Leuschen-Kohl, Rebecca Lynn

NSF Awards · FY 2026 · 2026-08

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2025. The fellowship supports research and training of the fellow that will contribute to biology in innovative ways. Hybrids dominate commercial crop production because crosses between pure lines produce offspring with characteristcs that result in better yields. This phenomenon is called hybrid vigor or heterosis. Heterosis is influenced by various factors, including the microbes (microbiome) that associate with the root tissue, although the exact mechanisms remain unclear. The fellow will use maize pure lines and hybrids to investigate how immune responses to microbes differ between the plants. Immune responses are important for initial recognition of microbes and for plant defense. Learning more about how hybrid immunity plays a role in plant health will inform crop protection strategies and offer new methods for integrating microbiome science into sustainable agriculture. Additionally, this project includes hands-on training of undergraduate students in the interdisciplinary field of plant health, combining elements of microbiology, plant biology, and bioinformatics, to prepare them for future agricultural and biological sciences careers. Recent studies have highlighted the duality between maize heterosis and soil microbiome composition, where hybrid offspring not only show distinct microbial communities compared to their parents but also exhibit these superior traits dependent on live microbial presence. Hypotheses suggest that microbiota-dependent heterosis may involve inbred immunodeficiency or inbred immunity overreaction. Such hypotheses rely on mechanisms like microbe-triggered immunity (MTI), where pattern recognition receptors (PRRs) detect microbial signatures and initiate defense responses. This project examines the role of the maize microbiome's flagellin-derived signature (flg22) on gene expression and phenotypic outcomes. By comparing immune responses and PRR expression, this project aims to accomplish two goals: (1) identify key epitopes of flg22 within the maize microbiome, assessing their influence on root colonization, and (2) determine whether MTI activation and expression of FLS2 alleles contribute to the heterotic patterns of maize hybrids. The fellow will receive training in research methods of microbial ecology, metagenomics, scientific writing and undergraduate mentorship. They will also gain experience in applying evidence-based teaching practices through curriculum development, preparing them to both support and improve future science classrooms. 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.