Speciation in Pyricularia inferred from multilocus phylogenetic analysis.

Pyricularia isolates from various host plants were subjected to a multilocus phylogenetic analysis based on rDNA-ITS, actin, beta-tubulin, and calmodulin loci. A combined gene tree resolved seven groups with 100% BS support, suggesting that they are monophyletic groups supported concordantly by all four loci. By incorporating biological and morphological species criteria, each of the seven groups was considered to be a current species. However, phylogenetic relationships among these species were unresolved in the single-gene trees and in the combined tree. Furthermore, the transition from concordance to conflict occurred more than once in the combined gene tree. They were interpreted by assuming that Pyricularia has evolved through repeated species radiation. The transition point other than the current species limit was considered to be the limit of the former species.