Taxonomy of Penicillium chrysogenum and related xerophilic species, based on isozyme analysis

Eighty-four isolates of Penicillium chrysogenum and related species were examined by isozyme analysis. Four main groups could be defined by cluster analysis; P. chrysogenum var. chrysogenum, P. flavigenum sp. nov., P. chrysogenum var. dipodomyis and P. nalgiovense. P. flavigenum is described as new species, and P. chrysogenum var. dipodomyis raised to species level as P. dipodomyis. The genetic distance between these groups was calculated by employing a formula that accounts for the differences in alleles and loci obtained by isozyme analysis of these fungi. The genetic distances and cluster analysis suggest that the groups should be considered as four separate species. The practical implication of the separation and the ecological characteristics of the four species are discussed.