College of Life Sciences, Northwest A & F University, Yangling, China.
Phytochemistry. 2022 Jul;199:113177. doi: 10.1016/j.phytochem.2022.113177. Epub 2022 Mar 28.
Phenolic acids are the major bioactive metabolites produced in Salvia miltiorrhiza, a traditional Chinese medicine called Danshen. Many phytohormone elicitor treatments induce phenolic acid biosynthesis, even though the underlying mechanism remains obscure. Expression pattern analysis showed that SmMAPK3 was highly expressed in leaves, and SmMAPK3 was significantly induced by salicylic acid (SA) and methyl jasmonate (JA). Bioinformatics analysis revealed that SmMAPK3 belongs to group A and contains a TEY motif in the activation loop together with three conserved regions (P-loop, C-loop and CD-domain). A previous study speculated that SmMAPK3 is likely a positive regulator in the biosynthesis of phenolic acids in S. miltiorrhiza. In this study, overexpression of SmMAPK3 increased phenolic acid biosynthetic gene expression and enhanced the accumulation of phenolic acids in S. miltiorrhiza plantlets. Yeast two-hybrid (Y2H) analysis and firefly luciferase complementation imaging (LCI) assays revealed that SmMAPKK2/4/5/7-SmMAPK3-SmJAZs form a cascade that regulates the accumulation of phenolic acids. In summary, this work deepens our understanding of the posttranscriptional regulatory mechanisms of phenolic acid biosynthesis and sheds new light on metabolic engineering in S. miltiorrhiza.
酚酸是丹参这种传统中药中产生的主要生物活性代谢物。许多植物激素诱导剂处理会诱导酚酸生物合成，尽管其潜在机制尚不清楚。表达模式分析表明，SmMAPK3 在叶片中高度表达，并且 SmMAPK3 被水杨酸 (SA) 和茉莉酸甲酯 (JA) 显著诱导。生物信息学分析表明，SmMAPK3 属于 A 组，在激活环中含有一个 TEY 基序，以及三个保守区域（P 环、C 环和 CD 结构域）。先前的研究推测 SmMAPK3 可能是丹参中酚酸生物合成的正向调节因子。在本研究中，SmMAPK3 的过表达增加了酚酸生物合成基因的表达，并增强了丹参植物中的酚酸积累。酵母双杂交 (Y2H) 分析和萤火虫荧光素酶互补成像 (LCI) 实验表明，SmMAPKK2/4/5/7-SmMAPK3-SmJAZs 形成一个级联，调节酚酸的积累。总之，这项工作加深了我们对酚酸生物合成的转录后调控机制的理解，并为丹参的代谢工程提供了新的思路。
