Mating type distribution in Georgia turfgrass populations of Magnaporthe grisea
Tredway, L.P.; Stevenson, K.L.; Burpee, L.L.
Phytopathology 91(6 Suppl): S89
Magnaporthe grisea (anamorph Pyricularia grisea) causes gray leaf spot, a disease of increasing importance in the turfgrass industry. Mating type distribution in fungal populations determines the potential for genetic recombination to occur through sexual reproduction. The distribution of M. grisea mating types in Georgia turfgrass populations was determined using a previously developed PCR assay. Symptomatic leaves were collected from St. Augustinegrass and tall fescue turf in 1999 and 2000, and single-spore isolates were obtained for mating type analysis. Of 489 M. grisea isolates from tall fescue, 10 were Mat1-1 and 479 were Mat1-2. The distribution of mating types in tall fescue was not influenced by location or cultivar, although differences among years were observed. Of 485 isolates from St. Augustinegrass, 484 were Mat1-1, whereas one isolate was Mat1-2. This Mat1-2 isolate was obtained in 1999 from cv. Palmetto in central Georgia. Because opposite mating types are associated with both St. Augustinegrass and tall fescue, there is a potential for sexual reproduction in Georgia turfgrass populations of M. grisea.