Pleiotropic effects of the mioC mutation on the physiology of P seudomonas aeruginosa PAO 1

Flavodoxin ( F ld) is a bacterial electron‐transfer protein that possesses flavin mononucleotide as a prosthetic group. In the genomes of the P seudomonas species, the mioC gene is the sole gene, annotated F ld, but its function remains unclear. In this study, phenotype microarray analysis was performed using the wild‐type and mioC mutant of pathogenic P seudomonas aeruginosa PAO 1. Our results showed that the mioC mutant is very resistant to oxidative stress. Different antibiotics and metals worked differently on the sensitivity of the mutant. Other pleiotropic effects of mutation in the mioC gene, such as biofilm formation, aggregation ability, motility and colony morphology, were observed under iron stress conditions. Most of the phenotypic and physiological changes could be recovered in the wild type by complementation. Mutation of the mioC gene also influenced the production of pigments. The mioC mutant and mioC over‐expressed complementation cells, over‐produced pyocyanin and pyoverdine, respectively. Various secreted chemicals were also changed in the mutant, which was confirmed by 1 H NMR analysis. Interestingly, physiological alterations of the mutant strain were restored by the cell‐free supernatant of the wild type. The present study demonstrates that the mioC gene plays an important role in the physiology of P . aeruginosa and might be considered as a suitable drug target candidate in pathogenic P . aeruginosa .