Genetic Diversity Among Iranian Isolates of Rhizoctonia solani Kühn Anastomosis Group1 Subgroups Based on Isozyme Analysis and Total Soluble Protein Pattern

Rhizoctonia solani is a destructive fungal pathogen with a wide host range. The R. solani complex species includes several divergent groups delimited by affinities for hyphal anastomosis. In this study, genetic variation among 20 isolates of R. solani anastomosis group 1 (AG1) subgroups (AG1-IA and AG1-IB) collected from Maˆ zandaran province, Iran, and standard isolates of these subgroups, was determined by isozyme analysis and total soluble protein profile. Mycelial protein pattern and isozyme analysis were studied using denaturing and non-denaturing polyacrylamide gel electrophoresis, respectively. A total of 15 enzyme systems were tested, among which six enzymes including esterase, alkaline phosphatase, superoxide dismutase, octanol dehydrogenase, lactate dehydrogenase and mannitol dehydrogenase generated distinct and reproducible results. The soluble protein patterns were similar among the R. solani isolates examined; however, minor differences in banding pattern were observed between the two subgroups. In isozyme analysis, a total of 64 electrophoretic phenotypes were detected for all six enzymes used. Based on cluster analysis and similarity matrix, the fungal isolates were divided into two genetically distinct groups of I and II consistent with the previously reported AG1-IA and AG1-IB subgroups in AG1. Group I represented all isolates belonging to AG1-IA subgroup, whereas group II represented all isolates belonging to AG1-IB subgroup. Results from isozyme analysis suggest that the subgrouping concept within AGs is genetically based.