Continental-scale characterization of pesticide cocktails in paddy soils: Associations with microbial community...

Modern agricultural practices lead to complex pesticide cocktails in paddy ecosystems, yet their extensive ecological associations with microbial communities and soil biogeochemical cycles remain largely uncharacterized under real-world conditions. Continental-scale investigation across 48 Chinese paddy regions revealed pervasive pesticide contamination, detecting 50 prevalent pesticide residues with widespread co-occurrence patterns (≥ 9 compounds at 90 % sites). Triazole fungicides correlated with suppression of nitrification, denitrification, and dissimilatory nitrate reduction to ammonium (DNRA) genes, suggesting potential disruptions in nitrogen fluxes and nutrient dynamics, possibly contributing to nitrate/nitrite accumulation. Risk quotient-based stratification revealed that high-risk sites exhibited reduced network robustness and modularity, alongside elevated metabolic potential for xenobiotic biodegradation. Notably, 41.2 % of the recovered metagenome-assembled genomes, dominated by Chitinophagales and Gemmatimonadales, encoded dual capabilities for xenobiotic biodegradation and nitrogen cycling, highlighting a potential trade-off. Ubiquitous extracellular vesicles (EVs) were detected in paddy soils at substantial concentrations and were functionally enriched in TonB-dependent transporters and stress-response proteins, suggesting their potential involvement in overcoming pesticide bioavailability barriers. In vitro co-incubation assays further confirmed EVs' capacity as nanoscale carriers for pesticides like tebuconazole. This continental-scale multi-omics integration (pesticide-microbe-EV) advances our understanding of pesticide cocktails' impacts on soil ecological resilience, with significant implications for the sustainability of global rice cultivation systems.