Role of siderophore in Pseudomonas fluorescens biofilm formation and spoilage potential function

We investigated the function of pyoverdine in the biofilm formation, motility, and spoilage potential of Pseudomonas fluorescens. We targeted and identified two major genes (pvdA and pvdE) that are involved in the biosynthesis of siderophores. We next constructed ΔpvdA and ΔpvdE mutants of P. fluorescens PF08 and found that the deletion of pyoverdine led to a biofilm-to-motivity transition as both ΔpvdA and ΔpvdE mutants displayed enhanced motility, reduced level of exopolysaccharides (EPSs), and attenuated biofilm formation. In addition, the lack of synthesis of pyoverdine promoted the spoilage of fish fillets stored at 4 °C. Based on the effect of pyoverdine deletion on the phenotype; we report that pyoverdine regulates the transcription levels of htpX, phoA, flip, flgA, and RpoS, suggesting that pyoverdine-mediated iron absorption may affect the regulation of flagellum and stress resistance. This study emphasizes the important role of pyoverdine in the formation of biofilm, motility, and spoilage of P. fluorescens PF08.