title: ALLENE OXIDE CYCLASE (AOC) gene family members of Arabidopsis thaliana: tissue- and organ-specific promoter activities and in vivo heteromerization.
abstract: Jasmonates are important signals in plant stress responses and plant development. An essential step in the biosynthesis of jasmonic acid (JA) is catalysed by ALLENE OXIDE CYCLASE (AOC) which establishes the naturally occurring enantiomeric structure of jasmonates. In Arabidopsis thaliana, four genes encode four functional AOC polypeptides (AOC1, AOC2, AOC3, and AOC4) raising the question of functional redundancy or diversification. Analysis of transcript accumulation revealed an organ-specific expression pattern, whereas detailed inspection of transgenic lines expressing the GUS reporter gene under the control of individual AOC promoters showed partially redundant promoter activities during development: (i) In fully developed leaves, promoter activities of AOC1, AOC2, and AOC3 appeared throughout all leaf tissue, but AOC4 promoter activity was vascular bundle-specific; (ii) only AOC3 and AOC4 showed promoter activities in roots; and (iii) partially specific promoter activities were found for AOC1 and AOC4 in flower development. In situ hybridization of flower stalks confirmed the GUS activity data. Characterization of single and double AOC loss-of-function mutants further corroborates the hypothesis of functional redundancies among individual AOCs due to a lack of phenotypes indicative of JA deficiency (e.g. male sterility). To elucidate whether redundant AOC expression might contribute to regulation on AOC activity level, protein interaction studies using bimolecular fluorescence complementation (BiFC) were performed and showed that all AOCs can interact among each other. The data suggest a putative regulatory mechanism of temporal and spatial fine-tuning in JA formation by differential expression and via possible heteromerization of the four AOCs.
authors.affiliation: Department of Natural Product Biotechnology, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle (Saale), Germany.
authors.forename: Irene
authors.initials: I
authors.lastname: Stenzel
authors.forename: Markus
authors.initials: M
authors.lastname: Otto
authors.forename: Carolin
authors.initials: C
authors.lastname: Delker
authors.forename: Nils
authors.initials: N
authors.lastname: Kirmse
authors.forename: Diana
authors.initials: D
authors.lastname: Schmidt
authors.forename: Otto
authors.initials: O
authors.lastname: Miersch
authors.forename: Bettina
authors.initials: B
authors.lastname: Hause
authors.forename: Claus
authors.initials: C
authors.lastname: Wasternack
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism*; D019281:Dimerization; D035264:Flowers / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D019746:Intramolecular Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D009154:Mutation; D009928:Organ Specificity; D054883:Oxylipins / Q000378:metabolism*; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D058526:Plant Vascular Bundle / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D025941:Protein Interaction Mapping; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D012639:Seeds / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D054883:Oxylipins; D012333:RNA, Messenger; D018749:RNA, Plant; C011006:jasmonic acid; D019746:Intramolecular Oxidoreductases; C517319:AOC2 protein, Arabidopsis; C021377:hydroperoxide isomerase