组蛋白H2B单泛素化参与VD-toxins胁迫应答及调控细胞微管骨架动态的作用机制

In this research project, we will use wild-type and hub, ubc mutants that lack histone H2B monoubiquitination (H2B ub) of Arabidopsis to explore the molecular mechanisms of H2B ub is involved in regulating the dynamic microtubule cytoskeleton during the defence responses to VD-toxins. We will investigate that the role of H2B ub in the regulation of dynamic microtubules cytoskeleton, and the relation linking H2B ub with tyrosine phosphorylation/dephosphorylation processes mediated by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs), and the activation of microtubule-associated proteins (MAPs) that control the dynamic properties and organization of microtubule may be regulated through tyrosine phosphorylation and dephosphorylation switches, and the changes in defense-related gene expression after treatment with VD-toxins. The results will provide evidence that H2B ub is involved in the regulation of microtubule assembly and disassembly and microtubule functions. The results will suggest a functional relationship between H2B ub and dynamic microtubule cytoskeleton and it will be helpful to reveal the molecular mechanisms of H2B ub controlling the defense response against VD-toxins. The results will provide novel insight into the mechanisms of epigenetic regulation in plant defence responses to Verticillium dahliae.

本项目利用拟南芥野生型和组蛋白H2B单泛素化基因缺失的系列突变体，以拟南芥幼苗与VD-toxins互作为研究体系，研究组蛋白H2B单泛素化参与VD-toxins胁迫应答及调控细胞微管骨架动态的作用机制。通过研究VD-toxins处理对野生型和突变体细胞微管骨架的时空动态变化、酪氨酸磷酸化信号通路和微管结合蛋白MAP65、MAP18活性及磷酸化水平的影响，从细胞、分子水平上阐述组蛋白H2B单泛素化调控微管骨架动态的作用机制，阐述组蛋白H2B单泛素化参与调控植物抗VD-toxins防卫反应中的功能，进而阐明表观遗传调控植物抗黄萎病作用机制的细胞学基础。本研究对阐明植物抗黄萎病的抗性机理具有重要意义，为全面揭示植物抗棉花黄萎病的表观遗传调控机制提供新内容，为利用基因工程手段控制棉花黄萎病开阔新领域。

组蛋白 H2B 单泛素化 (H2Bub) 是组蛋白翻译后修饰的一种类型。H2Bub 通过影响组蛋白与 DNA 双链的亲和性, 改变染色质的构象, 从而调控基因的转录。利用拟南芥突变体对基因功能的研究证明，HUB1、HUB2、UBC1、UBC2和UBC3参与调控植物的种子萌发、根和叶的生长、开花等发育过程，同时, 也证明H2Bub 在植物防卫反应中起关键作用。但目前有关组蛋白H2B单泛素化基因调控植物防卫反应的作用机制了解甚少。本项目利用拟南芥野生型和hub1、 hub2、 ubc1、ubc2、 ubc3单突变体、hub1-hub2、ubc1-ubc2、ubc1-ubc3、ubc2-ubc3双突变体及突变体互补系，研究组蛋白H2B单泛素化参与VD-toxins胁迫应答及调控细胞微管骨架动态的作用机制。研究结果表明，组蛋白H2B单泛素化基因参与调控拟南芥响应Vd-toxins胁迫应答反应，是响应Vd-toxins胁迫应答的正调控因子。组蛋白H2B单泛素化调控微管骨架的动态变化；调控H2O2合成关键酶NADPH氧化酶基因的表达；调控MAPKs信号途径；调控转录因子WRKY33的表达；组蛋白H2B单泛素化基因通过影响酪氨酸磷酸化信号通路，调控细胞微管骨架的动态变化，继而调控下游的防卫反应基因表达。本研究阐述组蛋白H2B单泛素化参与调控植物抗VD-toxins防卫反应中的功能，进而阐明表观遗传调控植物抗黄萎病作用机制的细胞学基础。研究结果对阐明植物抗黄萎病的抗性机理具有重要意义，为全面揭示植物抗棉花黄萎病的表观遗传调控机制提供新内容，为利用基因工程手段控制棉花黄萎病开阔新领域。