Genome wide transcriptional analysis of P. aeruginosa PAO1, response to phosphate limitation

P. aeruginosa PAO1 grown as lawns on Nematode Growth Medium prepared without supplementation (NGM Pi<0.1 mM) has high killing ability against C. elegans, however, no mortality in worms has been observed during 48 hrs when feeding on PAO1 lawns grown on phosphate supplemented full NGM Pi 25 mM, pH 6.0 medium. We used a microarray to define the virulence-related genes in P. aeruginosa grown as lawns in NGM Pi<0.1 mM vs NGM Pi25 mM pH 6.0 All samples for gene expression analysis were prepared in biological triplicate. P. aeruginosa MPAO1 cells collected from lawns grown on NGM/[Pi]25 mM, pH 6.0 or NGM/Pi<0.1 mM were used for RNA isolation. Microarray analysis was performed using Affymetrix P. aeruginosa GeneChips (Affymetrix, Santa Clara, CA) at the University of Chicago Functional Genomics Facility