Department of Bioengineering, Huainan Normal University, Huainan, Anhui Province, 232038, China.
Department of Bioengineering, Huainan Normal University, Huainan, Anhui Province, 232038, China; Key Laboratory of Bioresource and Environmental Biotechnology of Anhui Higher Education Institutes, Huainan Normal University, Huainan, Anhui Province, 232038, China.
Plant Sci. 2020 Jan;290:110293. doi: 10.1016/j.plantsci.2019.110293. Epub 2019 Oct 2.
Class I TGA transcription factors (TFs) are known to participate in plant resistance responses, however, their regulatory functions in the biosynthesis of secondary metabolites were rarely revealed. In this study, a class I TGA TF, TwTGA1, from Tripterygium wilfordii Hook.f. was cloned and characterized. Overexpression of TwTGA1 in T. wilfordii Hook.f. cells increased the production of triptolide and two sesquiterpene pyridine alkaloids, which was further enhanced by methyl jasmonate (MeJA) treatment. RNA interference of TwTGA1 showed no significant effects on the production of these metabolites, indicating the existence of other TGA partner(s) with overlapping functions. Heterologous expression of TwTGA1 in tobacco By-2 cells promoted the biosynthesis of pyridine alkaloids. Under the elicitation of MeJA, the contents of nonpyrrolidine alkaloids further increased but not for nicotine. TwTGA1 could induce the expression of Putrescine N-methyltransferase (PMT) and N-methylputrescine oxidase 1 (MPO1) through binding to their promoters. Finally, transient expression of TwTGA1 in leaves of Catharanthus roseus changed both the profiles of vinca alkaloids (increased contents of serpentine and catharanthine, but decreased that of vinblastine) and the expressions of biosynthesis-related genes. The metabolic and transcriptional data indicated a relationship between jasmonic acid signaling pathway and the functions of TwTGA1.
I 类 TGA 转录因子（TFs）已知参与植物抗性反应，但它们在次生代谢物生物合成中的调节功能很少被揭示。在这项研究中，从三尖杉中克隆并表征了一个 I 类 TGA TF，TwTGA1。TwTGA1 在三尖杉细胞中的过表达增加了雷公藤内酯和两种倍半萜吡啶生物碱的产生，而茉莉酸甲酯（MeJA）处理进一步增强了这一过程。TwTGA1 的 RNA 干扰对这些代谢物的产生没有显著影响，表明存在其他具有重叠功能的 TGA 伴侣。TwTGA1 在烟草 By-2 细胞中的异源表达促进了吡啶生物碱的生物合成。在 MeJA 的诱导下，非吡咯烷生物碱的含量进一步增加，但尼古丁没有增加。TwTGA1 可以通过结合到启动子上来诱导腐胺 N-甲基转移酶（PMT）和 N-甲基腐胺氧化酶 1（MPO1）的表达。最后，TwTGA1 在长春花叶片中的瞬时表达改变了长春碱类生物碱的（蛇根碱和长春质碱的含量增加，但长春碱的含量降低）和生物合成相关基因的表达。代谢和转录数据表明茉莉酸信号通路与 TwTGA1 的功能之间存在关系。
