title: Pathogen-Responsive MPK3 and MPK6 Reprogram the Biosynthesis of Indole Glucosinolates and Their Derivatives in Arabidopsis Immunity.
abstract: Antimicrobial compounds have critical roles in plant immunity; for example, Arabidopsis thaliana and other crucifers deploy phytoalexins and glucosinolate derivatives in defense against pathogens. The pathogen-responsive MITOGEN-ACTIVATED PROTEIN KINASE3 (MPK3) and MPK6 have essential functions in the induction of camalexin, the major phytoalexin in Arabidopsis. In search of cyanide, a coproduct of ethylene and camalexin biosynthesis, we found that MPK3 and MPK6 also affect the accumulation of extracellular thiocyanate ion derived from the indole glucosinolate (IGS) pathway. Botrytis cinerea infection activates MPK3/MPK6, which promote indole-3-yl-methylglucosinolate (I3G) biosynthesis and its conversion to 4-methoxyindole-3-yl-methylglucosinolate (4MI3G). Gain- and loss-of-function analyses demonstrated that MPK3/MPK6 regulate the expression of MYB51 and MYB122, two key regulators of IGS biosynthesis, as well as CYP81F2 and IGMT1/IGMT2, which encode enzymes in the conversion of I3G to 4MI3G, through ETHYLENE RESPONSE FACTOR6 (ERF6), a substrate of MPK3/MPK6. Under the action of PENETRATION2 (PEN2), an atypical myrosinase, and PEN3, an ATP binding cassette transporter, 4MI3G is converted to extracellular unstable antimicrobial compounds, possibly isothiocyanates that can react with nucleophiles and release the stable thiocyanate ion. Recent studies demonstrated the importance of PEN2/PEN3-dependent IGS derivatives in plant immunity. Here, we report that MPK3/MPK6 and their substrate ERF6 promote the biosynthesis of IGSs and the conversion of I3G to 4MI3G, a target of PEN2/PEN3-dependent chemical defenses in plant immunity.
authors.affiliation: Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China zhangsh@missouri.edu.
authors.forename: Juan
authors.identifier: 0000-0001-6683-6415
authors.initials: J
authors.lastname: Xu
authors.affiliation: Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Jie
authors.identifier: 0000-0002-9910-3119
authors.initials: J
authors.lastname: Meng
authors.affiliation: Division of Biochemistry, Interdisciplinary Plant Group, Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211.
authors.forename: Xiangzong
authors.initials: X
authors.lastname: Meng
authors.affiliation: Department of Horticulture, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Yanting
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Jianmin
authors.identifier: 0000-0002-4265-7399
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Tiefeng
authors.initials: T
authors.lastname: Sun
authors.affiliation: Division of Biochemistry, Interdisciplinary Plant Group, Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211.
authors.forename: Yidong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Horticulture, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Qiaomei
authors.identifier: 0000-0002-0757-5208
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China Division of Biochemistry, Interdisciplinary Plant Group, Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211 zhangsh@missouri.edu.
authors.forename: Shuqun
authors.identifier: 0000-0003-2959-6461
authors.initials: S
authors.lastname: Zhang
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D009699:N-Glycosyl Hydrolases / Q000235:genetics / Q000378:metabolism; D057865:Plant Immunity / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C582825:ERF6 protein, Arabidopsis; D014157:Transcription Factors; D003577:Cytochrome P-450 Enzyme System; C541880:CYP81F2 protein, Arabidopsis; C458516:AtMPK3 protein, Arabidopsis; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D009699:N-Glycosyl Hydrolases; C505663:PEN2 protein, Arabidopsis