Botrytis cinerea-induced F-box protein 1 enhances disease resistance by inhibiting JAO/JOX-mediated jasmonic acid catabolism in Arabidopsis

Jasmonic acid(JA)is a crucial phytohormone that regulates plant immunity.The endogenous JA level is determined by the rates of its biosynthesis and catabolism in plants.The activation of JA biosynthesis has been well documented;however,how plants repress JA catabolism upon pathogen infection remains elusive.In this study,we identified and characterized Botrytis cinerea-induced F-box protein 1(BFP1)in Arabidopsis.The expression of BFP1 was induced by B.cinerea in a JA signaling-dependent manner,and BFP1 protein was critical for plant defense against B.cinerea and plant response to JA.In addition,BFP1 overexpression increased plant defenses against broad-spectrum pathogens without fitness costs.Further experiments demonstrated that BFP1 interacts with and mediates the ubiquitination and degrada-tion of jasmonic acid oxidases(JAOs,also known as jasmonate-induced oxygenases,JoXs),the enzymes that hydroxylate JA to 12OH-JA.Consistent with this,BFP1 affects the accumulation of JA and 12OH-JA during B.cinerea infection.Moreover,mutation of JAo2 complemented the phenotypes of the bfp1 mutant.Collectively,our results unveil a new mechanism used by plants to activate immune responses upon path-ogeninfection:suppressing JA catabolism.