GIBBERELLA-FUJIKUROI - AVAILABLE POPULATIONS AND VARIABLE TRAITS

Gibberella fujikuroi is a complex species comprised of at least seven distinct mating populations (biological species) with Fusarium anamorphs. These fungi are common pathogens of maize, rice, and sorghum and cause billions of dollars of losses in these crops worldwide. Mating populations are biological species defined by cross-fertility of members of the same mating population with one another, and sterility whenever members of two different mating populations are crossed. Mating populations also differ in their electrophoretic karyotypes, their general ability to synthesize secondary metabolites, and their sensitivity to antifungal agents such as benomyl and hygromycin B. Within a mating population strains can be distinguished on the basis of their ability to form a heterokaryon with one another. This polygenic trait has been used to study the structure of some populations of these fungi. In some cases, pathogenic strains appear to be clones that are limited to a crop and (or) geographic location. More commonly, however, there is significant genetic variability present and sexual reproduction appears to be playing an important role in asserting that variability to different individuals.