Phylogeny and morphology of Ophiocordyceps puluongensis sp. nov. (Ophiocordycipitaceae, Hypocreales), a new fungal pathogen on termites from Vietnam

Termites are serious pests in agriculture and forestry, causing significant economic losses to property and the construction industry. However, only a few entomopathogenic fungi attack termites that are dominant members of most terrestrial biomes. This study contributes to the taxonomic knowledge of entomopathogenic fungi with the description of a new pathogen on termites collected from the Pu Luong Nature Reserve in Vietnam. The new termite pathogen, Ophiocordyceps puluongensis, is introduced on the basis of morphological and multigene phylogenetic evidence. Based on the combined dataset of five genes including the nuclear ribosomal small and large subunits (nr SSU and nr LSU ), the elongation factor 1α ( tef-1α ), and the largest and the second largest subunits of RNA polymerase II ( rpb1 and rpb2 ), phylogenetic analyses were performed by Maximum Likelihood and Bayesian inference methods to determine the phylogenetic position of O. puluongensis. Three samples of O. puluongensis are clustered in the Hirsutella thompsonii subclade of Hirsutella lineages in Ophiocordyceps, and clustered together with O. asiatica to form a separate clade from other Ophiocordyceps species. Morphologically, O. puluongensis differs from O. asiatica by its smaller and shorter perithecia, asci and ascospores, pink to reddish-orange stipes of stromata, as well as smaller fusiform or citriform conidia. The distinctiveness of this termite pathogen is strongly supported by both molecular phylogeny and morphology. The entomopathogenic fungus O. puluongensis could have the potential to be used as bioinsecticides to control termites.