Microbial population genomes from the Amazon River reveal possible modulation of the organic matter degradation process in tropical freshwaters
Microbial population genomes from the Amazon River reveal possible modulation of the organic matter degradation process in tropical freshwaters
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DOI：
10.1111/mec.16222
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发表时间：
2021-10
影响因子：
4.9
通讯作者：
C. D. Santos-Júnior;R. Logares;F. Henrique-Silva
中科院分区：
文献类型：
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作者：
C. D. Santos-Júnior;R. Logares;F. Henrique-Silva
河流通过运输和转化陆地有机物（TeOM）将陆地碳循环与水生生态系统的碳循环联系起来。亚马逊河从周围的雨林中接收大量的TeOM，促进了大量的微生物异养活动，从而释放出二氧化碳。在亚马逊河中，微生物降解了TeOM中高达55%的木质素。然而，参与TeOM降解的主要微生物基因组是未知的。在这里，我们表征了51个种群基因组（PG），代表了亚马逊河中最丰富的微生物，来自106个宏基因组。这51个重建的PG是亚马逊河中最丰富的微生物之一，其中53%不能降解TeOM。在能够降解TeOM的PG中，20%是完全纤维素分解的，而其他的PG也可以氧化木质素。木质素氧化副产物的运输和消耗似乎与氧化过程脱钩，显然是由不同的微生物群进行的。通过将亚马逊河丰富微生物的基因组特征与TeOM的降解机制联系起来，我们认为复杂的微生物群落可以解释之前在该生态系统中观察到的TeOM的快速周转。
Rivers connect the carbon cycle in land with that in aquatic ecosystems by transporting and transforming terrestrial organic matter (TeOM). The Amazon River receives huge loads of TeOM from the surrounding rainforest, promoting a substantial microbial heterotrophic activity and consequently, CO2 outgassing. In the Amazon River, microbes degrade up to 55% of the lignin present in the TeOM. Yet, the main microbial genomes involved in TeOM degradation were unknown. Here, we characterize 51 population genomes (PGs) representing some of the most abundant microbes in the Amazon River deriving from 106 metagenomes. The 51 reconstructed PGs are among the most abundant microbes in the Amazon River, and 53% of them are not able to degrade TeOM. Among the PGs capable of degrading TeOM, 20% were exclusively cellulolytic, while the others could also oxidize lignin. The transport and consumption of lignin oxidation byproducts seemed to be decoupled from the oxidation process, being apparently performed by different groups of microorganisms. By connecting the genomic features of abundant microbes in the Amazon River with the degradation machinery of TeOM, we suggest that a complex microbial consortium could explain the quick turnover of TeOM previously observed in this ecosystem.