The use of beneficial microbes that are capable of killing insects represents a more environmentally friendly and sustainable alternative to chemical pesticides. One such microbe is the insect pathogenic fungus Beauveria bassiana that has been commercialized for pest control applications. In addition to their ability to target insects, B. bassiana is also able to form mutualistic associations with plants, resulting in increased plant growth and resistance to insects. This project seeks to understand the biological (genetic and biochemical) basis for the interactions between B. bassiana, insects, and plants. Understanding this process has important implications in beneficial versus pathogenic outcomes, environmental microbiology, and ecosystem balance. Knowledge gained from the proposal can be used to improve the efficacy and safety of using microbes for pest control and plant growth promotion. These interactions present an excellent model system for student laboratory activities relating to fundamental principles of host-parasite biology and evolution, fungal and insect physiology, symbiosis and mutualism, and application of the scientific method. The program provides resources, curriculum development, and citizen science outreach in mycology and entomology for use in K-12 classrooms and beyond. Training at the high school, undergraduate, graduate, and post-doctoral levels are integrated within the scientific and outreach goals of the project.
Filamentous fungi are a major evolutionary branch of the eukaryotes. Several basal fungal lineages are parasites of invertebrates, and fungal-arthropod interactions represent ancient paradigms for examining pathogenesis. The filamentous fungus Beauveria bassiana is a pathogen of arthropods and forms endophytic relationships with plants. These two seemingly disparate interactions provide a tractable system with which to test and challenge some basic concepts regarding the evolution and persistence of mutualism and parasitism. Our central hypothesis is that in B. bassiana, mutualism and parasitism share underlying molecular determinants. To test this, our research aims to (a) perform a comparative molecular and biochemical analysis between the pathogenic insect interaction and the mutualistic plant interaction, emphasizing the transcriptional and regulatory networks involved, and (b) uncover additional molecular determinants of B. bassiana insect virulence and plant mutualism and examine their respective cross-contributions. This work would provide insight into the factors that contribute to trade-offs that occur during the establishment and/or maintenance of pathogenic versus mutualistic outcomes during organismal interactions. These interactions can be exploited to develop novel means of increasing the pest control and/or plant growth promotion potential of the fungus. Specific knowledge gained from the proposal aid understanding of two broad areas that address how organisms maintain phenotypic plasticity and sensitivity to dramatically different environments: (a) host-pathogen interactions and host-specificity, i.e. the pathways involved in insect virulence, and (b) mutualistic interactions, characterizing the pathways leading to endophyte establishment by the fungus.
