Diaporthe: formalizing the species-group concept

Diaporthe species have a worldwide distribution and are associated with economically important hosts as pathogens, endophytes, and saprobes. Taxonomic identification of Diaporthe species is challenging due to overlapping morphological traits and host associations. Herein, we have assembled a comprehensive dataset and inferred a phylogenetic tree of Diaporthaceae using combined sequence data of ITS, ef1 alpha, beta-tubulin, cal and his3. Diaporthe is not monophyletic and segregates into several phylogenetically distinct clades. We introduce 13 species complexes of Diaporthe to aid the identification of species in the genus and to make communication easier. Nine species were treated as singletons apart from the major clades. Two taxa of Diaporthaceae, Ophiodiaporthe cyatheae and Chiangraiomyces bauhiniae, are synonymized under D. cyatheae (= O. cyatheae) and D. pseudobauhiniae (= C. bauhiniae), respectively based on phylogenetic analyses and morphological characters. The phylogenetic relationships of Diaporthaceae are reappraised, and suggestions are given for future work.