Fig. 2: P. distasonis is selectively enriched by DOP.

a Schematic of P. distasonis enrichment by DOP in vitro. Briefly, we incubated these three dietary fibers (DOP, or inulin or β-glucan) independently with fecal bacteria from T2DM patients for 48 h. The majority of the fermented broth underwent centrifugation, while the resulting precipitation was used for 16S rRNA gene sequencing. Simultaneously, the supernatant was employed for the sugar content determination. Another portion of the fermented broth was coated in BHI agar medium, resulting in the isolation of 43 strains of P. distasonis. Finally, the 43 strains of P. distasonis were cultured in BHI medium (DOP as the sole carbon) for 24 h, and the OD₆₀₀ was measured. The strain with the highest △OD₆₀₀ was selected for further experiments. The tube in the image is referenced from Figure 1c of Ziesack et al (https://doi.org/10.1128/msystems.00352-19) with appropriate color modifications. b Relative abundance of bacteria at the genus level in different groups. c Principal coordinate analysis (PCoA) of DOP and Vehicle group by weighted UniFrac distance (ANOSIM test). d Taxonomic cladogram generated from LEfSe analysis (DOP and Vehicle group) by 16S rRNA gene amplicon sequencing. Each circle’s size is proportional to the taxon’s abundance. e LDA score representing the taxonomic data with significant differences between DOP and Vehicle groups. Only LDA scores >2 are shown. Green indicates enriched taxa in the Vehicle group. Red indicates enriched taxa in the DOP group. f The relative abundance of P. distasonis in DOP and Vehicle group was determined by qPCR. n = 30 per group. g The relative abundance of P. merdae, P. johnsonii, P. goldsteinii, and P. gordonii in DOP and Vehicle groups were determined by qPCR. n = 30 per group. h–i Mice were treated with 400 mg/kg DOP by daily gavage for 7 days. h Experimental scheme for i. n = 6 mice per group. i The change of relative abundance of fecal P. distasonis by DOP treatment. DOP (Dendrobium officinale polysaccharide); BG (β-glucan); IN (inulin). Data are presented as the mean ± SEM. Statistical analysis was performed using two-tailed Mann–Whitney test for f and g, two-tailed paired t-test for i. Source data are provided as a Source Data file.