CAROTENOID CLEAVAGE DIOXYGENASE4 Is a Negative Regulator of β-Carotene Content in Arabidopsis Seeds

• Published in: The Plant cell Vol. 25; no. 12; pp. 4812 - 4826
• Main Authors: Gonzalez-Jorge, Sabrina, Ha, Sun-Hwa, Magallanes-Lundback, Maria, Gilliland, Laura Ullrich, Zhou, Ailing, Lipka, Alexander E., Nguyen, Yen-Nhu, Angelovici, Ruthie, Lin, Haining, Cepela, Jason, Little, Holly, Buell, C. Robin, Gore, Michael A., DellaPenna, Dean
• Format: Journal Article
• Language: English
• Published: England American Society of Plant Biologists 01.12.2013
• Subjects: Alleles; Arabidopsis - enzymology; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis Proteins - physiology; beta Carotene - biosynthesis; Carotenoids; Cellular Senescence; Chromosome Mapping; Dioxygenases - genetics; Dioxygenases - metabolism; Dioxygenases - physiology; Enzymes; Genetic loci; Genetic variation; Haplotypes; Homeostasis; Large-Scale Biology; LARGE-SCALE BIOLOGY ARTICLE; Mutagenesis, Insertional; Plant cells; Plant Leaves - metabolism; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Proteins - physiology; Plants; Plants, Genetically Modified - metabolism; Polymorphism, Single Nucleotide; Quantitative Trait Loci; Seeds; Seeds - genetics; Seeds - metabolism; Sequence Deletion
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.113.119677

Experimental approaches targeting carotenoid biosynthetic enzymes have successfully increased the seed β-carotene content of crops. However, linkage analysis of seed carotenoids in Arabidopsis thaliana recombinant inbred populations showed that only 21% of quantitative trait loci, including those for β-carotene, encode carotenoid biosynthetic enzymes in their intervals. Thus, numerous locl remain uncharacterized and underutilized in biofortification approaches. Linkage mapping and genome-wide association studies of Arabidopsis seed carotenoids identified CAROTENOID CLEAVAGE DIOXYGENASE4 (CCD4) as a major negative regulator of seed carotenoid content, especially β-carotene. Loss of CCD4 function did not affect carotenoid homeostasis during seed development but greatly reduced carotenoid degradation during seed desiccation, increasing β-carotene content 8.4-fold relative to the wild type. Allelic complementation of a ccd4 null mutant demonstrated that single-nucleotide polymorphisms and insertions and deletions at the locus affect dry seed carotenoid content, due at least partly to differences in CCD4 expression. CCD4 also plays a major role in carotenoid turnover during dark-induced leaf senescence, with β-carotene accumulation again most strongly affected in the ccd4 mutant. These results demonstrate that CCD4 plays a major role in β-carotene degradation in drying seeds and senescing leaves and suggest that CCD4 orthologs would be promising targets for stabilizing and increasing the level of provitamin A carotenoids in seeds of major food crops.