Molecular mechanisms of potassium and sodium transport in plants

Abstract

Potassium is an important macronutrient in higher plants and K⁺ transporters play important roles in many physiological processes. Furthermore, sodium (Na⁺) uptake into plant cells has been suggested to be mediated by physiological K⁺ transporters. Genes that encode putative molecular mechanisms for K⁺ and Na⁺ transport have been isolated. By expression cloning, functional analysis in yeast, Xenopus oocytes, E. coli and plant cell cultures at least three gene families have been identified, that could contribute to K⁺ uptake into plant cells including K⁺ channels, the wheat HKT1 gene and the family of AtKUP/HAK/KT transporters. The long-term goal of research in several laboratories is to gain insight into the physiological roles, transport modes, expression patterns and subcellular localizations of cloned K⁺ and Na⁺ transporter genes. Advances at analysing the functions of individual genes from these families will be presented.