Elevated CO2 and nitrogen addition enhance the symbiosis and functions of rhizosphere microorganisms under cadmium exposure

Minghao Chen; Shuyidan Zhou; Ping Xiang; Yutao Wang; Xianzhen Luo; Xiaofeng Zhang; Dazhi Wen

doi:10.1016/j.jenvman.2023.120012

Elevated CO₂ and nitrogen addition enhance the symbiosis and functions of rhizosphere microorganisms under cadmium exposure

J Environ Manage. 2024 Feb:351:120012. doi: 10.1016/j.jenvman.2023.120012. Epub 2024 Jan 2.

Authors

Minghao Chen¹, Shuyidan Zhou², Ping Xiang¹, Yutao Wang³, Xianzhen Luo², Xiaofeng Zhang¹, Dazhi Wen⁴

Affiliations

¹ Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Science, Guangzhou, 510650, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China.
² Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Science, Guangzhou, 510650, China.
³ Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education and Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, 510631, China.
⁴ Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Science, Guangzhou, 510650, China; College of Life Sciences, Gannan Normal University, Ganzhou, Jiangxi, 341000, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China. Electronic address: dzwen@scbg.ac.cn.

PMID: 38171127
DOI: 10.1016/j.jenvman.2023.120012

Abstract

Soil microbes are fundamental to ecosystem health and productivity. How soil microbial communities are influenced by elevated atmospheric carbon dioxide (eCO₂) concentration and nitrogen (N) deposition under heavy metal pollution remains uncertain, despite global exposure of terrestrial ecosystems to eCO₂, high N deposition and heavy metal stress. Here, we conducted a four year's open-top chamber experiment to assess the effects of soil cadmium (Cd) treatment (10 kg hm^-2 year^-1) alone and combined treatments of Cd with eCO₂ concentration (700 ppm) and/or N addition (100 kg hm^-2 year^-1) on tree growth and rhizosphere microbial community. Relative to Cd treatment alone, eCO₂ concentration in Cd contaminated soil increased the complexity of microbial networks, including the number links, average degree and positive/negative ratios. The combined effect of eCO₂ and N addition in Cd contaminated soil not only increased the complexity of microbial networks, but also enhanced the abundance of microbial urealysis related UreC and nitrifying related amoA1 and amoA2, and the richness of arbuscular mycorrhiza fungi (AMF), thereby improving the symbiotic functions between microorganisms and plants. Results from correlation analysis and structural equation model (SEM) further demonstrated that eCO₂ concentration and N addition acted on functions and networks differently. Elevated CO₂ positively regulated microbial networks and functions through phosphorus (P) and Cd concentration in roots, while N addition affected microbial functions through soil available N and soil organic carbon (SOC) concentration and microbial network through soil Cd concentration. Overall, our findings highlight that eCO₂ concentration and N addition make microbial communities towards ecosystem health that may mitigate Cd stress, and provide new insights into the microbiology supporting phytoremediation for Cd contaminated sites in current and future global change scenarios.

Keywords: Cadmium pollution; Global change; Nutrient cycling; Phytoremediation; Rhizosphere symbiosis.

MeSH terms

Cadmium / chemistry
Carbon
Carbon Dioxide / analysis
Metals, Heavy* / analysis
Microbiota*
Nitrogen / analysis
Rhizosphere
Soil / chemistry
Soil Microbiology
Symbiosis

Substances

Cadmium
Carbon Dioxide
Nitrogen
Carbon
Soil
Metals, Heavy