《植物生理学报》 2017, 53(5): 865-872

甘薯八氢番茄红素合成酶基因的克隆与功能验证

程洁¹, 赵腾飞¹, 廖志华^1,2, 杨春贤^1,2,*

¹西南大学生命科学学院, 重庆400715; ²重庆市甘薯工程技术研究中心, 重庆400715

通信作者：杨春贤；E-mail: yangchunxian@163.com

摘　要：

八氢番茄红素合成酶(phytoene synthase, psy)是植物体内类胡萝卜素合成途径中的第一个关键酶。本研究从甘薯高类胡萝卜素新品系渝薯11-10-97中克隆了PSY基因, 命名为IbPSY。序列分析显示该基因编码区为1 320 bp, 编码的蛋白质含有439个氨基酸, 分子量为49.110 kDa, 等电点(pI)为9.14。进化分析表明IbPSY与栀子的PSY亲缘关系最近。亚细胞定位结果显示, IbPSY定位于植物细胞的叶绿体。在大肠杆菌PSY基因缺陷型菌株中表达IbPSY, 能够使缺陷型菌株合成类胡萝卜素; 在拟南芥中超表达IbPSY后, 拟南芥叶片中类胡萝卜的含量明显提高; 表明获得的IbPSY具有八氢番茄红素合成酶基因的功能。

关键词：甘薯; 八氢番茄红素合成酶; 基因克隆; 功能验证

收稿：2017-02-15   修定：2017-03-30

资助：重庆市社会事业与民生保障科技创新专项(CSTC2015-SHMS-ZTZX80003和cstc2015shms-ztzx0128)和“863”计划(2011AA100607和2012AA101204)。

Cloning and functional identification of phytoene synthase gene from sweetpotato

CHENG Jie¹, ZHAO Teng-Fei¹, LIAO Zhi-Hua^1,2, YANG Chun-Xian^1,2,*

¹School of Life Sciences, Southwest University, Chongqing 400715, China; ²Chongqing Engineering Research Center for Sweetpotato, Chongqing 400715, China

Corresponding author: YANG Chun-Xian; E-mail: yangchunxian@163.com

Abstract:

Phytoene synthase is the rate-limiting enzyme involved in the carotenoid biosynthetic pathway in plants. In this research, we cloned the phytoene synthase gene named IbPSY from a new sweetpotato variety named YUSHU 11-10-97. Sequence analysis showed that the coding region of IbPSY was 1 320 bp. The encoded protein contained 439 amino acids with a molecular weight of 49.110 kDa and an isoelectric point (pI) of 9.14. Phylogenetic analysis showed that IbPSY was closest to PSY in gardenia. Subcellular localization results showed that IbPSY was localized in chloroplasts. Expression of IbPSY resulted in the synthesis of carotenoid in PSY gene-deficient Escherichia coli strain. Finally, overexpression of IbPSY in Arabidopsis thaliana significantly increased the contents of carotenoids. The results showed that IbPSY has the function of the phytoene synthase.

Key words: sweetpotato; phytoene synthase; gene cloning; functional identification