NosZ I carrying microorganisms determine N2O emissions from the subtropical paddy field under elevated CO2 and strongly CO2-responsive cultivar

Zijian Qiu; Haiyang Yu; Chunwu Zhu; Weishou Shen

doi:10.1016/j.scitotenv.2024.173255

NosZ I carrying microorganisms determine N₂O emissions from the subtropical paddy field under elevated CO₂ and strongly CO₂-responsive cultivar

Sci Total Environ. 2024 May 17:935:173255. doi: 10.1016/j.scitotenv.2024.173255. Online ahead of print.

Authors

Zijian Qiu¹, Haiyang Yu², Chunwu Zhu³, Weishou Shen⁴

Affiliations

¹ Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
² Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315800, China; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
³ State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
⁴ Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China. Electronic address: wsshen@nuist.edu.cn.

PMID: 38761936
DOI: 10.1016/j.scitotenv.2024.173255

Abstract

Elevated CO₂ (eCO₂) decreases N₂O emissions from subtropical paddy fields, but the underlying mechanisms remain to be investigated. Herein, the response of key microbial nitrogen cycling genes to eCO₂ (ambient air +200 μmol CO₂ mol^-1) in four rice cultivars, including two weakly CO₂-responsive (W27, H5) and two strongly CO₂-responsive cultivars (Y1540, L1988), was investigated. Except for nosZ I, eCO₂ did not significantly alter the abundance of the other genes. NosZ I was a crucial factor governing N₂O emissions, especially under eCO₂ and a strongly responsive cultivar. eCO₂ affected the nosZ I gene abundance (p < 0.05), for instance, the nosZ I gene abundance of cultivar W27 increased from 1.53 × 10⁷ to 2.86 × 10⁷ copies g^-1 dw soil (p < 0.05). In the nosZ I microbial community, the known taxa were mainly Pseudomonadota (phylum) (19.74-31.72 %) and Alphaproteobacteria (class) (0.56-13.12 %). In the nosZ I community assembly process, eCO₂ enhanced the role of stochasticity, increasing from 35 % to 85 % (p < 0.05), thereby inducing diffusion limitations of weakly responsive cultivars to dominate (67 %). Taken together, the increase in nosZ I gene abundance is a potential reason for the alleviation of N₂O emissions from subtropical paddy fields under eCO₂.

Keywords: Elevated CO(2); Free-air CO(2) enrichment (FACE); Keystone taxa; N(2)O; Strongly/weakly CO(2)-responsive cultivar; nosZ I.