Fig. 5: Trans-kingdom interactions between ileal viruses and bacteria.

a Correlations between the α diversity metrics (richness, diversity [Shannon index and Simpson index], and evenness) of the ileal virome and bacteriome in HC, CD remission and flare-up, respectively. Spearman’s correlation coefficient was calculated, and statistical significance was determined for all pairwise comparisons. b Trans-kingdom correlations between the top 50 bacteriophages at the species level and the top 30 bacterial genera in HC, CD remission and flare-up, respectively. The correlations were calculated with FastSpar, and statistical significance was determined for all pairwise comparisons by a bootstrap method. Only statistically significant correlations were plotted. Red bubbles indicate positive correlations and blue bubbles indicate inverse correlations. The size and shading intensity are proportional to the magnitude of the correlation. Bacteriophages colour-coated in blue denote the species depleted in CD versus HC. Bacterial genera colour-coated in purple denote those genera also appeared in the bacteriome-virome ecology analysis in our later murine study (shown in Fig. 7j) to establish a causal effect and validate the finding in humans.