A C-type lectin-like receptor CD302 in yellow drum (Nibea albiflora) functioning in antibacterial activity and innate immune signaling.

Molecular dissection of disease resistance against Vibrio harveyi infection in yellow drum at the genome-wide level uncovered a C-type lectin-like receptor cluster of differentiation CD302 (named as YdCD302) in our previous study. Here, the gene expression pattern of YdCD302 and its function in mediating the defense response to V. harveyi attack were investigated. Gene expression analysis demonstrated that YdCD302 was ubiquitously distributed in various tissues with the highest transcript abundance in liver. The YdCD302 protein exhibited agglutination and antibacterial activity against V. harveyi cells. Binding assay indicated that YdCD302 can physically interact with V. harveyi cells in a Ca-independent manner, and the interaction can activate reactive oxygen species (ROS) production in the bacterial cells to induce RecA/LexA-mediated cell death. After infection with V. harveyi, the expression of YdCD302 can be up-regulated significantly in the main immune organs of yellow drum and potentially further trigger the cytokines involved innate immunity. These findings provide insight into the genetic basis of the disease resistance trait in yellow drum and shed light on the functioning of the CD302 C-type lectin-like receptor in host-pathogen interactions. The molecular and functional characterization of YdCD302 is a significant step towards a better understanding of disease resistance mechanisms and the development of new strategies for disease control.