Concentration-dependent effects of narciclasine on cell cycle progression in Arabidopsis root tips.

BACKGROUND: Narciclasine (NCS) is an Amaryllidaceae alkaloid isolated from Narcissus tazetta bulbs. NCS has inhibitory effects on a broad range of biological activities and thus has various potential practical applications. Here we examine how NCS represses plant root growth. RESULTS: Results showed that the inhibition of NCS on cell division in Arabidopsis root tips and its effects on cell differentiation are concentration-dependent; at low concentrations (0.5 and 1.0 µM) NCS preferentially targets mitotic cell cycle specific/cyclin complexes, whereas at high concentration (5.0 µM) the NCS-stimulated accumulation of Kip-related proteins (KRP1 and RP2) affects the CDK complexes with a role at both G1/S and G2/M phases. CONCLUSIONS: Our findings suggest that NCS modulates the coordination between cell division and differentiation in Arabidopsis root tips and hence affects the postembryonic development of Arabidopsis seedlings.