Fig 7. Rhamnolipid (rhlA) and pyocyanin biosynthetic (phzA1) genes show altered expression profiles in P. aeruginosa tat mutants and fail to respond to exogenous PQS.

(A) Light output from a chromosomal rhlA’-lux fusion as a function of growth (RLU/OD) over time when introduced into the wild type, pqsA and tatA mutants or complemented tatA mutant in the absence or presence of exogenous PQS (20 μM). (B) Maximal light output from a chromosomal phzA1’-lux fusion as a function of growth (RLU/OD₆₀₀) when introduced into the wild type, ΔpqsA, or ΔpqsA tatA mutants in the absence or presence of exogenous PQS (10 or 40 μM) or plasmid-borne pqsE or the pUCP18 vector control. Experiments were repeated in triplicate at least twice. ***p < 0.001, **p < 0.01, and *p < 0.05; n.s. not significant.