| Project Detail |
By vectoring plant pathogens, herbivorous insects are key determinants in the epidemiology of numerous plant blights. For a vector-borne phytopathogen, natural selection favors upgrading insect fitness to enhance transmission to an uninfected plant. It is currently unclear how a microbe balances this dual symbiotic lifestyle, featuring markedly different interaction outcomes: as a plant pathogen and an insect mutualist. Likewise, little is known about the molecular mechanisms underlying pathogen specificity, and the genomic basis and consequences of cross-kingdom host shifts along the parasitism-to-mutualism continuum. I will tackle these questions using an emergent model system: the interaction between the fungal pathogen Fusarium, the leaf beetle Chelymorpha alternans, and their shared host plant Ipomoea batatas. I recently described that C. alternans associates with a fusarial strain that coats the pupae of its host, protecting beetles against predators during metamorphosis. In exchange, the insect propagates its symbiont to its host plant, where it causes wilt disease. The unique biology and tractability of this study system affords unparalleled opportunities for experimentation. My approach will combine fieldwork and bioassays, with the latest developments in sequencing technologies, reverse genetics and metabolomics to characterize (1) the mechanistic features of symbiont-driven defense, (2) the genetic basis of infection in a cross-kingdom host-shift, (3) the genomic consequences of a dual symbiotic lifestyle, and (4) the breadth, origin as well as partner fidelity and chemical stability of a pathogen-vector interaction. Bridging the fields of chemical ecology, plant pathology and natural product research, this project will significantly further our understanding of the genetic-basis of cross-kingdom symbiotic interactions and the epidemiology of plant pathogens. |
