Integrated analysis of transcriptome and metabolome revealed clomazone biodegradation in maize seedlings

Clomazone (CMZ) is a pesticide widely used for weed control in soybean fields. However, its persistence in the environment, including soil, surface water, and groundwater, poses potential risks to subsequent crops and human health. To evaluate the ecotoxicological impacts of CMZ residues on maize growth, a comprehensive study was conducted using integrated transcriptomic and metabolomic analyses of maize seedlings. The results showed that maize seedlings absorb CMZ through the roots and translocate it to the shoots, which led to inhibited growth, reduced chlorophyll content, decreased dry weight, increased electrolyte leakage, and elevated antioxidant enzyme activities. Differentially expressed metabolites (DEMs) and genes (DEGs) were significantly altered in CMZ-stressed maize seedlings, with 1456 DEGs and 1461 DEMs in roots, and 2946 DEGs and 2999 DEMs in shoots. Metabolomic profiling revealed the accumulation of key metabolites involved in CMZ catabolism, including carbohydrates, amino acids, glutathione, and flavonoids. UPLC-Q-TOF/MS analysis identified twelve CMZ transformation products (TPs), which correlated with the activities of DEGs, DEMs, and antioxidant enzymes. These findings indicate that maize seedlings detoxify absorbed CMZ through specific pathways, including decarboxylation, and primarily via canonical phase I and phase II reactions. This study suggests that crops like maize can mitigate the toxicity and residues of CMZ, providing insights for strategies to manage and control CMZ ecotoxicity.