title: Indole Glucosinolate Biosynthesis Limits Phenylpropanoid Accumulation in Arabidopsis thaliana.
abstract: Plants produce an array of metabolites (including lignin monomers and soluble UV-protective metabolites) from phenylalanine through the phenylpropanoid biosynthetic pathway. A subset of plants, including many related to Arabidopsis thaliana, synthesizes glucosinolates, nitrogen- and sulfur-containing secondary metabolites that serve as components of a plant defense system that deters herbivores and pathogens. Here, we report that the Arabidopsis thaliana reduced epidermal fluorescence5 (ref5-1) mutant, identified in a screen for plants with defects in soluble phenylpropanoid accumulation, has a missense mutation in CYP83B1 and displays defects in glucosinolate biosynthesis and in phenylpropanoid accumulation. CYP79B2 and CYP79B3 are responsible for the production of the CYP83B1 substrate indole-3-acetaldoxime (IAOx), and we found that the phenylpropanoid content of cyp79b2 cyp79b3 and ref5-1 cyp79b2 cyp79b3 plants is increased compared with the wild type. These data suggest that levels of IAOx or a subsequent metabolite negatively influence phenylpropanoid accumulation in ref5 and more importantly that this crosstalk is relevant in the wild type. Additional biochemical and genetic evidence indicates that this inhibition impacts the early steps of the phenylpropanoid biosynthetic pathway and restoration of phenylpropanoid accumulation in a ref5-1 med5a/b triple mutant suggests that the function of the Mediator complex is required for the crosstalk.
authors.affiliation: Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Jeong Im
authors.identifier: http://orcid.org/0000-0002-5618-3948
authors.initials: JI
authors.lastname: Kim
authors.affiliation: Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Whitney L
authors.identifier: http://orcid.org/0000-0001-9069-9764
authors.initials: WL
authors.lastname: Dolan
authors.affiliation: Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Nickolas A
authors.identifier: http://orcid.org/0000-0002-6572-8954
authors.initials: NA
authors.lastname: Anderson
authors.affiliation: Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907 chapple@purdue.edu.
authors.forename: Clint
authors.identifier: http://orcid.org/0000-0002-5195-562X
authors.initials: C
authors.lastname: Chapple
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D053898:Biosynthetic Pathways; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005961:Glucosinolates / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism; D007211:Indoles / Q000378:metabolism; D008031:Lignin / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D020125:Mutation, Missense; D010091:Oximes / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D030821:Plants, Genetically Modified; D020005:Propanols / Q000378:metabolism*; D036226:Seedlings / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D005961:Glucosinolates; D007210:Indoleacetic Acids; D007211:Indoles; D008565:Membrane Proteins; D010091:Oximes; D010937:Plant Growth Regulators; D020005:Propanols; C529659:REF4 protein, Arabidopsis; C467098:indole-3-acetaldoxime; C439395:1-phenylpropanol; D008031:Lignin; D003577:Cytochrome P-450 Enzyme System; C530432:cytochrome P-450 79B2 protein, Arabidopsis; C530433:cytochrome P-450 79B3, Arabidopsis; C431937:CYP83B1 protein, Arabidopsis; D000444:Aldehyde Dehydrogenase; C487188:reduced epidermal fluorescence1 protein, Arabidopsis