Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, 570228, China.
Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
Plant Mol Biol. 2018 May;97(1-2):165-176. doi: 10.1007/s11103-018-0730-0. Epub 2018 Apr 19.
The accumulation of flavonoids is activated by various abiotic stresses, and the induction of reactive oxygen species (ROS) especially hydrogen peroxide (HO) is a general response to abiotic stress in plants. However, the direct link between flavonoids and HO and underlying mechanism remain elusive. In this study, we found that the concentrations of anthocyanin and flavonoids were significantly induced by HO treatment. Furthermore, we found that the transcript level of ZINC FINGER of ARABIDOPSIS THALIANA 6 (ZAT6) was significantly activated after exogenous HO treatment, and modulation of AtZAT6 expression positively affected the concentrations of both anthocyanin and total flavonoids. Notably, exogenous HO-induced anthocyanin synthesis was largely alleviated in AtZAT6 knockdown plants, but showed higher level in AtZAT6 overexpressing plants. AtZAT6 directly activated the expressions of TT5, TT7, TT3, TT18, MYB12, and MYB111 through binding to their promoters with TACAAT elements of these genes, and the activation of MYB12 and MYB111 up-regulated the expressions of TT4 and TT6. Taken together, this study indicates that AtZAT6 plays important role in HO-activated anthocyanin synthesis, via directly binding to the promoters of several genes that involved in anthocyanin synthesis.
类黄酮的积累被各种非生物胁迫激活，而活性氧（ROS）的诱导，特别是过氧化氢（HO），是植物对非生物胁迫的普遍反应。然而，类黄酮与 HO 之间的直接联系及其潜在机制仍不清楚。在本研究中，我们发现 HO 处理显著诱导了花青素和类黄酮的浓度。此外，我们发现 ZAT6 的转录水平在HO 处理后显著激活，并且 AtZAT6 表达的调节对花青素和总类黄酮的浓度都有积极的影响。值得注意的是，HO 诱导的花青素合成在 AtZAT6 敲低植物中得到了很大缓解，但在 AtZAT6 过表达植物中表现出更高的水平。AtZAT6 通过与这些基因的 TACAAT 元件结合到它们的启动子上，直接激活了 TT5、TT7、TT3、TT18、MYB12 和 MYB111 的表达，而 MYB12 和 MYB111 的激活上调了 TT4 和 TT6 的表达。综上所述，本研究表明，AtZAT6 通过直接结合参与花青素合成的几个基因的启动子，在 HO 激活的花青素合成中发挥重要作用。
