Molecular phylogeny of Magnaporthaceae (Sordariomycetes) with a new species Ophioceras chiangdaoense from Dracaena loureiroi in Thailand

Abstract

The phylogenetic relationship of the family Magnaporthaceae and allied genera were investigated using individual and combined analyses of 18S and 28S nuclear ribosomal DNA (rDNA) gene fragments. New DNA sequences representing six genera from Magnaporthaceae were analyzed phylogenetically based on Bayesian, likelihood and parsimony methods. Magnaporthaceae, encompassing genera such as Buergenerula, Gaeumannomyces, Magnaporthe, Ophioceras, Pseudohalonectria and anamorphic species including Mycoleptodiscus and Pyricularia, constitute a strongly supported monophyletic group. Results also indicate that Ophioceras is probably monophyletic. Magnaporthe salvinii is closely related to Gaeumannomyces, while M. grisea clusters with the anamorphic genus Pyricularia. The placement of Mycoleptodiscus coloratus and Ceratosphaeria lampadophora within the Magnaporthaceae is confirmed. Molecular data also provided further evidence to support the association of several anamorphic genera with the ascomycetous Magnaporthaceae. The phylogenetic significance of several morphologies currently used in the classification of members among Magnaporthaceae is discussed. Phylogenies also indicate that Magnaporthaceae bears close phylogenetic affinities to the order Diaporthales and Ophiostomatales. However, there appears to be sufficient evidence to establish a new order, Magnaporthales to accommodate the Magnaporthaceae. A new species (Ophioceras chiangdaoense sp. nov.) that was isolated from the leaves of Dracaena loureiroi is described and its phylogenetic relationship to is evaluated using the rDNA sequences.