Summary of Research

Polymerase Chain Reaction (PCR) primers were developed in the attempt to distinguish the important turfgrass pathogenic fungal species Rhizoctonia solani and Sclerotinia homoeocarpa on infected turfgrass samples in four hours. Previously, the pathogen would have to be isolated and cultured before an accurate diagnosis could be reached. This process typically took 2-3 days, thus allowing more time for the disease to spread.
R. solani and S. homoeocarpa are major pathogens of turfgrass, causing BROWN PATCH and DOLLAR SPOT, respectively. Primers were made to amplify the internal transcribed spacers (ITS), conserved regions of ribosomal DNA, from R. solani and S. homoeocarpa. The sequences of the ITS regions were aligned and species-specific PCR primers were designed in the rDNA regions conserved at the species level. Tests on the specificity of the designed primer for R. solani showed that the primer was specific only at the genus level. In 2 1/2 hours, an accurate diagnosis can be made from a fungal culture, but not from a turfgrass sample. Tests on the designed primer of S. homoeocarpa showed no specificity.