Jeffrey A. Rollins, and
Philip F. Harmon
Department of Plant Pathology, 1453 Fifield Hall, University of Florida, Gainesville 32611.
Go to article:
Accepted for publication 1 January 2012.
Morphology, vegetative compatibility groups, and molecular characteristics were compared among 47 isolates of the dollar spot pathogen Sclerotinia homoeocarpa. Isolates were collected from cool- and warm-season turfgrasses in Florida and the northern United States. Mycelial pigment accumulation, substratal stromata formation, and symptom development were used to separate the collection into two distinct morphological types: a common-type (C-type) and a Floridian-type (F-type). Phylogenetic relationships estimated from ITS sequences supported the morphological typing. Identification and characterization of the S. homoeocarpa mating-type locus revealed an idiomorphic organization for both C- and F-types with nearly equal frequencies of each mating types present in both groups. These findings suggest heterothallic control of mating and indicate potential for outcrossing in both groups. Dollar spot disease of turfgrass in Florida is caused by two distinct morphological types of S. homoeocarpa which may be cryptic species. These findings could have implications for disease management.
Additional keywords:heterothallism, host specificity, resting structures, sexual reproduction, stroma, turfgrass, vegetative incompatibility.
© 2012 The American Phytopathological Society