Microbial Inheritance in Seed Saving Networks: An Investigation into the Drivers of Fusarium Abundance and Transmission in Multiple Varieties of Corn Seeds

Presenter: Catherine Jaffe

Faculty Mentor: Brendan Bohannan, Lucas Nebert

Presentation Type: Poster 70

Primary Research Area: Science

Major: Biology, Environmental Science

Funding Source: UROP Mini-grant, University of Oregon UROP, $700

Seedborne pathogenic fungi in the genus Fusarium are prevalent in corn populations and pose human health risks due to their production of carcinogenic mycotoxins. Although much is known about the effects of domestication on the genetics of corn populations, less is understood about the impacts of agricultural management on the inheritance of microbes like Fusarium that live in and around these plants. Our research aims to better understand how networks of seed saving and crop management affect the abundance and transmission of Fusarium in corn seeds. Using preliminary datasets from a Community Research Network of farmers established by University of Oregon PhD student Lucas Nebert, we investigate how efficiently Fusarium is transmitted through seed saving networks and whether certain varieties of corn are prone to higher abundances of seedborne Fusarium. Additionally, we examine which agricultural practices affect the transmission of Fusarium from parent to offspring. We also gather and analyze new data using an interdisciplinary mix of interviews with farmers, in-lab DNA analysis techniques, and multivariate statistical tests. Since Fusarium population dynamics are a product of both the microbial ecology within the seed and human agricultural practices, this interdisciplinary approach provides a clearer window onto how agricultural methods influence microbial inheritance in seeds. Although our results are preliminary, we expect to see Fusarium abundance vary according to corn species, as previous studies have shown that microbial communities tend to be more similar between closely related plant varieties. The results of our research may have wide reaching implications due to the ubiquity of Fusarium and their potential to impact methods of sustainable agriculture.

Bacterial and Fungal Community Composition Within Corn Seed

Presenter(s): Roxanne Fieldhouse − Biology

Faculty Mentor(s): Lucas Nebert, Brendan Bohannan

Poster 58

Research Area: Natural Science

Funding: UnderGrEBES Research Award

All plants contain within them an associated microbial community, functioning similar to the human gut community. These plant associated bacteria and fungi have recently come into focus as an important factor in fitness, helping to aid plants by increasing drought resistance, increasing limiting macronutrients available, and providing pathogen resistance. Importantly, many of these beneficial microbes can be inherited in the seed. Because some species can become pathogenic when the plant comes under stress, agricultural communities look to sterilize their seed of these complex communities. Little is known about the ecology of seedborne bacteria and fungi. The objective was to evaluate the microbial community of corn seeds, determine significant environmental factors, such as seed type, climate, and farm, affecting the microbial community composition. Additionally, we attempt to separate these environment-microbe interactions from the microbe-microbe interactions happening within the seed. We hoped to find microorganisms that negatively affect the presence of pathogenic microbes, specifically Fusarium, a genus of fungi that contains multiple species of corn pathogens. These fungi are relevant to human health because they produce a mycotoxin, fumonosin, which negatively impacts neurological development and liver function. Preliminary results have shown type of corn is a significant environmental factor in determining the composition of the microbial community and that significant microbe-microbe associations occur within a subset of the data. This research could allow future investigators to more clearly understand how host microbe interactions operate and reinforces the importance of

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a diverse microbiota.