PDF(Pubmed)
Abstract：
Marine herbivorous fish that feed primarily on macroalgae, such as those from the genus Kyphosus, are essential for maintaining coral health and abundance on tropical reefs. Here, deep metagenomic sequencing and assembly of gut compartment-specific samples from three sympatric, macroalgivorous Hawaiian kyphosid species have been used to connect host gut microbial taxa with predicted protein functional capacities likely to contribute to efficient macroalgal digestion. Bacterial community compositions, algal dietary sources, and predicted enzyme functionalities were analyzed in parallel for 16 metagenomes spanning the mid- and hindgut digestive regions of wild-caught fishes. Gene colocalization patterns of expanded carbohydrate (CAZy) and sulfatase (SulfAtlas) digestive enzyme families on assembled contigs were used to identify likely polysaccharide utilization locus associations and to visualize potential cooperative networks of extracellularly exported proteins targeting complex sulfated polysaccharides. These insights into the gut microbiota of herbivorous marine fish and their functional capabilities improve our understanding of the enzymes and microorganisms involved in digesting complex macroalgal sulfated polysaccharides. IMPORTANCE This work connects specific uncultured bacterial taxa with distinct polysaccharide digestion capabilities lacking in their marine vertebrate hosts, providing fresh insights into poorly understood processes for deconstructing complex sulfated polysaccharides and potential evolutionary mechanisms for microbial acquisition of expanded macroalgal utilization gene functions. Several thousand new marine-specific candidate enzyme sequences for polysaccharide utilization have been identified. These data provide foundational resources for future investigations into suppression of coral reef macroalgal overgrowth, fish host physiology, the use of macroalgal feedstocks in terrestrial and aquaculture animal feeds, and the bioconversion of macroalgae biomass into value-added commercial fuel and chemical products.
摘要：
主要以大型藻类为食的海洋草食性鱼类，比如那些来自Kyphosus属的，对于维持热带珊瑚礁上的珊瑚健康和丰富至关重要。这里,来自三个同胞的肠室特异性样品的深宏基因组测序和组装，巨藻夏威夷金phosid物种已用于将宿主肠道微生物类群与预测的蛋白质功能能力联系起来，这可能有助于有效的巨藻消化。细菌群落组成，藻类膳食来源，平行分析了16个跨越野生鱼类中肠和后肠消化区域的宏基因组的预测酶功能。组装重叠群上的扩展碳水化合物（CAZy）和硫酸酯酶（SulfAtlas）消化酶家族的基因共定位模式用于鉴定可能的多糖利用基因座关联，并可视化靶向复合硫酸化多糖的细胞外出口蛋白质的潜在合作网络。这些对草食性海鱼的肠道微生物群及其功能能力的见解提高了我们对消化复杂巨藻硫酸多糖所涉及的酶和微生物的理解。重要性这项工作将特定的未培养的细菌分类群与海洋脊椎动物宿主缺乏的独特多糖消化能力联系起来，为解构复杂硫酸多糖的过程以及微生物获得扩大的巨藻利用基因功能的潜在进化机制提供了新的见解。已鉴定出数千个用于多糖利用的新的海洋特异性候选酶序列。这些数据为未来研究抑制珊瑚礁巨藻过度生长提供了基础资源，鱼类宿主生理学，在陆地和水产养殖动物饲料中使用大型藻类原料，以及将大型藻类生物质生物转化为增值商业燃料和化学产品。
