Flagellar apparatus and evolution of the peronosporomycetidae (oomycota)

鞭毛器和霜霉科（卵菌门）的进化

• 批准号: 371838-2009
• 负责人: Levesque, André
• 金额: $ 1.38万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2009
• 资助国家: 加拿大
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=434989
• 关键词: Flagellar; apparatus; evolution; peronosporomycetidae; oomycota

The oomycetes are fungus-like organisms also called water moulds. Most species can produce zoospores that swim in water with two different flagella attached at the same point on the zoospore. Most species of the Peronosporomycetidae, the targeted subclass for this study out of the two found in oomycetes, are terrestrial species causing diseases of plants or growing on dead organic matter. The two main genera are Pythium and Phytophthora. If enough free water is present, which is common in agricultural soil after heavy rain, the zoospores can actively swim towards the roots of a host by sensing changes in chemicals or electric charges. This directional movement is particularly noticeable if the roots are wounded. Interestingly, although several species of Pythium and particularly Phytophthora can only infect certain species, the zoospores do not seem to be able to sense if a host is suitable or not when they are swimming towards a root system. Many molecular studies have been dealing with the plant/pathogen interactions once the zoospore has reached the host since this is where many interesting gene for gene interactions occur leading to resistance or disease outcomes. However, few molecular studies have concentrated their efforts on the zoospore itself. Our laboratory has extensive expertise in taxonomy and molecular ecology of Pythium. We want to find unique genes involved in the flagellar apparatus, motility and behaviour of the zoospore and compared these gene sequences among Pythium species. We will turn off some of these genes in Pythium aphanidermatum and see their effect on zoospore. We have developed various tools to detect Pythium species in the environment but they cannot differentiate the kind of Pythium tissue being detected or if the pathogen is dormant or not. Once we have identified genes expressed exclusively in active zoospores or when the zoospores are being produced, we will be able to improve the systems we have developed by detecting RNA of active of zoospores and identifying the Pythium species from which the RNA was isolated, making it possible to predict accurately if a crop species is at risk or not. This would be a significant improvement of our diagnostics system being used commercially.

卵菌是一种类似真菌的生物，也被称为水霉菌。大多数物种能产生游动孢子，游动孢子上有两个不同的鞭毛附着在游动孢子的同一点上。霜霉科的大多数物种是引起植物疾病或生长在死亡有机物上的陆生物种，是本研究在卵菌纲中发现的两个目标亚类。两个主要的属是Pythium和Phytophthora。 如果有足够的自由水存在，这在大雨后的农业土壤中很常见，游动孢子可以通过感知化学物质或电荷的变化主动游向宿主的根部。如果根部受伤，这种定向运动特别明显。有趣的是，虽然腐霉属的几个物种，特别是疫霉属只能感染某些物种，但游动孢子在游向根系时似乎无法感知宿主是否合适。许多分子研究一直在处理游动孢子到达宿主后植物/病原体的相互作用，因为这是许多有趣的基因相互作用发生的地方，导致抗性或疾病结果。然而，很少有分子研究集中在游动孢子本身的努力。本实验室在腐霉属的分类学和分子生态学方面具有丰富的专业知识。我们希望找到参与鞭毛器，游动孢子的运动和行为的独特基因，并比较这些基因序列之间的腐霉物种。我们将关闭其中一些基因在腐霉aphanidermatum，看看他们对游动孢子的影响。我们已经开发了各种工具来检测环境中的腐霉物种，但它们无法区分被检测到的腐霉组织的种类或病原体是否处于休眠状态。一旦我们确定了只在活性游动孢子中表达的基因，或者当游动孢子产生时，我们将能够通过检测游动孢子活性的RNA并确定RNA分离的腐霉物种来改进我们开发的系统，从而可以准确预测作物物种是否处于风险之中。 这将是我们商业化使用的诊断系统的重大改进。