Volume 24, Issue 5 p. 2239-2258
Research article

Metagenomic insights into the environmental adaptation and metabolism of Candidatus Haloplasmatales, one archaeal order thriving in saline lakes

Heng Zhou

Heng Zhou

State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China

These authors contributed equally to this work.

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Dahe Zhao

Corresponding Author

Dahe Zhao

State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China

These authors contributed equally to this work.

For correspondence. E-mail [email protected]; [email protected]; Tel./Fax +86-10-64807472.

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Shengjie Zhang

Shengjie Zhang

State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China

College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China

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Qiong Xue

Qiong Xue

State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China

College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China

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Manqi Zhang

Manqi Zhang

State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China

College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China

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Haiying Yu

Haiying Yu

State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China

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Jian Zhou

Jian Zhou

State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China

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Ming Li

Ming Li

State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China

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Sumit Kumar

Sumit Kumar

Enzyme and Microbial Biochemistry Lab, Department of Chemistry, Indian Institute of Technology, Delhi, India

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Hua Xiang

Corresponding Author

Hua Xiang

State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China

College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China

For correspondence. E-mail [email protected]; [email protected]; Tel./Fax +86-10-64807472.

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First published: 20 January 2022
Citations: 4

Summary

The KTK 4A-related Thermoplasmata thrives in the sediment of saline lakes; however, systematic research on its taxonomy, environmental adaptation and metabolism is lacking. Here, we detected this abundant lineage in the sediment of five artificially separated ponds (salinity 7.0%–33.0%) within a Chinese soda-saline lake using culture-independent metagenomics and archaeal 16S rRNA gene amplicons. The phylogenies based on the 16S rRNA gene, and 122 archaeal ubiquitous single-copy proteins and genome-level identity analyses among the metagenome-assembled genomes demonstrate this lineage forming a novel order, Candidatus Haloplasmatales, comprising four genera affiliated with the identical family. Isoelectric point profiles of predicted proteomes suggest that most members adopt the energetically favourable ‘salt-in’ strategy. Functional prediction indicates the lithoheterotrophic nature with the versatile metabolic potentials for carbohydrate and organic acids as well as carbon monoxide and hydrogen utilization. Additionally, hydrogenase genes hdrABC-mvhADG are linked with incomplete reductive citrate cycle genes in the genomes, suggesting their functional connection. Comparison with the coupling of HdrABC-MvhADG and methanogenesis pathway provides new insights into the compatibility of laterally acquired methanogenesis with energy metabolism in the related order Methanomassiliicoccales. Globally, our research sheds light on the taxonomy, environmental adaptative mechanisms, metabolic potentials and evolutional significance of Ca. Haloplasmatales.