Multi-omics association analysis of the toxicity mechanism differences of typical veterinary antibiotics on tomatoes: From physiological inhibition to metabolic reprogramming.

Widespread application of veterinary antibiotics is contaminating soil via animal feces, leading to uptake by plants and environmental damage. Currently, research on the toxicological mechanisms associated with various classes of antibiotics remains inadequate. Therefore, this study utilized tomato as the test species and selected three representative antibiotics-chlortetracycline (CTC), enrofloxacin (ENR), and tylosin (TYL)-to systematically evaluate their differential toxicity and associated metabolic mechanisms through 14 and 28 days exposure experiments. At the individual level, antibiotics significantly suppressed biomass accumulation and photosynthesis in tomato seedlings, the ENR exhibited maximum inhibition rates of 37.4% for fresh weight and 26.7% for plant height. In contrast, the CTC recorded peak values of 28% for leaf area and 25.1% for SPAD measurements. Furthermore, exposure to antibiotics induced oxidative stress in tomato seedlings, with SOD demonstrating its highest activation rate of 18.3% in the TYL. Within the rhizosphere microenvironment, there was a notable decrease in the abundance of the dominant phylum Bryobacter, which was accompanied by alterations in bacterial community structure, an increase in network complexity, and a reduction in modularity. Under antibiotic stress, microbial communities demonstrated distinct metabolic responses: enhanced lipid metabolism in CTC, elevated carbohydrate metabolism with ENR, and activated nucleotide metabolism associated with TYL. In summary, antibiotics present global ecological risks by inhibiting plant growth and disrupting the rhizosphere microbiome. The class-specific toxicity of these substances necessitates the implementation of targeted risk management strategies.