Institute of Plant Biotechnology, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, PR China.
Laboratory of Medicinal Plant Biotechnology, College of Pharmacy, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, PR China.
J Exp Bot. 2019 Jan 1;70(1):243-254. doi: 10.1093/jxb/ery349.
Phenolic acids are important secondary metabolites produced in the Chinese medicinal plant Salvia miltiorrhiza, but little is known about the transcription factors involved in the regulation of tanshinone and phenolic acid biosynthesis. Here, a novel AP2/ERF transcription factor SmERF115 was isolated and functionally characterized. SmERF115 was most responsive to methyl jasmonate (MeJA) treatment and was localized in the nucleus. The phenolic acid production was increased in SmERF115-overexpressing hairy roots, but with a decrease in tanshinone content. In contrast, silencing of SmERF115 reduced the phenolic acid level, but increased tanshinone content. The expression of the key biosynthetic gene SmRAS1 was up-regulated in SmERF115 overexpression lines but was down-regulated in SmERF115-RNAi lines. Yeast one-hybrid (Y1H) assay and EMSA showed that SmERF115 directly binds to the promoter of SmRAS1, while dual-luciferase assays showed that SmERF115 could activate expression of SmRAS1 in vivo. Furthermore, global transcriptomic analysis by RNA sequencing revealed that expression of other genes such as PAL3, 4CL5, TAT3, and RAS4 was also increased in the overexpression line, implying that they were potentially involved in the SmERF115-mediated pathway. Our data show that SmERF115 is a positive regulator of phenolic acid biosynthesis, and may be a potential target for further metabolic engineering of phenolic acid biosynthesis in S. miltiorrhiza.
丹酚酸是中国药用植物丹参中重要的次生代谢产物，但关于参与丹参酮和酚酸生物合成调控的转录因子知之甚少。在这里，我们分离并功能表征了一个新型的 AP2/ERF 转录因子 SmERF115。SmERF115 对茉莉酸甲酯（MeJA）处理最敏感，并且定位于细胞核中。SmERF115 过表达毛状根中的酚酸产量增加，但丹参酮含量降低。相反，SmERF115 沉默降低了酚酸水平，但增加了丹参酮含量。关键生物合成基因 SmRAS1 的表达在 SmERF115 过表达系中上调，但在 SmERF115-RNAi 系中下调。酵母单杂交（Y1H）测定和 EMSA 表明 SmERF115 直接结合到 SmRAS1 的启动子上，而双荧光素酶测定表明 SmERF115 可以在体内激活 SmRAS1 的表达。此外，通过 RNA 测序进行的全转录组分析表明，过表达系中其他基因如 PAL3、4CL5、TAT3 和 RAS4 的表达也增加，这表明它们可能参与了 SmERF115 介导的途径。我们的数据表明 SmERF115 是酚酸生物合成的正调控因子，可能是丹参酚酸生物合成进一步代谢工程的潜在靶点。
