Vacuole

Endosome

Biophysics

Nutrient

Cell

Organic chemistry

Chemistry

Ecology

Cytoplasm

Membrane

Potassium

Biochemistry

Botany

Biology

Cell biology

Ion transporter

Frontiers in Plant Science

Modern agriculture relies on mineral fertilization. Unlike other major macronutrients, potassium (K+) is not incorporated into organic matter but remains as soluble ion in the cell sap contributing up to 10% of the dry organic matter. Consequently, K+ constitutes a chief osmoticum to drive cellular expansion and organ movements, such as stomata aperture. Moreover, K+ transport is critical for the control of cytoplasmic and luminal pH in endosomes, regulation of membrane potential, and enzyme activity. Not surprisingly, plants have evolved a large ensemble of K+ transporters with defined functions in nutrient uptake by roots, storage in vacuoles, and ion translocation between tissues and organs. This review describes critical transport proteins governing K+ nutrition, their regulation and coordinated activity, and summarizes our current understanding of signaling pathways activated by K+ starvation.

Regulation of K+ Nutrition in Plants