title: Soil Carbon-Fixation Rates and Associated Bacterial Diversity and Abundance in Three Natural Ecosystems.
abstract: CO2assimilation by autotrophic microbes is an important process in soil carbon cycling, and our understanding of the community composition of autotrophs in natural soils and their role in carbon sequestration of these soils is still limited. Here, we investigated the autotrophic C incorporation in soils from three natural ecosystems, i.e., wetland (WL), grassland (GR), and forest (FO) based on the incorporation of labeled C into the microbial biomass. Microbial assimilation of14C (14C-MBC) differed among the soils from three ecosystems, accounting for 14.2-20.2% of14C-labeled soil organic carbon (14C-SOC). We observed a positive correlation between the cbbL (ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) large-subunit gene) abundance,14C-SOC level, and14C-MBC concentration confirming the role of autotrophic bacteria in soil carbon sequestration. Distinct cbbL-bearing bacterial communities were present in each soil type; form IA and form IC RubisCO-bearing bacteria were most abundant in WL, followed by GR soils, with sequences from FO soils exclusively derived from the form IC clade. Phylogenetically, the diversity of CO2-fixing autotrophs and CO oxidizers differed significantly with soil type, whereas cbbL-bearing bacterial communities were similar when assessed using coxL. We demonstrate that local edaphic factors such as pH and salinity affect the C-fixation rate as well as cbbL and coxL gene abundance and diversity. Such insights into the effect of soil type on the autotrophic bacterial capacity and subsequent carbon cycling of natural ecosystems will provide information to enhance the sustainable management of these important natural ecosystems.
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Observation and Research Station for Agricultural Environment, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan Province, 410125, China.|Biotechnology Research Department, Ministry of Education, Kyaukse, Myanmar.
authors.forename: Tin Mar
authors.initials: TM
authors.lastname: Lynn
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Observation and Research Station for Agricultural Environment, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan Province, 410125, China. gtd@isa.ac.cn.|UWA-CAS Joint Laboratory in Soil System Science, Changsha, 410125, China. gtd@isa.ac.cn.
authors.forename: Tida
authors.initials: T
authors.lastname: Ge
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Observation and Research Station for Agricultural Environment, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan Province, 410125, China.
authors.forename: Hongzhao
authors.initials: H
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Observation and Research Station for Agricultural Environment, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan Province, 410125, China.
authors.forename: Xiaomeng
authors.initials: X
authors.lastname: Wei
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Observation and Research Station for Agricultural Environment, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan Province, 410125, China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wu
authors.affiliation: Center for Geomicrobiology, Department of Bioscience, Aarhus University, NyMunkegade 114, 8000, Aarhus C, Denmark.
authors.forename: Keqing
authors.initials: K
authors.lastname: Xiao
authors.affiliation: UWA-CAS Joint Laboratory in Soil System Science, Changsha, 410125, China.|School of Earth and Environment, The University of Western Australia, Crawley, WA, 6009, Australia.
authors.forename: Deepak
authors.initials: D
authors.lastname: Kumaresan
authors.affiliation: Biotechnology Research Department, Ministry of Education, Kyaukse, Myanmar.
authors.forename: San San
authors.initials: SS
authors.lastname: Yu
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Observation and Research Station for Agricultural Environment, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan Province, 410125, China.|UWA-CAS Joint Laboratory in Soil System Science, Changsha, 410125, China.
authors.forename: Jinshui
authors.initials: J
authors.lastname: Wu
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Observation and Research Station for Agricultural Environment, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan Province, 410125, China.|UWA-CAS Joint Laboratory in Soil System Science, Changsha, 410125, China.|School of Earth and Environment, The University of Western Australia, Crawley, WA, 6009, Australia.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Whiteley
mesh_terms: D052818:Autotrophic Processes / Q000235:genetics / Q000502:physiology*; D001419:Bacteria / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D057486:Carbon Cycle / Q000502:physiology*; D002245:Carbon Dioxide / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D065928:Forests; D065948:Grassland; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D053833:Wetlands
chemical_list: D004269:DNA, Bacterial; D012987:Soil; D002245:Carbon Dioxide; D002244:Carbon; D012273:Ribulose-Bisphosphate Carboxylase
keywords: 14C continuous labeling; Carbon sequestration; Edaphic factors; Natural soils; cbbL; coxL