Gaeumannomyces graminis, a soil-borne, filamentous fungus, causes crown and root disease of wheat, barley and rice and for several reasons this plant-pathogen interaction provides an excellent model for fungal adhesion to host tissue. First, the fungus, in response to plastic as well as plant surfaces, produces specialized attachment cells (hyphopodia), which can be at least partially purified. Second, G. graminis is not an obligate parasite and can be easily cultured. Third, the fungus can be manipulated by both classical and molecular genetic techniques. One of our goals is to determine if hyphopodia are important for fungal pathogenicity as suggested by preliminary work. Gene disruption with transforming plasmid DNA will be used to generate more hyp strains which lack the ability to produce hyphopodia. After they are genetically analyzed, mutants will be characterized as to their colonizing and pathogenic potential.
