RIBOSOMAL DNA ANALYSIS FOR RESOLUTION OF GENOTYPIC CLASSES OF PLEUROTUS

Pleurotus contains several species common to North America. Pleurotus is economically important worldwide, with many species commercially gr own. Despite its commercial importance, however, the systematics of th e genus is unclear. Previous phylogenetic analysis of the group has re lied on allozyme analysis, mating types and morphological characters. Genotypic classification of Pleurotus spp. has utilized allozyme analy sis. We present new methods of phylogenetic and genotypic classificati on based on RFLP analysis of PCR-amplified ribosomal DNA from 21 isola tes of Pleurotus spp. Our techniques resulted in greater resolution of P. ostreatus genotypes than with previous methods. The resulting phyl ogenetic tree suggests several putative species of Pleurotus may be sy nonymous with P. ostreatus. In addition, there may be more variation b etween geographically isolated populations within a species than betwe en different species of Pleurotus.