Brassinosteroids\nConfer Resistance to Isoproturon\nthrough OsBZR4-Mediated Degradation Genes in Rice (Oryza sativa L.)

Plants have complex detoxification and metabolic systems\nthat enable\nthem to deal with environmental pollutants. We report accumulation\nof the pesticide isoproturon (IPU) in a BR signaling pathway for mutant <i>bzr4-</i>3/5 rice to be significantly higher than in wild-type\n(WT) rice controls and for exogenous 24-epibrassinolide to reverse\ntoxic symptoms in WT rice but not in mutants. A genome-wide RNA sequencing\nstudy of WT/<i>bzr4</i> rice is performed to identify transcriptomic\nchanges and metabolic mechanisms under IPU exposure. Three differentially\nexpressed genes in yeast cells increase the degradation rate of IPU\nin a growth medium by factors of 1.61, 1.51, and 1.29 after 72 h.\nUsing UPLC/Q-TOF-MS/MS, five phase I metabolites and five phase II\nconjugates are characterized in rice grains, with concentrations generally\ndecreasing in <i>bzr4</i> rice grains. OsBZR4, a regulator\nof IPU degradation in rice, may eliminate IPU from edible parts of\nfood crops by regulating downstream metabolic genes.