Identification and differentiation of Phytophthora by electrophoresis of mycelial proteins and isoenzymes1

Total proteins (both native and denatured) and three isoenzyme systems (esterases, malate dehydrogenases, superoxide dismutases) were analysed for eight Phytophthora species and for eight strains of P. nicotianae. The results obtained showed low intraspecific variability (62‐100% of similarity index) for P. nicotianae and allowed the characterization of P. capsici, cinnamomi, cryptogea, megakarya, megasperma, nicotianae, palmivora and citrophthora by the polyacrylamide gel electrophoretic profiles of native proteins and isoenzymes. The interspecific variability between these eight species is high (27‐49% of similarity index). The results obtained support the use of these macromolecular criteria as an aid to the identification of Phytophthora spp.