Abstract
Strigolactones are plant secondary metabolites that function as host recognition signals for arbuscular mycorrhizal fungi and root parasitic plants, Striga and Orobanche. Recently, it has been reported that strigolactones act as a novel hormone in shoot branching. In this study, we try to design a strigolactone biosynthesis inhibitor. Strigolactones are synthesized from carotenoids, and in a proposed strigolactione biosynthesis pathway, carotenoid cleavage dioxygenase 7 (CCD7) and CCD8 play an important role. 9-cis-Epoxycarotenoid dioxygenase (NCED) is the most characterized CCD in plants, and a couple of NCED inhibitors including abamine and abamineSG were reported from our group. In this context we estimated that some of NCED inhibitors or their derivatives could inhibit strigolactone biosynthesis and we started to screen our chemical libraries targeted to NCED (CCD). In consequence we found that the treatment of abamine reduced the level of 5-deoxystrigol in root exudates from rice plants, while the treatment of abamineSG, a specific and potent inhibitor of NCED, did not reduced the level of 5-deoxystrigol. Now we continue screening strigolactone biosynthesis inhibitors and try to elucidate structure-activity relationship of abamine and its derivatives.
