Microbial community structure of the IgA positive (IgA+) and IgA negative (IgA−) fractions of the faecal microbiota in P2rx7−/− and WT mice. (a) PCoA of bacterial beta-diversity based on the Bray-Curtis dissimilarity. P2rx7−/− and WT mice are coloured in yellow and blue, respectively. IgA+ and IgA− samples are indicated as triangles and circles, respectively. (b) Mean relative abundances (%), at genus level, of the IgA+ and IgA− fractions of faecal microbiota from P2rx7−/− and WT mice. All bacterial genera with relative abundance <0.1% are reported together and labelled as “others”. (c,d) Mean relative abundances (%) of Firmicutes and Bacteroidetes in the IgA+ (c) and IgA− (d) fractions of faecal microbiota from P2rx7−/− and WT mice. The total abundance of all other phyla is reported as “others”. *p < 0.05, Wilcoxon rank-sum test calculated on the Firmicutes/Bacteroidetes ratio.