title: Identification and functional characterization of cation-chloride cotransporters in plants.
abstract: Chloride (Cl(-)) is an essential nutrient and one of the most abundant inorganic anions in plant tissues. We have cloned an Arabidopsis thaliana cDNA encoding for a member of the cation-Cl(-) cotransporter (CCC) family. Deduced plant CCC proteins are highly conserved, and phylogenetic analyses revealed their relationships to the sub-family of animal K(+):Cl(-) cotransporters. In Xenopus laevis oocytes, the A. thaliana CCC protein (At CCC) catalysed the co-ordinated symport of K(+), Na(+) and Cl(-), and this transport activity was inhibited by the 'loop' diuretic bumetanide, a specific inhibitor of vertebrate Na(+):K(+):Cl(-) cotransporters, indicating that At CCC encodes for a bona fide Na(+):K(+):Cl(-) cotransporter. Analysis of At CCC promoter-beta-glucuronidase transgenic Arabidopsis plants revealed preferential expression in the root and shoot vasculature at the xylem/symplast boundary, root tips, trichomes, leaf hydathodes, leaf stipules and anthers. Plants homozygous for two independent T-DNA insertions in the CCC gene exhibited shorter organs such as inflorescence stems, roots, leaves and siliques. The elongation zone of the inflorescence stem of ccc plants often necrosed during bolt emergence, while seed production was strongly impaired. In addition, ccc plants exhibited defective Cl(-) homeostasis under high salinity, as they accumulated higher and lower Cl(-) amounts in shoots and roots, respectively, than the treated wild type, suggesting At CCC involvement in long-distance Cl(-) transport. Compelling evidence is provided on the occurrence of cation-chloride cotransporters in the plant kingdom and their significant role in major plant developmental processes and Cl(-) homeostasis.
authors.affiliation: Centro de Genómica, Instituto Valenciano de Investigaciones Agrarias, Ctra. Moncada-Náquera Km. 5, 46113 Moncada, Valencia, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Colmenero-Flores
authors.forename: Germán
authors.initials: G
authors.lastname: Martínez
authors.forename: Gerardo
authors.initials: G
authors.lastname: Gamba
authors.forename: Norma
authors.initials: N
authors.lastname: Vázquez
authors.forename: Domingo J
authors.initials: DJ
authors.lastname: Iglesias
authors.forename: Javier
authors.initials: J
authors.lastname: Brumós
authors.forename: Manuel
authors.initials: M
authors.lastname: Talón
mesh_terms: D000483:Alleles; D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D005260:Female; D017353:Gene Deletion; D046913:Medicago truncatula / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D009865:Oocytes / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000235:genetics / Q000378:metabolism; D010944:Plants / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D028021:Sodium-Potassium-Chloride Symporters / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D014982:Xenopus laevis
chemical_list: D002712:Chlorides; D010940:Plant Proteins; D028021:Sodium-Potassium-Chloride Symporters