Background: Oribatid mites are a specious order of microarthropods within the subphylum Chelicerata, compromising about 11,000 described species. They are ubiquitously distributed across different microhabitats in all terrestrial ecosystems around the world and were among the first animals colonizing terrestrial habitats as decomposers and scavengers. Noted for their biosynthesis capacities and biochemical diversity, the majority of oribatid mites possess a pair of exocrine opisthonotal oil-glands used for chemical defense and communication. Genomic resources are lacking for oribatids despite their species richness and ecological importance. Results: We used a comparative genomic approach to investigate the developmental, sensory and glandular biosynthetic gene repertoire of the clonal, all-female oribatid mite species Archegozetes longisetosus Aoki, a model species used by numerous laboratories for the past 30 years. Here, we present a 190-Mb genome assembly constructed from Nanopore MinION and Illumina sequencing platforms with 23,825 predicted protein-coding genes. Genomic and transcriptional analyses revealed patterns of reduced body segmentation and loss of segmental identity gene abd-A within Acariformes, and unexpected expression of key eye development genes in these eyeless mites across developmental stages. Consistent with the soil dwelling lifestyle, investigation of the sensory genes revealed a species-specific expansion of gustatory receptors, the largest chemoreceptor family in the genome used in olfaction, and evidence of horizontally transferred enzymes used in cell wall degradation of plant and fungal matter, both components of the Archegozetes longisetosus diet. Using biochemical and genomic data, we were able to delineate the backbone biosynthesis of monoterpenes, an important class of compounds found in the major exocrine gland system of Oribatida - the oil glands. Conclusions: With the Archegozetes longisetosus genome, we now have the first high-quality, annotated genome of an oribatid mite genome. Given the mite's strength as an experimental model, the new sequence resources provided here will serve as the foundation for molecular research in Oribatida and will enable a broader understanding of chelicerate evolution.

中文翻译：

---

弓形虫基因组揭示了Oribatida的分子进化趋势和生物合成途径

背景：原蜥螨是Chelicerata属下的微型节肢动物纲，危害了约11,000个所述物种。它们无所不在地分布在世界各地所有陆地生态系统的不同微生境中，并且是最早作为分解器和清除剂定居在陆地栖息地的动物之一。因其生物合成能力和生化多样性而著称，大多数oribatid螨拥有一对用于化学防御和交流的外分泌阿鼻咽油腺。尽管orbatids物种丰富且具有生态重要性，但基因组资源仍然缺乏。结果：我们使用比较基因组学方法研究了全雌性奥里巴特螨小种Archegozetes longisetosus Aoki的发育，感觉和腺体生物合成基因库，这是过去30年来许多实验室使用的模型种。在这里，我们介绍了从Nanopore MinION和Illumina测序平台构建的190-Mb基因组，具有23,825个预测的蛋白质编码基因。基因组和转录分析揭示了减少的身体节段和节段同一性基因abd-A丢失的模式在无眼螨的整个发育阶段中，关键眼发育基因的意外表达。与土壤居住的生活方式一致，对感官基因的研究表明，味觉受体具有物种特异性的扩展，是嗅觉基因组中最大的化学感受器家族，并且有证据表明水平转移的酶可用于植物和真菌物质的细胞壁降解，弓形虫长寿饮食的两个组成部分。利用生化和基因组数据，我们能够描述单萜的骨架生物合成，单萜是在Oribatida-油腺的主要外分泌腺系统中发现的一类重要化合物。结论：长寿菌（Archegozetes longisetosus）基因组，我们现在有了第一个螨虫螨基因组的高质量，带注释基因组。鉴于螨虫作为实验模型的优势，此处提供的新序列资源将成为Oribatida分子研究的基础，并将使人们对螯合物的进化有更广泛的了解。