Identification of Mountain Pine Beetle Fungal Associates Using Whole Genome Sequence Data

The mountain pine beetle (MPB), Dendroctonus ponderosae, is a forest pest in western North America, infesting millions of hectares of pine forests and causing extensive tree mortality. As the MPB infests trees, it introduces fungal symbionts to the tree. These blue-stain fungi facilitate the beetle's colonization and reproduction within the tree. The blue stain fungi comprise multiple species, and our understanding of the diversity and prevalence of these individual species remains limited. This study aims to identify and characterize the fungal associates of the MPB, gain insight into fungal distribution, and aid in forest management strategies. The study was conducted by collecting 26 MPB specimens from various locations across North America and extracting DNA for whole-genome sequencing using next-generation Sequencing Illumina sequencing. A bioinformatic pipeline was developed to analyze the sequencing data and characterize the fungal community associated with individual MPB sequences. Here, we show that it is possible to use whole genome sequencing to identify the fungal associates transmitted by MPB. Our results align with previous literature characterizing the presence of Grosmannia clavigera and Ophiostoma montium as primary fungal partners in MPB populations across various regions. The analysis aims to understand the geographic distribution trends of these fungal species in different habitats. Furthermore, this project provides valuable insights into the role of these various fungi species in supporting MPB during range expansion.