Characterization of three members of the Arabidopsis carotenoid cleavage dioxygenase family demonstrates the divergent roles of this multifunctional enzyme family

Authors

  • Michele E. Auldridge,

    1. Plant Molecular and Cellular Biology Program, PO Box 110690, University of Florida, Gainesville, FL 32611, USA
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    • Present address: The Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA.

  • Anna Block,

    1. Plant Molecular and Cellular Biology Program, PO Box 110690, University of Florida, Gainesville, FL 32611, USA
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  • Jonathan T. Vogel,

    1. Plant Molecular and Cellular Biology Program, PO Box 110690, University of Florida, Gainesville, FL 32611, USA
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  • Carole Dabney-Smith,

    1. Plant Molecular and Cellular Biology Program, PO Box 110690, University of Florida, Gainesville, FL 32611, USA
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  • Isabelle Mila,

    1. UMR990 INRA/INP-ENSA Toulouse, Génomique et Biotechnologie des Fruits, Chemin de Borde Rouge, 31326 Castanet-Tolosan, France
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  • Mondher Bouzayen,

    1. UMR990 INRA/INP-ENSA Toulouse, Génomique et Biotechnologie des Fruits, Chemin de Borde Rouge, 31326 Castanet-Tolosan, France
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  • Maria Magallanes-Lundback,

    1. Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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  • Dean DellaPenna,

    1. Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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  • Donald R. McCarty,

    1. Plant Molecular and Cellular Biology Program, PO Box 110690, University of Florida, Gainesville, FL 32611, USA
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  • Harry J. Klee

    Corresponding author
    1. Plant Molecular and Cellular Biology Program, PO Box 110690, University of Florida, Gainesville, FL 32611, USA
      *(fax: +1 352 846 2063; e-mail hjklee@ifas.ufl.edu).
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*(fax: +1 352 846 2063; e-mail hjklee@ifas.ufl.edu).

Summary

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.

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