Bursaphelenchus xylophilus is an emerging pathogenic nematode that is responsible for a devastating epidemic of pine wilt disease worldwide, causing severe ecological damage and economic losses to forestry. Two forms of this nematode have been reported, i.e., with strong and weak virulence, commonly referred as virulent and avirulent strains. However, the pathogenicity-related genes of B. xylophilus are not sufficiently characterized. In this study, to find pathogenesis related genes we re-sequenced and compared genomes of two virulent and two avirulent populations. We identified genes affected by genomic variation, and functional annotation of those genes indicated that some of them might play potential roles in pathogenesis. The performed analysis showed that both avirulent populations differed from the virulent ones by 1576 genes with high impact variants. Demonstration of genetic differences between virulent and avirulent strains will provide effective methods to distinguish these two nematode virulence forms at the molecular level. The reported results provide basic information that can facilitate development of a better diagnosis for B. xylophilus isolates/strains which present different levels of virulence and better understanding of the molecular mechanism involved in the development of the PWD.

松材线虫（Bursaphelenchus xylophilus）是一种新兴的病原线虫，其造成全世界范围内毁灭性的松树枯萎病流行，给生态系统造成严重破坏，并给林业造成经济损失。已经报道了该线虫的两种形式，即具有强毒力和弱毒力，通常称为强毒力和无毒力的菌株。然而，木糖双歧杆菌的致病性相关基因没有足够的特征。在这项研究中，为了找到与发病机理相关的基因，我们重新测序并比较了两个有毒和两个无毒种群的基因组。我们鉴定了受基因组变异影响的基因，这些基因的功能注释表明其中一些可能在发病机理中发挥潜在作用。进行的分析表明，两个无毒种群与有毒种群的差异很大，有1576个基因。证明有毒力和无毒力菌株之间的遗传差异将提供在分子水平上区分这两种线虫毒力形式的有效方法。报告的结果提供了有助于促进对木糖双歧杆菌的更好诊断的基本信息。 分离株/菌株，它们表现出不同的毒力水平，并且对PWD的发展所涉及的分子机制有更好的了解。