Fig. 2: The fitness effect of glpT is linked to the high phosphate availability in the murine cecal lumen.
a The fitness advantage conferred by the glpT mutant is reduced when mice are fed chow with an eightfold lower phosphate concentration (0.1%). Statistical significance was tested with a two-sided unpaired t-test. Lines represent the median. n = 12 mice, combined from four independent experiments, indicated by different shapes. Please note that four data points for the regular 0.8% Pi chow control are also shown in panel 2b, as the same mice served as the control for both experiments for the sake of 3 R; these data points are shown as open circles. b The fitness advantage conferred by the glpT mutant is reduced when mice are fed 1% G3P via their drinking water. The statistical significance was tested with a two-sided unpaired t-test. Lines represent the median. n = 7 mice. The different shapes indicate they originate from two independent experiments. c The fitness advantage conferred by the glpT mutant is strongly reduced in the background of a strain deficient for the phosphate transporters pitA, pstS, and yjbB (Δ3Pi). The Δ3Pi strain likely has less access to Pi, which should lower the intracellular Pi concentration. The statistical significance was tested with a two-sided unpaired t-test. Lines represent the median. n = 7 mice for the wild-type background and n = 8 mice for the Δ3Pi background combined from three independent experiments. d Visualization of the three Pi transporters encoded by S. Tm. Adapted from Bruna et al., Adv. in Exp. Med and Bio., 2022 for illustrative purposes. Created in BioRender. Santamaria de Souza (2025) https://BioRender.com/x62f158 (e) Competitive indices of phosphate transport mutants show that the Pi concentration is high enough for mutants not to have a competitive disadvantage on day 1 post-infection. Significance was tested by comparing the median to the theoretical median of 1 using a one-sample Wilcoxon test (two-sided). Lines mark the median. n = 5 mice combined from two independent experiments. Source data are provided as a Source Data file.
