Detoxification and catabolism of mesotrione and fomesafen facilitated by a Phase II reaction acetyltransferase in rice

Introduction: The excessive dosage of pesticides required for agronomic reality results in growing con-tamination of pesticide residues in environment, thus bringing high risks to crop production and human health.Objectives: This study aims to unveil a novel mechanism for catabolism of two pesticides MTR and FSA facilitated by an uncharacterized Phase II reaction enzyme termed acetyltransferase-1 (ACE1) in rice and to make assessment of its potential for bioremediation to minimize the risks to crop production and food safety.Methods: We developed genetically improved cultivars overexpressing OsACE1 (OE) and knockout mutant lines by CRISPR-Cas9 technology to identify the MTR and FSA detoxic and metabolic functions and characterized their metabolites and conjugates by HPLC-LTQ-MS/MS.Results: OsACE1 overexpression conferred rice resistance to toxicity of MTR/FSA compared to wild-type, manifested by improved plant elongation and biomass, attenuated cellular injury, and increased chloro-phyll accumulation. The OE plants accumulated significantly less parent MTR/FSA and more degradative metabolites, and removed MTR/FSA from their growth medium by 1.38 and 1.61 folds over the wild-type. In contrast, knocking out OsACE1 led to compromised growth fitness and intensified toxic symptoms

Automated summary

This study unveiled a novel mechanism for the catabolism of pesticides MTR and FSA facilitated by an uncharacterized enzyme ACE1 in rice and assessed its potential for bioremediation to minimize the risks to crop production and food safety.