In the present study, we identified a FOXO from kuruma shrimp (Marsupenaeus japonicus) and found that it played a critical role in maintaining hemolymph and intestinal microbiota homeostasis by promoting the expression of Relish, the transcription factor of immune deficiency (IMD) pathway for expression of antimicrobial peptides (AMPs) in shrimp. The gene discussed is ADSL; the disease is Immunodeficiency.