Functional identification of C-type lectin in the diamondback moth, Plutella xylostella (L.) innate immunity

C-type lectins (CTLs) are a superfamily of Ca2+-dependent carbohydrate-recognition proteins, and an important pattern recognition receptor (PRR) in insect innate immunity which can mediate humoral cellular insects. In this study, we report novel dual domain (CRD) CTL from Plutella xylostella designate PxIML. PxIML is protein with 969 bp open reading frame (ORF) encoding 322 amino acids, containing signal peptide dual-CRD EPN (Glu124-Pro125-Asn126) QPD (Gln274-Pro275-Asp276) motifs. The expression mRNA the fat body was significantly higher than hemocytes midgut. relative levels whole were inhibited after infection Bacillus thuringiensis 8010 (Bt8010) at 18 h, while they upregulated Serratia marcescens IAE6 or Pichia pastoris. recombinant (rPxIML) could bind to tested pathogen-associated molecular patterns (PAMPs), bacteria Enterobacter sp. IAE5, S. IAE6, Staphylococcus aureus, Escherichia coli BL21, Bt8010 manner, however, it showed limited binding fungus, P. rPxIML exhibited strong activity presence Ca2+ agglutinate Bt8010, IAE5 but only weakly agglutinated E. not Furthermore, hemocytes, promote adsorption beads, enhance phenoloxidase (PO) melanization xylostella. Our results suggest that plays role pathogen mediating subsequent