Molecular cloning and characterization of a novel carotenoid cleavage dioxygenase 1 from Lycium chinense.

Carotenoids are key precursor for aroma compounds in plants. Although the fruit of Lycium chinense contains numerous carotenoids, the formation mechanism of aroma compounds in L. chinense is still poorly understood. In this study, a new carotenoid cleavage dioxygenase (termed LmCCD1) was identified from the leaves of L. chinense. Expression analysis by semiquantitative PCR reveals that LmCCD1 gene is expressed in different tissues of L. chinense, and dominant expression of LmCCD1 gene was found in leaves, flowers, and ripe fruits. In addition, the expression level of LmCCD1 in fruits is in accordance with the content of -ionone. Finally, recombinantly expressed LmCCD1 can cleave -carotene and lycopene to produce -ionone and pseudoionone in in vitro assays. These results indicate that LmCCD1 a novel carotenoids cleavage dioxygenase gene that may regulate the metabolic pathways responsible for aroma metabolite production (such as -ionone and pseudoionone) in L. chinense has been identified. (C) 2014 International Union of Biochemistry and Molecular Biology, Inc.