Basic Research on Molecular Recognition Between Host and Parasite Using Arabidopsis and Filamentous Fungal Pathogen

为了鉴定决定寄主-寄生虫侵染特异性的基因，构建了利用拟南芥和丝状真菌突变体侵染拟南芥的实验体系。为了鉴定与病原菌亲和性相关的植物基因，对诱变剂处理过的M2种子获得的拟南芥植株进行了亲和性筛选。我们筛选了2,032株，但目前还没有获得抗性或亲和性明显较高的植株。另一方面，为了鉴定与病原菌致病相关的基因，我们利用一种新的真菌标签突变技术REMI(限制性内切酶介导的整合)筛选出了致病力不足的突变体。通过这项技术，我们获得了三个突变体。它们是：1)表达弱致病性的突变体B3-16；2)既不能穿透寄主叶片也不能侵染植物细胞的纤维素膜的突变体E2-9；3)能穿透纤维素膜但不能侵染寄主叶片的突变体S1-27。这些突变体被认为在传染性的不同步骤中涉及的基因存在缺陷。目前还没有关于这些类型突变的报道。使用这些突变体，我们现在可以获得那些与传染性有关的基因的分离。

To identify genes that determine the host-parasite infection specificity, experimental system using mutants of Arabidopsis and filamentous fungal pathogen that infect Arabidopsis was constructed. To identify plant genes involved in compatibility to the pathogen, Arabidopsis plants derived from mutagen treated M2 seeds were screened for their compatibility to the pathogen alternaria brassicicola. We screened 2,032 plants, however at present, the plants expressing significantly higher resistance or compatibility were not acquired. On the other hand, to identify genes involved in the pathogenicity of the pathogen, we screened for pathogenicity deficient mutants of Colletotrichum higginsianum using REMI (Restriction Enzyme Mediated Integration), a novel technique for making tagging mutation of fungi. Through this technique, we got three mutants. these were 1) the mutant B3-16 expressing weak pathogenicity 2) the mutant E2-9 which can penetrate neither host leaves nor cellulose membranes used for the model substrate for plant cell 3) the mutant S1-27 which can penetrate cellulose membranes, but can not infect host leaves. These mutants are considered to be defective in genes involved in different steps in infectivity. There have been no reports for these type of mutants. Using these mutants, now we can access the isolation of those genes involves in infectivity.