1. Metagenomic and 14 C tracing evidence for autotrophic microbial CO 2 fixation in paddy soils.
- Author
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Xiao KQ, Ge TD, Wu XH, Peacock CL, Zhu ZK, Peng J, Bao P, Wu JS, and Zhu YG
- Subjects
- Autotrophic Processes, Bacteria chemistry, Bacteria classification, Bacterial Proteins genetics, Bacterial Proteins metabolism, Carbon Cycle, Carbon Isotopes metabolism, China, Isotope Labeling, Metagenome, Metagenomics, Photosynthesis, Ribulose-Bisphosphate Carboxylase genetics, Ribulose-Bisphosphate Carboxylase metabolism, Soil chemistry, Bacteria genetics, Bacteria metabolism, Carbon Dioxide metabolism, Carbon Isotopes analysis, Soil Microbiology
- Abstract
Autotrophic carbon dioxide (CO
2 ) fixation by microbes is ubiquitous in the environment and potentially contributes to the soil organic carbon (SOC) pool. However, the multiple autotrophic pathways of microbial carbon assimilation and fixation in paddy soils remain poorly characterized. In this study, we combine metagenomic analysis with14 C-labelling to investigate all known autotrophic pathways and CO2 assimilation mechanisms in five typical paddy soils from southern China. Marker genes of six autotrophic pathways are detected in all soil samples, which are dominated by the cbbL genes (67%-82%) coding the ribulose-bisphosphate carboxylase large chain in the Calvin cycle. These marker genes are associated with a broad range of phototrophic and chemotrophic genera. Significant amounts of14 C-CO2 are assimilated into SOC (74.3-175.8 mg14 C kg-1 ) and microbial biomass (5.2-24.1 mg14 C kg-1 ) after 45 days incubation, where more than 70% of14 C-SOC was concentrated in the relatively stable humin fractions. These results show that paddy soil microbes contain the genetic potential for autotrophic carbon fixation spreading over broad taxonomic ranges, and can incorporate atmospheric carbon into organic components, which ultimately contribute to the stable SOC pool., (© 2020 Society for Applied Microbiology and John Wiley & Sons Ltd.)- Published
- 2021
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