NO signaling and cytokinins

Cell death can be induced by cytokinin 6-benzylaminopurine (BA) at high dosage in suspension cultured Arabidopsis cells. We provide evidence that BA induces nitric oxide (NO) synthesis in a dose-dependent manner. A reduction in cell death can be observed when the cytokinin is supplemented with the NO scavenger (cPTIO) or the nitric oxide synthase (NOS) inhibitors (AET, l - NMMA), which suggests that NO is produced via a NOS enzyme and is a signaling component of this form of programmed cell death. In BA-treated cells, mitochondrial functioning is altered via inhibition of respiration. This inhibition can be prevented by addition of either cPTIO or AET.