DISSERTATION RESEARCH: Interactions between microbial mutualists and coninfecting pathogens

植物和动物经常与生活在它们上面和里面的微生物（微生物）接触。 这项研究将是确定有益细菌的存在如何改变病毒之间竞争的重要第一步，以及病毒感染是否会减少有益细菌对其宿主植物的益处。这项工作通过提供与农作物生产有关的数据直接使公众受益，并通过科学教育和宣传间接使公众受益。 豆类和其他豆类是全球重要的、高度可持续的膳食蛋白质来源。 更好地了解普通豆类中的微生物相互作用可以用来为改变疾病流行和提高作物产量的策略提供信息。 对这些知识的追求也将为本科生提供各种实践研究经验。最后，研究结果将通过向社区介绍和为6-12年级学生开发实践学习经验和微型课程向公众广泛传播。研究人员将研究宿主植物中额外的互利微生物物种的存在如何改变病毒竞争的结果和共同感染中的疾病严重程度，以及2）病原体的感染是否会减少宿主从互利微生物中获得的益处。将使用感染普通菜豆的病毒系统来研究占据同一宿主的多种病原体之间的生态和进化相互作用。互利主义者有可能通过影响宿主的生长和防御资源来改变共感染病原体之间的竞争结果。与此同时，病原体可以诱导宿主的全面免疫反应，这可能对微生物互利共生者造成损害。如果病原体感染减少了宿主从互利共生者那里获得的利益，这可能会破坏这种关联。普通豆类感染病原病毒和互惠固氮细菌（根瘤菌）提供了一个高度听话的系统，研究共感染病原体和互惠之间的相互作用。病原体竞争能力的两个措施，在主机的浓度和主机之间的传输，将在植物与无根瘤菌进行比较，以评估是否存在一个互利是不同的有益于一个病原体物种。通过测量植物免疫反应激素以及根瘤菌的根定殖和固氮作用来量化病原体感染对互利共生的可行性的影响。

Plants and animals are constantly in contact with microbes (microscopic organisms) that live on and inside them. This research will be an important first step in determining how competition between viruses is altered by the presence of beneficial bacteria and whether infection by viruses can reduce benefits from beneficial bacteria to their host plant, the common bean (Phaseolus vulgaris). This work benefits the public both directly by providing data that is relevant to agricultural crop production and indirectly through scientific education and outreach. Beans and other legumes are important, highly sustainable sources of dietary protein worldwide. A better understanding of microbial interactions in common beans can be used to inform strategies that could alter disease prevalence and increase crop yields. The pursuit of this knowledge will also provide a variety of hands-on research experiences for undergraduate students. Finally, the results of the research will be widely disseminated to the public through presentations to the community and the development of hands-on learning experiences and mini-courses for 6-12 grade students. The researchers will examine how the presence of additional mutualist microbial species in a host plant changes the outcome of virus competition and disease severity in coinfections and 2) whether infection by pathogens reduces the benefit that the host receives from mutualists. The ecological and evolutionary interactions between multiple pathogens which occupy the same host will be studied, using a system of viruses infecting the common bean. Mutualists have the potential to alter competitive outcomes between coinfecting pathogens by influencing host resources for growth and defense. At the same time, pathogens can induce a full immune response by the host that can be damaging to microbial mutualists. If pathogen infection reduces the benefit that the host receives from mutualists, this might destabilize the association. Common beans infected with pathogenic viruses and mutualistic nitrogen-fixing bacteria (rhizobia) offer a highly tractable system for studying the interactions between coinfecting pathogens and mutualists. Two measures of pathogen competitive ability, within host concentration and transmission between hosts, will be compared in plants with and without rhizobia to evaluate whether the presence of a mutualist is differentially beneficial to one pathogen species. The impact of pathogen infection on the viability of the mutualism will be quantified by measuring plant immune response hormones as well as rhizobial root colonization and nitrogen fixation.