Link between the Δhfq phenotypes and the biosynthesis of pantothenate and CoA.

(A) Schematic of the pantothenate and CoA biosynthesis pathway in C. crescentus. The solid arrows represent a single enzymatic step, while the dashed arrows denote multiple enzymatic steps. PanD and VOR are the only two enzymes in this pathway whose mRNA levels were affected by the hfq deletion. (B) panD and vor mRNA levels in the WT and Δhfq strains measured in RNA-Seq experiments. The error bars represent the standard deviations from 3 biological replicates. (C) Proposed mechanism underlying KG accumulation in Δhfq cells. Downregulation of panD expression and upregulation of vor expression lead to reduction in CoA abundance. In turn, lower CoA level reduces KGDH activity leading to KG accumulation. Inactivation of vor in the Δhfq vor::Tn5 suppressor strain partially restores CoA synthesis and improves KGDH activity, resulting in lower KG levels. (D) Phase contrast images of Δhfq cells grown in PYE with or without 1 mM pantothenate (Pan) for 20 h at 30°C. (E) Scatter plots of cell lengths and widths of populations described in (D). (F) Growth curves of WT and Δhfq strains cultured at 30°C in PYE with and without 1 mM Pan. Each curve represents the average of 3 replicates with the standard deviation shown in grey.