Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610064, China.
School of Life Sciences, Guangzhou University, Guangzhou, 510006, China.
Plant Sci. 2020 Mar;292:110355. doi: 10.1016/j.plantsci.2019.110355. Epub 2019 Nov 24.
Sumoylation is one of post-translational modification (PTM) in which SUMO (small ubiquitin-like modifier) are covalently conjugated to protein substrates through a range of biochemical steps. This paper presents evidence that SUMO E3 ligase SIZ1 positively regulates anthocyanin accumulation. Loss-of-function siz1 mutant seedlings exhibit anthocyanin accumulation-reduced phenotype under high light conditions. Moreover, SIZ1 interacts and sumoylates MYB75/PAP1, a key transcription factor in anthocyanin accumulation. Loss-of-function siz1 or K246R substitution in MYB75 blocked SIZ1-mediated sumoylation in vitro and in vivo. Anthocyanin accumulation in mutant myb75-c can not be rescued by expressing MYB75, but expression of wild-type MYB75 complements the mutant phenotype. It suggested that sumoylation is important for MYB75 function. We further prove that sumoylation is essential for MYB75 protein stability. And SIZ1 is involved in the light-induced accumulation of anthocyanins. Our findings reveal an important role for sumoylation of MYB in regulation of anthocyanin accumulation in plants.
SUMO 化是一种翻译后修饰（PTM）方式，其中 SUMO（小泛素样修饰物）通过一系列生化步骤与蛋白质底物共价结合。本文提供的证据表明，SUMO E3 连接酶 SIZ1 正向调节花青素的积累。在强光条件下，功能丧失的 siz1 突变体幼苗表现出花青素积累减少的表型。此外，SIZ1 与 MYB75/PAP1 相互作用并进行 SUMO 化，后者是花青素积累的关键转录因子。在体外和体内实验中，MYB75 的功能丧失或 K246R 取代都阻断了 SIZ1 介导的 SUMO 化。突变体 myb75-c 中的花青素积累不能通过表达 MYB75 来挽救，但表达野生型 MYB75 可以互补突变体表型。这表明 SUMO 化对于 MYB75 的功能很重要。我们进一步证明 SUMO 化对于 MYB75 蛋白稳定性至关重要。并且 SIZ1 参与了光诱导的花青素积累。我们的研究结果揭示了 SUMO 化在植物中调节花青素积累的重要作用。
