Transcriptional profiling analysis likely to indicate that c-di-GMP is involved in iron uptake in P. aeruginosa PAO1

Cyclic dimeric guanosine monophosphate (c-di-GMP), a small secondary messenger, regulates various bacteria physiological processes at transcriptional, posttranscriptional and post-translational levels. P. aeruginosa PAO1 genome contains multiple c-di-GMP metabolizing genes. Transposon mutant of PA0861, one of the c-di-GMP metabolizing genes, showed increased biofilm formation. Siderophores, mainly pyoverdine and pyochelin from P aeruginosa, are involved in iron uptake. In current study, mainly microarray and RT-PCR analysis were applied to compare the expression profile between wild type and mutant strains of P. aeruginosa. Our transcriptional profiling analysis indicated that pyoverdine synthesis was upregulated in PA0861 mutant. Through spectrophotometrically comparison, it was further demonstrated that pyoverdine production was increased in PA0861 mutant strain. Our results raise the possibility that c-di-GMP regulates siderophore synthetic genes, and affects biofilm formation. Further investigations will be needed to elucidate the mechanisms. Keywords: Biofilm formation; cyclic dimeric guanosine monophosphate (c-di-GMP); P. aeruginosa; pyoverdine; siderophores.