Identification and characterization of a Reeler domain containing protein in provides new insights into antibacterial immunity in crustacean.

Crayfish, as an invertebrate, relies only on the innate immune system to resist external pathogens. In this study, a molecule containing a single Reeler domain was identified from red swamp crayfish (named as Reeler). Tissue distribution analysis showed that Reeler was highly expressed in gills and its expression was induced by bacterial stimulation. Inhibiting the expression of Reeler by RNA interference led to a significant increase in the bacterial abundance in the gills of crayfish, and a significant increase in the crayfish mortality. Silencing of Reeler influenced the stability of the microbiota in the gills revealed by 16S rDNA high-throughput sequencing. Recombinant Reeler showed the ability to bind microbial polysaccharide and bacteria and to inhibit the formation of bacterial biofilms. These results provided direct evidence for the involvement of Reeler in the antibacterial immune mechanism of .