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

微生物无处不在，几乎与所有生物体有关。微生物与其宿主的关联或相互作用可以是有益的，也可以是有害的，可以是直接的或间接的。然而，考虑到地球上有数万亿种微生物，其中大部分多样性及其相互作用都是未知的。研究较少的一类是病毒。该项目的目标是开始发现栖息在真菌中的病毒的多样性（即真菌病毒），真菌病毒对这些真菌的影响，以及对植物宿主的间接相互作用和后果。这项研究的一个假设是，真菌病毒作为一个“隐形斗篷”，使真菌可以穿透植物，而不会激活植物的防御。该项目将侧重于栖息在咖啡植物中的有益真菌和致病真菌。虽然一些真菌病毒可能使真菌对其植物宿主更具致病性，但其他真菌病毒可能使其致病性较低（=弱毒力真菌病毒），因此在这些真菌的工程改造中具有潜在的应用，以造福作物。例如，将弱毒力真菌病毒导入植物病原性真菌中以使其成为非病原性的，或者另一方面，将其转化为有益真菌，使得其可以定殖于整个植物并提供针对疾病或气候影响的广泛和先天的保护（例如，干旱或高温）。该项目还将有助于鲍伊州立大学的研究议程的增长和学生在马里兰州的第一个历史上的黑人学院/大学（HBCU）的培训。该项目将研究真菌病毒（真菌病毒）的多样性及其对植物宿主内生真菌的影响，从而研究三方共生（病毒-真菌-植物）。该项目的具体目标是评估真菌病毒的多样性，在一个选定的收集真菌内生菌从野生茜草科（咖啡家族）;确定是否有一个系统发育和真菌病毒的发病率之间的关系，植物，宿主真菌，和真菌病毒;并比较，在体外和在planta，真菌病毒感染和真菌病毒免费内生真菌的影响。通过收集和鉴定与哥斯达黎加野生茜草科植物相关的真菌，使用传统和宏基因组/宏转录组方法筛选真菌病毒，从真菌中根除真菌病毒，并评估真菌病毒根除对真菌表型的影响（即，体外真菌生长速率，体外拮抗能力，和在植物中感染和成为内生菌的能力）。该项目的结果将增加真菌病毒作为另一个潜在的控制植物病原真菌的群体。例如，如果真菌病毒不是宿主特异性的，则可能用弱毒力真菌病毒感染植物病原体或共生体。除了真菌病毒外，从宏基因组和元转录组数据中，我们还可以获得内生细菌和真菌的数据，这对发现新的CRISPR-Cas系统很有吸引力。该奖项反映了NSF的法定使命，并通过使用基金会的知识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.