Identification of BxUGP-1 in Bursaphelenchus xylophilus and its functional characterization in response to fluopyram stress.

Pine wilt disease, caused by the pine wood nematode (Bursaphelenchus xylophilus), is a highly destructive disease affecting forests worldwide. Extensive reliance on traditional nematicides has promoted resistance, underscoring the need for new molecular targets to improve control. UDP-glucose pyrophosphorylase (UGPase), a key enzyme in carbohydrate metabolism, catalyzes the conversion of uridine triphosphate and glucose-1-phosphate to UDP-glucose, contributing to energy metabolism, glycosylation, and detoxification. However, its role in nematodes remains poorly understood. This study describes the identification and cloning of the UGPase-encoding gene BxUGP-1 from B. xylophilus, and characterizes its molecular properties and biological functions. The recombinant BxUGP-1 protein exhibited UGPase catalytic activity, while molecular docking predicted a possible structural association between BxUGP-1 and fluopyram. Additionally, fluopyram exposure induced significant BxUGP-1 expression, showing an initial increase followed by a decrease, indicating gene responsiveness to exogenous chemical stress. When fluopyram treatment was combined with RNA interference (RNAi), BxUGP-1 silencing significantly reduced nematode feeding and reproduction, increased fluopyram sensitivity, and weakened host plant infectivity. Overall, these findings demonstrate that BxUGP-1 is critical for adaptation to chemical stress in B. xylophilus. This study clarifies the role of a key carbohydrate metabolism enzyme in stress tolerance and pathogenicity in B. xylophilus, providing a foundation for developing novel control strategies against this pest.