Characterization of ectotrophic root-infecting fungi isolated from ultradwarf bermudagrass (Cynodon dactylon × C. transvaalensis) root materials
P. L. VINES (1), M. Tomaso-Peterson (1), T. Allen (1), B. Stewart (1), F. Meyer (1), J. Dubien (1). (1) Mississippi State University, Mississippi State, MS, U.S.A.
The growth and quality of bermudagrass putting greens decline during the summer and early fall months in the Deep South. Root systems appear blackened, rotted, or stunted and are frequently colonized with dark, runner hyphae that are characteristic of ectotrophic root-infecting (ERI) fungi. The focus of this study was to characterize ERI fungi isolated from ultradwarf bermudagrass roots. Colonized roots were cut into 1-cm sections, surface disinfested with a 0.6% NaOCl solution, rinsed three consecutive times with sterile-distilled water, plated on modified potato dextrose agar (PDA), and incubated for 7 days at room temperature under 24 hour fluorescent light. Hyphal tips were transferred to PDA. Genomic DNA was extracted from sterile, pure cultures of isolated fungi. The internal transcribed spacer (ITS) regions of rDNA were amplified by PCR using ITS1 and ITS4 primers and compared to known ITS sequences retrieved from the GenBank via BLAST. Evolutionary analyses of rDNA-ITS regions suggest that MSU isolates belong to six distinct, well-supported clades. Temperature controlled colony growth studies and pathogenicity tests were conducted on representative samples from each of the six clades.
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