The mitochondrial genome of the pinewood nematode (Bursaphelenchus xylophilus) lineage introduced in Europe

he pinewood nematode (PWN) Bursaphelenchus xylophilus is the causative agent of pine wilt disease and the greatest biological threat to conifer forests worldwide. Here we describe the near-complete mitochondrial DNA (mtDNA) sequence (12,945 bp) of the PWN lineage recently introduced in Europe. The absence of polymorphisms across the mtDNA of three Portuguese isolates suggests that a single mitochondrial lineage was introduced in southwestern Europe. We also found that Portuguese isolates have an incomplete stop codon (TA) at COX3, while the reference mtDNA from a South Korean isolate has a complete stop codon (TAA). Moreover, two insertion/deletion polymorphisms change the ND4 protein in a stretch of seven amino acids, and a polymorphic mononucleotide repeat alters the predicted structure of the tyrosine tRNA in different geographical isolates. Overall, the new PWN mtDNA sequence provides a basis for studying the European dispersion of this important invasive species.