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The study of the factors which are responsible for host-parasite specificity decided prior to penetration of plant pathogenic fungi

研究在植物病原真菌侵入之前决定的宿主-寄生虫特异性的因素

基本信息

批准号：
14360024
负责人：
YAMAOKA Naoto
金额：
$ 8.06万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

The powdery mildew fungus, Blumeria graminis an obligate parasite which infects only barley, needs to form an appressorium before it can penetrate the host plant. It is important for the fungus to form an appressorium(APP) on the host plant, because the fungus cannot be incubated on an artificial medium but only on a live host plant. So far it has been thought that APP formation could be observed equally both on the host plant and non-host plant, and the specificity between the fungus and the plants could be determined at the penetration stage or later. However, unlike on the host plant surface, we found that appressorial formation seemed to be inhibited on the non-host plant surfaces. These facts suggest that the specificity between the fungus and the plants could have been determined before the fungus tries to penetrate the plant. In this study, we focused on the chemical components, a decision factor for host-parasite specificity, on various plant surfaces to determine which chemical components are responsible for the appressorial formation of the fungus. Using infrared(IR) spectra and gas I iquid chromatography (GLC), we have identified the substance on the host plant surface that is effective for appressorial formation of the fungus and determined the chemical structure of it. Moreover, based on the results, we have found that the primary germ tube(PGT) which emerges prior to appressorial germ tube(AGT) is responsible for inducing susceptibility of the barley host plant. It acts as a probe to recognize the host plant, and the PGT adheres to the surface prior to AGT's emergence. These results were published in Physiological Molecular Plant Pathology and in "In Pursuit of the Essence of Plant Pathogenesis".

白粉病真菌，一种专性寄生虫，只感染大麦，在它能穿透寄主植物之前需要形成附着胞。真菌在寄主植物上形成附着胞（APP）是很重要的，因为真菌不能在人工培养基上孵育，只能在活的寄主植物上孵育。迄今为止，人们一直认为APP的形成在寄主植物和非寄主植物上都可以平等地观察到，真菌和植物之间的特异性可以在穿透阶段或之后确定。然而，与寄主植物表面不同，我们发现附着胞的形成在非寄主植物表面似乎受到抑制。这些事实表明，真菌和植物之间的特异性可能在真菌试图渗透植物之前就已经确定了。在本研究中，我们重点研究了不同植物表面的化学成分，这是决定寄主-寄生虫特异性的一个因素，以确定哪些化学成分负责真菌的附着形成。利用红外光谱（IR）和气相色谱（GLC）技术，鉴定了寄主植物表面对真菌吸附形成有效的物质，并确定了其化学结构。此外，我们还发现，在大麦寄主植物诱导敏感性的过程中，出现于附着胚管（AGT）之前的初代胚管（PGT）起着诱导作用。它作为一个探针来识别寄主植物，在AGT出现之前，PGT附着在表面。这些研究结果发表在《植物生理分子病理学》和《追求植物发病本质》上。