全面解析禾谷镰孢菌与寄主农作物时空特异性动态互作的分子机制

Fusarium graminearum can cause severe crop diseases such as Fusarium head blight on wheat and Gibberella stalk rot on maize, and contaminate grains with mycotoxins. Cultivars highly resistant to F. graminearum are still not available, therefore it is needed to comprehensive understand F. graminearum pathogenicity to explore new approaches for resistance design. The host infection process of F. graminearum is complex and temporal-spatial specific. We previously tracked F. graminearum infection of wheat and maize at cellular level, and obtained the specific fungal infection transcriptomes, elucidated the infection strategy transition of F. graminearum, and discovered the F. graminearum remodels membrane lipids to adapt apoplast phosphate starvation. In this project, we propose to comprehensively elucidate the temporal-spatial transcriptome dynamics of both pathogen and host during F. graminearum infection of wheat and maize, thoroughly identify candidate effector genes, identify novel secondary metabolite effectors and demonstrate how they suppress host defense; to elucidate susceptible host responsive transcriptomes with fine temporal-spatial resolution, construct susceptible response regulatory gene network, and identify key susceptible factors; to analyze interactive transcriptomes of pathogen and host to show how pathways of plant hormone metabolism and signaling cross-talk between host and pathogen, to elucidate how disease development affect host development through plant hormones. The result of this project will tell us that how F. graminearum deploys multiple effectors in a temporal-spatial specific manner, to achieve host susceptibility.

禾谷镰孢菌导致重要农作物病害小麦赤霉病和玉米赤霉茎腐病，产生真菌毒素。目前仍没有选育出高抗作物品种，迫切需要通过深入解析其致病机理，为抗病设计提供新手段。禾谷镰孢菌侵染寄主的过程时空差异显著，其致病的分子细胞机制仍不清楚。本研究组已揭示禾谷镰孢菌在小麦和玉米内部生长的细胞学进程和侵染表达谱，阐明其侵染策略的转换，发现了禾谷镰孢菌通过重塑膜脂克服玉米茎杆细胞间缺磷的新机制。本项目拟系统解析禾谷镰孢菌侵染小麦和玉米的时空特异性植病双方表达谱动态，全面揭示禾谷镰孢菌候选效应因子相关基因，鉴定新型次生代谢物类效应因子及其抑制植物防御的机制；构建小麦和玉米时空特异性的感病应答基因网络，揭示关键感病因子；分析植物激素代谢和信号途径的交叉和互动，揭示病原菌通过激素影响植物产量的机制。本项目的成果将较全面的揭示禾谷镰孢菌如何以时空特异性的方式综合利用各类效应因子，操纵植物途径，导致病害发生。

针对包括中国在内的全世界范围内趋向更为广发频发而有效防治手段不足的重要农作物病害小麦赤霉病和玉米赤霉茎腐病，结合植物免疫机制和病原致病机理研究理论知识框架和发展前沿，国家自然科学基金农作物与有害生物的互作与识别机制方向重点项目“全面解析禾谷镰孢菌与寄主农作物时空特异性动态互作的分子机制”在2018-2022年期间对导致小麦赤霉病和玉米赤霉茎腐病的病原真菌禾谷镰孢菌与寄主农作物小麦和玉米的分子互作开展综合性机制性原创性研究取得一系列重要成果，在Nature Communications、Journal of the American Chemical Society、Cell Reports、Molecular Plant Pathology、Frontiers in Microbiology等国际期刊发表标注论文。在禾谷镰孢菌与小麦特异性互作方面，发现鉴定禾谷镰孢菌特异产生的全新代谢物类效应分子非核糖体八肽镰孢菌素A和镰孢菌素B，并揭示它们赋予镰孢菌在小麦组织中细胞到细胞穿壁生长侵染小麦的致病能力，为小麦赤霉病防治提供全新靶标；在禾谷镰孢菌与玉米特异性互作方面，通过鉴定含有真菌特有CFEM结构域的分泌型蛋白家族多个成员为禾谷镰孢菌侵染玉米茎秆的效应蛋白，进一步发现证明玉米细胞壁相关受体激酶ZmWAK17是玉米茎腐病抗病蛋白且抗病作用幅度较大，而且阐明镰孢菌CFEM蛋白通过与玉米茎秆胞外蛋白ZmLRR5和ZmWAK17ET结合而抑制ZmWAK17抗茎腐病功能的机制，ZmWAK17全长转录产物具有抗茎腐病育种潜力；在禾谷镰孢菌与小麦、玉米互作共性方面，阐明活性氧清除酶KatG2在侵染寄主早期植病互作界面发挥显著作用，证明禾谷镰孢菌早期存在对寄主活性氧迸发敏感的活体侵染阶段，为禾谷镰孢菌早期防治策略明确方向；本项目还综合评估了系统获得性抗性分子羟基哌啶酸在小麦赤霉病抗病方面的应用潜力，为综合防治提供依据。