Characterization of PGRP-LB and immune deficiency in the white-backed planthopper Sogatella furcifera (Hemiptera: Delphacidae)

Abstract Peptidoglycan recognition proteins (PGRPs) participate in insect defense against bacterial pathogens by recognizing cell wall peptidoglycans (PGNs). Here, we identified the PGRP-LB gene white-backed planthopper Sogatella furcifera ( SfPGRP-LB ). is a secreted protein with typical PGN-binding domain and five conserved amino acid (aa) residues required for amidase activity. Expression analysis showed that transcript levels were significantly higher midgut than other tissues. Silencing dsRNA downregulated expression of Toll pathway genes Dorsal Imd Relish after Escherichia coli challenge. However, only expressions Staphylococcus aureus E. S. challenges rapidly strongly upregulated expression. Recombinantly expressed (rSfPGRP-LB) had strong affinities Dap-type PGN Lys-type agglutinated bacteria. rSfPGRP-LB inhibited but not growth. Furthermore, activity, degraded PGN, destroyed walls no such effects on PGN. Thus, recognizes binds various PGNs has activity