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BT corn

Zhi-Feng Sun, Tao Zhang, Jinyang Liu, Zhen-Ting Du, Huaiji Zheng
A convergent synthesis of four stereoisomers of the sex pheromone of the western corn rootworm (8-methyldecan-2-yl propionate, 1 ) from commercially available chiral starting materials is reported. The key step was Julia-Kocienski olefination between chiral BT-sulfone and chiral aldehyde. This synthetic route provided the four stereoisomers of 1 in 24-29% total yield via a six-step sequence. The simple scale-up strategy provides a new way to achieve the asymmetric synthesis of the sex pheromone.
March 15, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Galen P Dively, P Dilip Venugopal, Dick Bean, Joanne Whalen, Kristian Holmstrom, Thomas P Kuhar, Hélène B Doughty, Terry Patton, William Cissel, William D Hutchison
Transgenic crops containing the bacterium Bacillus thuringiensis (Bt) genes reduce pests and insecticide usage, promote biocontrol services, and economically benefit growers. Area-wide Bt adoption suppresses pests regionally, with declines expanding beyond the planted Bt crops into other non-Bt crop fields. However, the offsite benefits to growers of other crops from such regional suppression remain uncertain. With data spanning 1976-2016, we demonstrate that vegetable growers benefit via decreased crop damage and insecticide applications in relation to pest suppression in the Mid-Atlantic United States...
March 12, 2018: Proceedings of the National Academy of Sciences of the United States of America
T Yu, X Li, B-S Coates, Q Zhang, B-D Siegfried, X Zhou
Transgenic maize hybrids that express insecticidal Bacillus thuringiensis (Bt) crystalline (Cry) protein toxins effectively protect against the European corn borer, Ostrinia nubilalis, a devastating maize pest. Field monitoring and laboratory selections have detected varying levels of O. nubilalis resistance to Cry1Ab toxin. MicroRNAs (miRNAs) are short noncoding RNAs that are involved in post-transcriptional gene regulation. Their potential roles in the evolution of Bt resistance, however, remain largely unknown...
February 16, 2018: Insect Molecular Biology
Elisa Pellegrino, Stefano Bedini, Marco Nuti, Laura Ercoli
Despite the extensive cultivation of genetically engineered (GE) maize and considerable number of scientific reports on its agro-environmental impact, the risks and benefits of GE maize are still being debated and concerns about safety remain. This meta-analysis aimed at increasing knowledge on agronomic, environmental and toxicological traits of GE maize by analyzing the peer-reviewed literature (from 1996 to 2016) on yield, grain quality, non-target organisms (NTOs), target organisms (TOs) and soil biomass decomposition...
February 15, 2018: Scientific Reports
A M Alford, C H Krupke
Corn rootworm remains the key pest of maize in the United States. It is managed largely by Bt corn hybrids, along with soil insecticides and neonicotinoid seed treatments (NSTs), the latter of which are applied to virtually all conventionally (non-Bt) produced maize. Frequently, more than one of these pest-management approaches is employed at the same time. To determine the utility and relative contributions of these various approaches, a meta-analysis was conducted on plant health and pest damage metrics from 15 yr of insecticide efficacy trials conducted on Indiana maize to compare the pest-protection potential of NSTs to that of other insecticides and Bt hybrids...
January 29, 2018: Journal of Economic Entomology
Gerson A Silva, Marcelo C Picanço, Lino R Ferreira, Dalton O Ferreira, Elizeu S Farias, Thadeu C Souza, Nilson Rodrigues-Silva, Eliseu José G Pereira
In this study, we constructed crop life tables for Bacillus thuringiensis Berliner (Bt) Cry1Ab and non-Bt corn hybrids, in which yield-loss factors and abundance of predaceous arthropods were recorded during 2 yr at two locations. Corn kernel/grain was the yield component that had the heaviest losses and that determined the overall yield loss in the corn hybrids across years and locations. Yield losses in both corn hybrids were primarily caused by kernel-destroying insects. Helicoverpa zea (Boddie) and Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) were the key loss factors at one location, while at the other, the key loss factor was the silk fly larvae, Euxesta spp...
January 10, 2018: Journal of Economic Entomology
Muhammad Zeeshan Shabbir, Yudong Quan, Zhenying Wang, Alejandra Bravo, Mario Soberón, Kanglai He
Transgenic crops producing insecticidal proteins are effective to manage lepidopteran pests. Development of insect-resistance is the major threat to Bacillus thuringiensis (Bt) crops such as Cry1Ah-Maize. Laboratory selection with Bt-Cry1Ah toxin incorporated in artificial diet, during 48 generations of Asian corn borer (ACB) Ostrinia furnacalis produced 200-fold resistance. This resistant colony ACB-AhR readily consumed and survived on Cry1Ah-expressing Bt-maize. Cross-resistance analysis showed high cross-resistance to Cry1F (464-fold), moderate cross-resistance to Cry1Ab (28...
January 10, 2018: Scientific Reports
Xin Lu, Dong-Jian Jiang, Jia-Xiang Yan, Zhen-E Ma, Xiu-Er Luo, Tai-Long Wei, Yang Xu, Qing-Hua He
The rapid and widespread adoption of Bacillus thuringiensis (Bt) proteins in genetically modified (GM) crops has raised concerns about the impact of GM crops on environment and food safety. A sensitive and specific method for detecting Bt proteins in GM crops is of great significance for environment and food risk assessment. In this study, using Cry1Ab as a model Bt protein, an ultrasensitive electrochemical immunosensor for Cry1Ab protein has been developed based on phage displayed peptide. Phage displayed peptides against Cry1Ab protein were obtained from a phage displayed peptide library without animal immunization process through biopanning-elution strategy...
March 1, 2018: Talanta
David A Ingber, Charles E Mason, Lindsey Flexner
The fall armyworm, Spodoptera frugiperda (Smith; Lepidoptera: Noctuidae), is a highly polyphagous, multivoltine pest of commercial crops including corn (Zea mays L.), cotton (Gossypium spp. L.), rice (Oryza sativa L.), and pasture grasses. Fall armyworm has become a growing concern in agricultural communities across the Americas as field populations in many locales have evolved resistance to several Cry1 toxins derived from the bacterium Bacillus thuringiensis Berliner (Bt). An often overlooked aspect of fall armyworm biology is the existence of two host strains, the 'rice' and 'corn' strains...
February 9, 2018: Journal of Economic Entomology
Fei Yang, Graham P Head, Chris Sansone, Fangneng Huang, Ryan T Gilreath, David L Kerns
BACKGROUND: Fall armyworm, Spodoptera frugiperda, is a target pest of the Vip3A protein used in pyramided Bt corn and cotton in the U.S. In this study, we provide the first documentation of a resistance allele conferring Vip3A resistance in a field-derived population of S. frugiperda from U.S., and characterize its inheritance and cross-resistance. RESULTS: An F2 screen with 104 two-parent families generated from a field collection of S. frugiperda in Louisiana, U...
November 28, 2017: Pest Management Science
Veronica Calles-Torrez, Janet J Knodel, Mark A Boetel, Curt D Doetkott, Kellie K Podliska, Joel K Ransom, Patrick Beauzay, B Wade French, Billy W Fuller
Northern, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), and western, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), corn rootworms are economic pests of corn, Zea mays L. in North America. We measured the impacts of corn hybrids incorporated with Cry3Bb1, Cry34/35Ab1, and pyramided (Cry3Bb1 + Cry34/35Ab1) Bacillus thuringiensis Berliner (Bt) proteins, tefluthrin soil insecticide, and clothianidin insecticidal seed treatment on beetle emergence, larval feeding injury, and corn yield at five locations from 2013 to 2015 in eastern North Dakota...
February 9, 2018: Journal of Economic Entomology
Bruce E Tabashnik, Yves Carrière
Transgenic crops have revolutionized insect pest control, but their effectiveness has been reduced by evolution of resistance in pests. We analyzed global monitoring data reported during the first two decades of transgenic crops, with each case representing the responses of one pest species in one country to one insecticidal protein from Bacillus thuringiensis (Bt). The cases of pest resistance to Bt crystalline (Cry) proteins produced by transgenic crops increased from 3 in 2005 to 16 in 2016. By contrast, in 17 other cases there was no decrease in pest susceptibility to Bt crops, including the recently introduced transgenic corn that produces a Bt vegetative insecticidal protein (Vip)...
October 11, 2017: Nature Biotechnology
H M Lopes, C S Bastos, L S Boiteux, J Foresti, F A Suinaga
Helicoverpa armigera is the most significant pest of agriculture in Asia, Europe, Africa, and Australasia, causing damage to crops greater than US$2 billion annually and until 2013 it was not detected in Brazil. Helicoverpa zea is restricted to the American continent and is important to corn and a secondary pest of cotton and tomatoes. The wide range of crops exploited by H. armigera (mainly cotton, soybeans, chickpea, and corn), the possible mating between these species can promote population shifts, that could be assessed by RAPD-PCR technique...
September 21, 2017: Genetics and Molecular Research: GMR
J L Smith, M D Lepping, D M Rule, Y Farhan, A W Schaafsma
Western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), is a pest of corn (Zea mays L.) that has recently expanded its range into Ontario, Canada. Control of S. albicosta damage to corn hybrids containing event TC1507-expressing Cry1F Bacillus thuringiensis protein alone or pyramided with event MON 89034 expressing Cry1A.105 and Cry2Ab2 Bt proteins was tested in 2011-2015 in Ontario in small- and large-scale field plots with natural infestation. In 2011, significantly lower incidence and severity of kernel damage was sustained by Cry1F × Cry1A...
October 1, 2017: Journal of Economic Entomology
Sarah N Zukoff, Anthony L Zukoff
Western corn rootworm Diabrotica virgifera virgifera LeConte is an important pest of corn whose larvae exhibit particular quantifiable patterns of locomotion after exposure to, and removal from, host roots and nonhost roots. Using EthoVision software, the behavior and locomotion of the western corn rootworm larvae was analyzed to determine the level of host recognition to germinated roots of differing corn hybrids containing either rootworm targeted Bt genes, RNA interference (RNAi) technology, the stack of both Bt and RNAi, or the isoline of these...
January 1, 2017: Journal of Insect Science
Rahul Banerjee, James Hasler, Robert Meagher, Rodney Nagoshi, Lucas Hietala, Fangneng Huang, Kenneth Narva, Juan Luis Jurat-Fuentes
Evolution of resistance threatens sustainability of transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). The fall armyworm (Spodoptera frugiperda) is a devastating pest of corn in the Western Hemisphere initially controlled by transgenic Bt corn producing the Cry1Fa insecticidal protein (event TC1507). However field-evolved resistance to TC1507 was observed in Puerto Rico in 2007 and has subsequently been reported in a number of locations in North and South America...
September 7, 2017: Scientific Reports
Fábio A Pinto, Marcos V V Mattos, Farley W S Silva, Silma L Rocha, Simon L Elliot
Helicoverpa armigera, one of the world's most destructive crop pests, was first documented in Brazil in 2013. Within a few months, this polyphagous insect had spread over the Northeast and Central-West of Brazil, causing great agricultural losses. With several reports of populations resistant to pesticides and Bt crops around the world, there is great concern about the spread of this pest in Brazil. There is confusion about the actual distribution of this species due to the high morphological similarity with the native corn earworm Helicoverpa zea, which may also coexist with H...
September 4, 2017: Insects
Tiantao Zhang, Brad S Coates, Yueqin Wang, Yidong Wang, Shuxiong Bai, Zhenying Wang, Kanglai He
The Asian corn borer (ACB), Ostrinia furnacalis (Lepidoptera: Crambidae), is a highly destructive pest of cultivated maize throughout East Asia. Bacillus thuringiensis (Bt) crystalline protein (Cry) toxins cause mortality by a mechanism involving pore formation or signal transduction following toxin binding to receptors along the midgut lumen of susceptible insects, but this mechanism and mutations therein that lead to resistance are not fully understood. In the current study, quantitative comparisons were made among midgut expressed transcripts from O...
2017: International Journal of Biological Sciences
Jun-Zhi Wei, Jessica O'Rear, Ute Schellenberger, Barbara A Rosen, Young-Jun Park, Mark J McDonald, Genhai Zhu, Weiping Xie, Adane Kassa, Lisa Procyk, Claudia Perez Ortega, Jian-Zhou Zhao, Nasser Yalpani, Virginia C Crane, Scott H Diehn, Gary A Sandahl, Mark E Nelson, Albert L Lu, Gusui Wu, Lu Liu
The coleopteran insect western corn rootworm (WCR, Diabrotica virgifera virgifera) is an economically important pest in North America and Europe. Transgenic corn plants producing Bacillus thuringiensis (Bt) insecticidal proteins have been useful against this devastating pest, but evolution of resistance has reduced their efficacy. Here, we report the discovery of a novel insecticidal protein, PIP-47Aa, from an isolate of Pseudomonas mosselii. PIP-47Aa sequence shows no shared motifs, domains or signatures with other known proteins...
August 10, 2017: Plant Biotechnology Journal
Rodney N Nagoshi, Djima Koffi, Komi Agboka, Kodjo Agbeko Tounou, Rahul Banerjee, Juan Luis Jurat-Fuentes, Robert L Meagher
The fall armyworm (Spodoptera frugiperda, J.E. Smith) is a noctuid moth that is a major and ubiquitous agricultural pest in the Western Hemisphere. Infestations have recently been identified in several locations in Africa, indicating its establishment in the Eastern Hemisphere where it poses an immediate and significant economic threat. Genetic methods were used to characterize noctuid specimens infesting multiple cornfields in the African nation of Togo that were tentatively identified as fall armyworm by morphological criteria...
2017: PloS One
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