Bruno_2017_FEBS.Lett_591_792

Strigolactones are a new class of phytohormones synthesized from carotenoids via carlactone. The complex structure of carlactone is not easily deducible from its precursor, a cis-configured beta-carotene cleavage product, and is thus formed via a poorly understood series of reactions and molecular rearrangements, all catalyzed by only one enzyme, the carotenoid cleavage dioxygenase 8 (CCD8). Moreover, the reactions leading to carlactone are expected to form a second, yet unidentified product. In this study, we used (13) C and (18) O-labeling to shed light on the reactions catalyzed by CCD8. The characterization of the resulting carlactone by LC-MS and NMR, and the identification of the assumed, less accessible second product allowed us to formulate a minimal reaction mechanism for carlactone generation.