Centre for Plant Molecular Biology (CPMB), Osmania University, Hyderabad, Telangana, 500007, India.
Centre for Mass Spectrometry, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, 500007, India.
Plant Cell Rep. 2019 Sep;38(9):1127-1137. doi: 10.1007/s00299-019-02432-y. Epub 2019 Jun 1.
Genetically engineered onion expressing codon-optimized VvSTS1 gene accumulated stilbenes and extended life span in yeast and can serve as potential nutraceutical. Resveratrol (RV) is a natural polyphenolic compound found in certain plant species including grapes. RV is well known for its nutraceutical properties and to assuage several disease conditions. Onion is the second most consumed vegetable worldwide and contains large quantities of precursor molecules, malonyl-CoA and para-coumaroyl-CoA that are needed for RV biosynthesis. The present study reports the development of nutraceutical onion by engineering RV biosynthetic pathway. A codon-optimized grapevine synthetic stilbene synthase gene (VvSTS1) was synthesized using native grapevine sequence. Six-week-old healthy yellowish compact nodular calli were co-cultivated with Agrobacterium tumefaciens harbouring pCAMBIA1300-hpt II-CaMV35S-VvSTS1-nos. PCR analysis revealed the presence of VvSTS1 and hpt II genes in putative transgenics. Southern blot analysis confirmed the integration of VvSTS1 gene and independent nature of transformants. LC-ESI-HRMS analysis revealed the accumulation of variable quantities of RV (24.98-50.18 µg/g FW) and its glycosylated form polydatin (33.6-67.15 µg/g FW) in both leaves and bulbs, respectively, indicating the successful engineering of RV biosynthetic pathway into onion. The transgenic onion bulb extracts extended the life span in haploid yeast. The transgenic onion accumulating RV and polydatin, developed for the first of its kind, may serve as a potential nutraceutical resource.
利用基因工程手段培育的洋葱表达经过密码子优化的 VvSTS1 基因，可积累白藜芦醇类物质并延长酵母的寿命，有望成为潜在的营养保健品。白藜芦醇（RV）是一种天然多酚化合物，存在于某些植物物种中，包括葡萄。RV 以其营养保健品特性和缓解多种疾病状况而闻名。洋葱是全球消费第二大的蔬菜，含有大量用于 RV 生物合成的前体分子丙二酰-CoA 和对香豆酰-CoA。本研究报告了通过工程化 RV 生物合成途径开发营养保健品洋葱的情况。利用葡萄天然序列合成了经过密码子优化的葡萄合成白藜芦醇合酶基因（VvSTS1）。将 6 周龄健康的黄化紧实结节愈伤组织与携带 pCAMBIA1300-hpt II-CaMV35S-VvSTS1-nos 的根癌农杆菌共培养。PCR 分析显示在疑似转化体中存在 VvSTS1 和 hpt II 基因。Southern blot 分析证实了 VvSTS1 基因的整合和转化体的独立性。LC-ESI-HRMS 分析表明，在叶片和鳞茎中分别积累了不同数量的 RV（24.98-50.18μg/g FW）及其糖苷化形式白藜芦醇苷（33.6-67.15μg/g FW），表明 RV 生物合成途径已成功工程化到洋葱中。转基因洋葱鳞茎提取物可延长单倍体酵母的寿命。这种积累 RV 和白藜芦醇苷的转基因洋葱是首例，可能成为一种潜在的营养保健品资源。
