Ophiostomatalean fungi associated with bark beetles infesting Pinus armandii Franch., with characterizations of seven new species from Shaanxi, China.

Pinus armandii is widely distributed in western China and is of considerable ecological significance. However, recent bark beetle outbreaks have caused severe damage to forests in Shaanxi Province, and these outbreaks are closely associated with ophiostomatalean fungi (Ascomycota, Ophiostomatales). These fungi not only incite plant diseases but also facilitate the successful establishment of the beetles. At present, knowledge of the ophiostomatalean fungal communities associated with bark beetles infesting Pinus armandii in Shaanxi Province remains limited. This study aimed to identify ophiostomatalean fungi associated with P. armandii in Ankang City, Shaanxi Province. A total of 230 ophiostomatalean isolates were obtained from 46 gallery samples. Based on multilocus phylogenetic analyses, and morphological and physiological characteristics, we identified 20 species belonging to six genera. Among them were seven novel species, namely Ceratocystiopsis rugosa sp. nov., Graphilbum prolificum sp. nov., G. ramosus sp. nov., Masuyamyces huoditangensis sp. nov., Ophiostoma flavescens sp. nov., O. lenta sp. nov., and O. mediotumida sp. nov., along with two unidentified taxa (Ceratocystiopsis sp. 1 and Leptographium sp. 1), and eleven previously described species. This study provides a basis for understanding the relationship between the beetles and the ophiostomatalean fungi in Shaanxi Province, China.