DISSERTATION RESEARCH: A heritable symbiont shapes community structure of plant-associated organisms

植物上居住着大量的微生物，包括真菌和细菌。近年来，生物学家提出，这些微生物可能在塑造植物健康和生态方面发挥关键作用。到目前为止，大多数工作都依赖于不同植物物种之间微生物的比较研究；下一步是操纵植物微生物群落，以更好地了解它们是如何影响宿主植物的。在这项研究中，研究人员将操纵真菌和细菌在斑点草植物中的丰度和存在。斑点麻草是一种真菌的宿主，这种真菌可以合成一种强效的生物活性化合物，对牲畜有害。这种真菌是在种子中携带的，因此会传给下一代的野草。在美国西部，这些真菌和它们的麻草寄主之间的相互作用每年造成数百万美元的损失，但人们对这些真菌如何影响它们寄主的生长和繁殖能力知之甚少。此外，许多其他微生物栖息在杂草中，大多数具有未知的生态作用。研究人员将对野草中的微生物进行操作，以更好地了解这些重要植物中整个微生物群落的功能和重要性。因为微生物存在于所有的植物中，所以这个实验的结果将会影响到除草外的许多植物，包括农作物。研究人员将在科学过程中包括当地的高中生，将向科学界展示研究结果，并将结果向公众开放。该实验将验证内生微生物对植物定殖影响植物性状表达的假设。将对loloweed植株进行处理，去除可遗传的种子内生菌，并将与未经处理的植株一起安装在田间环境中。每个处理组的一个子集将用当地微生物类群的接种浆液进行处理。将分析处理组间植物性状的变异，包括生殖性状和防御性状。此外，每个处理组的节肢动物、真菌和细菌群落将被表征，并分析共发生模式，以了解植物微生物组成员如何相互影响和植物相关节肢动物。该研究将在植物微生物组的功能作用以及微生物之间的相互作用如何形成生态群落方面产生新的结果。

Plants are inhabited by an enormous number of microbes, including fungi and bacteria. In recent years, biologists have suggested that these microbes may play a critical role in shaping plant health and ecology. Most work so far has relied on comparative studies of microbes among different plant species; the next step forward is to manipulate plant microbial communities to better understand how they influence their host plants. In this study, researchers will manipulate the abundance and presence of fungi and bacteria in spotted locoweed plants. Spotted locoweed hosts a fungus that synthesizes a potent, bioactive compound that can harm livestock. This fungus is carried in seeds, and is thus passed down to the next generation of locoweeds. The interaction between these fungi and their locoweed hosts is responsible for millions of dollars in damages annually in the Western United States, yet little is known regarding how these fungi affect the ability of their hosts to grow and reproduce. In addition, many other microbes inhabit locoweeds, most with unknown ecological roles. Researchers will manipulate microbes in locoweeds to better understand the function and importance of the entire microbial communities in these important plants. Because microbes occur in all plants, results from this experiment will have implications that extend across many plants beyond locoweed, including agricultural crops. Researchers will include local high school students in the scientific process, will present findings to the scientific community, and will make results accessible to the general public.The experiment will test the hypothesis that colonization of plants by endophytic microbes influences plant trait expression. Locoweed plants will be treated to remove the heritable, seed-borne endophyte and will be installed in a field setting along with untreated plants. A subset of each treatment group will be treated with an inoculum slurry of local microbial taxa. Variation among treatment groups in plant traits, including reproductive and defensive traits, will be assayed. Additionally, arthropod, fungal, and bacterial communities of each treatment group will be characterized and co-occurrence patterns analyzed to understand how members of the plant microbiome influence one another and plant-associated arthropods. The study will generate novel results regarding the functional role of the plant microbiome and how interactions among microbes shape ecological communities.