In vivo RNA-sequencing of Vibrio cholerae during intestinal colonization of infant rabbits

To understand how cholera toxin (CT) produced by Vibrio cholerae modulates gene expression of this organism within the intestine, RNA-seq analysis was performed on two samples each of WT and the ∆ctx mutant bacteria harvested from either the infant rabbit ileum or the cecum one-day post-intragastric infection. We found that 243 genes that were significantly up-regulated in the WT compared to the ∆ctx mutant and these included 101 genes in ileum samples, 118 in the cecum samples, and 24 in both samples. We found that genes known to be induced under low-iron growth conditions were up-regulated in WT relative to the ∆ctx mutant in both the ileum and in the cecum, with a marked up-regulation in the ileum relative to the cecum. We also found that genes involved in TCA cycle metabolism, L-Lactate utilization, and LCFA utilization were significantly up-regulated in the WT in the ileum relative to the ∆ctx mutant during infection. We conclude that CT-induced disease creates an iron-depleted metabolic niche in the gut that modulates the transcriptional profile of this pathogen during infection. RNA-seq analysis was performed on two samples each of WT and the ∆ctx mutant V. cholerae harvested from either the infant rabbit ileum or the cecum one-day post-intragastric infection.