Comprehensive Insights Into Pinewood Nematode Effectors: Evolutionary Diversity, Functional Roles, and Implications for Pine Wilt Disease Management

ABSTRACT The pinewood nematode ( Bursaphelenchus xylophilus , PWN) is the causative agent of pine wilt disease (PWD), a devastating affliction that severely impacts pine forests, leading to significant economic losses and ecological consequences. Once PWN successfully established in healthy host trees, it can cause mortality within a latency period ranging from days to several years. However, the precise pathogenic mechanisms remain poorly understood. Recent studies have revealed that pathogenicity is primarily driven by a diverse array of effectors, including proteins and small molecules such as ascarosides, which is emerged as critical mediators for modulating host defense and immune responses, thereby enhancing nematode survival and promoting disease progression. This review provides an updated and comprehensive overview of PWN effectors, highlighting their diversity, evolutionary origins, methodological advancements, and functional roles. Additionally, we explore the implications of these findings for the development of targeted control strategies and highlight the critical challenges and future research directions essential for gaining a complete understanding of the complex pathogenicity of PWN.