Brassinosteroids Confer Resistance to Isoproturon through OsBZR4-Mediated Degradation Genes in Rice ( L.).

Plants have complex detoxification and metabolic systems that enable them to deal with environmental pollutants. We report accumulation of the pesticide isoproturon (IPU) in a BR signaling pathway for mutant 3/5 rice to be significantly higher than in wild-type (WT) rice controls and for exogenous 24-epibrassinolide to reverse toxic symptoms in WT rice but not in mutants. A genome-wide RNA sequencing study of WT/ rice is performed to identify transcriptomic changes and metabolic mechanisms under IPU exposure. Three differentially expressed genes in yeast cells increase the degradation rate of IPU in a growth medium by factors of 1.61, 1.51, and 1.29 after 72 h. Using UPLC/Q-TOF-MS/MS, five phase I metabolites and five phase II conjugates are characterized in rice grains, with concentrations generally decreasing in rice grains. OsBZR4, a regulator of IPU degradation in rice, may eliminate IPU from edible parts of food crops by regulating downstream metabolic genes.