The Gut Microbiota Determines the High-Altitude Adaptability of Tibetan Wild Asses (Equus kiang) in Qinghai-Tibet Plateau.
The Gut Microbiota Determines the High-Altitude Adaptability of Tibetan Wild Asses (Equus kiang) in Qinghai-Tibet Plateau.
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DOI：
10.3389/fmicb.2022.949002
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发表时间：
2022
影响因子：
5.2
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中科院分区：
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很早以前就已经认识到，微生物在动物进化中发挥了关键作用。藏野驴(TWA，Equus kiang)是青藏高原仅有的野生周指动物，也是我国第一批国家重点保护动物，但其肠道微生物区系与宿主适应性之间的关系尚不清楚。本研究采用16S rRNA和总基因组测序方法，对TWA的肠道微生物区系-宿主关联性进行了研究，并与牦牛(Bos Grunnies)和藏羊(Ovis Aries)的肠道微生物区系关联性进行了比较。结果表明，牦牛和藏羊的肠道微生物区系经历了趋同进化。相比之下，TWA的肠道微生物区系向使宿主能够以稀少和低质量的饲料为生的方向分化。同时，较高的微生物多样性(Shannon和Chao1指数)、纤维分解活性以及丰富的指示种，如螺旋藻、拟杆菌、普氏杆菌1和密螺旋体2，支持了TWA肠道中饲料的消化和短链脂肪酸的产生。同时，肠型鉴定分析表明，TWA为了更好地利用饲料氮和短链脂肪酸的产生，改变了它们的肠型，以适应低品质的饲料。元基因组分析表明，植物生物量降解微生物群落、基因和酶，如纤维分解菌(普氏瘤胃杆菌、黄色瘤胃球菌、白色瘤胃球菌、纤维状丁状弧菌和嗜淀粉瘤胃杆菌)、碳水化合物代谢基因(GH43、GH3、GH31、GH5和GH10)和酶(β-葡萄糖苷酶、木聚糖酶和β-木糖苷酶等)。在TWA中有明显更高的富集度。我们的结果表明，肠道微生物区系可以通过植物生物量的降解和能量维持来提高TWA在面对营养缺乏时的适应能力，这也为理解肠道微生物区系在QTP野生动物面对恶劣摄食环境时的适应提供了有力的理论基础。
It was acknowledged long ago that microorganisms have played critical roles in animal evolution. Tibetan wild asses (TWA, Equus kiang) are the only wild perissodactyls on the Qinghai-Tibet Plateau (QTP) and the first national protected animals; however, knowledge about the relationships between their gut microbiota and the host's adaptability remains poorly understood. Herein, 16S rRNA and meta-genomic sequencing approaches were employed to investigate the gut microbiota–host associations in TWA and were compared against those of the co-resident livestock of yak (Bos grunnies) and Tibetan sheep (Ovis aries). Results revealed that the gut microbiota of yak and Tibetan sheep underwent convergent evolution. By contrast, the intestinal microflora of TWA diverged in a direction enabling the host to subsist on sparse and low-quality forage. Meanwhile, high microbial diversity (Shannon and Chao1 indices), cellulolytic activity, and abundant indicator species such as Spirochaetes, Bacteroidetes, Prevotella_1, and Treponema_2 supported forage digestion and short-chain fatty acid production in the gut of TWA. Meanwhile, the enterotype identification analysis showed that TWA shifted their enterotype in response to low-quality forage for a better utilization of forage nitrogen and short-chain fatty acid production. Metagenomic analysis revealed that plant biomass degrading microbial consortia, genes, and enzymes like the cellulolytic strains (Prevotella ruminicola, Ruminococcus flavefaciens, Ruminococcus albus, Butyrivibrio fibrisolvens, and Ruminobacter amylophilus), as well as carbohydrate metabolism genes (GH43, GH3, GH31, GH5, and GH10) and enzymes (β-glucosidase, xylanase, and β-xylosidase, etc.) had a significantly higher enrichment in TWA. Our results indicate that gut microbiota can improve the adaptability of TWA through plant biomass degradation and energy maintenance by the functions of gut microbiota in the face of nutritional deficiencies and also provide a strong rationale for understanding the roles of gut microbiota in the adaptation of QTP wildlife when facing harsh feeding environments.