Mortality of Western Corn Rootworm Larvae on MIR604 Transgenic Maize Roots: Field Survivorship Has No Significant Impact on Survivorship of F1 Progeny on MIR604

2010 ◽  
Vol 103 (6) ◽  
pp. 2187-2196 ◽  
Author(s):  
Bruce E. Hibbard ◽  
Thomas L. Clark ◽  
Mark R. Ellersieck ◽  
Lisa N. Meihls ◽  
Ahmed A. El Khishen ◽  
...  
2012 ◽  
Vol 136 (10) ◽  
pp. 721-729 ◽  
Author(s):  
T. L. Clark ◽  
D. L. Frank ◽  
B. W. French ◽  
L. J. Meinke ◽  
D. Moellenbeck ◽  
...  

2011 ◽  
Vol 104 (5) ◽  
pp. 1584-1591 ◽  
Author(s):  
Bruce E. Hibbard ◽  
Daniel L. Frank ◽  
Ryan Kurtz ◽  
Eric Boudreau ◽  
Mark R. Ellersieck ◽  
...  

2014 ◽  
Vol 111 (14) ◽  
pp. 5141-5146 ◽  
Author(s):  
A. J. Gassmann ◽  
J. L. Petzold-Maxwell ◽  
E. H. Clifton ◽  
M. W. Dunbar ◽  
A. M. Hoffmann ◽  
...  

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xu Hu ◽  
Chad J. Boeckman ◽  
Bin Cong ◽  
Joe P. Steimel ◽  
Nina M. Richtman ◽  
...  

Abstract Transgenic maize plants expressing dsRNA targeting western corn rootworm (WCR, Diabrotica virgifera virgifera) DvSSJ1 mRNA, a Drosophila snakeskin (ssk) ortholog, show insecticidal activity and significant plant protection from WCR damage. The gene encodes a membrane protein associated with the smooth sepate junction (SSJ) which is required for intestinal barrier function. To understand the active RNA form that leads to the mortality of WCR larvae by DvSSJ1 RNA interference (RNAi), we characterized transgenic plants expressing DvSSJ1 RNA transcripts targeting WCR DvSSJ1 mRNA. The expression of the silencing cassette results in the full-length transcript of 901 nucleotides containing a 210 bp inverted fragment of the DvSSJ1 gene, the formation of a double-stranded RNA (dsRNA) transcript and siRNAs in transgenic plants. Our artificial diet-feeding study indicates that dsRNAs greater than or equal to approximately 60 base-pairs (bp) are required for DvSSJ1 insecticidal activity. Impact of specificity of dsRNA targeting DvSSJ1 mRNA on insecticidal activities was also evaluated in diet bioassay, which showed a single nucleotide mutation can have a significant impact or abolish diet activities against WCR. These results provide insights as to the functional forms of plant-delivered dsRNA for the protection of transgenic maize from WCR feeding damage and information contributing to the risk assessment of transgenic maize expressing insecticidal dsRNA.


2013 ◽  
Vol 106 (6) ◽  
pp. 2506-2513 ◽  
Author(s):  
Daniel L. Frank ◽  
Anthony Zukoff ◽  
Julie Barry ◽  
Matthew L. Higdon ◽  
Bruce E. Hibbard

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Brad S. Coates ◽  
Emeline Deleury ◽  
Aaron J. Gassmann ◽  
Bruce E. Hibbard ◽  
Lance J. Meinke ◽  
...  

Abstract Background Resistance of pest insect species to insecticides, including B. thuringiensis (Bt) pesticidal proteins expressed by transgenic plants, is a threat to global food security. Despite the western corn rootworm, Diabrotica virgifera virgifera, being a major pest of maize and having populations showing increasing levels of resistance to hybrids expressing Bt pesticidal proteins, the cell mechanisms leading to mortality are not fully understood. Results Twenty unique RNA-seq libraries from the Bt susceptible D. v. virgifera inbred line Ped12, representing all growth stages and a range of different adult and larval exposures, were assembled into a reference transcriptome. Ten-day exposures of Ped12 larvae to transgenic Bt Cry3Bb1 and Gpp34/Tpp35Ab1 maize roots showed significant differential expression of 1055 and 1374 transcripts, respectively, compared to cohorts on non-Bt maize. Among these, 696 were differentially expressed in both Cry3Bb1 and Gpp34/Tpp35Ab1 maize exposures. Differentially-expressed transcripts encoded protein domains putatively involved in detoxification, metabolism, binding, and transport, were, in part, shared among transcripts that changed significantly following exposures to the entomopathogens Heterorhabditis bacteriophora and Metarhizium anisopliae. Differentially expressed transcripts in common between Bt and entomopathogen treatments encode proteins in general stress response pathways, including putative Bt binding receptors from the ATP binding cassette transporter superfamily. Putative caspases, pro- and anti-apoptotic factors, as well as endoplasmic reticulum (ER) stress-response factors were identified among transcripts uniquely up-regulated following exposure to either Bt protein. Conclusions Our study suggests that the up-regulation of genes involved in ER stress management and apoptotic progression may be important in determining cell fate following exposure of susceptible D. v. virgifera larvae to Bt maize roots. This study provides novel insights into insect response to Bt intoxication, and a possible framework for future investigations of resistance mechanisms.


2018 ◽  
Vol 112 (2) ◽  
pp. 683-690
Author(s):  
E J Bernklau ◽  
B E Hibbard ◽  
L B Bjostad

Abstract Methyl anthranilate (MA), a compound in maize roots that is repellent to western corn rootworm larvae (Diabrotica virgifera virgifera LeConte) was tested in behavioral bioassays in a soil environment. MA prevented larvae from locating roots of a maize seedling, and the repellency strengthened with increasing rates of MA. In a simple push–pull strategy between an MA-treated seedling and an untreated seedling, granules containing 0.1 mg/g MA pushed larvae to the untreated seedling. This push effect increased with dose, with 90% repellency observed for the highest dose tested (100 mg/g). Chemical analysis showed that MA concentrations remained high for 4 wk in dry, sterilized or unsterilized soil, but declined rapidly in moist soil. After 7 d, 50% less MA was recovered in moist, sterilized soil than in dry soil, and only a trace of MA remained in unsterilized moist soil, suggesting that both moisture and microbial activity contributed to the loss of MA. Various (MA) carrier granules were tested in bioassays after aging in moist soil. After 1 d, all of the MA granules were repellent at the 10 mg/g rate and clay granules were also effective at 1 mg/g. After 1 wk, only molecular sieve granules elicited repellency, but that activity disappeared after 2 wk. These results demonstrate that MA is repellent to western corn rootworm larvae in the soil environment and may have potential as a rootworm treatment if formulations can be developed that protect the material from decomposition in the soil.


2019 ◽  
Vol 70 (19) ◽  
pp. 5327-5342 ◽  
Author(s):  
Christopher F Strock ◽  
Hannah M Schneider ◽  
Tania Galindo-Castañeda ◽  
Benjamin T Hall ◽  
Bart Van Gansbeke ◽  
...  

Abstract Soil biota have important effects on crop productivity, but can be difficult to study in situ. Laser ablation tomography (LAT) is a novel method that allows for rapid, three-dimensional quantitative and qualitative analysis of root anatomy, providing new opportunities to investigate interactions between roots and edaphic organisms. LAT was used for analysis of maize roots colonized by arbuscular mycorrhizal fungi, maize roots herbivorized by western corn rootworm, barley roots parasitized by cereal cyst nematode, and common bean roots damaged by Fusarium. UV excitation of root tissues affected by edaphic organisms resulted in differential autofluorescence emission, facilitating the classification of tissues and anatomical features. Samples were spatially resolved in three dimensions, enabling quantification of the volume and distribution of fungal colonization, western corn rootworm damage, nematode feeding sites, tissue compromised by Fusarium, and as well as root anatomical phenotypes. Owing to its capability for high-throughput sample imaging, LAT serves as an excellent tool to conduct large, quantitative screens to characterize genetic control of root anatomy and interactions with edaphic organisms. Additionally, this technology improves interpretation of root–organism interactions in relatively large, opaque root segments, providing opportunities for novel research investigating the effects of root anatomical phenes on associations with edaphic organisms.


PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242791
Author(s):  
Yong Yin ◽  
Stanislaw Flasinski ◽  
William Moar ◽  
David Bowen ◽  
Cathy Chay ◽  
...  

The Western corn rootworm (WCR) Diabrotica virgifera virgifera LeConte is one of the most economically important insect pests in North America. Since 2003, transgenic maize expressing WCR-active proteins from Bacillus thuringiensis (Bt) have been widely adopted as the main approach to controlling WCR in the U.S. However, the emergence of field resistance to the Bt proteins in current commercial products has been documented in recent years, highlighting the need to develop additional tools for controlling this devasting pest. Here we report the discovery of Vpb4Da2 (initially assigned as Vip4Da2), a new insecticidal protein highly selective against WCR, through high-throughput genome sequencing of a Bt strain sourced from grain dust samples collected in the eastern and central regions of the US. Vpb4Da2 contains a sequence and domain signature distinct from families of other WCR-active proteins. Under field conditions, transgenic maize expressing Vpb4Da2 demonstrates commercial-level (at or below NIS 0.25) root protection against WCR, and reduces WCR beetle emergence by ≥ 97%. Our studies also conclude that Vpb4Da2 controls WCR populations that are resistant to WCR-active transgenic maize expressing Cry3Bb1, Cry34Ab1/Cry35Ab1 (reassigned as Gpp34Ab1/Tpp35Ab1), or DvSnf7 RNA. Based on these findings, Vpb4Da2 represents a valuable new tool for protecting maize against WCR.


2019 ◽  
Vol 76 (1) ◽  
pp. 268-276 ◽  
Author(s):  
Aaron J Gassmann ◽  
Ram B Shrestha ◽  
Abigail L Kropf ◽  
Coy R St Clair ◽  
Ben D Brenizer

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