Microbial traits determine soil C emission in response to fresh carbon inputs in forests across biomes

• Published in: Global change biology Vol. 28; no. 4; pp. 1516 - 1528
• Main Authors: Ren, Chengjie, Wang, Jieying, Bastida, Felipe, Delgado‐Baquerizo, Manuel, Yang, Yuanhe, Wang, Jun, Zhong, Zekun, Zhou, Zhenghu, Zhang, Shuohong, Guo, Yaoxin, Zhou, Sha, Wei, Gehong, Han, Xinhui, Yang, Gaihe, Zhao, Fazhu
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.02.2022
• Subjects: Aromatic compounds; Bacterial genomes; Biodegradation; Carbon; Carbon 13; carbon metabolism; Climate; cold; Ecosystem; Ecosystems; Emissions; forest biomes; Forests; Genes; Genomes; global change; Glucosidase; lignin; Metabolism; metagenomic sequencing; Metagenomics; microbial functional profiles; Microorganisms; Priming; priming effect; Saccharides; Soil; soil carbon; Soil Microbiology; Soil microorganisms; Soil temperature; Soils; Stocks; sugars; Temperate forests; temperature; Tropical climate; Tropical forests; metagenomic sequencing; genomes; priming effect; forest biomes; microbial functional profiles
• ISSN: 1354-1013; 1365-2486; 1365-2486
• DOI: 10.1111/gcb.16004

Soil priming is a microbial‐driven process, which determines key soil–climate feedbacks in response to fresh carbon inputs. Despite its importance, the microbial traits behind this process are largely undetermined. Knowledge of the role of these traits is integral to advance our understanding of how soil microbes regulate carbon (C) emissions in forests, which support the largest soil carbon stocks globally. Using metagenomic sequencing and 13C‐glucose, we provide unprecedented evidence that microbial traits explain a unique portion of the variation in soil priming across forest biomes from tropical to cold temperature regions. We show that microbial functional profiles associated with the degradation of labile C, especially rapid simple sugar metabolism, drive soil priming in different forests. Genes involved in the degradation of lignin and aromatic compounds were negatively associated with priming effects in temperate forests, whereas the highest level of soil priming was associated with β‐glucosidase genes in tropical/subtropical forests. Moreover, we reconstructed, for the first time, 42 whole bacterial genomes associated with the soil priming effect and found that these organisms support important gene machinery involved in priming effect. Collectively, our work demonstrates the importance of microbial traits to explain soil priming across forest biomes and suggests that rapid carbon metabolism is responsible for priming effects in forests. This knowledge is important because it advances our understanding on the microbial mechanisms mediating soil–climate feedbacks at a continental scale. Microbial traits explain a unique portion of variation in soil priming across forest biomes and the reconstructed genomes of bacterial species, which support important gene machinery involving in this soil process in forests. During this process, microbial C decomposition genes indirectly drive variation in soil priming effect through altering soil substrates and the activity of soil enzymes related to C cycling. In addition, soils dominated by genes involved in the degradation of lignin and aromatic compounds were negatively associated with priming effects in temperate forests, whereas the highest level of soil priming was associated with β‐glucosidase genes in tropical/subtropical forests.