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Cytological and Molecular Biological Analyses of Mechanisms of Signal Recognition and Host Specificity at Incipient Infection Stage

感染初期信号识别机制和宿主特异性的细胞学和分子生物学分析

基本信息

批准号：
12052214
负责人：
KUNOH Hitoshi
金额：
$ 25.47万
依托单位：
MIE UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

Powdery mildew conidia were known to release extracellular materials (ECM)immediately after contact to hydrophobic membranes. In this study, Blumeria graminis hordei and B.g.tritici, Erysiphe pisi were confirmed to release ECM on host surfaces. ECM contributes to adhesion of conidia and determination of the emergence site of germtubes. Immuno electron and confocal microscopies revealed that materials were moved from conidia to host epidermis and vice versa via ECM within 30 min after conidial contact. Epidermal cells of barley that contacted ECM of B.g.tritici and E.pisi (both nonpathogens to barley) were directed towards inaccessibility within 6-7 h after conidial contact, while those that contacted ECM of B.g.hordei (pathogen to barley) were directed towards neither accessibility nor inaccessibility. These results show that signal transduction and host response initiate immediately after conidium-host cell contact. The host range of Acidovorax avenae is wide among monocotyledonous but individual strains can infect only one or a few host species. Recently we reported that incompatible strain of A.avenae caused the resistance response, but compatible strain did not. We also reported that the resistance response was induced by flagellin from the incompatible strain. To investigate the mechanism of rice defense response induced by the incompatible strain and the role of flagellin on this defense induction, rice cDNA microarray analysis was performed. The microarray analysis showed that induction of 25 genes was regulated by the incompatible flagellin perception. We also investigated induction specificity of resistant response between incompatible and compatible flagellins. Induction analysis of resistant response in cultured rice cells using purified flagellins and recombinant flagellins showed that the flagellin specificity is involved in the post-translational modification of flgaellins.

已知白粉病分生孢子在接触疏水膜后立即释放细胞外物质（ECM）。在本研究中，证实了灰蓝菌（Blumeria graminis hordei）和b.b. tritici、Erysiphe pisi在寄主表面释放ECM。ECM有助于分生孢子的粘附和胚管出芽位置的测定。免疫电镜和共聚焦显微镜显示，物质在接触后30 min内通过ECM从分生孢子转移到寄主表皮，反之反之。与大麦非致病菌B.g.tritici和E.pisi ECM接触的大麦表皮细胞在分生孢子接触后6 ~ 7 h内呈不可接近状态，而与大麦致病菌B.g.hordei ECM接触的大麦表皮细胞既无可接近状态也无不可接近状态。这些结果表明，分生细胞与宿主细胞接触后，信号转导和宿主反应立即启动。在单子叶植物中，avenidovorax的寄主范围很广，但单个菌株只能感染一种或几种寄主。最近我们报道了不相容菌株引起耐药反应，而亲和菌株则没有。我们还报道了抗性反应是由不相容菌株的鞭毛蛋白诱导的。为了研究不亲和性菌株诱导水稻防御反应的机制以及鞭毛蛋白在防御诱导中的作用，采用了水稻cDNA芯片分析方法。微阵列分析表明，25个基因的诱导受不相容鞭毛蛋白感知的调控。我们还研究了不相容和相容鞭毛蛋白之间耐药反应的诱导特异性。用纯化的鞭毛蛋白和重组的鞭毛蛋白诱导水稻细胞的抗性反应分析表明，鞭毛蛋白的特异性参与了鞭毛蛋白的翻译后修饰。