Molecular cloning and analysis of a C‐type lectin from silkworm Bombyx mori

C‐type lectins (CTLs) play a variety of roles in plants and animals. They are involved in animal development, pathogen recognition, and the activation of immune responses. CTLs carry one or more non‐catalytic carbohydrate‐recognition domains (CRDs) to bind specific carbohydrates reversibly. Here, we report the molecular cloning and functional analysis of a single‐CRD CTL, named C‐type lectin‐S2 (BmCTL‐S2) from the domesticated silkmoth Bombyx mori (Lepidoptera: Bombycidae). The ORF of CTL‐S2 is 666 bp, which encodes a putative protein of 221 amino acids. BmCTL‐S2 is expressed in a variety of immune‐related tissues, including hemocytes and fat body among others. BmCTL‐S2 mRNA level in the midgut and the fat body was significantly increased by bacterial challenges. The recombinant protein (rBmCTL‐S2) bound different bacterial cell wall components and bacterial cells. rBmCTL‐S2 also inhibited the growth of Bacillus subtilis and Staphylococcus aureus. Taken together, we infer that BmCTL‐S2 is a pattern‐recognition receptor with antibacterial activities.