Physiological and Genetic Analysis of Plasma Membrane Aquaporin Functions in Arabidopsis

Abstract

Terrestrial plants critically depend on a supply of water for their growth and development and display elaborate strategies to achieve water balance in the most adverse environments. The recent discovery in a large variety of organisms of water channel proteins named aquaporins has provided tremendous insights into the molecular mechanisms of transmembrane water transport and its regulation at the cellular level. Aquaporins belong to the large MIP family of membrane proteins, with members transporting water and/or small neutral solutes. Despite decades of physiological and biophysical research on water relations of plants, the discovery of aquaporins in both the intracellular and plasma membranes of plant cells was unexpected. This discovery revealed that the water and solute permeability of cell membranes may be more critical for plants than initially thought. The importance of aquaporins in plants is supported by their abundance, diversity and fine regulation at the gene and/or protein levels. Recent genetic and physiological evidence point to a crucial role for aquaporins in various processes including plant reproduction, cell elongation, root development and water uptake, and the adaptative responses of plants to dehydration and salinity.