ARS | Publication request: Characterization of six antibacterial response genes from the European corn borer (Ostrinia nubilalis) larval gut and their expression in response to bacterial challenge

Submitted to: Journal of Insect Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 3, 2010
Publication Date: January 30, 2011
Citation: Khajuria, C., Buschman, L.L., Chen, M., Zurek, L., Zhu, K. 2011. Characterization of six antibacterial response genes from the European corn borer (Ostrinia nubilalis) larval gut and their expression in response to bacterial challenge. Journal of Insect Physiology. 57:345-355.

Interpretive Summary: The innate immune response is among the main defense mechanisms of insects against microbial infection. The first step in the defense cascade of the host is to recognize the invading microorganisms. Several families of proteins involved in the recognition of the surface characteristics of microbes have been identified, such as peptidoglycan recognition proteins (PGRPs), Gram-negative binding proteins (GNBPs), lipopolysaccharides (LPS), and mannans. In this study, a group of genes encoding putative PGRPs were characterized from the European corn borer, a serious pest of corn. The information should be useful for future research on insect biocontrol utilizing microbes.

Technical Abstract: Six cDNAs encoding putative antibacterial response proteins (ARPs) were identified and characterized from the larval gut of the European corn borer (ECB, Ostrinia nubilalis). These ARPs include four peptidoglycan recognition proteins (PGRPs), one ß-1,3 glucanase-1 (ßglu-1), and one lysozyme. Tissue-specific analysis showed that these genes were highly expressed in the midgut, except for lysozyme. Analysis of expression of these genes by developmental stage showed that they were expressed in larval stages, but little or no detectable expression was found in egg, pupa and adult. When larvae were challenged with Gram-negative bacteria (Enterobacter aerogenes), the expression of all six genes was up-regulated in the fatbodies. However, when larvae were challenged with Gram-positive bacteria (Micrococcus luteus), only PGRP-C and lysozyme genes were up-regulated. This study provides additional insights into the expression of ARPs in ECB larvae and gives us a better understanding of the immune defense response in ECB.