Baxter, IvanBrazelton, Jessica N.Yu, DanniHuang, Yu S.Lahner, BrettYakubova, ElenaLi, YanBergelson, JoyBorevitz, Justin O.Nordborg, MagnusVitek, OlgaSalt, David E.2015-11-232015-11-231553-7404http://hdl.handle.net/1885/16602The genetic model plant Arabidopsis thaliana, like many plant species, experiences a range of edaphic conditions across its natural habitat. Such heterogeneity may drive local adaptation, though the molecular genetic basis remains elusive. Here, we describe a study in which we used genome-wide association mapping, genetic complementation, and gene expression studies to identify cis-regulatory expression level polymorphisms at the AtHKT1;1 locus, encoding a known sodium (Na(+)) transporter, as being a major factor controlling natural variation in leaf Na(+) accumulation capacity across the global A. thaliana population. A weak allele of AtHKT1;1 that drives elevated leaf Na(+) in this population has been previously linked to elevated salinity tolerance. Inspection of the geographical distribution of this allele revealed its significant enrichment in populations associated with the coast and saline soils in Europe. The fixation of this weak AtHKT1;1 allele in these populations is genetic evidence supporting local adaptation to these potentially saline impacted environments.This work was supported by the US National Institutes of Health (http://www.nih.gov/) grants R01 GM078536 and 3R01GM078536-03S1 and by Purdue University Center for Gene-Environment Interactions to DES.8 pages© This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.allelesarabidopsisarabidopsis proteinscation transport proteinsgene expression regulation, plantgenetic complementation testgenome, plantgenome-wide association studygeographyplant leavessodiumsymportersecosystemgenetic variationseawater2010-11-1110.1371/journal.pgen.10011932015-12-11