Tissue-specific responses and interactive characteristics of crop-microbe "One Health" system to soil chromium and ofloxacin pollution

Coexistence of antibiotics and heavy metals in agroecosystems promotes antibiotic resistance genes in crops, thus posing risks to human health. It is imperative to comprehensively understand the effects of such co-contaminated environments on the crop-microbe "One Health" system for assessing environmental risks and guiding agricultural practices. Therefore, this study aimed to investigated the tissue-specific responses and interactive characteristics of the crop-microbe system to co-pollution with ofloxacin (OFL) and chromium (Cr) in soil. The results emphasized the hormesis effect induced by low-dose OFL (1 mg L−1) on ginger plants subjected to soil Cr stress. However, plants co-stressed with high-dose OFL (100 mg L−1) and Cr exhibited reduced growth, root activity, antioxidant enzyme activities and photosynthesis-fluorescence performances. In addition, the reactive oxygen species (ROS) levels, reflected by superoxide radical (O2·-) and hydrogen peroxide (H2O2), significantly increased up to 43.34% and 78.63%, respectively, compared to other treatments. High-throughput sequencing indicated that OFL influenced rhizosphere microbial diversity, composition, and evolution, favoring Proteobacteriaproliferation under co-pollution. Notably, enrichments of the antibiotic resistance gene (qnrS) in edible rhizome and potential pathogenic bacteria in ginger rhizosphere were observed under OFL and Cr co-pollution, posing the risk of its spread in the environment and food chain.