Exogenous Epigallocatechin-3-Gallate Alleviates Pesticide Phytotoxicity and Reduces Pesticide Residues by Stimulating Antioxidant Defense and Detoxification Pathways in Melon

Epigallocatechin-3-gallate (EGCG), a secondary metabolite (flavonoid) with strong antioxidant capacity, can alleviate oxidative stress. The present study examined the role of EGCG in plant response to glyphosate and carbendazim treatments in melon ( Cucumis melo L.). The results showed that exogenous EGCG application alleviated pesticide phytotoxicity as reflected by significantly increased net photosynthetic rate ( P n ), attenuated oxidative stress, and decreased pesticide residues in melon leaves. Under glyphosate treatment, EGCG increased glutathione content, glutathione reductase (GR) activity, glutathione- S -transferase (GST) activity, and the expression of GR and GST1 . Under carbendazim treatment, EGCG induced the activities of ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) and upregulated the expression levels of APX3 , CAT1 and POD2 . These results revealed that exogenous EGCG application potentially accelerated glyphosate degradation by regulating the glutathione-dependent pesticide metabolism pathway, while EGCG alleviated carbendazim phytotoxicity through the glutathione-independent pathway by enhancing the activity of antioxidant enzymes and associated transcripts in melon leaves. The findings suggest that EGCG promotes the degradation of carbendazim and glyphosate possibly through two different pathways of xenobiotic detoxification. The study provides a theoretical basis for the application of EGCG in vegetable crops to attenuate pesticide phytotoxicity and improve food safety.