<i>rsa1-1</i> plants are hypersensitive to NaCl, and RSA1 is involved in Na⁺ homeostasis under salt stress.

<p>(A)–(C) Five-d-old wild-type and <i>rsa1-1</i> seedlings grown on MS medium were transferred to MS medium supplemented with different levels of NaCl and allowed to grow for an additional 8 d. Root elongation or shoot fresh weight was measured and is shown as a percentage relative to growth on normal MS medium. (D) Two-week-old wild-type and <i>rsa1-1</i> plants grown in soil were irrigated with 300 mM NaCl for 0 or 14 d. (E) Survival rate of wild-type and <i>rsa1-1</i> plants as shown in (D). (F) Seed germination of wild type and <i>rsa1-1</i> in response to various NaCl levels. There were 80–150 seeds per genotype per biological replicate. Seeds in which the radical had emerged through the seed coat were considered germinated. (G) Na⁺ content in soil-grown wild-type and <i>rsa1-1</i> plants. DW, dry weight. (H) K⁺ content in soil-grown wild-type and <i>rsa1-1</i> plants. (I) Ratio of Na⁺ to K⁺ accumulation in soil-grown wild-type and <i>rsa1-1</i> plants. WT, wild type. Error bars indicate the standard deviation (n = 30–40). The experiments in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003755#pgen-1003755-g001" target="_blank">Figure 1</a> were repeated at least five times with similar results, and data from one representative experiment are presented.