Cultivable, Host-Specific Bacteroidetes Symbionts Exhibit Diverse Polysaccharolytic Strategies
Cultivable, Host-Specific Bacteroidetes Symbionts Exhibit Diverse Polysaccharolytic Strategies
复制标题
DOI：
10.1128/aem.00091-20
复制
发表时间：
2020-04-01
影响因子：
4.4
通讯作者：
Sabree, Zakee L.
中科院分区：
文献类型：
--
作者：
de Leon, Arturo Vera-Ponce;Jahnes, Benjamin C.;Sabree, Zakee L.
有益的肠道微生物可以促进昆虫在不同的饮食中生长。杂食性美洲蟑螂，美洲大蠊（昆虫纲：大蠊科），在富含植物多糖的饮食中茁壮成长，并拥有丰富的肠道微生物群，对宿主的饮食有反应。拟杆菌门是美洲蠊和其他蟑螂中最丰富的类群之一，这些潜在的多糖细菌可能有助于宿主的饮食加工。从美洲假单胞菌消化道中分离出11株拟杆菌门，系统发育分析表明它们是新的拟杆菌门、Dysgonomonas、Paludibacter和Parabacteroides种，不同于以前从其他昆虫、人类和环境来源中分离出的拟杆菌门。此外，每个分离物都生成了完整的基因组，并在每个分离物基因组中注释了多糖利用位点（PULs）和几个非PULs相关的碳水化合物活性酶（CAZyme）编码基因，这些基因被认为针对淀粉、果胶和/或纤维素。在一些菌株中观察到带有相应的T9SS识别和输出c端结构域的IX型分泌系统（T9SS）和cazyme编码基因，表明这些cazyme通过非pul外膜转座子部署。此外，单底物生长和酶促分析证实了基因组预测，即拟杆菌和厌糖单胞菌分离物的一个子集可以降解淀粉、果胶和/或纤维素，并在这些底物作为单一糖源存在的情况下生长。植物多糖丰富了美洲假单胞虫的饮食，许多这些肠道分离物都很好地利用了宿主的饮食输入，并可能有助于肠道群落和宿主的营养可及性。重要性肠道微生物越来越被认为是动物营养可及性的关键贡献者。全球分布的杂食性美洲大蠊（美洲大蠊）含有许多细菌门（如拟杆菌门），这些细菌门在脊椎动物中含量丰富。美洲p.a americana在高度多样化的富含植物的饮食中茁壮成长，使这种昆虫成为非特征的多糖细菌的丰富潜在来源。我们已经培养了几种新的拟杆菌门细菌，对它们进行了完整的测序，并对它们进行了功能表征，这些细菌是美国p.a americana肠道特有的，其中许多菌株可以降解简单和复杂的多糖。这些拟杆菌门分离物的培养和基因组特征进一步使人们能够更深入地了解这些分类群如何参与多糖代谢，更广泛地说，它们如何影响动物的健康和发育。
Beneficial gut microbes can facilitate insect growth on diverse diets. The omnivorous American cockroach, Periplaneta americana (Insecta: Blattodea), thrives on a diet rich in plant polysaccharides and harbors a species-rich gut microbiota responsive to host diet. Bacteroidetes are among the most abundant taxa in P. americana and other cockroaches, based on cultivation-independent gut community profiling, and these potentially polysaccharolytic bacteria may contribute to host diet processing. Eleven Bacteroidetes isolates were cultivated from P. americana digestive tracts, and phylogenomic analyses suggest that they were new Bacteroides, Dysgonomonas, Paludibacter, and Parabacteroides species distinct from those previously isolated from other insects, humans, and environmental sources. In addition, complete genomes were generated for each isolate, and polysaccharide utilization loci (PULs) and several non-PUL-associated carbohydrate-active enzyme (CAZyme)-coding genes that putatively target starch, pectin, and/or cellulose were annotated in each of the isolate genomes. Type IX secretion system (T9SS)- and CAZyme-coding genes tagged with the corresponding T9SS recognition and export C-terminal domain were observed in some isolates, suggesting that these CAZymes were deployed via non-PUL outer membrane translocons. Additionally, single-substrate growth and enzymatic assays confirmed genomic predictions that a subset of the Bacteroides and Dysgonomonas isolates could degrade starch, pectin, and/or cellulose and grow in the presence of these substrates as a single sugar source. Plant polysaccharides enrich P. americana diets, and many of these gut isolates are well equipped to exploit host dietary inputs and potentially contribute to gut community and host nutrient accessibility.IMPORTANCE Gut microbes are increasingly being recognized as critical contributors to nutrient accessibility in animals. The globally distributed omnivorous American cockroach (Periplaneta americana) harbors many bacterial phyla (e.g., Bacteroidetes) that are abundant in vertebrates. P. americana thrives on a highly diverse plant-enriched diet, making this insect a rich potential source of uncharacterized polysaccharolytic bacteria. We have cultivated, completely sequenced, and functionally characterized several novel Bacteroidetes species that are endemic to the P. americana gut, and many of these isolates can degrade simple and complex polysaccharides. Cultivation and genomic characterization of these Bacteroidetes isolates further enable deeper insight into how these taxa participate in polysaccharide metabolism and, more broadly, how they affect animal health and development.