Expression of selected intergenic regions in response to increasing concentrations of XIP. qRT-PCR analysis of gene expression was performed with strain UA159 grown in CDM to an OD600 of 0.4 in the presence of increasing amounts of XIP. *, P < 0.05; ***, P < 0.001. Expression of selected intergenic regions in response to increasing concentrations of XIP. qRT-PCR analysis of gene expression was performed with strain UA159 grown in CDM to an OD600 of 0.4 in the presence of increasing amounts of XIP. *, P < 0.05; ***, P < 0.001. Iwona B. Wenderska et al. mSystems 2017; doi:10.1128/mSystems.00102-16