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You searched for +publisher:"Kansas State University" +contributor:("Larry L. BuschmanKun Yan Zhu"). Showing records 1 – 2 of 2 total matches.

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Kansas State University

1. Yao, Jianxiu. Genomic analysis of the genes expressed in the European corn borer (Ostrinia nubilalis) gut and their expression responses to BT toxins.

Degree: PhD, Department of Entomology, 2011, Kansas State University

European corn borer, Ostrinia nubilalis, is one of the most destructive insect pests of corn in the Midwest corn belt of the United States. The crystal protein toxin (Cry1Ab) expressed by the bacterium, Bacillus thuriginesis (Bt), specifically targets O. nubilalis gut and functions as “stomach poison”. Transgenic corn expressing Cry1Ab can effectively control O. nubilalis larval infestation. However, O. nubilalis has the potential to develop resistance to Bt toxins which prompts concerns that transgenic corn will lose its control efficacy. Previous studies found that O. nubilalis gut serine proteases and membrane proteins were involved in Bt toxicity and resistance. Therefore, this study was to identify and characterize gut transcripts potentially involved in Bt toxicity and resistance, and to compare their transcriptional responses to the ingestion of Cry1Ab protoxin and transgenic corn leaves expressing Cry1Ab toxin. We identified and characterized 34 cDNAs encoding putative trypsins, chymotrypsins, and trypsin- and chymotrypsin-like protease homologs from O. nubilalis gut-specific expressed sequence tags (ESTs). Blast and phylogenetic analysis of their deduced amino acid sequences indicated that 15 were putative trypsins belonging to Try-G2 and Try-G3 groups (none of them was grouped in Try-G1), another 15 were putative chymotrypsins in one large group (CTP-G1), and the remaining four were serine protease homologs in Try-G4 and CTP-G2 groups, respectively. The existence of diverse trypsins, chymotrypsins and serine protease homologs in O. nubilalis could be an adaptation to different food sources and also a defense mechanism against plant-specific protease inhibitors and Cry toxins from transgenic corn. The expressions of four putative trypsins (OnTry4, OnTry5, OnTry6 and OnTry14) were up-regulated in O. nubilalis larvae after the ingestion of Cry1Ab protoxin. The differential expressions of these protease transcripts may implicate a link to Cry1Ab intoxication. To better understand the basic physiology of insect gut and Bt toxin interactions, we developed a high-resolution 8×15K cDNA microarray chips based on the larval gut specific ESTs. Each microarray contains 12,797 probes representing 2,895 unique larval gut transcripts. The expressions of 174 transcripts were differentially regulated at least 2-fold (P-value ≤0.05) after the larvae fed Cry1Ab protoxin for 6 hours. Among them, 13 transcripts, putatively encoding eight serine protease, three aminopeptidase, one alkaline phosphatase, and one cadherin-like protein, were identified and further validated their expression ratios by quantitative PCR (qPCR). Three trypsin transcripts were up-regulated by more than 5-fold in larvae fed Cry1Ab protoxin. Sequence analysis suggests that they may have role in protoxin activation and toxin degradation. The transcriptional responses of laboratory-selected Cry1Ab resistant (R) and susceptible (S) strains of O. nubilalis to the ingestion of transgenic corn (MON811) leaves expressing Cry1Ab toxin were also examined. Even… Advisors/Committee Members: Larry L. BuschmanKun Yan Zhu.

Subjects/Keywords: O. nubilalis; gene expression; Entomology (0353)

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Yao, J. (2011). Genomic analysis of the genes expressed in the European corn borer (Ostrinia nubilalis) gut and their expression responses to BT toxins. (Doctoral Dissertation). Kansas State University. Retrieved from http://hdl.handle.net/2097/12131

Chicago Manual of Style (16th Edition):

Yao, Jianxiu. “Genomic analysis of the genes expressed in the European corn borer (Ostrinia nubilalis) gut and their expression responses to BT toxins.” 2011. Doctoral Dissertation, Kansas State University. Accessed January 24, 2020. http://hdl.handle.net/2097/12131.

MLA Handbook (7th Edition):

Yao, Jianxiu. “Genomic analysis of the genes expressed in the European corn borer (Ostrinia nubilalis) gut and their expression responses to BT toxins.” 2011. Web. 24 Jan 2020.

Vancouver:

Yao J. Genomic analysis of the genes expressed in the European corn borer (Ostrinia nubilalis) gut and their expression responses to BT toxins. [Internet] [Doctoral dissertation]. Kansas State University; 2011. [cited 2020 Jan 24]. Available from: http://hdl.handle.net/2097/12131.

Council of Science Editors:

Yao J. Genomic analysis of the genes expressed in the European corn borer (Ostrinia nubilalis) gut and their expression responses to BT toxins. [Doctoral Dissertation]. Kansas State University; 2011. Available from: http://hdl.handle.net/2097/12131


Kansas State University

2. Khajuria, Chitvan. Genomic, expression and functional analysis of genes from larval gut of the European corn borer, Ostrinia nubilalis (Hübner).

Degree: PhD, Department of Entomology, 2010, Kansas State University

Genomic information for lepidopteran insects, particularly agricultural pest species, is very limited but urgently needed due to their economic importance and biodiversity. The huge economic losses ($ 1-2 billons / year) caused by the European corn borer (Ostrinia nubilalis, Hübner, ECB) makes this insect species one of the major pests of corn in the United States and western world. Management of ECB by conventional methods is limited but has had a great success by transgenic Bt (Bacillus thuringiensis) corn, which targets insect gut. However, the widespread use of Bt corn may lead to the development of Bt resistance in ECB. Knowledge of genes expressed in the insect gut is considered crucial for understanding basic physiology of food digestion, their interactions with Bt toxins and pathogens, and for discovering new targets for pest management. A large database of 15,000 expressed sequence tags (ESTs) was established from the ECB larval gut. To our knowledge, this database represents the largest gut-specific EST database from a lepidopteran pest. Analysis of 10 aminopeptidase-like genes between Cry1Ab–resistant and –susceptible ECB larvae revealed that aminopeptidase P-like (OnAPP) gene is a strong candidate for its role in Bt toxicity and resistance. The RNA interference mediated reduction in the transcript level of OnAPP gene in ECB larvae resulted in their reduced susceptibily to Cry1Ab. Analysis of the chitinase-like gene (OnCht) revealed its essential role in regulating chitin content of peritrophic membrane (PM). Our results suggest that OnCht may influence food digestion, nutrient absorption or movement of digestive enzymes through the PM and can be an important target for insect management. We also identified and characterized six genes involved in the innate immune defense response in ECB and showed that the expression of these genes were induced when challenged with bacteria. In addition to these results, this research generated significant genomic information for the development of microarray from the larval gut of ECB. The establishment of the feeding-based RNA interference technique could potentially help in delivering dsRNA orally to ECB for high throughput screening of effective genes to be targeted for insect pest management. Advisors/Committee Members: Larry L. BuschmanKun Yan Zhu.

Subjects/Keywords: European corn borer; gut; Express sequence tag; Biology, Entomology (0353)

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Khajuria, C. (2010). Genomic, expression and functional analysis of genes from larval gut of the European corn borer, Ostrinia nubilalis (Hübner). (Doctoral Dissertation). Kansas State University. Retrieved from http://hdl.handle.net/2097/2461

Chicago Manual of Style (16th Edition):

Khajuria, Chitvan. “Genomic, expression and functional analysis of genes from larval gut of the European corn borer, Ostrinia nubilalis (Hübner).” 2010. Doctoral Dissertation, Kansas State University. Accessed January 24, 2020. http://hdl.handle.net/2097/2461.

MLA Handbook (7th Edition):

Khajuria, Chitvan. “Genomic, expression and functional analysis of genes from larval gut of the European corn borer, Ostrinia nubilalis (Hübner).” 2010. Web. 24 Jan 2020.

Vancouver:

Khajuria C. Genomic, expression and functional analysis of genes from larval gut of the European corn borer, Ostrinia nubilalis (Hübner). [Internet] [Doctoral dissertation]. Kansas State University; 2010. [cited 2020 Jan 24]. Available from: http://hdl.handle.net/2097/2461.

Council of Science Editors:

Khajuria C. Genomic, expression and functional analysis of genes from larval gut of the European corn borer, Ostrinia nubilalis (Hübner). [Doctoral Dissertation]. Kansas State University; 2010. Available from: http://hdl.handle.net/2097/2461

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