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Formation of norisoprenoid flavor compounds in carrot (Daucus carota L.) roots: Characterization of a cyclic-specific carotenoid cleavage dioxygenase 1 gene

Permanent URL:
http://handle.nal.usda.gov/10113/58545
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Abstract:
Carotenoids are isoprenoid pigments that upon oxidative cleavage lead to the production of norisoprenoids that have profound effect on flavor and aromas of agricultural produce. The biosynthetic pathway to norisoprenoids in carrots (Daucus carota L.) is still widely unknown. We found that geranial is the major norisoprenoid volatile in freshly cut carrots of different colored cultivars. The volatile norisoprenoids farnesylacetone, a-ionone and ß-ionone accumulated in Nairobi, Rothild and Purple Haze cultivars, but not in Yellowstone and Creme de Lite, in a pattern reflecting their carotenoid content. A cDNA encoding a protein with carotenoid cleavage dioxygenase activity, DcCCD1, was identified in carrot, and was overexpressed in E. coli strains previously engineered to produce different carotenoids. The recombinant DcCCD1 enzyme cleaves cyclic carotenes to generate a- and ß-ionone. No cleavage products were found when DcCCD1 was co-expressed in E. coli strains accumulating noncyclic carotenoids such as phytoene or lycopene. Our results suggest a role for DcCCD1 in carrot flavor biosynthesis.
Author(s):
Mosaab Yahyaa , Einat Bar , Neeraj Kumar Dubey , Ayala Meir , Rachel Davidovich-Rikanati , Joseph Hirschberg , Radi Aly , Dorothea Tholl , Philipp W. Simon , Yaakov Tadmor , Efraim Lewinsohn , Mwafaq Ibdah
Subject(s):
Daucus carota , Escherichia coli , biosynthesis , carotenes , carrots , complementary DNA , cultivars , cutting , enzyme activity , flavor , flavor compounds , gene overexpression , genes , geranial , norisoprenoids , pigments , roots
Source:
Journal of Agricultural and Food Science 2013 11 30 v.61 no.50
Language:
English
Year:
2013
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.