Multigene phylogenies and morphological characterization of five new Ophiostoma spp. associated with spruce-infesting bark beetles in China

Ophiostoma spp. (Ophiostomatales, Ascomycota) are well-known fungi associated with bark beetles (Coleoptera: Scolytinae). Some of these are considered to be serious tree pathogens, while the majority is blue-stain agents of timber. In recent years, various bark beetle species have been reported as attacking spruce forests in Qinghai province, China, causing significant damage. Due to the limited number of studies about Ophiostoma spp. associated with bark beetles in China, a preliminary survey was done to explore the diversity of these fungi on spruce. The aims of the present study were firstly to identify and characterize new Ophiostoma spp. isolated from spruce-infesting bark beetles and their galleries in Qinghai Province, and secondly to resolve the phylogenetic relationships of some Ophiostoma spp. related to the Chinese isolates by using multigene phylogenetic analyses. Results obtained from four gene regions (ribosomal internal transcribed spacer regions, β-tubulin, calmodulin, translation elongation factor-1α) revealed five new Ophiostoma spp. from Qinghai. These included O. nitidus sp. nov., O. micans sp. nov., and O. qinghaiense sp. nov. in a newly defined O. piceae complex. The other two new species, O. poligraphi sp. nov. and O. shangrilae sp. nov., grouped in the O. brunneo-ciliatum complex. Based on DNA sequence and morphological comparisons, we also show that O. arduennense and O. torulosum are synonyms of O. distortum, while O. setosum is a synonym of O. cupulatum.