Nitrate transport and assimilation in plants: a potential review

Nitrogen (N) plays a key role for plant life cycle. It is available in agricultural soils as the form of nitrate and ammonium (NH4+) where nitrate (NO3−) is a major nutrient. Plants are able to sense NO3− in their environment, allowing them to quickly respond to the dramatic fluctuations of its availability. As a main feature of plant autotrophy, assimilation of inorganic N is not only of fundamental interest to the crop, but also a crucial factor in crop productivity. Furthermore, over the last couple of years, N sensing has been shown to be affected by different external factors, which act as local signals to trigger systemic signaling coordinated by mobile signals in plants body. During recent years, a breakthrough arising from the improved knowledge is a better understanding of NO3− integration and hormone signaling pathways of plants that explains the extraordinary developmental plasticity of NO3− response. This review highlights the novel aspect of N responsive sensors, transporters, and signaling molecules in plants with a brief introduction on the metabolic pathways and discusses their potential roles in N sensing.