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

• Published in: The Plant journal : for cell and molecular biology 2006-03, Vol.45 (6), p.982-993
• Main Authors: Auldridge, Michele E., Block, Anna, Vogel, Jonathan T., Dabney‐Smith, Carole, Mila, Isabelle, Bouzayen, Mondher, Magallanes‐Lundback, Maria, DellaPenna, Dean, McCarty, Donald R., Klee, Harry J.
• Format: Article
• Language: English
• Subjects: Agricultural sciences; Agronomy; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis Proteins - physiology; Arabidopsis thaliana; Biological and medical sciences; Biotechnology; branching; Carotenoids - metabolism; Dioxygenases - genetics; Dioxygenases - metabolism; Dioxygenases - physiology; Enzymes; Escherichia coli - genetics; Flowers & plants; Fundamental and applied biological sciences. Psychology; Genes; hormones; Indoleacetic Acids - metabolism; Life Sciences; Metabolism; Multigene Family; Mutation; Oxygenases - genetics; Oxygenases - metabolism; Oxygenases - physiology; Phenotype; Pigments; Plant Leaves - enzymology; Plant Leaves - genetics; Plant Leaves - growth & development; Plant physiology and development; Plant Shoots - enzymology; Plant Shoots - genetics; Plant Shoots - growth & development; seeds; Seeds - genetics; Seeds - metabolism; Storage and secretion, pigments, phytochrome; Vegetal Biology
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313X.2006.02666.x

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.