CAREER: Integrating the Next Generation into Investigating Cross-kingdom Interactions between Mycorrhizal Fungi and Hyphosphere Bacteria

This project will advance understanding of how beneficial soil fungi and bacteria interact to improve plant nutrition and support sustainable agriculture. Arbuscular mycorrhizal fungi form symbiotic partnerships with most land plants, helping roots acquire nutrients, while bacteria associated with fungal hyphae can influence fungal growth, colonization, and nutrient exchange. However, the mechanisms governing these cross-kingdom interactions remain poorly understood. This work will address a fundamental question in soil ecology and plant biology: how mycorrhizal fungi recruit helpful bacteria and how those bacteria, in turn, enhance fungal symbiosis with plant roots. By uncovering the rules that shape these partnerships, the project will contribute to basic knowledge of microbial ecology and may inform future strategies and biotechnology priorities to reduce fertilizer dependence, improve crop productivity, and support environmentally sustainable agriculture. The project will also provide interdisciplinary training for students in microbiology, plant science, and molecular biology, strengthening workforce development in agricultural research. The project will use maize, the arbuscular mycorrhizal fungus Rhizophagus irregularis, and the bacterium Azotobacter vinelandii as a model system to test how fungal hyphal exudates influence bacterial persistence and how bacterial partners affect mycorrhization. Using compartmented growth chambers that separate plant roots from fungal hyphae, the project will analyze fungal exudates by metabolomics, measure gene expression changes in plant roots, fungi, and bacteria by transcriptomics, and quantify fungal colonization and bacterial population dynamics across varying nitrogen and phosphorus conditions. The project will also test whether bacterial strains differ in their ability to promote fungal growth and whether these effects depend on bacterial nitrogen metabolism or other helper functions. Together, these experiments will identify metabolites, genes, and ecological conditions that regulate mutualistic interactions between fungi and bacteria. The results are expected to reveal how microbial partnerships are established and maintained in soil and how they can be harnessed to improve nutrient acquisition and plant health. 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. NSF Award ID: 2542340 | Program: 01003031DB NSF RESEARCH & RELATED ACTIVIT,01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Devanshi Khokhani | Institution: University of Minnesota-Twin Cities, MINNEAPOLIS, MN | Award Amount: $822,505 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2542340 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2542340.html