COMT1 overexpression resulting in increased melatonin biosynthesis contributes to the alleviation of carbendazim phytotoxicity and residues in tomato plants. (September 2019)

• Record Type: Journal Article
• Authors: Yan, Yanyan; Sun, Shasha; Zhao, Ning; Yang, Wanying; Shi, Qinghua; Gong, Biao
• Is Part Of: Environmental pollution. Volume 252(2019):Part A
• Page Start: 51
• Page End: 61
• Publication Date: 2019-09
• Subjects: COMT1 -- Melatonin -- Pesticide metabolism -- Tomato; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2019.05.052
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Melatonin (Mel) serves as an important signalling molecule in various aspects of stress tolerance in plants. However, the function of Mel in pesticide metabolism remains unknown. Here, selecting the widely used fungicide carbendazim (MBC) as the model, we found that exogenous Mel had the ability to alleviate pesticide phytotoxicity and residues in tomato as well as in some other vegetables. Additionally, overexpression of the Mel biosynthetic gene caffeic acid O-methyltransferase 1 ( COMT1 ) significantly enhanced the capacity of the tomato to reduce MBC phytotoxicity and residue. This outcome was mainly because of the Mel-induced antioxidant capability, as well as the key detoxification process. Indeed, levels of reactive oxygen species (ROS) and lipid peroxides significantly decreased after applying exogenous Mel or overexpressing COMT1, which resulted from direct ROS scavenging, and increased Mel levels significantly enhanced antioxidant enzymatic activity. More importantly, Mel activated the ascorbate-glutathione cycle to participate in glutathione S-transferase-mediated pesticide detoxification. A grafting experiment showed that rootstocks from COMT1 transgenic plants increased the Mel accumulation of wild-type scions, resulting in MBC metabolism in the scions. To our knowledge, this is the first report providing evidence of Mel-induced pesticide metabolism, which provides a novel approach for minimizing pesticide residues in crops by exploiting plant self-detoxification mechanisms. Graphical abstract: Model of induced ascorbate-glutathione detoxification pathway for pesticide stress tolerance and pesticide metabolism by exogenous melatonin (Mel) and COMT1 -overexpression in tomato plants. Left boxes indicate changes of enzymes' activities in carbendazim (MBC) treatment compared with control treatment, and right boxes represent the changes of enzymes' activities in Mel/ COMT1 with MBC treatment compared with only MBC treatment. Increased enzymes activities are marked by red, and decreased enzymes activities are marked by green. Image 1 Highlights: Melatonin plays a critical role in pesticide metabolism. COMT1 -mediated melatonin activates ASA-GSH cycle to promote pesticide metabolism. COMT1 -overexpressed rootstocks promote the pesticide metabolism of WT scions. Abstract : COMT1 -induced melatonin promotes pesticide metabolism.