Fig. 3

Distinct functional characteristics of PD-RBD(+) compared to PD-RBD(−) and HC. A Bar plot displaying the counts of differentially abundant KEGG orthology (KO) across the group comparisons. The orientation and color of the bars signify which group the KOs are enriched in. B Venn diagrams illustrate the counts of differentially abundant KOs identified in the DA analyses comparing PD-RBD(+) with both PD-RBD(−) with HC. C Scatter plot illustrates the results of DA analyses of functional profiles comparing PD-RBD(+) with PD-RBD(−) (x-axis) and HC (y-axis). Positive values on both axes denote a positive association with PD-RBD(+), while negative values suggest an inverse one. Red represents genes engaged in Biofilm formation–Escherichia coli pathway, while green indicates those involved in the UDP-GlcNAc synthesis/recycling pathway. D, E Results of KEGG enrichment analyses using differentially abundant KOs in PD-RBD(+) compared to (D) HC and (E) PD-RBD(−). Only results with adjusted p < 0.1 are presented. The pathways discussed in the main text are emphasized in bold. PD Parkinson’s disease, RBD rapid eye movement sleep behavior disorder, HC healthy control, KEGG Kyoto Encyclopedia of Genes and Genomes, ρ Spearman’s rank correlation coefficient