MCA: Diversity of mycoviruses in fungal endophytes and their cryptic roles in plant health

微生物无处不在，几乎与所有活着的有机体都有联系。微生物与宿主的联系或相互作用可能是有益的，也可能是有害的，也可能是直接或间接的。然而，考虑到地球上有数万亿的微生物，其中大部分的多样性及其相互作用是未知的。病毒是一个研究很少的群体。这个项目的目标是开始发现寄生在真菌中的病毒的多样性(又名。生活在植物体内的真菌)，真菌病毒对这些真菌的影响，以及对植物寄主的间接相互作用和后果。这项研究的一个假说是，分枝病毒充当了一件“隐形斗篷”，因此真菌可以穿透植物而不激活植物的防御系统。该项目将专注于咖啡树上的有益真菌和致病真菌。虽然一些分支病毒可能使真菌在植物寄主上更具致病性，但另一些可能使它们的致病性较低，因此在改造这些真菌以造福于作物方面具有潜在的应用。例如，将低毒力的分支杆菌病毒接种到植物病原真菌中使其成为非致病真菌，或者另一方面，接种有益真菌使其能够在整个植物上定居，并对疾病或气候(例如干旱或高温)的影响提供广泛的固有保护。该项目还将有助于鲍伊州立大学的研究议程的发展和对马里兰第一所历史上的黑人学院/大学(HBCU)的学生的培训。该项目将研究真菌病毒的多样性及其对内生真菌、植物宿主以及由此产生的三方共生(病毒-真菌-植物)的影响。该项目的具体目标是评估从野生茜草科(咖啡科)中挑选的真菌内生真菌的多样性；确定植物、寄主真菌和真菌之间是否存在系统发育和真菌病毒感染关系；以及在体外和植物中比较感染和不感染真菌病毒的内生真菌的影响。这些目标将通过收集和鉴定与哥斯达黎加野生茜草科植物有关的真菌，使用传统和后基因组/后转录方法对它们进行筛选，从真菌中根除真菌病毒，并评估根除真菌病毒对真菌表型(即真菌体外生长速度、体外拮抗能力和感染内生真菌的植物能力)的影响来实现。这一项目的结果将使分枝杆菌病毒成为控制植物病原真菌的另一个潜在类群。例如，如果分枝病毒不是宿主特有的，那么就有可能用低毒力的分枝病毒感染植物病原体或互助体。除了分枝杆菌病毒，从后基因组和后转录数据中，我们可以从内菌丝细菌和噬菌体获得数据，这些数据在发现新的CRISPR-CAS系统方面很有吸引力。这一奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Microbes are ubiquitous and associated with almost all living organisms. The associations or interactions microbes have with their hosts may range from beneficial to detrimental, and may be direct or indirect. However, considering that there are trillions of microorganisms on Earth, much of that diversity and their interactions are unknown. A poorly studied group are viruses. The objective of this project is to begin to discover the diversity of viruses that inhabit fungi (a.k.a. mycoviruses) that live inside plants, the effects of mycoviruses on those fungi, and the indirect interactions and consequences on the plant hosts. One hypothesis of this study is that mycoviruses serve as an “invisibility cloak”, so that fungus can penetrate the plant without activating the plant defenses. The project will focus on beneficial and pathogenic fungi that inhabit coffee plants. While some mycoviruses may make a fungus more pathogenic on its plant host, others may make them less pathogenic (=hypovirulent mycoviruses), thus having potential applications in the engineering of those fungi to benefit crops. For example, inoculating hypovirulent mycoviruses into a plant pathogenic fungus to make it non-pathogenic, or, on the other hand, inoculating a beneficial fungus so that it can colonize an whole plant and provide a broad and innate protection against diseases or the effects of climate (e.g., drought or high temperatures). The project will also contribute to the growth of Bowie State University’s research agenda and the training of students at the first historically black college/university (HBCU) in Maryland.The project will study the diversity of mycoviruses (viruses of fungi) and their effects on endophytic fungi, the plant hosts, and consequently, the tripartite symbiosis (virus-fungus-plant). The specific objectives of the project are to assess the diversity of mycoviruses in a selected collection of fungal endophytes from wild Rubiaceae (the coffee family); determine if there is a phylogenetic and mycovirus-incidence relationship between the plant, host fungus, and the mycovirus; and compare, in vitro and in planta, the effects of mycovirus-infected and mycovirus-free endophytic fungi. The objectives will be accomplished by collecting and identifying the fungi associated to wild Rubiaceae plants in Costa Rica, screening them for mycoviruses using traditional and metagenomic/metatranscriptomic approaches, eradicating the mycoviruses from the fungi, and assessing the effects of mycovirus eradication on the phenotype of the fungus (i.e., fungal growth rate in vitro, antagonistic ability in vitro, and in planta capacity to infect and become endophytic). Results from this project will add mycoviruses as another potential group to control plant pathogenic fungi. For example, if mycoviruses are not host-specific, it may be possible to infect plant pathogens or mutualists with hypovirulent mycoviruses. In addition to mycoviruses, from the metagenomic and metranscriptomic data, we may obtain data from endohyphal bacteria and phages, which are attractive in the discovery of new CRISPR-Cas systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.