Cloning and Sequence Analysis of Six Sucrose Transporter Genes from Hevea brasiliensis(para rubber tree)

蔗糖是绿色植物光合作用同化碳的主要运输形式,而蔗糖的跨膜运输是由蔗糖转运蛋白(SUT)所介导完成的。通过简并性RT-PCR和RACE技术,笔者首次从巴西橡胶树(Hevea brasiliensis)中克隆了6个SUT基因的全长cDNA,分别命名为HbSUT1、HbSUT2A、HbSUT2B、HbSUT3、HbSUT4和HbSUT5,相应序列已在GenBank上登录(登录号分别为DQ985466、DQ985467、DQ985465、EF067334、EF067335和EF067333)。氨基酸序列的同源性比对与系统进化分析表明,所得到的6个HbSUT基因可分为3个亚类,分别被聚为双子叶植物SUT基因的3种类型,即SUT1-type、SUT2-type和SUT4-type。在所分析的39种植物SUT基因中,HbSUT基因与同为大戟科的木薯、蓖麻和乳浆大戟SUT基因的同源性最高,反映这些基因的系统进化与物种进化的一致性。本文为进一步研究橡胶树SUT基因的功能奠定了基础,并将有助于巴西橡胶树中不同库组织,尤其是乳管的蔗糖供给与调控分子机理的阐明。

In plants, sucrose （Suc） is a major or even sole carbon source for long-distance transport, and is both a source of carbon skeletons and energy for plant growth and development. Sucrose transmembrane events are carried out by a kind of carrier protein, i.e. sucrose transporter （SUT）. Using the techniques of degenerate RT-PCR and RACE, full-length cDNAs of six SUT genes were cloned for the first time from Hevea brasiliensis, respectively, named HbSUT1, HbSUT2A, HbSUT2B, HbSUT3, HbSUT4 and HbSUTS. Their sequences had been deposited in GenBank, with accession Nos DQ985466, DQ985467, DQ985465, EF067334, EF067335 and EF067333. Amino acid sequence alignment and phylogeny analysis revealed that the 6 HbSUT genes could be classified in three subgroups, which were respectively grouped into 3 SUT types of dicots. Among the 39 SUT genes analyzed in plants, the SUT genes of rubber tree shared the highest homology in amino acid with the SUT genes of Manihot esculenta and Ricinus communis, which all belong to the same family of Euphorbiaceae. The results contribute to further functional analysis of these SUT genes, and help elucidate the molecular mechanisms of sucrose transportation and its regulation in rubber tree.