Jia Huiping, Tang Liping, Fu Yajun, Xiong Yu, Yan Liping, Shao Changliang, Li Kai, Zhang Dong, Hu Defu
School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, 100083, China.
Xinjiang Kalamaili Mountain Ungulate Nature Reserve Management Center, Xinjiang, China.
Parasit Vectors. 2025 Jul 11;18(1):278. doi: 10.1186/s13071-025-06851-7.
Petrovinema skrjabini (Nematoda: Strongylidae, Cyathostominae) is a parasitic nematode colonizing the cecum and colon of equids. Like other cyathostomins, its larvae (L3) invade the intestinal mucosa, forming encysted nodules that may remain dormant for years. Mass larval emergence triggers larval cyathostominosis-a severe syndrome characterized by hemorrhagic typhlocolitis and diarrhea, with mortality rates exceeding 50%. However, owing to the morphological indistinguishability of cyathostomin and frequent mixed infections in natural settings, species-specific contributions to pathogenesis remain unresolved. Previous studies on P. skrjabini have predominantly focused on its morphology, with limited molecular information available.
The complete mitogenome of Petrovinema skrjabini was sequenced using the Illumina NovaSeq 6000 platform, followed by assembly and annotation. We performed a phylogenetic analysis using Bayesian inference (BI) and maximum likelihood (ML) methods, based on 12 protein-coding genes from mitogenomes, to assess the evolutionary relationships of 34 Strongylidae species.
The complete mitogenome of P. skrjabini comprises 13,885 base pairs with 12 protein-coding genes, two ribosomal-RNA genes, 22 transfer-RNA genes, and two non-coding regions. The gene arrangement of the P. skrjabini mitogenome was consistent with the GA3 arrangement found in other Strongylidae species. The mitogenome exhibited a high AT bias (75.4%), which is consistent with other species in other Strongylidae species. Phylogenetic analysis showed that two Strongylus species (belonging to subfamily Strongylinae) formed a clade and located in the base of Strongylidae, while three Triodontophorus (belonging to subfamily Strongylinae) species and P. skrjabini formed another clade within in subfamily Cyathostominae within Strongylidae, based on 12 protein-coding genes from mitogenomes, suggesting that the genus Triodontophorus should transfer to the subfamily Cyathostominae.
The characterization of the complete mitochondrial genomes of P. skrjabini is reported for the first time. This study provided helpful genetic markers for P. skrjabini identification and taxonomy, facilitating early nematode diagnosis and treatment to decrease equine parasitic nematode burdens. Our mitochondrial phylogeny analyses further corroborate the hypothesis that the genus Triodontophorus belongs to Cyathostominae. The present study enriches the database of strongylids mitogenomes and provides a new insight into the systematics of the family Strongylidae.
斯氏彼得罗线虫（线虫纲：圆线科，杯环线虫亚科）是一种寄生于马属动物盲肠和结肠的线虫。与其他杯环线虫一样，其幼虫（L3）侵入肠黏膜，形成包囊结节，这些结节可能会休眠数年。大量幼虫出现会引发幼虫杯环线虫病——一种以出血性盲结肠炎和腹泻为特征的严重综合征，死亡率超过50%。然而，由于杯环线虫在形态上难以区分，且在自然环境中经常混合感染，其物种对发病机制的具体贡献仍未明确。以往对斯氏彼得罗线虫的研究主要集中在其形态学上，分子信息有限。
使用Illumina NovaSeq 6000平台对斯氏彼得罗线虫的完整线粒体基因组进行测序，随后进行组装和注释。我们基于线粒体基因组中的12个蛋白质编码基因，采用贝叶斯推断（BI）和最大似然（ML）方法进行系统发育分析，以评估34种圆线科物种的进化关系。
斯氏彼得罗线虫的完整线粒体基因组由13,885个碱基对组成，包含12个蛋白质编码基因、两个核糖体RNA基因、22个转运RNA基因和两个非编码区。斯氏彼得罗线虫线粒体基因组的基因排列与其他圆线科物种中发现的GA3排列一致。线粒体基因组表现出较高的AT偏向性（75.4%），这与其他圆线科物种一致。系统发育分析表明，基于线粒体基因组中的12个蛋白质编码基因，两种圆线属（属于圆线亚科）物种形成一个进化枝，位于圆线科的基部，而三种三齿线虫属（属于圆线亚科）物种和斯氏彼得罗线虫在圆线科的杯环线虫亚科内形成另一个进化枝，这表明三齿线虫属应转移到杯环线虫亚科。
首次报道了斯氏彼得罗线虫完整线粒体基因组的特征。本研究为斯氏彼得罗线虫的鉴定和分类提供了有用的遗传标记，有助于早期线虫诊断和治疗，以减轻马属动物的寄生线虫负担。我们的线粒体系统发育分析进一步证实了三齿线虫属属于杯环线虫亚科的假设。本研究丰富了圆线科线粒体基因组数据库，并为圆线科的系统学提供了新的见解。
