Morphological reexamination and molecular phylogeny of Phyllosticta originating to Japan

Abstract

Many species of Phyllosticta are known as the causal fungi of leaf spot diseases of various plants in the world. First, 224 species of genus Phyllosticta s.l. from Japan were reexamined on the basis of herbarium specimens and literatures. As a result, these were reclassified into 20 hitherto known species of Phyllosticta s.str., and 7 species were newly recorded to Japanese mycoflora. Moreover, 16 species should be described as new species of Phyllosticta, and also, 3 species were transferred to Phyllosticta s.str. from other related genera. Next, the phylogenetic relationships among the Japanese species of Phyllosticta s.str. and its teleomorph, Guignardia were analyzed using rDNA sequences. rDNA sequences extracted from fungal cultures obtained from various host plants were divided into two subgroups. The first group included the isolates having the wide host range and the isolates recognized as endophytes obtained from a symptom-less plant. The second group were composed from the isolates originated from various host plants; and besides, these formed the distinct clades refrected by those host genera. The isolates belonging to the first group generally grew faster on oatmeal agar. To classify the species of Phyllosticta s.str. it is necessary to consider an integrated approach such as the molecular phylogeny, host, colony growth, symptom, and morphological characteristics that has not been paid attention before.