巴西橡胶树一个新的法尼基焦磷酸合酶基因的克隆及表达分析

Cloning and Expression of a New Farnesyl Pyrophosphate Synthase Gene in Hevea brasiliensis

利用同源克隆的方法在橡胶树中获得一个新的法尼基焦磷酸合酶基因,命名为Hb FPS2。序列分析显示,Hb FPS2基因组序列长4 171 bp,由12个外显子和11个内含子组成,c DNA全长1 288 bp,包含1 029 bp的开放阅读框、105 bp的5′-UTR和154 bp的3′-UTR,编码342个氨基酸,推测分子量为39.6 ku,等电点为5.27。氨基酸序列比对显示,Hb FPS2具有FPS家族保守的5个结构域。进化分析结果表明,Hb FPS2和Hb FPS1亲缘关系最近,与大戟科的蓖麻、大戟、麻风树法尼基焦磷酸合酶聚为一个亚类。定量PCR结果表明,Hb FPS2在橡胶树根、树皮、叶、花和胶乳等组织中均有表达,在花和胶乳中表达量较高,在根中表达量最低;茉莉酸和乙烯处理均能提高Hb FPS2基因的表达量,处理9 h时基因表达量分别提高了36倍和8倍。结果为分析法尼基焦磷酸合酶基因表达特性及其在天然橡胶生物合成途径中的作用机制奠定基础。

Farnesyl pyrophosphate synthase is a key enzyme in nature rubber biosynthesis in Hevea brasiliensis.In this study, a new gene coding for farnesyl pyrophosphate synthase, designated as Hb FPS2, was isolated by homology-based candidate gene method in Hevea brasiliensis. Sequence analysis revealed that the Hb FPS2 genome sequence is 4 171 bp, contained 12 exons and 11 introns. The full-length c DNA of Hb FPS2 is 1 288 bp with1 029 bp open reading frame, encoding 342 amino acid residues with molecular mass of 39.6 ku, and p I 5.27.Multiple sequence alignment showed that the Hb FPS2 included 5 domains with highly conserved amino acids. The phylogenetic analyses revealed that Hb FPS2 belong to plant farnesyl pyrophosphate synthase family, in which Hevea brasiliensis, Ricinus communis, Euphorbia pekinensis and Jatropha curcas were clustered into one clade. The results of real time PCR analysis indicated that Hb FPS2 expressed at different levels with the highest transcription in the flowers, followed by the latex, and lowest in the roots. The transcription of Hb FPS2 was induced in the latex by jasmonic acid and ethylene, increased 36 and 8-fold respectively. This research lays a foundation for studying the gene expression pattern and regulating mechanisms of Hb FPS2 in nature rubber biosynthesis.