植物细胞一氧化氮信号转导研究进展

Research Progress on Nitric Oxide Signaling in Plant Cells

一氧化氮(nitric oxide,NO)作为重要的信号分子,调控植物的种子萌发、根形态建成和花器官发生等许多生长发育过程,并参与气孔运动的调节以及植物对多种非生物胁迫和病原体侵染的应答过程。已经知道,精氨酸依赖的NOS途径和亚硝酸盐依赖的NR途径是植物细胞NO产生的主要酶促合成途径。NO及其衍生物能够直接修饰底物蛋白的金属基团、半胱氨酸和酪氨酸残基,通过金属亚硝基化、巯基亚硝基化和Tyr-硝基化等化学修饰方式,调节靶蛋白的活性,并影响cGMP和Ca2+信使系统等下游信号途径,调控相应的生理过程。最新的一些研究结果也显示,MAPK级联系统与NO信号转导途径之间存在复杂的交叉调控。此外,作为活跃的小分子信号,NO和活性氧相互依赖并相互影响,共同介导了植物的胁迫应答和激素响应过程。文章综述了植物NO信号转导研究领域中一些新的研究进展,对NO与活性氧信号途径间的交叉作用等也作了简要介绍。

Nitric oxide （NO） has been recently characterized as an important signal molecule that mediates many developmental and physiological processes in plant cells. NO can be generated from nitrite by nitrate reductase （NR） and arginine by NO synthase- like enzymes. NO induces various processes in plants, including seed germination, root development, inflorescence initiation, stomatal closure and abiotic and biotic stress responses. The redox chemistry of NO allows it to react with the haem groups, cysteine and tyrosine residues on target proteins, which result in post-translational protein modification, metal nitrosylation, Snitrosylation, and tyrosine nitration. Intracellular signaling responses to NO also include generation of cyclic guanosine monophosphate, elevation of cytosolic calcium, and activation of mitogen-activated protein kinases. However, divergence and crosstalk of reactive oxygen species and NO signaling pathways occur in the plant response to hormone and stresses. Here, we provide a brief summary of new insights into NO signaling in plants and the cross-talk between reactive oxygen species and NO signaling.