Bacterial Endosymbionts of Endophytic Fungi: Diversity, Coevolution, and Ecological Roles.

内生真菌的细菌内共生体：多样性、共同进化和生态作用。

• 批准号: 0626520
• 负责人: Anne Arnold
• 金额: $ 2.99万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0626520&HistoricalAwards=false
• 关键词: Bacterial; Endosymbionts; Endophytic; Fungi; Diversity

Fungal endophytes and fungi that live within healthy plant tissues without causing disease are known from all major lineages of land plants. These diverse but little-known symbionts are united by the absence of disease symptoms on their hosts during a significant phase of the infection cycle, and in many cases have beneficial effects on the plants they inhabit (e.g., pest deterrence). Recent work has shown that many plant-associated fungi are inhabited by bacterial endosymbionts, which can influence pathogenicity of those fungi. Endophytes are closely related to plant pathogens, but the evolutionary, ecological, or genetic factors that may predispose them to pathogenicity or avirulence are unknown. In preliminary studies, bacterial endosymbionts were shown to be present in apparently pure cultures of endophytic fungi, but the diversity, taxon composition, and ecological roles of these bacteria have never been explored. The proposed work will take advantage of a unique library of over 8000 living endophyte cultures to (1) determine the frequency with which bacterial endosymbionts occur among endophytic fungi; (2) compare the diversity, geographic distribution, and host specificity of endosymbiotic bacteria with those of endophytic fungi; and (3) experimentally assess the ecological roles of bacterial endosymbionts in endophytic and related plant-pathogenic fungi. This project will shed light on the ways in which bacteria mediate virulence in fungi, providing an important tool in the study of fungal-plant interactions. The intellectual merit of this study lies in disentangling a newly discovered level of complexity in plant-microbe symbioses, and in capturing the diversity of endosymbionts that themselves live within a hyperdivese guild of symbiotic microbes. This project will contribute to the training of one to three undergraduates and one graduate student, with a special focus on training individuals from groups that are traditionally under-represented in the sciences.

真菌内生菌和真菌生活在健康的植物组织中而不引起疾病，这在陆地植物的所有主要谱系中都是已知的。这些多样但鲜为人知的共生体在感染周期的一个重要阶段对其宿主没有疾病症状，并且在许多情况下对它们所栖息的植物有有益的影响（例如，害虫威慑）。最近的研究表明，许多与植物相关的真菌都有细菌内共生体居住，这可以影响这些真菌的致病性。内生菌与植物病原体密切相关，但进化、生态或遗传因素可能使它们倾向于致病性或无毒性尚不清楚。在初步研究中，细菌内共生体被证明存在于内生真菌的纯培养物中，但这些细菌的多样性、分类群组成和生态作用从未被探索过。拟议的工作将利用超过8000个活内生菌培养物的独特文库来(1)确定内生真菌中细菌内共生体发生的频率；(2)比较内生细菌和内生真菌的多样性、地理分布和宿主特异性；(3)实验评估细菌内共生体在内生真菌和相关植物病原真菌中的生态作用。该项目将揭示细菌介导真菌毒力的途径，为研究真菌与植物的相互作用提供重要工具。这项研究的智力价值在于解开了植物-微生物共生中新发现的复杂性水平，并捕获了生活在共生微生物超多样性协会中的内共生体的多样性。该项目将有助于培训一至三名本科生和一名研究生，特别侧重于培训来自传统上在科学领域代表性不足的群体的个人。