Taxonomic relationships within the fungal genus Pleurotus as determined by isoelectric focusing analysis of enzyme patterns

Summary: Isoenzymes from 23 isolates belonging to the fungal genus Pleurotus, subdivision Basidiomycotina, were examined by polyacrylamide gel isoelectric focusing and protein blotting. A numerical analysis was then done based on the zymograms for acid phosphatase, diaphorase, esterases, leucine aminopeptidase, phosphoglucomutase and phenoloxidases. The resulting dendrogram of taxonomic distances demonstrated the suitability of enzyme isoelectric focusing for use in systematics, as it clearly distinguished the four well-defined species P. cornucopiae, P. cystidiosus, P. eryngii and P. flabellatus. The species P. ostreatus, whose taxonomy is controversial, was separated from P. pulmonarius, and P. columbinus was classified as a distinct taxon. The delimitation of P. sajor-caju and P. sapidus strains appeared to be more difficult as they seemed to be closely related, the former with P. pulmonarius and the latter with P. ostreatus. Isoenzymes also proved to be valuable for Pleurotus strain characterization. Their potential application for providing biochemical markers useful in taxonomy is discussed.