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

Abstract

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 (Dendroctonus micans) 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 D. micans 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 D. micans infesting Picea crassifolia. We identified that the isolated strains belonged to eight ophiostomatoid species, including five new species (Ophiostoma huangnanense sp. nov., Ophiostoma maixiuense sp. nov., Ophiostoma sanum sp. nov., Leptographium sanjiangyuanense sp. nov., and Leptographium zekuense sp. nov.), one undefined species (Ophiostoma sp. 1), and two known species (Ophiostoma bicolor and Endoconidiophora laricicola), using phylogenetic analysis of multigene DNA sequences and morphological characteristics. This is the first time that E. laricicola, a pioneer invader and virulent pathogen, has been reported in China. We found that E. laricicola 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 D. micans and elucidated that it carried the virulent pathogen E. laricicola at a surprisingly high frequency. Our findings show increased species association between D. micans and ophiostomatoid fungi and provide a basis for understanding the occurrence of forest diseases and pests.

Pathophysiology and transcriptomic analysis of Picea koraiensis inoculated by bark beetle-vectored fungus Ophiostoma bicolor

“…Ophiostoma bicolor is one of the dominant associate fungi with Ips spp. and Dendroctonus micans , which attacked various spruce species in Europe and north China ( Giordano et al, 2013 ; Nève Repe et al, 2018 ; Chang et al, 2019 , 2020 ; Chakraborty et al, 2020 ; Wang et al, 2020c , 2021 ). Previous studies have confirmed that the pioneer species in the associated fungal community of Ips , like Endoconidiophora spp., showed strong virulence, which could cause severe host necrosis and induce a drastic resistance response of host conifers.…”