Grape Cell Vacuoles: Structure-Function and Solute Transport Across the Tonoplast

Abstract

Grape berry cells have a complex vacuolar membranous system highly specialised in solute storage. Vacuoles are the main reservoirs of sugars, organic acids, aromas, flavours, ions and water. After veraison, when growth occurs exclusively by cell enlargement, the vacuole volume greatly increases due to the massive sugar and water uptake. A large number of tonoplast proteins, including pumps, carriers, ion channels and receptors support the numerous functions of the plant vacuole. Some of them have been well characterised in several plant models at the biochemical and molecular level, including the most abundant ones, V-ATPase, V-PPase, and water channels (aquaporins). The present chapter provides an overview on the diversity and storage role of the vacuole of grape cells, and the molecular mechanism involved in solute transport across the tonoplast is updated and discussed.

Keywords: ATP-binding cassette transporter, Fluorescein diacetate, Grape vacuoles, Solute storage, Tonoplast, Tonoplast intrinsic protein, Tonoplast transporters, Vacuolar ATPase, Vacuolar pyrophosphatase, Vacuole isolation.