Position-Specific Metabolic Probing and Metagenomics of Microbial Communities Reveal Conserved Central Carbon Metabolic Network Activities at High Temperatures
Position-Specific Metabolic Probing and Metagenomics of Microbial Communities Reveal Conserved Central Carbon Metabolic Network Activities at High Temperatures
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DOI：
10.3389/fmicb.2019.01427
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发表时间：
2019-07
影响因子：
5.2
通讯作者：
Scott C Thomas;Kevin O. Tamadonfar;Cale O. Seymour;Dengxun Lai;J. Dodsworth;S. Murugapiran;E. Eloe-Fadrosh-E.-E
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文献类型：
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作者：
Scott C Thomas;Kevin O. Tamadonfar;Cale O. Seymour;Dengxun Lai;J. Dodsworth;S. Murugapiran;E. Eloe-Fadrosh-E.-E
温度是微生物群落组成和分类多样性的主要驱动因素；然而，在群落水平上，温度对中心碳代谢途径（CCMPs）特征的影响程度尚不清楚。本研究采用16S rRNA基因扩增子、宏基因组测序和13c标记代谢物探测相结合的方法，在60-95°C的温度梯度下，对大沸泉地区CCMPs群落的碳代谢进行了研究。16S rRNA基因扩增子多样性与温度成反比，古菌在较高温度下占主导地位。KO的丰富度和多样性也与温度成反比，但CCMP基因在温度梯度上的表现相似，许多个体宏基因组组装的基因组具有完整的途径。相比之下，编码纤维素的基因和许多参与植物物质降解和光合作用的基因在高温下缺失。葡萄糖、丙酮酸和乙酸标记同位素对的原位13C-CO2生产表明，在60°C时，戊糖磷酸氧化途径活性和/或发酵较低，在较高温度下维持能量需求稳定或减少。在85℃下观察13c标记的柠檬酸盐、琥珀酸盐、l -丙氨酸、l -丝氨酸和l -半胱氨酸的分解代谢，显示出广泛的异养活性，并证实了TCA循环的功能。总之，这些结果表明，温度驱动的地热系统中生物多样性和基因含量的损失可能不会改变CCMP的功能或维持群落水平的能量需求。
Temperature is a primary driver of microbial community composition and taxonomic diversity; however, it is unclear to what extent temperature affects characteristics of central carbon metabolic pathways (CCMPs) at the community level. In this study, 16S rRNA gene amplicon and metagenome sequencing were combined with 13C-labeled metabolite probing of the CCMPs to assess community carbon metabolism along a temperature gradient (60–95°C) in Great Boiling Spring, NV. 16S rRNA gene amplicon diversity was inversely proportional to temperature, and Archaea were dominant at higher temperatures. KO richness and diversity were also inversely proportional to temperature, yet CCMP genes were similarly represented across the temperature gradient and many individual metagenome-assembled genomes had complete pathways. In contrast, genes encoding cellulosomes and many genes involved in plant matter degradation and photosynthesis were absent at higher temperatures. In situ 13C-CO2 production from labeled isotopomer pairs of glucose, pyruvate, and acetate suggested lower relative oxidative pentose phosphate pathway activity and/or fermentation at 60°C, and a stable or decreased maintenance energy demand at higher temperatures. Catabolism of 13C-labeled citrate, succinate, L-alanine, L-serine, and L-cysteine was observed at 85°C, demonstrating broad heterotrophic activity and confirming functioning of the TCA cycle. Together, these results suggest that temperature-driven losses in biodiversity and gene content in geothermal systems may not alter CCMP function or maintenance energy demands at a community level.