NO , PO and SO deprivation reduced LKT1-mediated low-affinity K uptake and SKOR-mediated K translocation in tomato and Arabidopsis plants.

Regulation of essential macronutrients acquisition by plants in response to their availability is a key process for plant adaptation to changing environments. Here we show in tomato and Arabidopsis plants that when they are subjected to NO , PO and SO deprivation, low-affinity K uptake and K translocation to the shoot are reduced. In parallel, these nutritional deficiencies produce reductions in the messenger levels of the genes encoding the main systems for low-affinity K uptake and K translocation, i.e. AKT1 and SKOR in Arabidopsis and LKT1 and the tomato homolog of SKOR, SlSKOR in tomato, respectively. The results suggest that the shortage of one nutrient produces a general downregulation of the acquisition of other nutrients. In the case of K nutrient, one of the mechanisms for such a response resides in the transcriptional repression of the genes encoding the systems for K uptake and translocation.