scholarly journals Nutrition affects insect susceptibility to Bt toxins

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Carrie A. Deans ◽  
Spencer T. Behmer ◽  
Ashley E. Tessnow ◽  
Patricia Tamez-Guerra ◽  
Marianne Pusztai-Carey ◽  
...  
Keyword(s):  
Bt Toxins ◽  
Insect Susceptibility

scholarly journals Detection of alternative splicing in Diabrotica virgifera virgifera LeConte, in association with Bt resistance using RNA-seq and PacBio Iso-Seq

2020 ◽  
Author(s):  
Zixiao Zhao ◽  
Christine G. Elsik ◽  
Bruce E. Hibbard ◽  
Kent S. Shelby
Keyword(s):  
Alternative Splicing ◽  
Matrix Protein ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Rna Seq ◽  
Bt Resistance ◽  
Bt Toxins ◽  
Alternatively Spliced

AbstractBackgroundAlternative splicing is one of the major mechanisms that increases transcriptome diversity in eukaryotes, including insect species that have gained resistance to pesticides and Bt toxins. In western corn rootworm (Diabrotica virgifera virgifera LeConte), neither alternative splicing nor its role in resistance to Bt toxins has been studied.ResultsTo investigate the mechanisms of Bt resistance we carried out single-molecule real-time (SMRT) transcript sequencing and Iso-seq analysis on resistant, eCry3.1Ab-selected and susceptible, unselected, western corn rootworm neonate midguts which fed on seedling maize with and without eCry3.1Ab for 12 and 24 hours. We present transcriptome-wide alternative splicing patterns of western corn rootworm midgut in response to feeding on eCry3.1Ab-expressing corn using a comprehensive approach that combines both RNA-seq and SMRT transcript sequencing techniques. We found that 67.73% of multi-exon genes are alternatively spliced, which is consistent with the high transposable element content of the genome. One of the alternative splicing events we identified was a novel peritrophic matrix protein with two alternative splicing isoforms. Analysis of differential exon usage between resistant and susceptible colonies showed that in eCry3.1Ab-resistant western corn rootworm, expression of one isoform was significantly higher than in the susceptible colony, while no significant differences between colonies were observed with the other isoform.ConclusionOur results provide the first survey of alternative splicing in western corn rootworm and suggest that the observed alternatively spliced isoforms of peritrophic matrix protein may be associated with eCry3.1Ab resistance in western corn rootworm.

Long-Term Empirical and Observational Evidence of Practical Helicoverpa zea Resistance to Cotton With Pyramided Bt Toxins

2018 ◽  
Vol 111 (4) ◽  
pp. 1824-1833 ◽  
Author(s):  
Dominic D Reisig ◽  
Anders S Huseth ◽  
Jack S Bacheler ◽  
Mohammad-Amir Aghaee ◽  
Lewis Braswell ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Observational Evidence ◽  
Bt Toxins

scholarly journals Functional validation of DvABCB1 as a receptor of Cry3 toxins in western corn rootworm, Diabrotica virgifera virgifera

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiping Niu ◽  
Adane Kassa ◽  
James Hasler ◽  
Samantha Griffin ◽  
Claudia Perez-Ortega ◽  
...  
Keyword(s):  
Resistant Strain ◽  
Insect Pest ◽  
Amino Acid Level ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Hek293 Cells ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Functional Validation ◽  
Bt Toxins

Abstract Western corn rootworm (WCR), Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), is a serious insect pest in the major corn growing areas of North America and in parts of Europe. WCR populations with resistance to Bacillus thuringiensis (Bt) toxins utilized in commercial transgenic traits have been reported, raising concerns over their continued efficacy in WCR management. Understanding the modes of action of Bt toxins is important for WCR control and resistance management. Although different classes of proteins have been identified as Bt receptors for lepidopteran insects, identification of receptors in WCR has been limited with no reports of functional validation. Our results demonstrate that heterologous expression of DvABCB1 in Sf9 and HEK293 cells conferred sensitivity to the cytotoxic effects of Cry3A toxins. The result was further validated using knockdown of DvABCB1 by RNAi which rendered WCR larvae insensitive to a Cry3A toxin. However, silencing of DvABCB2 which is highly homologous to DvABCB1 at the amino acid level, did not reduce the sensitivity of WCR larvae to a Cry3A toxin. Furthermore, our functional studies corroborate different mode-of-actions for other insecticidal proteins including Cry34Ab1/35Ab1, Cry6Aa1, and IPD072Aa against WCR. Finally, reduced expression and alternatively spliced transcripts of DvABCB1 were identified in a mCry3A-resistant strain of WCR. Our results provide the first clear demonstration of a functional receptor in the molecular mechanism of Cry3A toxicity in WCR and confirmed its role in the mechanism of resistance in a mCry3A resistant strain of WCR.

Baseline Plant-to-Plant Larval Movement of Spodoptera eridania in Bt and Non-Bt Soybean and Its Possible Impacts on IRM

2020 ◽  
Vol 113 (4) ◽  
pp. 1741-1752
Author(s):  
Thiago L M Fanela ◽  
Edson L L Baldin ◽  
Thomas E Hunt ◽  
Rodrigo D Faria
Keyword(s):  
Larval Mortality ◽  
Pest Species ◽  
Spodoptera Eridania ◽  
Refuge Strategy ◽  
Bt Toxins ◽  
Incomplete Resistance ◽  
Insect Populations ◽  
Transgenic Technologies ◽  
Lepidopteran Pest ◽  
Larval Movement

Abstract The widespread use of transgenic technologies has led to the emergence of insect populations resistant to Bt toxins. Some lepidopteran pest species also appear to naturally have some level of tolerance to certain proteins, such as some species of Spodoptera to Cry1Ac. One of the main strategies to manage resistance is the use of refuge areas, the success of which is in part dependent on larval movement of the target pest. Thus, in order to assess the viability of a refuge strategy addressing Spodoptera eridania Stoll (Lepidoptera: Noctuidae) in Bt soybean, it was evaluated the larval movement across plants in Bt and non-Bt soybean, as well as the larval development and mortality on Bt and non-Bt soybean cultivars. We concluded that apparent S. eridania incomplete resistance resulting from high larval mortality and low adaptability on Bt plants, high larval dispersal, nondirectional larval movement, and random larval spatial dispersion suggest that structured refuge is more suitable than mixed refuge for managing resistance in S. eridania populations.

scholarly journals Differences between two populations of bollworm, Helicoverpa zea (Lepidoptera: Noctuidae), with variable measurements of laboratory susceptibilities to Bt toxins exposed to non-Bt and Bt cottons in large field cages

PLoS ONE ◽  
2019 ◽  
Vol 14 (3) ◽  
pp. e0212567 ◽  
Author(s):  
Nathan S. Little ◽  
Blake H. Elkins ◽  
R. Michelle Mullen ◽  
Omaththage P. Perera ◽  
Katherine A. Parys ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Large Field ◽  
Bt Toxins ◽  
Lepidoptera Noctuidae ◽  
Two Populations
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