title: Characterization of three members of the Arabidopsis carotenoid cleavage dioxygenase family demonstrates the divergent roles of this multifunctional enzyme family.
abstract: Arabidopsis thaliana has nine genes that constitute a family of putative carotenoid cleavage dioxygenases (CCDs). While five members of the family are believed to be involved in synthesis of the phytohormone abscisic acid, the functions of the other four enzymes are less clear. Recently two of the enzymes, CCD7/MAX3 and CCD8/MAX4, have been implicated in synthesis of a novel apocarotenoid hormone that controls lateral shoot growth. Here, we report on the molecular and genetic interactions between CCD1, CCD7/MAX3 and CCD8/MAX4. CCD1 distinguishes itself from other reported CCDs as being the only member not targeted to the plastid. Unlike ccd7/max3 and ccd8/max4, both characterized as having highly branched phenotypes, ccd1 loss-of-function mutants are indistinguishable from wild-type plants. Thus, even though CCD1 has similar enzymatic activity to CCD7/MAX3, it does not have a role in synthesis of the lateral shoot growth inhibitor. Rather, it may have a role in synthesis of apocarotenoid flavor and aroma volatiles, especially in maturing seeds where loss of function leads to significantly higher carotenoid levels.
authors.affiliation: Plant Molecular and Cellular Biology Program, PO Box 110690, University of Florida, Gainesville, FL 32611, USA.
authors.forename: Michele E
authors.initials: ME
authors.lastname: Auldridge
authors.forename: Anna
authors.initials: A
authors.lastname: Block
authors.forename: Jonathan T
authors.initials: JT
authors.lastname: Vogel
authors.forename: Carole
authors.initials: C
authors.lastname: Dabney-Smith
authors.forename: Isabelle
authors.initials: I
authors.lastname: Mila
authors.forename: Mondher
authors.initials: M
authors.lastname: Bouzayen
authors.forename: Maria
authors.initials: M
authors.lastname: Magallanes-Lundback
authors.forename: Dean
authors.initials: D
authors.lastname: DellaPenna
authors.forename: Donald R
authors.initials: DR
authors.lastname: McCarty
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Klee
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002338:Carotenoids / Q000378:metabolism; D049308:Dioxygenases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics; D007210:Indoleacetic Acids / Q000378:metabolism; D005810:Multigene Family; D009154:Mutation; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010641:Phenotype; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D018520:Plant Shoots / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D012639:Seeds / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D002338:Carotenoids; C030737:indoleacetic acid; C475746:MAX4 protein, Arabidopsis; D010105:Oxygenases; D049308:Dioxygenases; C431939:carotenoid cleavage dioxygenase 1