National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, Shaanxi Normal University, Xi'an 710062, China.
College of Natural Resources and Environment, Northwest A&F University, Xianyang 712100, China.
Plant Sci. 2023 Feb;327:111565. doi: 10.1016/j.plantsci.2022.111565. Epub 2022 Dec 13.
Jasmonic acid (JA), as an important plant hormone, can induce the synthesis of phenolic acids in Salvia miltiorrhiza Bunge, a model medicinal plant, but the specific mechanism remains to be further elucidated. JA-responsive SmMYB111 positively regulates the biosynthesis of salvianolic acid B (SalB), but the molecular mechanism is unclear. Here, we found that SmMYB111 directly binds to the promoters of SmTAT1 and SmCYP98A14 and activates their transcription. Yeast two hybrid and bimolecular fluorescent complementation assay indicated that SmMYB111 interacts with SmJAZ4. Furthermore, we systematically characterized the function of SmJAZ4, which was highly expressed in flowers and roots and located in the nucleus and cell membrane. The contents of phenolic acids in the SmJAZ4-overexpressed transgenic plantlets and SmJAZ4-overexpressed transgenic hairy roots decreased significantly. SmJAZ4 interacts with SmMYC2 or SmMYB111 to repress their transcriptional activation activity on target enzyme genes of the biosynthesis pathway of phenolic acids. Overall, the molecular mechanism of SmJAZ4-SmMYC2/SmMYB111 module participating in JA signaling regulation of SalB biosynthesis was elucidated, which give a clue for the molecular regulation of phenolic acids biosynthesis in S. miltiorrhiza.
茉莉酸（JA）作为一种重要的植物激素，可以诱导丹参模式药用植物中酚酸的合成，但具体机制仍有待进一步阐明。JA 响应型 SmMYB111 正向调控丹酚酸 B（SalB）的生物合成，但分子机制尚不清楚。在这里，我们发现 SmMYB111 直接结合到 SmTAT1 和 SmCYP98A14 的启动子上，并激活它们的转录。酵母双杂交和双分子荧光互补实验表明 SmMYB111 与 SmJAZ4 相互作用。此外，我们系统地研究了 SmJAZ4 的功能，SmJAZ4 在花和根中高度表达，定位在细胞核和细胞膜中。在 SmJAZ4 过表达的转基因苗和 SmJAZ4 过表达的转基因毛状根中，酚酸含量显著降低。SmJAZ4 与 SmMYC2 或 SmMYB111 相互作用，抑制它们对酚酸生物合成途径中靶酶基因的转录激活活性。总之，阐明了 SmJAZ4-SmMYC2/SmMYB111 模块参与 JA 信号调节 SalB 生物合成的分子机制，为丹参酚酸生物合成的分子调控提供了线索。
