Decoding the Pine Wood Nematode's survival mystery: Gene family expansion drives adaptation revealed by dual-omics.

The pine wood nematode (PWN) Bursaphelenchus xylophilus is a highly destructive invasive pest that has spread from North America to Eurasia, demonstrating remarkable adaptability across environments. However, the molecular mechanisms underlying environmental adaptation of B. xylophilus remain poorly understood. In this study, we integrated genomic and transcriptomic analyses of B. xylophilus and its native sibling species B. mucronatus, which is native in China. Functional validation of key genes was conducted using RNA interference, BAX, and inoculation assays. Our research focused on three rapidly expanding gene families in B. xylophilus, including the BolA-like superfamily, diacylglycerol acyltransferase (DGAT), and papain-like cysteine peptidase (PLCP). Key genes were functionally validated to elucidate their roles in environmental adaptability. The BolA-like genes were identified as critical stress-response elements, enabling B. xylophilus to survive under harsh conditions. The DGAT genes are essential for lipid biosynthesis and play pivotal roles in resisting starvation and cold. Regarding pathogenicity, the PLCP gene family has been identified as a critical virulence determinant facilitating B. xylophilus infection on host pine trees. These expanded gene families collectively enhance stress tolerance and virulence in B. xylophilus. The findings of this study not only reveal the genetic basis of PWN's invasive success, but also provide a foundation for managing climate-driven disease spread.