Jasmonic acid prevents the accumulation of cyclin B1;1 and CDK‐B in synchronized tobacco BY‐2 cells

Jasmonic acid (JA) plays a crucial role in plant fertility and defense responses. It exerts an inhibitory effect on plant growth when applied exogenously. This effect seems to be somehow related to a negative regulation of cell cycle progression in the meristematic tissues. In this report, we focus on the molecular events that occur during JA‐induced G2 arrest. We demonstrate that JA prevents the accumulation of B‐type cyclin‐dependent kinases and the expression of cyclin B1;1, which are both essential for the initiation of mitosis. This feature suggests the existence of an early G2 checkpoint that is affected by JA.