Fig. 4

a Overview of meta-pathway of Gigantidas haimaensis mussel’s gut microbiome in carbon, sulphur and nitrogen cycles. b Overview of the Bacteroides starch utilisation system (Sus) in this study. IM Inner membrane; OM Outer membrane; A-G: starch utilisation system (Sus) locus A-G. c Overview of starch and sucrose metabolism-related genes (more details in Additional file 1: Table S5) with positive influence (red) after transplantation. Disaccharides are marked by green. Other abbreviations are provided in Additional file 1: Table S6, and the figure was created with BioRender.com (https://app.biorender.com/)