Resistance to <i>P. aeruginosa</i> phenazine toxins requires MDT-15.

<p>(A) Wild-type N2, <i>mdt-15(tm2182)</i> and <i>pmk-1(km25)</i> animals were tested in the toxic phenazine <i>P. aeruginosa</i> pathogenesis assay (also called “fast killing” assay). <i>C. elegans</i> young adult animals were exposed to wild-type (WT) <i>P. aeruginosa</i>, <i>P. aeruginosa</i> carrying a deletion in both of the phenazine biosynthetic operons (<i>Δphz</i>) or <i>E. coli</i> OP50. The difference between <i>mdt-15(tm2182)</i> and N2 animals exposed to <i>P. aeruginosa</i> WT is significant (<i>p</i><0.001), as is the difference in <i>mdt-15(tm2182)</i> animals exposed to <i>P. aeruginosa</i> WT and <i>P. aeruginosa Δphz (p</i><0.001). There is no significant difference in <i>pmk-1(km25)</i> animals exposed to <i>P. aeruginosa</i> WT and <i>P. aeruginosa Δphz</i> (<i>p</i>>0.05). This assay is representative of two independent experiments. <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1004143#ppat.1004143.s006" target="_blank">Figure S6A</a> presents the control condition for this experiment showing that both <i>C. elegans</i> N2 and <i>mdt-15(tm2182)</i> at the L4 stage are sensitive to toxic phenazine-mediated killing (<i>p</i><0.001). (B) Vector control (L4440), <i>mdt-15(RNAi)</i> and <i>pmk-1(RNAi)</i> animals were exposed to high osmolarity “fast kill” media (pH 5) with <i>E. coli</i> as the food source in the presence or absence of phenazine-1-carboxylic acid and 1-hydroxyphenazine (labeled “toxic phenazines” above) at the approximate concentrations produced by <i>P. aeruginosa</i> under standard assay conditions. The difference in killing between <i>mdt-15(RNAi)</i> animals exposed to toxic phenazines and the other conditions is significant (<i>p</i><0.001). See also <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1004143#ppat.1004143.s006" target="_blank">Figure S6</a>. For sample sizes, see <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1004143#ppat.1004143.s009" target="_blank">Table S3</a>.</p>