cdGMP controls chiB transcription, which enhances biofilm formation. (A) F. novicida strains U112 (WT) and KKF457 [ΔFTN(0451–0456)], either without plasmid or carrying plasmid pKEK1525 (+ VCA0956), were grown in CDM, and mRNA abundances for chiA and chiB were determined by quantitative reverse transcription-PCR (see Materials and Methods for details). Results shown represent three biological replicates consisting of three technical replicates for each strain. **, P < 0.005. (B) F. novicida strains U112 (WT), KKF555 (chiA), KKF556 (chiB), KKF457 [Δ(FTN0451-0456)], KKF557 [Δ(FTN0451-0456) chiA], and KKF558 [Δ(FTN0451-0456) chiB], either with no plasmid (−) or carrying plasmid pKEK1525 (VCA0956), were assayed for biofilm formation as described in Materials and Methods. *, P < 0.05; ***, P < 0.0005.