A low K+signal is required for functional high-affinity K+uptake through HAK5 transporters

What is it about?

Plant nutrient sensing and signaling is an important area of research since nutrient deficiencies hinder crop yield worldwide. The three main plant macronutrients are Nitrogen (N), Phosphorous (P), and Potassium (K), and this macronutrients are present in most fertilizers formulas (NPK fertilizers). When a deficiency appears, plants respond increasing the mechanism of nutrient uptake with more efficient transporters. These signaling pathways have crossroads not well elucidated yet. This study shows how all N, P and K deficiency decrease the membrane potential of roots of tomato and Arabidopsis. In general, a lower membrane potential facilitates the uptake of positive charged cations, however, deficiencies in N or P where not able to induce K uptake whereas K deficiency increases K transport. Interestingly, all deficiencies induced the transcription of the high affinity transporter HAK5 in tomato and Arabidopsis, but this transporters seems to be functional only when the plant has been K deprived. The results suggest that a K-specific signal is required for the formation of a functional efficient transporter.

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