Biological Species in Pleurotus
RONALD H. PETERSEN, KAREN W. HUGHES, AND NADEZHDA PSURTSEVA
Enzymological Identification
The technique measures differences between enzyme complexes produced by various isolates. These isolates can come from the same taxon or different taxa, from the same general location or widely scattered. Most commonly investigated have been laccase and superoxide dismutase, the former being more popular. Differences between the various isozymes (i.e. different forms of the same enzyme) are measured by their size, envisioned through their mobility in an electrophoretic gel. The process can be sharpened somewhat by the subsequent application of isoelectric focusing (see Zervakis and Labarère, 1992).
Bresinsky et al (1977) showed that the isozymes of laccase could be used to distinguish between P. ostreatus and P. pulmonarius. Zervakis and Labarère (1992) submitted several putatively interspecific strains to isoelectric focussing in order to elucidate taxonomy within Pleurotus, but their acceptance of the names which accompanied the original strains led to confusing results (i.e. P. "sapidus" strains segregated in several directions; some strains were accepted as P. sajor-caju, see above).
Petersen (1995) reported on work done by Hughes using laccase electrophoresis within worldwide collections of P. pulmonarius. Regional similarities were detected, with the rainforest of western North America producing some unique combinations not seen elsewhere.