<i>amrZ</i> mutants show characteristics of Rugose Small Colony Variant Strains.

<p><b>A Δ<i>amrZ</i> mutants have RSCV phenotype.</b> Images represent colony morphology after overnight growth on VBMM agar. RSCV phenotype was observed in Δ<i>amrZ</i> and R22A DNA-binding deficient <i>amrZ</i> mutants but not in the parental PAO1. Chromosomal complementation of <i>amrZ</i> reverts the colony morphology to that of the smooth parental PAO1. Δ<i>wspF</i> is included as a known RSCV strain. Scale bars indicate 1 mm. <b>B Δ</b><b><i>amrZ</i></b><b> mutants exhibit increased intracellular c-di-GMP.</b> Direct LC-MS/MS measurement of c-di-GMP in plate-grown bacteria indicates that a Δ<i>amrZ</i> mutant accumulates significantly more intracellular c-di-GMP than the wild-type PAO1. The DNA binding deficient R22A AmrZ mutant has elevated c-di-GMP. Individual measurements are displayed, along with mean and standard error of the mean. Statistical significance was determined using Student's t-test. (** p≤0.01, *** p≤0.001).