Cloning arginine kinase gene and its RNAi in Bursaphelenchus xylophilus causing pine wilt disease

Since Bursaphelenchus xylophilus causes serious losses in pine forestry, new ways of controlling this nematode damage are urgently needed. Arginine kinase (AK) is a phosphotransferase, which plays a critical role in cellular energy metabolism in invertebrates. It is only present in invertebrates and may be a suitable chemotherapeutic target in the control of this pest. RNA interference (RNAi) technology has been developed in biological science in recent decades as a powerful tool to silence the target gene function in the post-translational status. In this study, one AK gene, BxAK1 (GeneBank accession No. EU853862) was firstly cloned, and then its functions were identified by RNAi technology. Results show that the full-length cDNA of the BxAK1 gene contains 1206 base pairs and an 1086 bp open reading frame encoding 361 amino acids. The length of the BxAK1 genomic coding region contains 2430 bp consisting of four introns of 421, 117, 475, and 268 bp respectively, and five exons of 57, 207, 309, 360, and 215 bp respectively. A dsRNA targeting BxAK1 was constructed and tested for its RNAi effect on B. xylophilus by soaking bioassays. RNAi not only significantly increased the mortality of B. xylophilus, but also greatly reduced its fecundity and fertility. These results suggest that RNAi targeting BxAK1 may be an effective approach for controlling nematode pests.