Abundance and Diversity of Ophiostomatoid Fungi Associated With the Great Spruce Bark Beetle () in the Northeastern Qinghai-Tibet Plateau.

The role of several virulent tree pathogens in host death has been overlooked because of the aggressiveness of their associated bark beetles. The great spruce bark beetle () is a widely distributed beetle that infests coniferous plants in Eurasia; however, its associated fungi have been poorly studied. Therefore, in this study, we elucidated the diversity of ophiostomatoid fungi associated with in the northeastern Qinghai-Tibet Plateau through field investigation, laboratory isolation, and culture analyses. A total of 220 strains of ophiostomatoid fungi were isolated from adults and tunnel galleries of infesting We identified that the isolated strains belonged to eight ophiostomatoid species, including five new species ( sp. nov., sp. nov., sp. nov., sp. nov., and sp. nov.), one undefined species ( sp. 1), and two known species ( and ), using phylogenetic analysis of multigene DNA sequences and morphological characteristics. This is the first time that , a pioneer invader and virulent pathogen, has been reported in China. We found that was the dominant species, accounting for 40.91% of the total number of ophiostomatoid communities. This study enriched the knowledge of the fungal associates of and elucidated that it carried the virulent pathogen at a surprisingly high frequency. Our findings show increased species association between and ophiostomatoid fungi and provide a basis for understanding the occurrence of forest diseases and pests.