Veneault-Fourrey Claire, Laugé Richard, Langin Thierry
School of Biological and Chemical Sciences, University of Exeter, Washington Singer Laboratories, Exeter EX4 4QG, United Kingdom.
Appl Environ Microbiol. 2005 Aug;71(8):4761-70. doi: 10.1128/AEM.71.8.4761-4770.2005.
The fungal bean pathogen Colletotrichum lindemuthianum differentiates appressoria in order to penetrate bean tissues. We showed that appressorium development in C. lindemuthianum can be divided into three stages, and we obtained three nonpathogenic strains, including one strain blocked at each developmental stage. H18 was blocked at the appressorium differentiation stage; i.e., no genuine appressoria were formed. H191 was blocked at the appressorium maturation stage; i.e., appressoria exhibited a pigmentation defect and developed only partial internal turgor pressure. H290 was impaired in appressorium function; i.e., appressoria failed to penetrate into bean tissues. Furthermore, these strains could be further discriminated according to the bean defense responses that they induced. Surprisingly, appressorium maturation, but not appressorium function, was sufficient to induce most plant defense responses tested (superoxide ion production and strong induction of pathogenesis-related proteins). However, appressorium function (i.e., entry into the first host cell) was necessary for avirulence-mediated recognition of the fungus.
豆类真菌病原体菜豆炭疽菌（Colletotrichum lindemuthianum）会分化形成附着胞以穿透豆类组织。我们发现，菜豆炭疽菌附着胞的发育可分为三个阶段，并且我们获得了三个非致病菌株，其中每个发育阶段都有一个菌株受阻。H18在附着胞分化阶段受阻，即未形成真正的附着胞。H191在附着胞成熟阶段受阻，即附着胞表现出色素沉着缺陷，仅产生部分内部膨压。H290的附着胞功能受损，即附着胞无法穿透豆类组织。此外，这些菌株可以根据它们诱导的豆类防御反应进一步区分。令人惊讶的是，附着胞成熟而非附着胞功能足以诱导所测试的大多数植物防御反应（超氧离子产生和病程相关蛋白的强烈诱导）。然而，附着胞功能（即进入第一个宿主细胞）对于无毒力介导的真菌识别是必需的。
