State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
Laboratory of Forest Pathogen Integrated Biology, Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing, China.
Mol Ecol. 2020 Mar;29(5):940-955. doi: 10.1111/mec.15378. Epub 2020 Feb 17.
Gene gain/loss in the context of gene family dynamics plays an important role in evolutionary processes as organisms, particularly invasive species, adapt to new environments or niches. One notable example of this is the duplication of digestive proteases in some parasitic insects and helminths to meet nutritional requirements during animal parasitism. However, whether gene family expansion participates in the adaptation of a plant parasite nematode to its host remains unknown. Here, we compared the newly sequenced genomes of the pinewood nematode, Bursaphelenchus xylophilus, with the genomes of free-living, animal-parasitic and plant-parasitic nematodes. The results showed gene expansions occurring in 51 gene families in B. xylophilus, especially in xenobiotic detoxification pathways, including flavin monooxygenase (FMO), cytochrome P450 (CYP450), short chain dehydrogenase (SDR), alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), UDP-glucuronosyltransferase (UGT) and glutathione S-transferase (GST). Although a majority of these expansions probably resulted from gene duplications, nine ADH genes were potentially acquired by horizontal gene transfer (HGT) from fungi. From the transcriptomes of B. xylophilus treated with pine saplings and terpenes, candidate xenobiotic detoxification genes were identified. We propose that host defence chemicals led to gene family expansions of xenobiotic detoxification pathways in B. xylophilus facilitating its survival in pine resin ducts. This study contributes to a better understanding of how a parasitic nematode adapts to its host.
基因的获得和丢失在基因家族动态变化的背景下，在进化过程中起着重要作用，因为生物体，特别是入侵物种，需要适应新的环境或小生境。一个值得注意的例子是，一些寄生昆虫和蠕虫的消化蛋白酶基因的复制，以满足动物寄生期间的营养需求。然而，基因家族的扩张是否参与植物寄生线虫对其宿主的适应仍然未知。在这里，我们比较了松材线虫（Bursaphelenchus xylophilus）的新测序基因组与自由生活、动物寄生和植物寄生线虫的基因组。结果表明，B. xylophilus 中发生了 51 个基因家族的基因扩张，特别是在 Xenobiotic 解毒途径中，包括黄素单加氧酶（FMO）、细胞色素 P450（CYP450）、短链脱氢酶（SDR）、醇脱氢酶（ADH）、醛脱氢酶（ALDH）、UDP-葡萄糖醛酸转移酶（UGT）和谷胱甘肽 S-转移酶（GST）。尽管这些扩张中的大多数可能是由于基因复制导致的，但有九个 ADH 基因可能是通过真菌的水平基因转移（HGT）获得的。从用松树苗和萜烯处理的 B. xylophilus 的转录组中，鉴定出了候选的 Xenobiotic 解毒基因。我们提出，宿主防御化学物质导致 Xenobiotic 解毒途径的基因家族在 B. xylophilus 中扩张，使其能够在松脂管中生存。这项研究有助于更好地理解寄生线虫如何适应其宿主。
