桃果实八氢番茄红素合成酶基因的克隆与表达分析

利用基因克隆技术获得桃果实八氢番茄红素合成酶(PSY)基因的全长核苷酸序列,命名为PpPSY。PpPSY全长1 532 bp,编码区长度627 bp,共编码翻译成208个氨基酸。进化树分析发现,PpPSY与梅果实PmPSY亲缘性较高。蛋白质序列分析表明,PpPSY包含底物结合位点、Mg²⁺结合位点、活性位点残基盖、催化残基、天冬氨酸富集区等功能结构域,其属于isoprenoid biosynthesis enzymes class 1超级家族。实时荧光定量PCR结果显示,PpPSY基因在黄肉品种金丽发育组织中的表达高于白肉品种湖景,且在金丽品种中,PpPSY基因在花苞和硬核果中的表达显著高于在花、叶芽和软核果中的表达。本实验桃果实PpPSY基因的克隆及表达分析为研究桃果实类胡萝卜素生物合成分子机理奠定了良好的基础。

Cloning and expression analysis of phytoene synthase gene from peach fruit

Full-length cDNAs of phytoene synthase (PSY) was isolated from peach fruits using gene cloning method. PpPSY was 1 532 bp in full length and encoded a predicted protein of 208 amino acids (ORF length 627 bp). Phylogenetic analysis indicated that PpPSY was similar to PSY from Prunus mume. Deduced amino acid sequence demonstrated that PpPSY protein contained substrate binding pocket, substrate-Mg²⁺ binding site, active site lid residues, catalytic residues and aspartate-rich region, which belonged to the isoprenoid biosynthesis enzymes Class 1 superfamily. The quantitative real-time PCR showed that expression level of PpPSY gene in developmental tissues of yellow flesh variety Jinli was higher than that of white flesh variety Hujing, and the expression of PpPSY gene in flower bud, hardcore fruit was significantly higher than that in flower, sprout and softcore fruit. For the cloning and expression analysis of PpPSY from peach fruits was reported, it lays the foundation for further research of carotenoid biosynthetic pathway.