Characterization of host-microbiota interactions in sea urchin (Strongylocentrotus intermedius) with “black mouth disease”

In recent years, the frequent outbreaks of black mouth disease have severely impacted the development and survival of sea urchin. Nevertheless, the mechanisms underlying host-microbiota interactions remains unclear. This study analyzed the structural and functional characteristics of the microbial community and investigated the host transcriptional patterns within the mouthparts of diseased sea urchins (Strongylocentrotus intermedius). The results showed that black mouth disease significantly affected the structure of the mouthparts microbiota in the S. intermedius. The dominant bacterial genera in the disease group are represented by Vibrio, Photobacterium, and Arcobacter. A total of 4645 differentially expressed genes were identified in the mouthpart of diseased S. intermedius, of which 1753 genes were upregulated and 2892 genes were downregulated. Multi-omics analysis revealed that infections by potential pathogens bacteria associated with black mouth disease, such as Vibrio, Arcobacter, Fusibacter, and Photobacterium, are associated with the upregulation of genes in host, including HSP70IV, ATF5, NFkB1, Jun, CTSL and C3. This upregulation enhances functions related to the complement system, transcription factors, and the mitochondrial unfolded protein response, potentially contributing to enhanced immune responses. The research has certain reference significance for the study of pathogenic host-microbiota interactions in aquatic organisms, and provides a theoretical basis for the prevention and control of sea urchin diseases.