Two tonoplast MATE proteins function as turgor-regulating chloride channels in <i>Arabidopsis</i>

Abstract

Significance Turgor pressure is the driving force for cell growth in plants, and the large central vacuole provides the major space for turgor regulation. However, the molecular identity and function of many transporters that control water and solute fluxes in and out of vacuoles remain unknown. We report here that two Multidrug and Toxic Compound Extrusion (MATE)-type transporters show previously unrecognized function as chloride channels essential for turgor regulation in Arabidopsis . The MATE transporters are highly conserved from bacteria, fungi, plants, to animals, and widely accepted as transporters of organic compounds. This study, showing some MATE transporters as chloride channels, thus breaks the old dogma on the functional definition of this large family of transporters.