Discovery of attributes that distinguish pathogens from non pathogens and symbionts from pathogens or non-pathogens is the focus of contemporary research in plant pathology and an overall goal of our work. This endeavor overlaps with our study of fungal reproductive strategies, since both are fundamentally recognition issues. For pathogenic, symbiotic, or mutualistic associations, the issue is how cells of different organisms (e.g., a fungus and its plant host) communicate with each other to effect their partnership or cause disease; for reproduction, the question is how cells (or nuclei) of the same organism recognize self from non-self. Both forms of recognition allow one cell to form an intimate association, or to fuse with, another. Of practical importance, is the fact that fungi travel in the field by spore dissemination, thus, complete understanding of the spore developmental pathway provides an avenue for design of global solutions for preventing plant disease. We apply a wide range of classical genetic, molecular genetic, genomic, biochemical, and cytological tools and use three model fungi, Cochliobolus heterostrophus, a necrotrophic pathogen of corn, Setosphaeria turcica, a hemibiotrophic pathogen of corn, and Fusarium graminearum/Gibberella zeae, a necrotrophic pathogen of wheat, corn, barley and rice to address our questions.
Current projects focus on:
- Secondary metabolism/natural products:
- The role of metabolites produced by nonribosomal peptide synthetases or polyketide synthases in the life of the fungal cell and in both necrotrophic and hemibiotrophic interactions with plant hosts.
- Extracellular and intracellular siderophores; roles in iron homeostasis and fungal development (siderophores, sex, and virulence).
- Unraveling the evolutionary origin and genetic mechanism responsible for production of T-toxin, a host-selective polyketide toxin, required for high virulence of heterostrophus race T to corn.
- Oxidative stress, iron acquisition, and virulence in the Cochliobolus-maize and Setosphaeria-maize interactions.
- Mechanisms of sexual reproduction in self-incompatible and self-compatible ascomycetes.
- Role of extracellular DNases in virulence of fungi to hosts.