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摘 要：禾谷镰孢（Fusarium graminearum）是一种丝状真菌，广泛侵染多种农作物，禾谷镰孢的基因组编码约14000个基因，已有上百个基因被证明与其致病性相关，但禾谷镰孢致病机制的全貌仍不清楚。该研究组运用激光显微切割技术和芯片杂交，以小麦赤霉病的病原真菌-禾谷镰孢为对象，直接从感染的小麦组织中分离出不同侵染阶段的禾谷镰孢，获得阶段特异性的体内生长真菌全基因表达谱；通过发展细胞类型特异性芯片数据分析相关生物信息学方法，系统分析禾谷镰孢在宿主体内的表达谱动态，观察到细胞壁降解酶分阶段提升、环境活性氧清除先于活性氧分泌、乙醛酸循环早期提升、多种次生代谢物毒素在后期诱导等现象，推导提出禾谷镰孢侵染小麦胚芽鞘时依次采取隐蔽型胞间延伸、快速胞内生长、公开型全面破坏三种侵染策略转换，并通过基因敲除及互补等鉴定出多个毒力基因，验证了提出的侵染策略，揭示了禾谷镰孢侵染植物分子路线概貌。
关键词：禾谷镰孢 激光显微切割 植物细胞壁降解酶
Abstract：The ascomycete Fusarium graminearum is a destructive fungal pathogen of wheat. To better understand how this pathogen proliferates within the host plant， we tracked pathogen growth inside wheat coleoptiles， and then examined pathogen gene expression inside wheat coleoptiles at 16， 40 and 64 hours post-inoculation （hpi） using laser capture microdissection and microarray analysis. A total of 344 genes were identified to be preferentially expressed during hyphal growth in planta. Evaluation of 134 putative plant cell wall degrading enzyme genes suggests limited cell wall degradation at 16 hpi and extensive degradation at 64 hpi. Evaluation of reactive oxygen species （ROS）-related enzymes indicates that F. graminearum primarily scavenges extracellular ROS in advance of a later burst of pathogen-produced extracellular ROS-generating enzymes. The expression patterns of genes involved in primary metabolic pathways suggest that F. graminearum might rely on the glyoxylate cycle at an early stage of plant infection. A novel secondary metabolite biosynthesis gene cluster was specifically induced at 64 hpi and was required for virulence. Our results indicate that F. graminearum initiates infection of coleoptiles using covert growth strategies， and switches to overt cellular destruction of tissues at an advanced stage of infection.
Key Words：Fusarium graminearum；Laser microdissection；Plant cell wall degrading-enzymes
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关键词：禾谷镰孢 激光显微切割 植物细胞壁降解酶
Abstract：The ascomycete Fusarium graminearum is a destructive fungal pathogen of wheat. To better understand how this pathogen proliferates within the host plant， we tracked pathogen growth inside wheat coleoptiles， and then examined pathogen gene expression inside wheat coleoptiles at 16， 40 and 64 hours post-inoculation （hpi） using laser capture microdissection and microarray analysis. A total of 344 genes were identified to be preferentially expressed during hyphal growth in planta. Evaluation of 134 putative plant cell wall degrading enzyme genes suggests limited cell wall degradation at 16 hpi and extensive degradation at 64 hpi. Evaluation of reactive oxygen species （ROS）-related enzymes indicates that F. graminearum primarily scavenges extracellular ROS in advance of a later burst of pathogen-produced extracellular ROS-generating enzymes. The expression patterns of genes involved in primary metabolic pathways suggest that F. graminearum might rely on the glyoxylate cycle at an early stage of plant infection. A novel secondary metabolite biosynthesis gene cluster was specifically induced at 64 hpi and was required for virulence. Our results indicate that F. graminearum initiates infection of coleoptiles using covert growth strategies， and switches to overt cellular destruction of tissues at an advanced stage of infection.
Key Words：Fusarium graminearum；Laser microdissection；Plant cell wall degrading-enzymes
閱读全文链接（需实名注册）：http：//www.nstrs.cn/xiangxiBG.aspx？id=49707&flag=1