Salt tolerance assay in mature transgenic <i>Arabidopsis</i> lines under salt stress.

<p>(A) Effect of salt stress on wild type (WT, Col-0) and transgenic <i>Arabidopsis</i> lines expressing <i>VrNHX1</i> constitutively (Line 1, 35S::<i>VrNHX1</i>) and inducibly (Line 4, RD29A::<i>VrNHX1</i>) subjected to 250 mM NaCl treatment for 2 weeks (B) Relative transgene expression level of <i>VrNHX1</i> in transgenic <i>Arabidopsis</i> lines under unstressed and salt stressed conditions. No transgene expression was observed in WT. A 0.283 kb fragment of <i>VrNHX1</i>::35SployA and 0.150 kb fragment of <i>AtUBQ1</i> was amplified in quantitative RT-PCR analysis (C) Na⁺ and (D) K⁺ content (µmoles/g DW) was estimated in leaves of unstressed (0 mM NaCl) and salt stressed (250 mM NaCl) WT and transgenic lines, as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0106678#s2" target="_blank">materials and methods</a>. Values indicate means ± SE (n = 3). Statistically significant values at P≤0.05 are indicated as “*”, using Bonferroni analysis.