title: The plasma membrane Na+/H+ antiporter SOS1 is essential for salt tolerance in tomato and affects the partitioning of Na+ between plant organs.
abstract: We have identified a plasma membrane Na(+)/H(+) antiporter gene from tomato (Solanum lycopersicum), SlSOS1, and used heterologous expression in yeast to confirm that SlSOS1 was the functional homolog of AtSOS1. Using post-transcriptional gene silencing, we evaluated the role played by SlSOS1 in long-distance Na(+) transport and salt tolerance of tomato. Tomato was used because of its anatomical structure, more complex than that of Arabidopsis, and its agricultural significance. Transgenic tomato plants with reduced expression of SlSOS1 exhibited reduced growth rate compared to wild-type (WT) plants in saline conditions. This sensitivity correlated with higher accumulation of Na(+) in leaves and roots, but lower contents in stems of silenced plants under salt stress. Differential distribution of Na(+) and lower net Na(+) flux were observed in the xylem sap in the suppressed plants. In addition, K(+) concentration was lower in roots of silenced plants than in WT. Our results demonstrate that SlSOS1 antiporter is not only essential in maintaining ion homeostasis under salinity, but also critical for the partitioning of Na(+) between plant organs. The ability of tomato plants to retain Na(+) in the stems, thus preventing Na(+) from reaching the photosynthetic tissues, is largely dependent on the function of SlSOS1.
authors.affiliation: Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Olías
authors.forename: Zakia
authors.initials: Z
authors.lastname: Eljakaoui
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Paz Alvarez
authors.initials: PA
authors.lastname: De Morales
authors.forename: Mari Carmen
authors.initials: MC
authors.lastname: Marín-Manzano
authors.forename: Jose M
authors.initials: JM
authors.lastname: Pardo
authors.forename: Andrés
authors.initials: A
authors.lastname: Belver
mesh_terms: D018506:Gene Expression Regulation, Plant; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D018749:RNA, Plant / Q000235:genetics; D055051:Salt-Tolerant Plants / Q000235:genetics / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics / Q000378:metabolism*; D052584:Xylem / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D018749:RNA, Plant; D017923:Sodium-Hydrogen Exchangers; D012964:Sodium