Termites are among the most successful insect lineages on the globe and are responsible for providing numerous ecosystem services. They mainly feed on wood and other plant material at different stages of humification. Lignocellulose is often a principal component of such plant diet, and termites largely rely on their symbiotic microbiota and associated enzymes to decompose their food efficiently. While lower termites and their gut flagellates were given larger scientific attention in the past, the gut lignocellulolytic bacteria of higher termites remain less explored. Therefore, in this study, we investigated the structure and function of gut prokaryotic microbiomes from 11 higher termite genera representative of Syntermitinae, Apicotermitinae, Termitidae and Nasutitermitinae subfamilies, broadly grouped into plant fibre- and soil-feeding termite categories. Despite the different compositional structures of the studied termite gut microbiomes, reflecting well the diet and host lineage, we observed a surprisingly high functional congruency between gut metatranscriptomes from both feeding groups. The abundance of transcripts encoding for carbohydrate active enzymes as well as expression and diversity profiles of assigned glycoside hydrolase families were also similar between plant fibre- and soil-feeding termites. Yet, dietary imprints highlighted subtle metabolic differences specific to each feeding category. Roughly, 0.18% of de novo re-constructed gene transcripts were shared between the different termite gut microbiomes, making each termite gut a unique reservoir of genes encoding for potentially industrially applicable enzymes, e.g. relevant to biomass degradation. Taken together, we demonstrated the functional equivalence in microbial populations across different termite hosts. Our results provide valuable insight into the bacterial component of the termite gut system and significantly expand the inventory of termite prokaryotic genes participating in the deconstruction of plant biomass.

中文翻译：

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植物纤维和土壤喂养的高级白蚁肠道中生物质降解微生物群落的组成和功能表征。

白蚁是全球最成功的昆虫家族之一，并负责提供众多的生态系统服务。它们主要在腐殖化的不同阶段以木材和其他植物材料为食。木质纤维素通常是这种植物饮食的主要成分，白蚁在很大程度上依靠其共生微生物和相关的酶有效地分解其食物。过去，尽管对白蚁及其肠道鞭毛的研究受到了更大的科学关注，但对白蚁对肠道木质纤维素的分解作用仍然较少。因此，在这项研究中，我们研究了来自11个较高的白蚁属，白蚁，近端白蚁，白蚁和鼻白蚁亚科的肠道原核微生物组的结构和功能，大致分为植物纤维和土壤喂养白蚁类别。尽管所研究的白蚁肠道微生物群的组成结构不同，很好地反映了饮食和宿主谱系，但我们观察到两个喂养组的肠道元转录组之间的功能一致性非常高。植物纤维和土壤喂养的白蚁之间，编码碳水化合物活性酶的转录本的丰富度以及指定的糖苷水解酶家族的表达和多样性特征也相似。然而，饮食印记突出显示了针对每种喂养类别的细微代谢差异。大约在不同的白蚁肠道微生物群中共有0.18％的从头重建基因转录本共享，从而使每个白蚁肠道成为编码可能在工业上应用的酶的独特基因库，例如与生物质降解有关。综上所述，我们证明了不同白蚁宿主之间微生物种群的功能等效性。我们的结果为白蚁肠道系统的细菌成分提供了有价值的见解，并显着扩大了参与植物生物量解构的白蚁原核基因的库存。