Transcriptomic responses of harmful dinoflagellate Prorocentrum donghaiense to nitrogen and light

Prorocentrum donghaiense is a notoriously harmful bloom species in the coastal waters of China. The molecular processes by which P. donghaiense assimilates nitrogen (N) are poorly understood. Expression of 12 genes involved in N transport and assimilation in P. donghaiense was studied under different conditions of N availability, irradiance and diel cycle. We demonstrated that expression of 5 genes was regulated by N limitation and 7 genes regulated by different N sources or irradiances. The diel cycle had little effect on the regulation of the studied genes. The responses of the genes involved in the ornithine-urea cycle (OUC) were different from those found in model diatoms. Constitutive expression of genes related to N transport and assimilation may assist P. donghaiense efficient utilization of different N sources in varying marine environments. The OUC of P. donghaiense may play a minor role in the distribution and repackaging of carbon and N.