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United States Department of Agriculture

Agricultural Research Service

Research Project: Insecticide Resistance Management and New Control Strategies for Pests of Corn, Cotton, Sorghum, Soybean, and Sweet Potato

Location: Southern Insect Management Research Unit

Title: Microarray analysis of global gene regulation in the Cry1Ab-resistance and - susceptible strains of Diatraea saccharalis

Authors
item Guo, Zibiao
item ZHU, YU CHENG
item Huang, Fangneng -
item LUTTRELL, RANDALL
item Leonard, Rogers -

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 13, 2011
Publication Date: January 6, 2012
Citation: Guo, Z., Zhu, Y., Huang, F., Luttrell, R.G., Leonard, R. 2012. Microarray analysis of global gene regulation in the Cry1Ab-resistance and - susceptible strains of Diatraea saccharalis. Pest Management Science. 68:718-730. http//olinelibrary.wiley.com/doi/10.1002/ps.2318/pdf

Interpretive Summary: The sugarcane borer is an economically important corn pest in the mid-South region of the United States. Extensive adoption of transgenic Bt corn in recent years for stalk borer control has increased risk of adaptation and resistance evolution in the target pest populations. A Bt-resistant strain, selected from field populations using F2 screen, was approximately 100-fold more tolerant to Cry1Ab toxin than the susceptible counterpart. To better understand the molecular mechanisms of Bt resistance, the Cry1Ab-susceptible (Cry1Ab-SS) and –resistant (Cry1Ab-RR) strains of the sugarcane borer were subjected to a microarray analysis. Results showed that the expression levels of many genes were significantly different between the Cry1Ab-RR and -SS strains. Analysis of 7,145 cDNAs using microarray revealed 384 differentially expressed genes. Two hundred seventy-three genes were up-regulated and 111 genes were down-regulated in Cry1Ab-resistant strain. Three genes, coding for a glutathione S-transferase omega 1 (GST), a chymotrypsin-like protease (CHY), and a lipase (LP), were significantly up-regulated by 2.44, 2.00, and 6.57-fold, respectively. Considering potential involvement in Bt toxicity, the elevated expression levels of these genes were verified by using real-time PCR, suggesting a reproducibility of the microarray data. Analyses of biological and molecular functional profiles revealed that substantially more metabolic- or catalytic-related genes were up-regulated in the resistant strain, indicating a potential large increase of catalytic or metabolic activities in the Cry1Ab-RR strain. This cDNA microarray gene expression data could be used to characterize and identify new genes that are associated with Bt resistance development in D. saccharalis.

Technical Abstract: The sugarcane borer, Diatraea saccharalis, is an economically important corn pest in the mid-South region of the United States. Extensive adoption of transgenic Bt corn in recent years for stalk borer control has increased risk of adaptation and resistance evolution in the target pest populations. A Bt-resistant strain, selected from field populations using F2 screen, was approximately 100-fold more tolerant to Cry1Ab toxin than the susceptible counterpart . To better understand the molecular mechanisms of Bt resistance, the Cry1Ab-susceptible (Cry1Ab-SS) and –resistant (Cry1Ab-RR) strains of D. saccharalis were subjected to a microarray analysis. Results showed that the expression levels of many genes were significantly different between the Cry1Ab-RR and -SS strains. Analysis of 7,145 cDNAs using microarray revealed 384 differentially expressed genes. Two hundred seventy-three genes were up-regulated and 111 genes were down-regulated in Cry1Ab-resistant strain. Three genes, coding for a glutathione S-transferase omega 1 (GST), a chymotrypsin-like protease (CHY), and a lipase (LP), were significantly up-regulated by 2.44, 2.00, and 6.57-fold, respectively. Considering potential involvement in Bt toxicity, the elevated expression levels of these genes were verified by using real-time PCR, suggesting a reproducibility of the microarray data. Analyses of biological and molecular functional profiles revealed that substantially more metabolic- or catalytic-related genes were up-regulated in the resistant strain, indicating a potential large increase of catalytic or metabolic activities in the Cry1Ab-RR strain. This cDNA microarray gene expression data could be used to characterize and identify new genes that are associated with Bt resistance development in D. saccharalis.

Last Modified: 8/19/2014
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