Isolates of Rhizoctonia solani (anastomosis groups AG1 and AG4) and binucleate isolates of other unidentified species, all pathogenic to Eucalyptus in Brazil, were characterized by protein and isozyme (ACP, 6-PGDH, LAP, SOD, MDH e IDH) analysis. Japanese strains of R. solani AG1 and other Brazilian isolates from others hosts were also included for comparison. Differences in protein patterns and isozyme phenotypes were observed between binucleate and multinucleate isolates, and among isolates of different anastomosis groups and subgroups. The protein patterns and isozyme phenotypes of Japanese isolates of R. solani AG1 differed from those of Brazilian isolates of the same anastomosis groups and the same morphological subgroups. Some Brazilian isolates morphologically similar to R. solani AG1-IB presented high similarity in protein patterns and isozyme phenotypes. This similarity was independent of the host plant and geographical origin. Polymorphisms in protein and isozyme patterns were also observed within the Brazilian R. solani AG4 group. We discuss the usefulness of protein and isozyme analyses for characterization of Rhizoctonia spp. isolates and for genetic and phylogenetic studies of fungi of this genus.
