Payne Paige E, Knobbe Loren N, Chanton Patricia, Zaugg Julian, Mortazavi Behzad, Mason Olivia U
Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, Florida, USA.
Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, USA.
mSystems. 2025 Jan 21;10(1):e0116224. doi: 10.1128/msystems.01162-24. Epub 2024 Dec 23.
, particularly uncultured representatives, are one of the most abundant microbial groups in coastal salt marshes, dominating the belowground rhizosphere, where over half of plant biomass production occurs. However, this class generally remains poorly understood, particularly in a salt marsh context. Here, novel metagenome-assembled genomes (MAGs) were generated from the salt marsh rhizosphere representing , , JAAYZQ01, B4-G1, JAFGEY01, UCB3, and orders. Metagenome and metatranscriptome reads were mapped to annotated MAGs, revealing nearly all encoded and transcribed genes required for oxidation of carbon compounds ranging from simple sugars to complex polysaccharides, fermentation, and carbon fixation. Furthermore, the majority of expressed genes involved in anaerobic and aerobic respiration and secondary metabolite production. The data revealed that the belowground salt marsh in the rhizosphere are important players in carbon cycling, including degradation of simple carbon compounds and more recalcitrant plant material, such as cellulose, using a diversity of electron acceptors and represent an unexplored reservoir of novel secondary metabolites.IMPORTANCEGiven that coastal salt marshes are recognized as biogeochemical hotspots, it is fundamentally important to understand the functional role of the microbiome in this ecosystem. In particular, are abundant members of the salt marsh rhizosphere and have been identified as core microbes, suggesting they play an important functional role. Yet, little is known about the metabolic pathways encoded and expressed in this abundant salt marsh clade. Using an 'omics-based approach, we determined that are capable of oxidizing a range of carbon compounds, including simple sugars to complex carbon compounds, while also encoding fermentation and carbon fixation. Surprisingly, encoded and transcribed genes involved in aerobic respiration, which was unexpected given the reduced nature of the salt marsh rhizosphere. Finally, the majority of appear to be involved in secondary metabolite production, suggesting that this group represents an unexplored reservoir of novel and important secondary metabolites.
特别是未培养的代表菌群，是沿海盐沼中最丰富的微生物群体之一，在地下根际占主导地位，而植物生物量生产的一半以上发生在根际。然而，这一类群通常仍未得到充分了解，尤其是在盐沼环境中。在这里，从盐沼根际生成了新的宏基因组组装基因组（MAGs），代表了[具体菌群名称未给出]、[具体菌群名称未给出]、JAAYZQ01、B4 - G1、JAFGEY01、UCB3和[具体菌群名称未给出]目。宏基因组和宏转录组读数被映射到注释的MAGs上，揭示了从单糖到复杂多糖的碳化合物氧化、发酵和碳固定所需的几乎所有编码和转录基因。此外，大多数表达的基因参与厌氧和好氧呼吸以及次级代谢产物的产生。数据表明，根际地下盐沼[具体菌群名称未给出]是碳循环的重要参与者，包括利用多种电子受体降解简单碳化合物和更难降解的植物物质，如纤维素，并且代表了一个未被探索的新型次级代谢产物库。
重要性
鉴于沿海盐沼被认为是生物地球化学热点，了解微生物群落在这个生态系统中的功能作用至关重要。特别是[具体菌群名称未给出]是盐沼根际的丰富成员，并已被确定为核心微生物，表明它们发挥着重要的功能作用。然而，对于这个丰富的盐沼进化枝中编码和表达的代谢途径知之甚少。使用基于“组学”的方法，我们确定[具体菌群名称未给出]能够氧化一系列碳化合物，包括从单糖到复杂碳化合物，并同时编码发酵和碳固定。令人惊讶的是，[具体菌群名称未给出]编码并转录了参与有氧呼吸的基因，考虑到盐沼根际的还原性质，这是出乎意料的。最后，大多数[具体菌群名称未给出]似乎参与次级代谢产物的产生，这表明该群体代表了一个未被探索的新型和重要次级代谢产物库。
