致病疫霉菌致病关键的效应蛋白基因的鉴定和初步利用研究

Loss of disease resistance against plant pathogens has been a serious problem affecting sustainable production of a wide range of crops. It's known that effector genes in the pathogen are the key allowing their corresponding resistance genes effective, mutations in sequence or changes in the expression patterns of effector genes are the major causes that render the pathogens avoid being recognized and lead to loss of disease resistance. Therefore, understanding and identification of disease resistance genes with broad spectrum and durable characters have been a major focus in the fields of host-pathogen interaction and the applied plant pathology. In this research, we focus on the late blight of potato caused by Phytophthora infestans, a devastating crop disease problem across China and in the world. Assuming that the successful recognition by the host plant of pathogen effector proteins essential for pathogenesis is indicative of durable and broad spectrum resistance, we aim at identification of RXLR effector genes essential for early infection of potato by P. infestans through integrated approaches of transcriptome, functional genomics and molecular biology analyses. The identified candidate effector genes will be used to screen potato germplasm via Agrobacterium tumefaciens -mediated transient expression for novel disease resistance genes against P. infestans. The results will aid the development of pathogen effector recognition-based identification of novel disease resistance genes, the understanding of P. infestans pathogenesis, and the identification and application of broad-spectrum and durable disease resistance.

抗病性丧失问题在作物生产中十分突出，严重威胁可持续生产。业已明确病菌效应基因是其相应植物抗病基因发挥抗病作用的关键基因，其突出特点是可变性，通过序列变异或表达特征的变化而逃避被识别，这是作物抗病性丧失的最重要原因。因此，作物广谱和持久抗病性的鉴定和利用长期以来是植物病理学的热点和难点问题。本申请项目针对重要粮食作物马铃薯重大病害晚疫病问题，基于"识别病菌致病关键的效应蛋白的抗病基因更有可能具有持久和广谱的特性"这一假设，通过转录组学、功能基因组学和分子生物学方法，系统分析和鉴定病菌侵染早期致病关键的RXLR效应基因，并采用根癌农杆菌介导的基因瞬时表达筛选马铃薯种质资源、探索鉴定新型抗晚疫病基因，为建立基于病菌效应蛋白识别的新型抗晚疫病基因的鉴定和利用奠定基础，推动晚疫病菌致病机理的深入认识，为探索和利用作物广谱和持久抗病性的新途径和新方法提供科学依据。

致病疫霉菌（Phytophthora infestans）引致的马铃薯晚疫病，至今仍然是国内外马铃薯最为严重的病害。利用抗病品种是作物病害最为经济、安全和有效的途径，然而品种抗性丧失问题突出，严重威胁可持续生产。本申请项目针对重要粮食作物马铃薯重大病害晚疫病问题，基于“识别病菌致病关键的效应蛋白的抗病基因更有可能具有持久和广谱的特性”这一假设，通过转录组学、功能基因组学和分子生物学方法，系统分析和鉴定病菌侵染早期致病关键的RXLR效应基因，取得了以下研究成果：基于课题组前期研究结果，我们选择了六个具有遗传多样性的致病疫霉菌菌株进行转录组测序，鉴定到一系列晚疫病菌侵染早期表达的RXLR效应蛋白基因；系统分析了晚疫病菌侵染早期致病关键候选RXLR效应蛋白基因的表达特征、群体遗传变异、毒性功能等；对候选效应蛋白基因E54、E5、Avrblb2家族等几个候选RXLR效应蛋白进行了进一步的功能验证，初步探索了其作用机理。本项目的开展为建立基于病菌致病关键效应蛋白识别的新型抗病基因的鉴定和利用奠定了基础，为进一步探索和利用作物广谱和持久抗病性的新途径、新方法提供了理论依据。