Turgeon DEB 9806935 Species of the ascomycete genus Cochliobolus and its allied genera have been chosen as the focus for this study for their array of reproductive strategies, their suitability for genetic and molecular technology, and the ability of certain species within the group to cause devastating diseases of important crops. Our goal is to understand the evolution of fungal reproductive strategies and, eventually, pathogenic capability. Results will be directly relevant to the assessment of fungal biodiversity, to the exploitation of fungi in bioprospecting programs, and to design of strategies for control of diseases caused by fungi. Fungi are favorable subjects for these studies because they are small, tractable in the laboratory, and have features which make them ideal for comparative studies of reproduction. Closely related fungi can be self sterile (requiring a partner for mating), self-fertile (no partner required), obligately sexual or obligately asexual. We will use DNA sequences for genes that regulate sexual development the mating type (MAT) genes to explore the evolution of reproductive strategies in sexual and asexual fungi. MAT genes hold great promise for tracing relationships among fungal groups because they have superior phylogenetic resolving power. We will determine: 1) If asexual fungi really are asexual or if the sexual state is just undiscovered, 2) if MAT genes can be used to delineate species, and 3) if MAT gene phylogenies, together with new information on sexuality and species boundaries, can be used to predict future changes in fungal pathogenicity, and possibly the evolution of new pathogenic races. In addition, phylogenetic information will guide identification of fungi producing metabolites with potential pharmaceutical application and ongoing investigations into the molecular mechanisms of fungal pathogenesis.
