Peptide-driven changes in rice roots shift microbial metabolism and reduce methane emissions
Waterlogged paddy soils create anaerobic environments that support the growth of methanogenic archaea, contributing 7-17% of global methane (CH4) emissions. Prior work has shown that rice varieties with more extensive root aerenchyma can better oxygenate the surrounding soil, thereby reducing CH4 emissions. Additionally, peptides such as PLANT PEPTIDES CONTAINING SULFATED TYROSINE (PSY) have been shown to influence root growth in Arabidopsis thaliana and affect the production of root exudates that could serve as substrates for CH4 production. Here, Shi and coauthors tested if overexpressing rice OsPSY1 (oxOsPSY1) and OsPSY2 (oxOsPSY2) could modulate root architecture, rhizosphere microbial activity, and CH4 cycling. They found that oxOsPSY1 and oxOsPSY2 lines developed longer seminal roots and enhanced aerenchyma formation. Compared to Kitaake control, these genotypes released ~38% and ~58% less cumulative CH4 over a 10-week growth period. Although the overall microbial community structure in oxOsPSY1 remained largely unchanged, transcriptional activities were notably altered: CH4-producing genes were less active, H2-consuming hydrogenases were upregulated, and H2-producing hydrogenases were downregulated. Metabolomic analysis and metabolic modeling further supported these observations, predicting higher H2 consumption and lower H2 production in the oxOsPSY1 rhizosphere. Taken together, this study reveals a plant peptide-driven strategy to mitigate rice paddy methane emissions by restructuring microbial H2 metabolism in the rhizosphere. (Summary by Aditi Bhat @jumpy_botanist) Nature Comms 10.1038/s41467-026-68640-9
