Plant-microbe alliances in greenhouse gas mitigation in terrestrial soils: a systematic review.

One of the challenges for climate-smart agriculture and ecosystem restoration is mitigating greenhouse gas (GHG) emissions. This study evaluated how plant-microbe interactions mitigate GHG emissions in terrestrial soils and identified the biological mechanisms underpinning these effects. A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. We retrieved 2,647 studies, and 24 met the inclusion criteria. We assessed study quality using predefined criteria and synthesized findings using a semi-quantitative approach. Most studies reported that plant-microbe interactions in terrestrial soils substantially reduce GHG emissions. Plant species mainly involved in the plant-microbe interactions are rice (17.9%), maize (14.3%), and tomato (10.7%). Fungi (53.6%), bacteria (42.9%), and archaea (3.6%) dominated the microbial groups. Of all the taxa, Bacillus had the highest occurrence (14.3%), followed by arbuscular mycorrhizal fungi (12.2%), Rhizophagus (10.2%), and Pseudomonas (6.1%). Mechanisms involved have been proposed to include carbon sequestration, regulation of nitrification and denitrification pathways, and stimulation of methane oxidation. The decrease substantially outweighed the increase across all GHGs. Up to 30.23% of the studies reported decreased carbon dioxide (CO2) and nitrous oxide (N2O) emissions, and 13.95% reported decreased methane (CH4) emissions. Studies reporting increased emissions accounted for 4.65%, 6.98%, and 4.65% of the total for CO2, N2O, and CH4, respectively. The substantial decrease relative to the increase across all gases indicates a net mitigation effect and suggests the potential of plant-microbe partnerships as practical, natural ways to mitigate greenhouse gas emissions.