ISOZYME VARIATION AND GENETIC RELATEDNESS AMONG NATURAL-POPULATIONS OF PLEUROTUS-OSTREATUS

The genetic relatedness among thirty-three natural isolates of an edib le mushroom, Pleurotus ostreatus, collected from Japan, Europe, U.S.A. and Korea was characterized by isoelectric focusing on polyacrylamide gels. The activities of acid phosphatase, alcohol dehydrogenase, este rase, laccase and malate dehydrogenase displayed 19, 9, 32, 11 and 10 distinct isozyme patterns, respectively. By combining the isozyme patt erns obtained with the five enzymes, every isolate showed its own dist inct electrophoretic phenotype. A distance matrix calculated between a ll pairs of the 33 electrophoretic phenotypes based on the presence or absence of isozyme bands was analyzed by the group-average method. Re sults of the cluster analysis assigned the 33 phenotypes into four maj or groups, each of which coincided with geographically distinct popula tions. These results suggest that geographical distance between natura l populations of P. ostreatus is correlated with the genetic divergenc e.