Frontiers Science Center for Transformative Molecules, Joint International Research Laboratory of Metabolic and Developmental Sciences, Plant Biotechnology Research Center, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA.
New Phytol. 2021 Sep;231(5):2050-2064. doi: 10.1111/nph.17514. Epub 2021 Jun 28.
Plant glandular secretory trichomes (GSTs) produce various specialized metabolites. Increasing GST density represents a strategy to enhance the yield of these chemicals; however, the gene regulatory network that controls GST initiation remains unclear. In a previous study of Artemisia annua L., we found that a HD-ZIP IV transcription factor, AaHD1, promotes GST initiation by directly regulating AaGSW2. Here, we identified two AaHD1-interacting transcription factors, namely AaMIXTA-like 2 (AaMYB16) and AaMYB5. Through the generation and characterization of transgenic plants, we found that AaMYB16 is a positive regulator of GST initiation, whereas AaMYB5 has the opposite effect. Notably, neither of them regulates GST formation independently. Rather, they act competitively, by interacting and modulating AaHD1 promoter binding activity. Additionally, the phytohormone jasmonic acid (JA) was shown to be associated with the AaHD1-AaMYB16/AaMYB5 regulatory network through transcriptional regulation via a JASMONATE-ZIM DOMAIN (JAZ) protein repressor. These results bring new insights into the mechanism of GST initiation through regulatory complexes, which appear to have similar functions in a range of vascular plant taxa.
植物腺毛状分泌细胞（GSTs）产生各种特殊的代谢物。增加 GST 的密度代表了提高这些化学物质产量的一种策略；然而，控制 GST 起始的基因调控网络仍然不清楚。在之前对黄花蒿（Artemisia annua L.）的研究中，我们发现一个 HD-ZIP IV 转录因子，AaHD1，通过直接调节 AaGSW2 来促进 GST 的起始。在这里，我们鉴定了两个 AaHD1 相互作用的转录因子，即 AaMIXTA-like 2（AaMYB16）和 AaMYB5。通过转基因植物的生成和鉴定，我们发现 AaMYB16 是 GST 起始的正调控因子，而 AaMYB5 则有相反的作用。值得注意的是，它们都不能独立调节 GST 的形成。相反，它们通过相互作用和调节 AaHD1 启动子结合活性来进行竞争。此外，茉莉酸（JA）这种植物激素被证明通过 JASMONATE-ZIM DOMAIN（JAZ）蛋白抑制剂的转录调控与 AaHD1-AaMYB16/AaMYB5 调控网络相关。这些结果通过调控复合物为 GST 起始的机制提供了新的见解，这些复合物在一系列维管植物类群中似乎具有相似的功能。
