麻疯树质体甘油-3-磷酸酰基转移酶(JcGPAT2)cDNA的克隆及序列分析

Cloning and sequence analysis of the cDNA of plastid-located glycerol-3-phosphate acyltransferase(JcGPAT2) from Jatropha curcas L.

甘油-3-磷酸酰基转移酶(GPAT:EC2.3.1.15)是催化脂肪酰基转移到甘油-3-磷酸的Sn-1位上合成1-酰基-Sn-甘油-3-磷酸(溶血磷脂酸)的酶。通过设计兼并引物和RACE引物,克隆得到麻疯树质体JcGPAT2基因(GenBank登录号:FJ952147),其cDNA全长1 516 bp,其中编码区1 389 bp,编码462个氨基酸,与蓖麻等植物GPAT基因高度同源,且含有4个保守功能结构域(Ⅰ、Ⅱ、Ⅲ、Ⅳ)。表达分析表明,JcGPAT2在麻疯树各组织中为组成型表达,在胚中最高而茎中最低;在种子发育过程中,Ⅰ、Ⅱ期表达量较高,Ⅲ期表达量减弱后在IV期又显著增强;在冷处理麻疯树叶片中,其受冷诱导后表达量在处理4 h时显著增加,12 h后又逐渐降低。表明JcGPAT2在种子油脂合成和抗冷性反应中可能起到重要作用。

Glycerol-3-phosphate acyltransferase （GPAT： EC2.3.1.15） catalyzes the acyl group of aeyl-ACP （acyl-carrier protein） transfer to the sn-1 position of glyeerol-3-phosphate to generate 1-acylglycerol-3-phosphate （lysophosphatidate, LPA）. Using degenerate primers and RACE primers, we cloned the JcGPA T2 gene ofJ. curcas, which contained 1 516 bp nucleotides with an open reading frame （ORF） of 1 389 bp, comprises of 462 amino acid residues, highly conserved with the GPA T sequences of Ricinus eommtmis and some other plants, and contained four conserved domains. JcGPA 112 showed constitutive expression pattern in different tissues of J. curcas, highly expressed in embryo and lowly in stem. During the maturation of seed, it highly expressed in stage I and II, a slight decrease in stage III and a subtle increase in stage IV. It was induced by cold in leaves, a sharp increase in 4 h after cold treat and decreased from 12 h. It illustrated that JcGPAT2 played an important role in seed lipid synthesis and cold resistance.