Rakitin Andrey L, Kulichevskaya Irina S, Beletsky Alexey V, Mardanov Andrey V, Dedysh Svetlana N, Ravin Nikolai V
Institute of Bioengineering, Research Center of Biotechnology, Russian Academy of Sciences, Moscow 119071, Russia.
Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, Moscow 119071, Russia.
Microorganisms. 2024 Nov 8;12(11):2271. doi: 10.3390/microorganisms12112271.
The phylum is one of the main groups of soil prokaryotes, which remains poorly represented by cultivated organisms. The major recognized role of in soils is the degradation of plant-derived organic matter. These bacteria are particularly abundant in peatlands, where xylan-type hemicelluloses represent one of the most actively decomposed peat constituents. The aim of this work was to characterize the microorganisms capable of hydrolyzing xylan under the anoxic conditions typical of peatland soils. The laboratory incubation of peat samples with xylan resulted in the pronounced enrichment of several phylotypes affiliated with the , , and . Sequencing of the metagenome of the enrichment culture allowed us to recover high-quality metagenome-assembled genomes (MAGs) assigned to the genera , (), (), () and the uncultured genus-level lineage of the family (). The latter bacterium, designated " Chthoniomicrobium xylanophilum" SH-KS-3, dominated in the metagenome and its MAG was assembled as a complete closed chromosome. An analysis of the SH-KS-3 genome revealed potential endo-1,4-beta-xylanases, as well as xylan beta-1,4-xylosidases and other enzymes involved in xylan utilization. A genome analysis revealed the absence of aerobic respiration and predicted chemoheterotrophic metabolism with the capacity to utilize various carbohydrates, including cellulose, and to perform fermentation or nitrate reduction. An analysis of other MAGs suggested that and could play the role of primary xylan degraders while other community members probably took advantage of the availability of xylo-oligosaccharides and xylose or utilized low molecular weight organics.
该菌门是土壤原核生物的主要类群之一，但其培养生物的代表性仍然很差。该菌门在土壤中的主要公认作用是降解植物衍生的有机物质。这些细菌在泥炭地中特别丰富，在那里木聚糖型半纤维素是最易分解的泥炭成分之一。这项工作的目的是鉴定在泥炭地土壤典型的缺氧条件下能够水解木聚糖的微生物。用木聚糖对泥炭样品进行实验室培养，导致与该菌门、该菌门和该菌门相关的几种系统型显著富集。对富集培养物的宏基因组进行测序，使我们能够获得高质量的宏基因组组装基因组（MAG），这些基因组被分配到该属、该属（该属）、该属（该属）、该属（该属）以及该科未培养的属级谱系（该属）。后一种细菌，命名为“嗜木栖地微菌”SH-KS-3，在宏基因组中占主导地位，其MAG被组装成一个完整的封闭染色体。对SH-KS-3基因组的分析揭示了潜在的内切-1,4-β-木聚糖酶、木聚糖β-1,4-木糖苷酶和其他参与木聚糖利用的酶。基因组分析表明，该菌缺乏有氧呼吸，预测其具有化学异养代谢能力，能够利用包括纤维素在内的各种碳水化合物，并进行发酵或硝酸盐还原。对其他MAG的分析表明，该属和该属可能发挥主要木聚糖降解者的作用，而其他群落成员可能利用木寡糖和木糖的可用性，或利用低分子量有机物。
