油菜CAMTA3对菌核病抗性的调控功能及机制分析

The white mould disease caused by Sclerotinia sclerotiorum, is the most devastating disease in oilseed rape. Resistance resource for this disease is lacking, and molecular mechanisms underlying the resistance to this disease are poorly understood. Such kind of research in rapeseed is especially lacking. Oxidative burst is an important mechanism of plant resistance to many pathogens including S. sclerotiorum. However, the transcriptional regulating mechanism underlying the oxidative burst is currently unclear. This project aims to analyze the functions of CAMTA3, an important transcription factor of calcium signaling, in regulating accumulation of reactive oxygen species (ROS) and resistance to Sclerotinia white mould disease in oilseed rape, dissect the structure-function relationship in regulating ROS accumulation, identify new target genes for transcriptional regulation and interacting proteins of BnCAMTA3, thereby elucidate the molecular mechanisms of BnCAMTA3 to regulate ROS accumulation and S. sclerotiorum resistance. The achieved results should unveil a new mechanism for ROS and resistance to S. sclerotiorum, and thus provide insights into the molecular mechanisms of regulation of ROS accumulation, the key factor to initiate disease resistance, as well as improve the molecular mechanisms of regulation of resistance to white mould disease. Meanwhile, this project could provide a set of resistance regulatory genes that are potentially usefull for breeding of improved resistance to white mould disease.

由Sclerotinia sclerotiorum引起的菌核病是我国油菜第一大病害，但是该病害抗性资源匮乏，抗性分子机制研究也还不够深入，尤其在油菜作物本身的研究更少。侵染早期活性氧迸发积累是植物对包括S. sclerotiorum在内的多种病原物抗性的重要机制。但目前对该活性氧迸发的转录调控机制尚不明确。本项目拟在油菜上研究Ca2+信号途径重要转录因子CAMTA3对活性氧积累以及菌核病抗性的调控功能，明确油菜CAMTA3调控活性氧积累的结构-功能关系，鉴定油菜CAMTA3转录调控靶标基因以及互作蛋白，阐明油菜CAMTA3转录调控活性氧积累和菌核病抗性的分子机制。所获结果将揭示活性氧和菌核病抗性调控新机制，有力促进对活性氧这个植物抗病性关键因子的分子调控机制的认识，同时增进对菌核病抗性分子机制的理解，并为菌核病抗性新种质创制和抗病新品种分子选育提供基因资源。

由核盘菌（Sclerotinia sclerotiorum）引起的菌核病是我国油菜第一大病害，每年造成巨大经济损失。该病害抗性资源匮乏，抗性分子机制研究也还不够深入。本项目以重要作物油菜和模式植物拟南芥为植物对象，围绕Ca2+信号途径重要转录因子CAMTA3对核盘菌抗性的调控功能及分子机制开展了系统研究。通过采用转基因植株和突变体材料，结合多种组学、遗传学、生物化学、细胞生物学、分子生物学和植物病理学等技术，阐明了CAMTA3对核盘菌抗性的重要调控功能，解析了CAMTA3调控活性氧积累、基因沉默和核盘菌抗性的分子机制，揭示了一系列CAMTA3调控植物抗病性的新机制，包括阐明了CAMTA3通过直接调节RBOHF和GOX调控活性氧积累和核盘菌抗性的机制；首次揭示了CAMTA3通过直接结合并正调控AGO1基因转录、下调靶标AGO1的miR168b、解除AGO5/AGO6对AGO1的转录抑制作用三种途径促进AGO1转录本积累，从而正调控植物基因沉默的作用机制，进而揭示了CAMTA3通过直接调控基因沉默调控核盘菌抗性这一菌核病抗性调控新机制；鉴定了CAMTA3的直接作用靶标SARD1/CBP60g，并阐明CAMTA3-SARD1/CBP60g模块在调控对死体营养型病原真菌抗性中的重要调控作用；明确了CAMTA3对Pep激发抗核盘菌DTI免疫的重要调控功能，揭示Pep通过解除CAMTA3对SARD1/CBP60g的抑制作用产生抗性的机制；筛选获得了一系列油菜CAMTA3互作因子，揭示TFIID和TFIIE直接促进CAMTA3转录、CAMTA3直接结合一系列氧化还原调控蛋白在蛋白互作水平上调控氧化还原的机制。这些结果有力增进了对CAMTA3的生物学调控功能及机制、基因沉默调控作用机制、活性氧和氧化还原调控新机制以及植物抗病性调控分子机制的理解，并为菌核病的绿色防控提供新策略和新资源。