Insights into pine wilt disease: a review on biology and pathogenicity of Bursaphelenchus xylophilus and B. mucronatus

Pine wilt disease (PWD), caused by the pinewood nematode, Bursaphelenchus xylophilus, is a major ecological and economic threat to pine forests worldwide. Native to North America, B. xylophilus, considered a quarantine species by the European and Mediterranean Plant Protection Organisation, has spread to Asia and Europe, causing severe damage to pine species and resulting in substantial economic and ecological losses. The Bursaphelenchus genus, also includes the species B. mucronatus, the B. xylophilus closest related species, sharing similar morphological and ecological characteristics. To date, no major economic or ecological damage has been caused by B. mucronatus. However, over the years, some studies have suggested that it has a certain degree of pathogenicity in stressed trees, particularly those under drought and heat stress. This review provides a comprehensive synthesis of current knowledge on both species, covering their biology, distribution, life cycle, and methods for morphological and molecular identification. We further examine the known pathogenicity mechanisms, drawing from transcriptomic, genomic, and proteomic studies. By integrating recent advances across multiple disciplines, this review aims to clarify the similarities and distinctions between these two species, identify knowledge gaps, and contribute to future research and management strategies.