NSF Postdoctoral Fellowship in Biology: Genomic and Metagenomic Mechanisms of flood Tolerance in Maize and Tripsacum dactyloides

Swift, Joel F, Eudora KS

Investigators

Abstract

This action funds an NSF Plant Genome Postdoctoral Research Fellowship in Biology for FY 2023. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Joel F. Swift is "Genomic and metagenomic mechanisms of flood tolerance in maize and Tripsacum dactyloides" The host institution for the fellowship is the University of Kansas and the sponsoring scientist is Dr. Maggie R. Wagner. As the global climate changes, flood events are becoming more frequent and severe. While water is a basic requirement for plants, too much can have dramatic consequences. When flooded, fundamental root functions like gas diffusion decline dramatically. This leads to oxygen starvation, the buildup of ethylene (a key stress hormone), and eventually plant death. Many plant species cope by producing root aerenchyma, a spongy tissue that assists in gas diffusion. Some species continuously form aerenchyma, while other species only form aerenchyma under stress. Ethylene acts as the stimulus for both modes, but the mechanisms of formation differ. Root-associated microorganisms can break down ethylene precursors, which modifies ethylene levels, and potentially contributes to plant flood stress adaptation. This research will explore the links between plant genetics, root physiology, and the microbiome to understand their effects on plant flood responses. This will provide key information to assist in breeding flood-resilient crops. The researcher will develop expertise in quantitative genetics, plant physiology, and anatomical analysis. As a community college graduate, Joel will engage and mentor students from the host institution and local community colleges; seeking to further promote diversity in STEM and instill an interest in plant science careers, from the basic to applied biological perspectives. Zea mays (corn or maize) is a globally important crop that is cultivated widely across temperate North America. Corn’s closest temperate relative is Tripsacum dactyloides (gamagrass). Corn (stress-induced) and gamagrass (constitutive) represent the spectrum of aerenchyma production strategies. This project will utilize these species as a comparative system for examining the effects of intra- and inter-specific root trait variation on the microbiome under flood stress. Several corn genotypes will be used to establish a temporal baseline for flood responses. Corn gene expression, elemental composition, and root microbiome composition will be measured before, during, and after recovery from waterlogging and submergence. Root phenotypic variation will be quantified across a gamagrass diversity panel. Root gene expression of accessions with contrasting performance under waterlogging will be compared, with a focus on the differential transcriptional regulation of ethylene biosynthesis. Conditioned soils from waterlogging experiments will be collected and reinoculated onto new seedlings to test whether root-driven changes in the soil microbiota affect corn and gamagrass phenotypes and fitness in a contemporary flood. Results will be disseminated via conference presentations, publication in open-access journals, and by depositing sequence data and code into public repositories including the NCBI Short Read Archive, GitHub, and Zenodo. 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.