CAREER: Mechanisms of Hidden Microbes: Secretion System Usage by Endofungal Bacteria

Fungi pose challenges and opportunities in both the field and hospital, where they can cause devastating diseases, create useful compounds, and promote the well-being of other organisms. The roles of fungi as pathogens, beneficial species, and nutrient cyclers within ecosystems are dramatically affected by their relationship with other microbes present in the same place. Bacteria can even directly inhabit fungi, living internally within their cells and communicating with them through unknown molecules. This project seeks to understand how endofungal bacteria communicate with and control the fungi that they inhabit. The long-term goal of this research is to inform new biotechnology applications to control fungi causing disease and promote fungi providing benefits. Complementary educational goals will integrate undergraduate students in course-based and laboratory-based research experiences early in their college journeys, to improve their training as new scientists. Additionally, visitors to the campus botanical gardens will learn through short courses, informational booths, and new signage about the role of microbes in nature and biotechnology. Though bacteria and fungi interact everywhere from soils to hosts, a lack of understanding how bacterial secretion systems facilitate cross-kingdom microbial interactions with fungi represents a barrier to our ability to predict and alter emergent properties of microbial communities. To gain a framework-level perspective, this project will interrogate bacterial-fungal interactions for two tractable organisms that occupy the endofungal niche but that exhibit vastly different relationship specificity and interaction mechanisms with their hosts. In aim 1, the focus will be on the effector protein repertoire of fungal-targeting Type III secretion systems, with a goal of molecular characterization of proteins transported by syringe-like secretion systems in Mycetohabitans spp. and other Burkholderia-related endobacteria that are highly coevolved with their host fungi and divergent from free-living species. The second aim is to discover the function of the harpoon-like, Type VI secretion system in Luteibacter mycovicinus, a newly described species that genetically resembles free-living relatives and can transiently colonize different fungi. This project will combine in silico prediction, transcriptomic sequencing, mutagenesis strategies, phenotyping assays, and reporter technologies to answer the central question at both cellular and organismal levels. 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: 2541782 | Program: 01003031DB NSF RESEARCH & RELATED ACTIVIT,01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Morgan Carter | Institution: University of North Carolina at Charlotte, CHARLOTTE, NC | Award Amount: $1,004,780 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2541782 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2541782.html