Islam M T, Tahara S
Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan.
Biosci Biotechnol Biochem. 2001 Sep;65(9):1933-48. doi: 10.1271/bbb.65.1933.
Zoospores of phytopathogenic fungi accumulate at the potential infection sites of host roots by chemotaxis. The aggregated spores then adhere, encyst, germinate, and finally penetrate into the root tissues to initiate infection. Some of the host-specific attractants have already been identified. The host-specific attractants also induce cell differentiation of certain zoospores under laboratory conditions. This indicates that a signal released from the roots of the host plant guides the pest propagules for orientation and prepares them for establishing a host-pathogen relationship by necessary physiological changes. Some non-host plant secondary metabolites were found to markedly regulate behavior and viability of zoospores, suggesting that non-host compounds may also play a role in protecting the non-host plants from the attack of zoosporic fungi. We hypothesized that zoospores perceive the host signal(s) by specific G-protein-coupled receptors and translate it into responses by way of the phosphoinositide-Ca2+ signaling cascade. The details of the signal transduction mechanism in fungal zoospores are yet to be discovered. In this report, we review the signaling and communications between phytopathogenic fungal zoospores and host and non-host plants with special reference to Aphanomyces cochlioides.
植物病原真菌的游动孢子通过趋化作用在宿主根部的潜在感染部位聚集。聚集的孢子随后粘附、形成孢囊、萌发，最终穿透根组织引发感染。一些宿主特异性引诱剂已被鉴定出来。在实验室条件下，宿主特异性引诱剂还能诱导某些游动孢子的细胞分化。这表明宿主植物根部释放的信号引导害虫繁殖体定向，并通过必要的生理变化使它们为建立宿主 - 病原体关系做好准备。发现一些非宿主植物次生代谢产物能显著调节游动孢子的行为和活力，这表明非宿主化合物可能也在保护非宿主植物免受游动孢子真菌攻击方面发挥作用。我们假设游动孢子通过特定的G蛋白偶联受体感知宿主信号，并通过磷脂酰肌醇 - Ca2+信号级联反应将其转化为反应。真菌游动孢子中信号转导机制的细节还有待发现。在本报告中，我们特别参考了嗜贝丝囊霉，综述了植物病原真菌游动孢子与宿主和非宿主植物之间的信号传导和通讯。
