金锈菌属真菌分类学和分子系统发育研究

Biotrophic rust fungi of the genus Chrysomyxa are widespread in the northern hemisphere where they cause witches' brooms and needle and cone diseases, mainly on Picea. Chrysomyxa rusts are responsible for significant economic losses, especially in spruce plantations. The traditional identifications of the rust genus, which is based on host specificity and spore morphology, leave many open questions, and the taxonomy and phylogenetic relationship of Chrysomyxa species in China are also challenging. The project aims to better understand the taxonomy and phylogenetic relationship of the genus of Chrysomyxa based on comparative analyses of molecular phylogeny and morphology. To be more specific, we will use light and scanning electron microscopy and genomics approaches to determine the taxonomic status of the rust genus and the patterns of evolution as well as host specialization, fields investigation and inoculation experiments will also be conducted to compare their hosts ranges and life cycles because they are either unresolved or show unusual patterns with regard to host or geography. Our overall objective is to compare the DNA polymorphisms of Chrysomyxa species with different host ranges and different life cycles, and to establish more acute diagnostic and molecular monitoring system due to crack DNA code of each species of Chrysomyxa. Moreover, We will gain insight into disease development and to identify resistance-based management strategies based on the genomics of rust fungi and host- pathogen interactions. Thus, disease protection and management in further control will be assured, which will help us understand the disease thoroughly, and the disease can be controlled successfully based on our research results.

金锈菌属真菌引起的云杉叶锈病和球果锈病作为云杉林的重要病害，严重威胁云杉林健康，并造成了巨大的经济损失。我国对金锈菌属缺乏系统研究，同时传统分类方法造成了种类鉴定的混乱，不能有效揭示其种间的分类学和系统发育关系。本项目结合形态学观察和分子系统学方法，从形态特征、生活史和分子水平上系统开展我国金锈菌分类和系统发育研究， 分析金锈菌 "形态学种"与分子系统发育分支之间的相关性；进行人工接种试验，并从分子水平上证实金锈菌的生活史和转主寄生关系，从而明确中国金锈菌的种类，提出可用于金锈菌种的分类的有效分类依据，确立重要的金锈菌快速检测分子标记和DNA barcoding。其成果将填补国内对该病原菌分类研究的空白，为制定云杉锈病的防治策略提供科学依据和理论基础。

金锈菌属真菌引起的云杉叶锈病和球果锈病作为云杉林的重要病害，严重威胁云杉林健康，并造成了巨大的经济损失。我国对金锈菌属缺乏系统研究，同时传统分类方法造成了种类鉴定的混乱，不能有效揭示其种间的分类学和系统发育关系。本项目利用光学和生物电镜技术，并结合分子生物学技术，从形态学和分子水平上研究了我国金锈菌属(Chrysomyxa)的分类学及其系统关系。摸清和确立了我国金锈菌属的种类及其地理分布，首次全面系统地对分布于中国的金锈菌进行了形态学观察和分子系统发育研究；提出了新的有效的可用于种的水平上的形态学分类依据，认为锈孢子和夏孢子表面结构以及包被细胞内外壁表面结构可作为稳定的分类学特征应用于金锈菌在种水平上的分类和鉴定中；研究了金锈菌属与裸春孢锈菌属的关系，订正了一些裸春孢锈菌的分类学地位；发现并记述了寄生于粗枝云杉（Picea asperata）上的2个金锈新种，分别为Chrysomyxa diebuensis C. J. You & J. Cao 和Chrysomyxa zhuoniensis C. J. You & J. Cao；首次在中国发现琥珀金锈菌Chrysomyxa succinea (Sacc.) Tranz.的锈孢子阶段并详细描述了其特征。同时，研究了金锈菌属与Diaphanopellis属的关系，发现并记述了寄生于Rhododendron oreodoxa上的一个新种，Diaphanopellis purpurea C. J. You & J. Cao；同时，基于28S和ITS序列信息，建立了金锈菌的分子系统学关系，揭示了不同金锈菌各个孢子阶段之间的关系，明确了其生活史。该研究将为云杉叶锈病、云杉球果锈病、云杉芽锈病以及由金锈菌属引起的危险性植物病害的检测和控制提供指导，也为植物病原菌系统学、锈菌与寄主植物协同进化关系以及更深入的分子遗传学等研究工作奠定基础。