Fig. 2

Specific fecal microbial ecosystem in children and adolescents with MDD. A Box and whiskers plots (in the style of Turkey) for the α-diversity analysis of four indices (Simpson, Chao1 and Shannon) at the microbial strain level between MDD patients (n = 83) and HCs (n = 58). B Principal component analysis (PCoA) indicates a partial but significant separation between patients with MDD and HCs at microbial strain level. Significance was determined using permutational multivariate analysis of variance (Binomial distance). C Visualization of constructed co-occurrence network for the relative abundance of all the 793 metagenome-assembled genomes (MAGs) by using Sparcc in HCs (left) and MDD groups (right). D Violin chart demonstrating the connectivity property of the network including network node degree and natural connective (Wilcox test p-value; ** < 0.01, **** < 0.0001). E Fragility of the co-occurrence network was measured by the natural connective after removing the nodes. A larger natural connective indicated the corresponding network was more robust/less fragile. F The cladogram shows the 104 MAGs were differentially abundant between MDD and HCs by using LEfSe analysis, including 58 up-regulated and 46 down-regulated MAGs in MDD group. G Box and whiskers plots (in the style of Turkey) show the 6 MDD-associated microbial Kyoto Encyclopedia of Genes and Genomes (KEGG) modules in amino acids (AAs) pathways between MDD and HCs (Wilcox test p-value; * p-value < 0.05)