A key effector,BxSapB2, plays a role in the pathogenicity of the pine wood nematode Bursaphelenchus xylophilus

The pine wood nematode (PWN), Bursaphelenchus xylophilus, causes huge economic losses in pine forests. The plant‐parasitic nematodes have a complex life cycle that includes the secretion of effector proteins through a stylet into the host cell to promote parasitism. In this study, SignalP 4.1 and TMHMM 2.0 were used in preliminary screens for candidate effectors and were expressed in Nicotiana benthamiana through the PVX virus expression vector. The yeast signal sequence trap system was used to further study the function of the signal peptide of an effector, BxSapB2. In situ hybridization was conducted to investigate the localization of BxSapB2, followed by RNA interference technology (RNAi) to assess the functions of BxSapB2. The results demonstrate that BxSapB2 is a secreted protein that induces cell death in N. benthamiana and is highly expressed in esophageal gland cells and amphids of B. xylophilus. BxSapB2 was determined to be related to the pathogenicity of B. xylophilus. The results of this work indicate that BxSapB2 plays an important role in the interactions between B. xylophilus and the hosts.