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

Board Of Regents, Nshe, Obo University Of Nevada, Reno, Reno NV

Investigators

Abstract

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.