Physiology, Biochemistry, and Transcriptomics Jointly Reveal the Phytotoxicity Mechanism of Acetochlor on Pisum sativum L.

This article focuses on the toxic effects of acetochlor, a widely used pre-emergent herbicide, on pea (Pisum sativum L.) seedlings and the plants’ physiological and molecular responses to this stress. The study found that acetochlor exposure at concentrations of 10 mg/kg and above caused dose-dependent growth inhibition, including dwarfing and stem base browning, accompanied by oxidative damage indicated by increased malondialdehyde and antioxidant enzyme activities. Transcriptomic analysis revealed upregulation of genes involved in flavonoid and lignin biosynthesis, suggesting enhanced antioxidant defense and cell wall thickening, while glutathione metabolism and glutathione S-transferase (GST) activity were significantly induced at higher acetochlor levels, indicating a detoxification response. Additionally, alterations in gibberellin (GA) signaling pathway genes were associated with growth inhibition, providing insight into the herbicide’s phytotoxic mechanism and pea seedlings’ resistance strategies.