Vacuolar Ion Channels: Roles as Signalling Mechanisms and in Plant Nutrition

Abstract

Vacuoles play various roles in many physiologically relevant processes in plants. Some of the more prominent are turgor provision, the storage of minerals and nutrients and cellular signalling. To fulfil these functions a complement of membrane transporters is present at the tonoplast. Prolific patch clamp studies have shown that amongst these, both selective and non selective cation channels (NSCCs) control key vacuolar functions: The non-selective SV channel is Ca 2+ permeable and has been proposed to have signalling roles during germination, stomatal opening and in response to pathogens. The K + selective VK channel impacts on K + nutrition and stomatal closure. Ligand-gated channels form possible pathways for vacuolar Ca 2+ release whereas the FV channel may be important in overall K + homeostasis. This chapter will summarise and review the main functions of vacuolar ion channels with particular emphasis on their roles in abiotic and biotic stress.