Molecular variations of the quarantine nematode Bursaphelenchus xylophilus among virulent and avirulent forms

The pine wood nematode, Bursaphelenchus xylophilus is a causative agent of the pine wilt disease (PWD). Every year thousands of trees displaying symptoms of PWD are felled and removed in the affected areas. Up to date studies have revealed that the pathogenicity of B. xylophilus associated with conifers varied among different populations. Two forms of B. xylophilus have been reported, i.e., virulent and avirulent. In 2011, the complete nuclear genome sequences for B. xylophilus have been reported. However, the knowledge about genetic determinants affecting different levels of pathogenicity among the nematode populations is still limited. The aim of the conducted study was to reveal genetic differences among the virulent and avirulent B. xylophilus populations. It was achieved by performing NGS followed by comparison and analysis of the complete nuclear genome sequences of two virulent and two avirulent populations of this nematode.The research allowed for identification of genetic differences that might affect the pathogenicity, as well as the loss of pathogenicity in B. xylophilus. Genes involved in a number of key biological processes, as well as genes related to molecular functions and cellular components, of which many could be viable control targets, have been identified. The obtained genome sequences for virulent and avirulent B. xylophilus populations increase the diversity of genomic data available for nematodes, can be an important resource for understanding the biology of this pest, and can contribute to the eradication of the devastating disease caused by this nematode. Moreover, the results obtained from the bioinformatic analysis can form a basis for functional testing with the use of a wide range of techniques.This study was supported by the National Science Centre, Poland (2017/01/X/NZ9/01708).