The Plant cellDec 26, 2013

Carotenoid cleavage dioxygenase4 reduces beta-carotene levels in Arabidopsis seeds

Updated Feb 26, 2026

Abstract

Loss of CCD4 function increased β-carotene content 8.4-fold relative to the wild type.

Only 21% of quantitative trait loci for seed carotenoids in Arabidopsis thaliana encode carotenoid biosynthetic enzymes.
CAROTENOID cleavage dioxygenase4 (CCD4) is identified as a major negative regulator of seed carotenoid content.
Loss of CCD4 function does not disrupt carotenoid balance during seed development but prevents carotenoid degradation during seed drying.
Single-nucleotide polymorphisms and insertions/deletions at the CCD4 locus influence dry seed carotenoid content, likely through variations in CCD4 expression.
CCD4 also significantly impacts carotenoid levels during leaf aging, particularly affecting β-carotene accumulation.

Simplified

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 loci 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.

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