sX13 activity does not require Hfq.

Abstract

<p>(A) Northern blot analysis. Total RNA from NYG-grown <i>Xcv</i> strains 85-10 (wt), the <i>hfq</i> frameshift mutant (<i>hfq⁻</i>) and the <i>hfq</i> mutant ectopically expressing Hfq (p<i>hfq</i>) was analyzed using sX13- or sX14-specific probes. 5S rRNA was probed as loading control. The experiment was performed twice with two independent mutants and with similar results. (B) Plant infection assay. The <i>Xcv</i> wild-type 85-10 (wt) and <i>hfq</i> mutant strain (<i>hfq⁻</i>) were inoculated at 2×10⁸ cfu/ml into leaves of susceptible ECW and resistant ECW-10R plants. Disease symptoms were photographed 6 dpi. The HR was visualized 2 dpi by ethanol bleaching of the leaves. Dashed lines indicate the inoculated areas. The experiment was repeated three times with similar results. (C) GFP fluorescence of NYG-grown <i>Xcv</i> 85-10 (wt), the <i>hfq</i> mutant (<i>hfq⁻</i>), the <i>sX13</i> deletion mutant (Δ<i>sX13</i>) and the double mutant (Δ<i>sX13hfq⁻</i>) carrying pFX<i>3927</i> or pFX<i>hfq</i>. <i>Xcv</i> autofluorescence was determined by <i>Xcv</i> 85-10 carrying pFX0 (control). Data points and error bars represent mean values and standard deviations obtained with at least four independent experiments. GFP fluorescence of the wt was set to 1. Asterisks denote statistically significant differences (<i>t</i>-test; <i>P</i><0.01).</p