Danchin Etienne G J, Perfus-Barbeoch Laetitia, Rancurel Corinne, Thorpe Peter, Da Rocha Martine, Bajew Simon, Neilson Roy, Guzeeva Elena Sokolova, Da Silva Corinne, Guy Julie, Labadie Karine, Esmenjaud Daniel, Helder Johannes, Jones John T, den Akker Sebastian Eves-van
INRA, Université Côte d'Azur, CNRS, ISA, 06903, Sophia Antipolis Cedex, France.
Cell and Molecular Sciences Group, Dundee Effector Consortium, James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK.
Genes (Basel). 2017 Oct 23;8(10):287. doi: 10.3390/genes8100287.
Nematodes have evolved the ability to parasitize plants on at least four independent occasions, with plant parasites present in Clades 1, 2, 10 and 12 of the phylum. In the case of Clades 10 and 12, horizontal gene transfer of plant cell wall degrading enzymes from bacteria and fungi has been implicated in the evolution of plant parasitism. We have used ribonucleic acid sequencing (RNAseq) to generate reference transcriptomes for two economically important nematode species, and , representative of two genera within the early-branching Clade 2 of the phylum Nematoda. We used a transcriptome-wide analysis to identify putative horizontal gene transfer events. This represents the first in-depth transcriptome analysis from any plant-parasitic nematode of this clade. For each species, we assembled ~30 million Illumina reads into a reference transcriptome. We identified 62 and 104 transcripts, from and , respectively, that were putatively acquired via horizontal gene transfer. By cross-referencing horizontal gene transfer prediction with a phylum-wide analysis of Pfam domains, we identified Clade 2-specific events. Of these, a GH12 cellulase from was analysed phylogenetically and biochemically, revealing a likely bacterial origin and canonical enzymatic function. Horizontal gene transfer was previously shown to be a phenomenon that has contributed to the evolution of plant parasitism among nematodes. Our findings underline the importance and the extensiveness of this phenomenon in the evolution of plant-parasitic life styles in this speciose and widespread animal phylum.
线虫至少在四个独立的进化阶段中演化出了寄生植物的能力，植物寄生线虫存在于该门的进化枝1、2、10和12中。在进化枝10和12的情况下，植物细胞壁降解酶从细菌和真菌的水平基因转移与植物寄生的进化有关。我们利用核糖核酸测序（RNAseq）为两种具有经济重要性的线虫物种（分别代表线虫门早期分支进化枝2中的两个属）生成了参考转录组。我们使用转录组范围的分析来识别假定的水平基因转移事件。这是对该进化枝中任何植物寄生线虫的首次深入转录组分析。对于每个物种，我们将约3000万个Illumina读数组装成一个参考转录组。我们分别从两种线虫中鉴定出62个和104个假定通过水平基因转移获得的转录本。通过将水平基因转移预测与全门范围的Pfam结构域分析进行交叉参考，我们确定了进化枝2特有的事件。其中，对一种线虫的GH12纤维素酶进行了系统发育和生化分析，揭示了其可能的细菌起源和典型的酶功能。水平基因转移先前已被证明是一种促进线虫植物寄生进化的现象。我们的研究结果强调了这一现象在这个种类繁多且分布广泛的动物门中植物寄生生活方式进化中的重要性和广泛性。
