Protective effect of Glutamicibacter sp. ZY1 against Vibrio parahaemolyticus YDE17 pathogenicity in the clam Ruditapes philippinarum.

The use of probiotics is preferable to the use of antibiotics for the control of vibriosis. In this study, artificial infection showed that Glutamicibacter sp. ZY1 significantly protected the Manila clam Ruditapes philippinarum from infection by Vibrio parahaemolyticus YDE17, with a relative percent survival of 82.16%. Glutamicibacter sp. ZY1 significantly reduced the total numbers of culturable Vibrio and V. parahaemolyticus in the infected clam R. philippinarum. Histopathological observation revealed that the pathological damage to the gills of individuals infected by V. parahaemolyticus YDE17 was alleviated by Glutamicibacter sp. ZY1. Furthermore, preinoculation with Glutamicibacter sp. ZY1 inhibited the biofilm formation of V. parahaemolyticus YDE17. Transcriptomic analysis revealed that V. parahaemolyticus YDE17 downregulated genes related to the immune response and peptide cross-linking in the clam R. philippinarum, and inhibited β-alanine metabolism and fatty acid degradation. Glutamicibacter sp. ZY1 activated the immune response, oxidative stress response, and heme/tetrapyrrole binding, and it upregulated pathways involved in arachidonic acid metabolism, arginine and proline metabolism, and the folate-mediated one-carbon pool. Glutamicibacter sp. ZY1 alleviated immune suppression and upregulated steroid hormone biosynthesis and linoleic acid metabolism. Taken together, Glutamicibacter sp. ZY1 shows promise as a probiotic candidate for protecting the clam R. philippinarum against Vibrio infection.