Résumé
Stomata are pores localised at leaf epidermis. They consist of a pore surrounded by a pair of specialised cells – the guard cells. Guard cells modify their volume and turgor pressure to tune the aperture of the stomata pore, allowing plants to control gas exchanges and water transpiration. This process, regulated by the perception of the environmental conditions, plays a significant role in plant adaptation to climate modifications. Indeed, it impacts on plant biomass production and tolerance to water stress. The regulation of the pore aperture is under the control of ions fluxes through the plasma and the vacuolar membrane. Our recent data showed that AtALMT5, a member of the aluminium activated malate transporter family, is a vacuolar anion channel mediating chloride and malate influx into the vacuole during stomatal opening. Almt5 loss-of-function plants present reduced stomatal aperture in response to light. Our data introduce AtALMT5 as a new player in the regulation of stomatal aperture and thus of leaf transpiration. Understanding its function in plant cells will allow to understand the importance of ALMT5 for the adaptation to climate changes.