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甘油-3-磷酸酰基转移酶(glycerol-3-phosphate acyltransferase,GPAT)是三酰甘油生物合成Kennedy途径中的关键酶,在植物的油脂合成与抗逆等方面起着重要作用。本研究在转录组数据基础上,通过RACE技术,从我国重要木本食用油料树种油茶中克隆了2个GPAT基因CoATS1和CoGPAT6的全长cDNA序列,编码序列长度分别为1 353和1 488 bp,分别编码450和495个氨基酸。蛋白结构预测发现2个蛋白C-端都含有1个酰基转移酶结构域,CoGPAT6的N-端还具有1个类卤酸脱卤酶结构域。多序列比对和系统进化分析结果表明,CoATS1与茶树的CsGPAT聚为一类,CoGPAT6与芝麻的SiGPAT6聚为一类。实时荧光定量PCR分析表明,CoATS1和CoGPAT6基因在检测的各样本中均有表达,其中CoATS1在叶片中的表达量显著高于其他组织,在种子的发育过程中,表达呈递减变化;CoGPAT6在花瓣中表达量最高,在种子中呈“降低-升高-降低”的表达特征。本研究为阐明GPAT类基因在油茶种子油脂合成途径中的功能奠定了基础。
Glycerol-3-phosphate acyltransferase (GPAT) is a key enzyme in the Kennedy pathway of biosynthesis of triacylglycerols and plays an important role in plant lipid synthesis and stress resistance. In this study, based on the transcriptome data, we cloned the full-length cDNA sequences of two GPAT genes CoATS1 and CoGPAT6 from Camellia oleifera, an important edible oilseeds species in China, by RACE technology. The coding sequences were 1 353 and 1 488 bp in length, Encoding 450 and 495 amino acids, respectively. Protein structure prediction found that two proteins C-terminal contains an acylase domain, CoGPAT6 N-terminal also has a halogeno-acid dehalogenase domain. Multiple sequence alignment and phylogenetic analysis indicated that CoGPAT6 clustered into one type with CoATS1 and SiGPAT6 from sesame. Real-time quantitative PCR analysis showed that CoATS1 and CoGPAT6 genes were expressed in all the samples tested. The expression level of CoATS1 in leaves was significantly higher than that in other tissues. The expression of CoATS1 decreased progressively in the seed development. The highest expression in the seeds showed “down-increase-decrease” expression characteristics. This study lays the foundation for elucidating the function of GPAT genes in the oil synthesis pathway of Camellia oleifera.