MAPK支架蛋白GhMORG1调控棉花对枯萎病抗性的分子机制

Cotton is an important economic crop in China, while many diseases seriously threaten the development of China's cotton industry. How to improve the disease resistance is one of the key problems in cotton breeding. Based on the previous studies for GhMKK6-GhMPK4 signaling pathway regulated on cotton disease resistance response，combining with the latest research progress that MAPK scaffold protein is the control center of MAPK cascade signaling pathway, we isolated the MAPK scaffold protein GhMORG1 of this signaling pathway from cotton for the first time. Silencing GhMORG1 significantly reduced cotton resistance to Fusarium oxysporum. However, the molecular mechanism of GhMORG1 regulating cotton disease resistance response is still unclear. Using phosphorylated proteomics sequencing, mass spectrometry and other molecular biology techniques, this project intends to clarify the biological function of GhMORG1 in cotton resistance to Fusarium wilt, identify the substrate proteins of GhMORG1-mediated MAPK cascade signaling pathway, and explore the application potential of GhMORG1 and downstream substrate protein in cotton disease resistance breeding. These results not only reveal the molecular mechanism of GhMORG1 regulating the disease resistant function of GhMKK6-GhMPK4 signaling pathway, but also provide important theoretical basis for cotton disease resistance breeding.

棉花是我国重要的经济作物，多种病害严重威胁我国棉花产业的发展。如何提高棉花的抗病性是目前棉花育种方面亟待解决的重要问题。本项目是在前期研究GhMKK6-GhMPK4信号通路调控棉花对枯萎病抗性的基础上，结合MAPK支架蛋白是MAPK级联信号通路控制中心这一最新研究进展，首次从棉花中分离出该信号通路的支架蛋白GhMORG1。沉默GhMORG1显著降低了棉花对枯萎病菌的抗性。然而，GhMORG1调控棉花抗病反应的分子机制尚不清楚。本项目拟利用磷酸化蛋白质组学测序、质谱分析等技术，解析GhMORG1调控棉花对枯萎病抗性的生物学功能，明确GhMORG1介导的MAPK级联信号通路的底物蛋白，探明GhMORG1及下游底物蛋白在棉花抗病育种中的应用潜力。所得结果将揭示MAPK支架蛋白GhMORG1调控GhMKK6-GhMPK4信号通路抗病功能的分子机制，为棉花抗病遗传育种提供重要的理论依据。

MAPK支架蛋白对于调节MAPK级联信号通路的功能至关重要。然而，目前在植物中仅报道了少量MAPK支架蛋白，对于支架蛋白调控MAPK级联功能的分子机制尚不清楚。本项目在前期研究的基础上，筛选到一个新的植物MAPK级联通路支架蛋白GhMORG1。利用棉花转基因等手段，深入解析并验证了GhMORG1调控棉花对枯萎病菌抗性的生物学功能；通过酵母双杂交、免疫共沉淀等技术，明确了GhMORG1与GhMKK6、GhMPK4之间的互作及磷酸化关系，完善了GhMKK6-GhMPK4级联信号通路；通过磷酸化蛋白质组学测序、酵母双杂交筛库等技术，筛选出多个GhMORG1介导GhMKK6-GhMPK4级联通路调控棉花免疫反应的重要底物蛋白；利用质谱分析技术，明确了GhMKK6-GhMPK4级联信号通路底物蛋白GhRIN4和GhbHLH122的磷酸化位点；通过病毒介导的基因沉默及植物遗传转化技术，探明了GhRIN4和GhbHLH122在调控棉花对枯萎病菌抗性方面的生物学功能；利用转录组测序技术，筛选出GhMKK6-GhMPK4级联信号通路下游重要的转录因子家族，IIc亚族WRKY转录因子，并明确了其通过调控类黄酮的生物合成影响棉花对枯萎病菌抗性的分子机制。通过本项目，系统阐明了MAPK级联通路支架蛋白GhMORG1介导的GhMKK6-GhMPK4信号通路调控棉花免疫反应的分子机制，明确了GhMORG1及多个底物蛋白在棉花抗病遗传育种方面的应用潜力，为棉花遗传性状改良提供了重要的理论依据和新的实践方向。