c‐di‐GMP impacts T6SS at the transcriptional level. A. Western blot using Hcp, TssB, ClpV, and RpoA (Loading control) antibodies on whole cell lysate of ΔexoR cells transformed with either Empty Vector control or psadC grown to early exponential phase in 523 medium or AB‐MES pH7.0. B. qRT‐PCR on RNA isolated from cells transformed with either an empty vector control, psadC or psadC* grown to early exponential phase. Expression quantified using primers specific to either tssB, fha, hcp, clpV and 16s rRNA which serves as a normalization control. Statistical significance was determined using students t‐test with p < 0.05 *, p < 0.01 **, p < 0.001*** comparing the vector control to psadC. C. qRT‐PCR on RNA isolated from cells transformed with either an empty vector control, pGFP, patu2691 or patu5372 grown to early exponential phase. Expression quantified using primers specific to either tssB, fha, hcp, clpV or 16s rRNA which serves as a normalization control. Statistical significance was determined using students t‐test with p < 0.05 *, p < 0.01 **, p < 0.001*** comparing each strain to the expression control pGFP. All experiments are the mean of three independent biological experiments with standard deviation error bars.