<p>The two inactivated <i>phz</i> gene clusters with their flanking genes in <i>Pseudomonas</i> sp. M18 (A) and the growth curves (B) and PCA production (C) in wild type strain and the two mutants M18ΔP1 and M18ΔP2 with or without exogenous PCA molecules. Symbols in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019413#pone-0019413-g001" target="_blank">figure 1A</a>: red solid arrows denote the two <i>phz</i> core gene clusters; empty arrows, the <i>phz</i> flanking genes; fine line, Gm, genamycin resistence gene; +1, indicates the transcriptional start site (TSS) and the numbers indicate the relative length from TSS; black lines, intergenic regions between <i>phz</i> gene clusters and flanking genes; black solid lines denote the 88 bp sequence homologous to that in <i>P. aeruginosa</i> PAO1; grey solid line denotes additional 56 bp sequence in strain M18. Symbols in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019413#pone-0019413-g001" target="_blank">figure 1B and 1C</a>: square, wild type strain M18; triangle, mutant M18ΔP1; circle, mutant M18ΔP2; red solid and blue empty denote presence or absence of exogenous PCA in culture, respectively. All experiments were performed in triplicate, and each value is presented as the average ± standard deviation.</p
