Decreased apical dominance1/Petunia hybrida CAROTENOID CLEAVAGE DIOXYGENASE8 Gene Affects Branch Production and Plays a Role in Leaf Senescence, Root Growth, and Flower Development

• Published in: The Plant cell 2005-03, Vol.17 (3), p.746-759
• Main Authors: Snowden, Kimberley C, Simkin, Andrew J, Janssen, Bart J, Templeton, Kerry R, Loucas, Holly M, Simons, Joanne L, Karunairetnam, Sakuntala, Gleave, Andrew P, Clark, David G, Klee, Harry J
• Format: Article
• Language: English
• Subjects: Alleles; Amino Acid Sequence; Base Sequence; Branches; Branching; carotenoid cleavage dioxygenase; Carotenoids; Carotenoids - metabolism; cotyledons; Dad1 gene; Dioxygenases - genetics; DNA Transposable Elements - genetics; DNA, Plant - genetics; flowering; Flowers; Flowers - growth & development; gene expression; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; genes; Genes, Plant; hybrids; Leaves; Molecular Sequence Data; Mutants; Mutation; nucleotide sequences; oxygenases; Petunia - enzymology; Petunia - genetics; Petunia - growth & development; Petunia axillaris; Petunia hybrida; Petunia integrifolia; Phenotype; Phenotypes; Phylogeny; Plant growth; Plant Leaves - growth & development; Plant roots; Plant Roots - growth & development; Plants; Plants, Genetically Modified; Polymerase chain reaction; promoter regions; root growth; senescence; Sequence Homology, Amino Acid; Stems; Transposons
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.104.027714

Carotenoids and carotenoid cleavage products play an important and integral role in plant development. The Decreased apical dominance1 (Dad1)/PhCCD8 gene of petunia (Petunia hybrida) encodes a hypothetical carotenoid cleavage dioxygenase (CCD) and ortholog of the MORE AXILLARY GROWTH4 (MAX4)/AtCCD8 gene. The dad1-1 mutant allele was inactivated by insertion of an unusual transposon (Dad-one transposon), and the dad1-3 allele is a revertant allele of dad1-1. Consistent with its role in producing a graft-transmissible compound that can alter branching, the Dad1/PhCCD8 gene is expressed in root and shoot tissue. This expression is upregulated in the stems of the dad1-1, dad2, and dad3 increased branching mutants, indicating feedback regulation of the gene in this tissue. However, this feedback regulation does not affect the root expression of Dad1/PhCCD8. Overexpression of Dad1/PhCCD8 in the dad1-1 mutant complemented the mutant phenotype, and RNA interference in the wild type resulted in an increased branching phenotype. Other differences in phenotype associated with the loss of Dad1/PhCCD8 function included altered timing of axillary meristem development, delayed leaf senescence, smaller flowers, reduced internode length, and reduced root growth. These data indicate that the substrate(s) and/or product(s) of the Dad1/PhCCD8 enzyme are mobile signal molecules with diverse roles in plant development.