Electrophoretic study of three related Phytophthora species

Morphological and cultural characters currently used for the classification of species of Phytophthora are inadequate to distinguish P. cryptogea, P. drechsleri and P. erythroseptica. In this study isolates of the above-mentioned species, including type and/or authentic cultures of P. cryptogea and P. drechsleri were compared. Morphological and cultural characters, together with electrophoretic patterns of both total mycelial proteins and isozymes (arylesterase and malate dehydrogenase), allowed the distinction of P. erythroseptica from the others. Authentic cultures of P. cryptogea and P. drechsleri showed distinctly different electrophoretic patterns of arylesterase and malate dehydrogenase isozymes and of total mycelial proteins. Some Italian isolates previously identified as P. cryptogea or P. drechsleri showed features of both species, therefore it was impossible to discriminate the two species solely on the basis of the electrophoretic patterns of mycelial proteins.