Cloning and functional analysis of glutathione S-transferase gene BxGST3 and BxGST1 in Bursaphelenchus xylophilus

Introduction Pine wilt disease (PWD), caused by the pine wood nematode Bursaphelenchus xylophilus , is a devastating disease affecting pine forests worldwide. Glutathione S-transferases (GSTs) are key detoxification enzymes that protect organisms against oxidative stress and xenobiotic compounds. However, the roles of specific GST genes in B. xylophilus pathogenicity remain poorly understood. Methods In this study, we cloned the full-length cDNAs of two GST genes, BxGST3 and BxGST1 , using rapid amplification of cDNA ends (RACE). Quantitative PCR was performed to examine their expression during infection of Pinus thunbergii . In situ hybridization was used to localize their expression in nematode tissues. RNA interference (RNAi) was employed to silence these genes and assess their effects on nematode physiology. Results Both genes were up-regulated during infection, with peak expression at 24 hours post-inoculation (5.1-fold for BxGST3 and 3.1-fold for BxGST1 ). In situ hybridization localized their expression to the esophageal glands, gonads, and intestine. RNAi-mediated silencing of BxGST3 and BxGST1 reduced feeding activity and reproduction, and delayed pine wilt symptoms. Discussion These findings demonstrate that BxGST3 and BxGST1 contribute to B. xylophilus pathogenicity, likely through detoxification of host defense compounds.