0300 Changes in gene expression in European corn borer larvae (Ostrinia nubilalis) in response to Bacillus thuringiensis Cry1Ab protoxin exposure

Monday, December 13, 2010: 9:32 AM
Sunrise (Town and Country Hotel and Convention Center)
Jianxiu Yao , Plant pathology, Kansas State University, Manhattan, KS
Chitvan Khajuria , Entomology, Kansas State University, Manhattan, KS
Buschman Lawrent , Entomology, Kansas State University, Manhattan, KS
Kun Zhu , Entomology, Kansas State University, Manhattan, KS
The European corn borer (ECB), Ostrinia nubilalis, is the target pest for corn varieties expressing insecticidal toxins from Bacillus thuringiensis (Bt). We developed a cDNA microarray based on 15,000 cDNA elements representing 2,755 unique genes identified from ECB larval gut. This microarray was used to monitor gene expression in early fourth instar Bt-susceptible ECB larvae after 6 h feeding on diet with or without Cry1Ab protoxin. We identified 169 genes from the gut for which the expression was changed more than 2-fold for larvae exposed to Cry1Ab, in which 57 annotated genes were classified based on their molecular functions: 35 genes are involved in catalytic activity, 13 for binding activity, and the remaining genes for other functions. Thirty-six up-regulated transcripts may be involved in insect defense and signaling, and 21 down-regulated genes may have roles in Cry1Ab protoxin activation, and toxin binding processes. Twelve of these genes are potentially involved in Bt toxicity and resistance, which include 7 serine protease, 1 alkaline phosphatase, 3 aminopeptidase, and 1 cadherin-like genes. The expression of serine protease genes was variable (one was up-regulated and six were down-regulated), but the three Bt-binding proteins, aminopeptidase, alkaline phosphatase and cadherin, were down regulated under Cry1Ab protoxin exposure. This study is the first large-scale survey of Cry1Ab protoxin induced transcriptional responses in ECB gut tissue and also provides a platform for functional studies of toxin-insect interactions.

doi: 10.1603/ICE.2016.51527