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25 páginas.- 7 figuras.- 2 tablas.- referencias., Chloride (Cl-) has been revealed as an essential micronutrient and a beneficial macronutrient for adequate plant growth and development, while it can be toxic under salt stress conditions. Active transporters involved in cell Clinflux, along with channels that mediate Clefflux are important points of regulation of plant Clhomeostasis. Presently, there is adequate understanding of plant Cltransport mechanisms at the electrophysiological level. However, the molecular identity of many transporters remains uncharacterized. Rapid-type ALMT anion channels mediate malate, sulphate, Cland nitrate (NO3-) transport in plant cells and participate in many biological functions. In this work, functional characterization of the Arabidopsis thaliana anion channel AtALMT10 has been initiated. Contrary to the Slow-type AtSLAH1 and AtSLAH3 channels, whose root gene expression is strongly repressed by water deficit (WD), salt stress and exogenous application of the phytohormone abscisic acid, the AtALMT10 gene is specifically induced by WD. To better understand the biological role of AtALMT10, the almt10-1 and almt10-3 mutant lines were segregated and genotyped. Both knockout mutants showed higher Cland lower NO3- content in the xylem sap and in shoot tissues respect to the Col-0 wild-type, suggesting a role of AtALMT10 in the regulation of Cland NO3- homeostasis. We are currently working on the tissuespecific and subcellular location of AtALMT10. This gene is of interest at both the research and agronomic levels given its potential relevance on the regulation of plant nutrition of essential elements and the plant response to abiotic stress.