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https://www.readbyqxmd.com/read/28492498/assessment-of-inheritance-and-fitness-costs-associated-with-field-evolved-resistance-to-cry3bb1-maize-by-western-corn-rootworm
#1
Aubrey R Paolino, Aaron J Gassmann
The western corn rootworm, Diabrotica virgifera virgifera LeConte, is among the most serious insect pests of maize in North America. One strategy used to manage this pest is transgenic maize that produces one or more crystalline (Cry) toxins derived from the bacterium Bacillus thuringiensis (Bt). To delay Bt resistance by insect pests, refuges of non-Bt maize are grown in conjunction with Bt maize. Two factors influencing the success of the refuge strategy to delay resistance are the inheritance of resistance and fitness costs, with greater delays in resistance expected when inheritance of resistance is recessive and fitness costs are present...
May 11, 2017: Toxins
https://www.readbyqxmd.com/read/28484967/biotic-potential-and-life-table-of-helicoverpa-armigera-h%C3%A3-bner-lepidoptera-noctuidae-from-three-brazilian-regions
#2
I F Silva, E L L Baldin, A Specht, D R Sosa-Gómez, V F Roque-Specht, R Morando, S V Paula-Moraes
This study aimed to evaluate the biotic potential and life table of individuals of Helicoverpa armigera (Hübner) from different host plants (citrus, corn, and cotton) and Brazilian states (São Paulo, Distrito Federal, and Bahia) in artificial diet, under laboratory conditions (25 ± 1°C, 70 ± 10% RH, 14 h photophase). The longevity, pre-, post- and oviposition periods, fecundity, and fertility of 15 mating pairs per origin were evaluated. We also compared the reproductive parameters of each group of insects (São Paulo (SP), Distrito Federal (DF), and Bahia (BA)), including the net reproductive rate (Ro), mean generation time (T), intrinsic rate of increase (r m), and finite rate of increase (λ)...
May 8, 2017: Neotropical Entomology
https://www.readbyqxmd.com/read/28481307/histopathological-effects-of-bt-and-tcda-insecticidal-proteins-on-the-midgut-epithelium-of-western-corn-rootworm-larvae-diabrotica-virgifera-virgifera
#3
Andrew J Bowling, Heather E Pence, Huarong Li, Sek Yee Tan, Steven L Evans, Kenneth E Narva
Western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte) is a major corn pest in the United States, causing annual losses of over $1 billion. One approach to protect against crop loss by this insect is the use of transgenic corn hybrids expressing one or more crystal (Cry) proteins derived from Bacillus thuringiensis. Cry34Ab1 and Cry35Ab1 together comprise a binary insecticidal toxin with specific activity against WCR. These proteins have been developed as insect resistance traits in commercialized corn hybrids resistant to WCR feeding damage...
May 8, 2017: Toxins
https://www.readbyqxmd.com/read/28430986/field-trial-performance-of-herculex-xtra-cry34ab1-cry35ab1-and-smartstax-cry34ab1-cry35ab1-cry3bb1-hybrids-and-soil-insecticides-against-western-and-northern-corn-rootworms-coleoptera-chrysomelidae
#4
K D Johnson, L A Campbell, M D Lepping, D M Rule
Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), and northern corn rootworm, Diabrotica barberi Smith and Lawrence (Coleoptera: Chrysomelidae), are important insect pests in corn, Zea mays L. For more than a decade, growers have been using transgenic plants expressing proteins from the bacterium Bacillus thuringiensis (Bt) to protect corn roots from feeding. In 2011, western corn rootworm populations were reported to have developed resistance to Bt hybrids expressing Cry3Bb1 and later found to be cross-resistant to hybrids expressing mCry3A and eCry3...
April 18, 2017: Journal of Economic Entomology
https://www.readbyqxmd.com/read/28369407/nitrogen-rate-effects-on-cry3bb1-and-cry3bb1-cry34-35ab1-expression-in-transgenic-corn-roots-resulting-root-injury-and-corn-rootworm-beetle-emergence
#5
T M Leaf, K R Ostlie
Nitrogen (N) application rates have been recommended historically for maximum economic yield of corn (Zea mays L.), but not for optimal expression or impacts of Bt (Bacillus thuringiensis Berliner) Cry protein(s) on target insects. This study explored the need to adjust N rates to optimize expression of corn rootworm-active Bt (Bt-RW) protein(s) in a single and a pyramided trait hybrid and resulting impacts on beetle emergence and root injury, under field conditions. The experiment featured a factorial treatment arrangement in a split-plot randomized complete block design with six N rates as the main plots and three hybrids (MON88017 expressing Cry3Bb1, MON88017 x DAS-59122 expressing Cry3Bb1 + Cry34/35Ab1, and a non-Bt-RW hybrid) as the subplots...
March 20, 2017: Journal of Economic Entomology
https://www.readbyqxmd.com/read/28358336/patterns-of-gene-expression-in-western-corn-rootworm-diabrotica-virgifera-virgifera-neonates-challenged-with-cry34ab1-cry35ab1-and-cry34-35ab1-based-on-next-generation-sequencing
#6
Haichuan Wang, Seong-Il Eyun, Kanika Arora, Sek Yee Tan, Premchand Gandra, Etsuko Moriyama, Chitvan Khajuria, Jessica Jurzenski, Huarong Li, Maia Donahue, Ken Narva, Blair Siegfried
With Next Generation Sequencing technologies, high-throughput RNA sequencing (RNAseq) was conducted to examine gene expression in neonates of Diabrotica virgifera virgifera (LeConte) (Western Corn Rootworm, WCR) challenged with individual proteins of the binary Bacillus thuringiensis insecticidal proteins, Cry34Ab1 and Cry35Ab1, and the combination of Cry34/Cry35Ab1, which together are active against rootworm larvae. Integrated results of three different statistical comparisons identified 114 and 1300 differentially expressed transcripts (DETs) in the Cry34Ab1 and Cry34/35Ab1 treatment, respectively, as compared to the control...
March 30, 2017: Toxins
https://www.readbyqxmd.com/read/28334330/survivorship-of-z-pheromone-race-european-corn-borer-lepidoptera-crambidae-on-a-range-of-host-plants-varying-in-defensive-chemistry
#7
Kelsey E Fisher, Charles E Mason, J Lindsey Flexner, Judith Hough-Goldstein, John H McDonald
The European corn borer, Ostrinia nubilalis (Hübner), was introduced in North America in the early 1900s and became a major pest of corn. After its introduction, it was found on > 200 other plant hosts, but corn remained its primary host. Early life history studies indicated that European corn borer had the potential of a wide host range. For nearly 80 yr before the introduction of Bt corn, the European corn borer was a major pest of corn in North America. This study investigated the growth and survivorship of the Z-pheromone race European corn borer on a range of hosts that vary in defensive chemistries and historic degree of infestation to better understand the current host plant range of Z-pheromone race of O...
March 3, 2017: Journal of Economic Entomology
https://www.readbyqxmd.com/read/28326506/influence-of-calcareous-soil-on-cry3bb1-expression-and-efficacy-in-the-field
#8
David S Wangila, Arnubio Valencia J, Haichuan Wang, Blair D Siegfried, Lance J Meinke
Greater than expected injury by western corn rootworm (WCR) (Diabrotica virgifera virgifera LeConte) to Cry3Bb1 expressing maize hybrids (Zea mays L.) has been reported in southwestern Nebraska. Affected areas of some fields are often associated with high pH calcareous soils where maize growth is poor and iron chlorosis is common. As part of a comprehensive study to understand potential causes of unexpected injury, experiments were conducted during 2013 and 2014 to ascertain whether the calcareous soil conditions and associated poor maize growth negatively affect the expression of Cry3Bb1...
June 2017: Transgenic Research
https://www.readbyqxmd.com/read/28186125/responses-of-the-cutworm-spodoptera-litura-lepidoptera-noctuidae-to-two-bt-corn-hybrids-expressing-cry1ab
#9
Shu Yinghua, Du Yan, Chen Jin, Wei Jiaxi, Wang Jianwu
To examine the responses of the secondary lepidopteran pest Spodoptera litura to two Bacillus thuringiensis (Bt) corn hybrids [5422Bt1 (Event Bt11), 5422CBCL (MON810)] expressing Cry1Ab, larval bioassays with Cry1Ab toxin, corn leaves or kernels and bagging on corn plants were conducted. The results showed that larvae displayed a similar performance when fed kernels, but not leaves of 5422Bt1, 5422CBCL and their near-isogenic non-Bt corn (5422). Significantly higher Cry1Ab amounts were detected in larvae fed leaves than kernels of both Bt hybrids, with different molecular weights of protein band in plants (72 and 90 kDa for 5422Bt1 and 5422CBCL, respectively), gut contents (65 kDa), feces (50 kDa), which indicated that larvae had lower ingestion, higher degradation and excretion of Cry1Ab when fed kernels not leaves of both Bt hybrids...
February 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28073978/effects-of-bt-corn-and-egg-density-on-western-corn-rootworm-coleoptera-chrysomelidae-adult-emergence-and-estimation-of-effective-bt-dose
#10
L A Campbell, P L Prasifka, N P Storer, D M Rule, W H Hendrix
Since 2003, rootworm-protected transgenic corn has been commercially deployed in the United States as a principal method of control of western corn rootworm, Diabrotica virgifera virgifera LeConte. Durability of this technology depends partly on larval mortality ("dose") exerted by the traits, but density-dependent mortality can confound calculations of dose. Research reported here examined the effects of density-dependent mortality on adult emergence and estimates of trait dose. At sites in Illinois and Indiana, western corn rootworm eggs were infested at four densities on non-Bt corn and at a single density on corn hybrids with transgenic events MON 88017 (VT Triple PRO), DAS-59122-7 (Herculex Insect Protection), and MON 88017 × DAS-59122-7 (SmartStax corn)...
April 1, 2017: Journal of Economic Entomology
https://www.readbyqxmd.com/read/28073976/effects-of-carriers-emulsifiers-and-biopesticides-for-direct-silk-treatments-on-caterpillar-feeding-damage-and-ear-development-in-sweet-corn
#11
P J Westgate, B B Schultz, R V Hazzard
In the northeastern United States, control of Lepidopteran pests of sweet corn, particularly corn earworm [Helicoverpa zea (Boddie)], is difficult using organic methods. The direct application of corn oil and Bacillus thuringiensis (Bt) to corn silk has been shown to reduce ear damage from corn earworm in past studies; these studies sought to optimize this method by evaluating additional carrier and biopesticide mixtures that comply with the United States Federal Insecticide, Fungicide, and Rodenticide Act and National Organic Standards...
April 1, 2017: Journal of Economic Entomology
https://www.readbyqxmd.com/read/28060922/cry3bb1-resistant-western-corn-rootworm-diabrotica-virgifera-virgifera-leconte-does-not-exhibit-cross-resistance-to-dvsnf7-dsrna
#12
William Moar, Chitvan Khajuria, Michael Pleau, Oliver Ilagan, Mao Chen, Changjian Jiang, Paula Price, Brian McNulty, Thomas Clark, Graham Head
BACKGROUND AND METHODOLOGY: There is a continuing need to express new insect control compounds in transgenic maize against western corn rootworm, Diabrotica virgifera virgifera (LeConte) (WCR). In this study three experiments were conducted to determine cross-resistance between the new insecticidal DvSnf7 dsRNA, and Bacillus thuringiensis (Bt) Cry3Bb1; used to control WCR since 2003, with field-evolved resistance being reported. Laboratory susceptible and Cry3Bb1-resistant WCR were evaluated against DvSnf7 dsRNA in larval diet-incorporation bioassays...
2017: PloS One
https://www.readbyqxmd.com/read/28006032/evaluation-of-bt-corn-with-pyramided-genes-on-efficacy-and-insect-resistance-management-for-the-asian-corn-borer-in-china
#13
Fan Jiang, Tiantao Zhang, Shuxiong Bai, Zhenying Wang, Kanglai He
A Bt corn hybrid (AcIe) with two Bt genes (cry1Ie and cry1Ac) was derived by breeding stack from line expressing Cry1Ie and a line expressing Cry1Ac. Efficacy of this pyramided Bt corn hybrid against the Asian corn borer (ACB), Ostrinia furnacalis, was evaluated. We conducted laboratory bioassays using susceptible and resistant ACB strains fed on artificial diet or fresh plant tissues. We also conducted field trials with artificial infestations of ACB neonates at the V6 and silk stages. The toxin-diet bioassay data indicated that mixtures of Cry1Ac and Cry1Ie proteins had synergistic insecticidal efficacy...
2016: PloS One
https://www.readbyqxmd.com/read/27907051/battle-in-the-new-world-helicoverpa-armigera-versus-helicoverpa-zea-lepidoptera-noctuidae
#14
José P F Bentivenha, Silvana V Paula-Moraes, Edson L L Baldin, Alexandre Specht, Ivana F da Silva, Thomas E Hunt
The corn earworm Helicoverpa zea (Boddie) and the old world bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) are allopatric species and occur in important agricultural crops. In maize, both species tend to infest the ear. The introduction of H. armigera in Brazil has created a new scenario, where these Helicoverpa species might cohabit and interact with one another, affecting the prevalence of each species in the agroecosystem, integrated pest management, and insect resistance management. In this study, larval occurrence and proportion of these species in maize was assessed in three regions of Brazil during three crop seasons...
2016: PloS One
https://www.readbyqxmd.com/read/27782120/genetic-hitchhiking-and-resistance-evolution-to-transgenic-bt-toxins-insights-from-the-african-stalk-borer-busseola-fusca-noctuidae
#15
P Campagne, C Capdevielle-Dulac, R Pasquet, S J Cornell, M Kruger, J-F Silvain, B LeRü, J Van den Berg
Since transgenic crops expressing Bacillus thuringiensis (Bt) toxins were first released, resistance evolution leading to failure in control of pests populations has been observed in a number of species. Field resistance of the moth Busseola fusca was acknowledged 8 years after Bt maize was introduced in South Africa. Since then, field resistance of this corn borer has been observed at several locations, raising questions about the nature, distribution and dynamics of the resistance trait. Using genetic markers, our study identified four outlier loci clearly associated with resistance...
April 2017: Heredity
https://www.readbyqxmd.com/read/27769625/effect-of-genetically-modified-corn-on-the-jejunal-mucosa-of-adult-male-albino-rat
#16
Marwa A A Ibrahim, Ebtsam F Okasha
Genetically modified (GM) plants expressing insecticidal traits offer a new strategy for crop protection. GM-corn contains Bacillus thuringiensis (Bt) genes producing delta endotoxins in the whole plant. Diet can influence the characteristics of the gastrointestinal tract altering its function and structure. The aim of this study was to evaluate the effect of GM-corn on the histological structure of jejunal mucosa of adult male albino rat using different histological, immunohistochemical and morphometrical methods...
November 2016: Experimental and Toxicologic Pathology: Official Journal of the Gesellschaft Für Toxikologische Pathologie
https://www.readbyqxmd.com/read/27708055/a-selective-insecticidal-protein-from-pseudomonas-for-controlling-corn-rootworms
#17
Ute Schellenberger, Jarred Oral, Barbara A Rosen, Jun-Zhi Wei, Genhai Zhu, Weiping Xie, Mark J McDonald, David C Cerf, Scott H Diehn, Virginia C Crane, Gary A Sandahl, Jian-Zhou Zhao, Timothy M Nowatzki, Amit Sethi, Lu Liu, Zaiqi Pan, Yiwei Wang, Albert L Lu, Gusui Wu, Lu Liu
The coleopteran insect western corn rootworm (WCR) (Diabrotica virgifera virgifera LeConte) is a devastating crop pest in North America and Europe. Although crop plants that produce Bacillus thuringiensis (Bt) proteins can limit insect infestation, some insect populations have evolved resistance to Bt proteins. Here we describe an insecticidal protein, designated IPD072Aa, that is isolated from Pseudomonas chlororaphis. Transgenic corn plants expressing IPD072Aa show protection from WCR insect injury under field conditions...
November 4, 2016: Science
https://www.readbyqxmd.com/read/27659816/development-of-monoclonal-antibody-based-sensitive-elisa-for-the-determination-of-cry1ie-protein-in-transgenic-plant
#18
Yuwen Zhang, Wei Zhang, Yan Liu, Jianhua Wang, Guoying Wang, Yunjun Liu
Cry1Ie is a kind of Bacillus thuringiensis (Bt) toxin protein which has a different action model than the Cry1Ab and Cry1Ac protein. The transgenic maize expressing Cry1Ie might be commercially used in the near future and it is urgent to develop a method to detect Cry1Ie protein in transgenic plants and their products. To develop an ELISA method, Cry1Ie protein was expressed in Escherichia coli strain Transetta DE3, purified with the Ni-NTA spin columns, and then validated by sequencing. Bioassay results showed that the purified Cry1Ie protein was highly toxic to the Asian corn borer...
November 2016: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/27518813/genetic-basis-of-cry1f-resistance-in-a-laboratory-selected-asian-corn-borer-strain-and-its-cross-resistance-to-other-bacillus-thuringiensis-toxins
#19
Yueqin Wang, Yidong Wang, Zhenying Wang, Alejandra Bravo, Mario Soberón, Kanglai He
The Asian corn borer (ACB), Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae), is the most destructive insect pest of corn in China. Susceptibility to the Cry1F toxin derived from Bacillus thuringiensis has been demonstrated for ACB, suggesting the potential for Cry1F inclusion as part of an insect pest management program. Insects can develop resistance to Cry toxins, which threatens the development and use of Bt formulations and Bt crops in the field. To determine possible resistance mechanisms to Cry1F, a Cry1F-resistant colony of ACB (ACB-FR) that exhibited more than 1700-fold resistance was established through selection experiments after 49 generations of selection under laboratory conditions...
2016: PloS One
https://www.readbyqxmd.com/read/27510165/efficacy-of-bt-maize-producing-the-cry1ac-protein-against-two-important-pests-of-corn-in-china
#20
Hong-Xing Chen, Rui Yang, Wang Yang, Liu Zhang, Ibrahima Camara, Xue-Hui Dong, Yi -Qing Liu, Wang-Peng Shi
Ostrinia furnacalis (Guenée) and Helicoverpa armigera (Hübner) are the most important pests of maize in China. A laboratory study and a 2-year field study on the efficacy of transgenic maize expressing the Cry1Ac protein BT38 against O. furnacalis and H. armigera were performed. We found that the husks, kernels, and silks of BT38 showed significant efficacy against larvae of O. furnacalis and H. armigera. In the field, when neonate larvae of O. furnacalis and H. armigera were on plants at different growth stages and when levels of leaf-damage or number of damaged silks were used to score efficacy, we found that BT38 showed significant insecticidal efficacy against O...
November 2016: Environmental Science and Pollution Research International
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