Dimorphic growth and resting structure development in plant pathogenic verticillium species

植物致病黄萎病菌的二态性生长和休眠结构发育

• 批准号: 216879-2006
• 负责人: Dobinson, Katherine
• 金额: $ 1.27万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=330996
• 关键词: Dimorphic; growth; resting; structure; development

Verticillium dahliae, V. albo-atrum, and V. longisporum are soilborne fungi that cause vascular wilt disease in a variety of annual crops and perennials that are grown commercially in Canada and worldwide, including tomato, potato, oilseed rape, and other brassica crops.  The soil habitat of these pathogens, their inaccessibility during infection, and their ability to survive for many years in the soil, pose formidable challenges to disease control.  Few verticillium wilt-resistant cultivars are available, and chemical fumigants, which reduce levels of V. dahliae in the soil, are environmentally harmful, and destroy beneficial soil microorganisms.  Given the present and potential economic impact of the pathogen, new approaches to disease control must be considered.    One approach with much potential for disease control is to specifically target, and interfere with, the molecular processes which are critical for the growth of Verticillum in the plant, and/or its survival in the soil.  The proposed research program will focus on molecular and genetic studies of: 1) the development of the long-lived resting structures, microsclerotia or melanized mycelia, which are produced in dying plant tissues, and provide the primary source of disease inoculum, and 2) dimorphic growth (production of both yeast-like spores and mycelia), which occurs in liquid culture, and in the plant vascular system during infection.  Previous studies have shown that V. dahliae carries a gene that encodes a hydrophobin protein which is required for microsclerotia production.  The same gene has been identified in V. albo-atrum, which does not produce microsclerotia; the role of this gene in V. albo-atrum is therefore unknown.  A comparison of expression in V. albo-atrum and V. dahliae of these genes, and their respective proteins, will be carried out using reporter genes, mutational, and biochemical analysis.  In addition, DNA microarray analyses will be used to identify additional genes that are highly expressed during resting structure development and/or dimorphic growth.  Such genes will be candidates for further characterization.

大丽黄萎病、白化黄萎病和长孢黄萎病是土传真菌，可引起加拿大和世界各地商业种植的各种一年生作物和多年生植物的维管束枯萎病，包括番茄、马铃薯、油菜和其他芸苔属作物。  这些病原体的土壤栖息地、感染期间难以接近以及它们在土壤中存活多年的能力，给疾病控制带来了巨大的挑战。  很少有抗黄萎病的品种，而化学熏蒸剂会降低土壤中大丽黄萎病的水平，对环境有害，并会破坏有益的土壤微生物。  鉴于病原体当前和潜在的经济影响，必须考虑新的疾病控制方法。    一种具有很大潜力的疾病控制方法是专门针对和干扰对于植物中黄萎病的生长和/或其在土壤中的生存至关重要的分子过程。  拟议的研究计划将重点关注以下分子和遗传学研究：1）长寿命静止结构、微菌核或黑化菌丝体的发育，它们在垂死的植物组织中产生，并提供疾病接种物的主要来源；2）二态性生长（酵母样孢子和菌丝体的产生），发生在液体培养物和感染期间的植物维管系统中。  先前的研究表明，大丽弧菌携带一种编码疏水蛋白的基因，该蛋白是微菌核产生所必需的。  在 V. albo-atrum 中也发现了相同的基因，它不产生微菌核；因此，该基因在 V. albo-atrum 中的作用尚不清楚。  将使用报告基因、突变和生化分析来比较这些基因及其各自的蛋白质在 V. albo-atrum 和 V. dahliae 中的表达。  此外，DNA 微阵列分析将用于识别在静止结构发育和/或二态性生长过程中高度表达的其他基因。  这些基因将成为进一步表征的候选基因。