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Geisert RW, Huynh MP, Pereira AE, Shapiro Ilan DI, Hibbard BE. An improved bioassay for the testing of entomopathogenic nematode virulence to the western corn rootworm (Diabrotica virgifera virgifera) (Coleoptera: Chrysomelidae): with focus on neonate insect assessments. JOURNAL OF ECONOMIC ENTOMOLOGY 2023; 116:726-732. [PMID: 37021702 DOI: 10.1093/jee/toad052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/20/2023] [Accepted: 03/06/2023] [Indexed: 06/14/2023]
Abstract
Bioassays involving newly hatched larval insects can be limited by the larvae's feeding state. Assays attempting to monitor mortality effects can be negatively affected by starvation effects on the larvae. Neonate western corn rootworms have significant reductions in viability if not provided food within 24 h post hatch. The recent development of an improved artificial diet for western corn rootworm larvae provides a new bioassay type for evaluating entomopathogenic nematodes that also makes the testing arena easy to observe. Here, we evaluated four species of entomopathogenic nematodes including Heterorhabditis bacteriophora Poinar, Steinernema carpocapsae (Weiser), Steinernema diaprepesi Nguyen & Duncan, and Steinernema rarum (de Doucet) against neonate western corn rootworm, Diabrotica virgifera virgifera LeConte, in 96-well plate diet bioassays. Nematode inoculation levels were 0, 15, 30, 60, and 120 nematodes per larva. Percentage mortality increased for each species as the rate of inoculation increased. Overall, H. bacteriophora and S. carpocapsae caused the greatest amount of larval mortality. The diet-based bioassays were shown to be an effective method for nematode exposure to insect pests. The assays provided adequate moisture to keep nematode from desiccating while also allowing freedom of movement around the arenas. Both rootworm larvae and nematodes were contained within the assay arenas. The addition of nematodes did not cause any significant deterioration of the diet within the three-day period of testing. Overall, the diet bioassays worked well as a measure of entomopathogenic nematode virulence.
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Affiliation(s)
- Ryan W Geisert
- Division of Plant Science & Technology, University of Missouri, Columbia, MO, USA
| | - Man P Huynh
- Division of Plant Science & Technology, University of Missouri, Columbia, MO, USA
- Department of Plant Protection, Can Tho University, Can Tho, Vietnam
| | - Adriano E Pereira
- Plant Genetics Research Unit, USDA-Agricultural Research Service, Columbia, MO, USA
| | - David I Shapiro Ilan
- David I Shapiro Ilan, USDA-ARS, Fruit and Tree Nut Research Station, Byron, GA, USA
| | - Bruce E Hibbard
- Plant Genetics Research Unit, USDA-Agricultural Research Service, Columbia, MO, USA
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2
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Pereira AE, Geisert RW, Hibbard BE. Maize Inbred Mp708 is Highly Susceptible to Western Corn Rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), in Field and Greenhouse Assays. JOURNAL OF INSECT SCIENCE (ONLINE) 2022; 22:8. [PMID: 36480227 PMCID: PMC9731326 DOI: 10.1093/jisesa/ieac067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Indexed: 06/17/2023]
Abstract
The western corn rootworm (WCR), Diabrotica vifgirera virgifera LeConte, (Coleoptera: Chrysomelidae) causes significant economic damage in corn production each year. Resistance to insecticides and transgenic corn with Bacillus thuringiensis (Bt), Berliner toxins have been reported throughout the United States Corn Belt. Corn breeding programs for natural resistance against WCR larvae could potentially assist in rootworm management. Root damage and root regrowth of eight corn lines were evaluated in field assays at three different locations. Results indicated the inbred 'Mp708' had the greatest root damage and was significantly greater than damage for the susceptible control, B37×H84. In greenhouse assays, we evaluated four of these lines plus a hybrid expressing the mCry3A Bt toxin for damage. The results indicated that Mp708 had significantly higher root damage when compared to 'CRW3(S1)C6' and 'MIR604'. Despite previous work suggesting otherwise, we conclude that Mp708 is highly susceptible to the WCR larvae based on root damage in field and greenhouse plant assays.
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Affiliation(s)
| | - Ryan W Geisert
- Division of Plant Sciences & Technology, University of Missouri, Columbia, MO, 65211, USA
| | - Bruce E Hibbard
- USDA/ARS, University of Missouri, 205 Curtis Hall, Columbia, MO, 65211, USA
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3
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Boeckman CJ, Ballou S, Gunderson T, Huang E, Linderblood C, Olson T, Stolte B, LeRoy K, Walker C, Wang Y, Woods R, Zhang J. Characterization of the Spectrum of Activity of IPD079Ea: A Protein Derived From Ophioglossum pendulum (Ophioglossales: Ophioglossaceae) With Activity Against Western Corn Rootworm [Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae)]. JOURNAL OF ECONOMIC ENTOMOLOGY 2022; 115:1531-1538. [PMID: 35640234 PMCID: PMC9554786 DOI: 10.1093/jee/toac079] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Indexed: 06/15/2023]
Abstract
Western corn rootworm (Diabrotica virgifera virgifera LeConte) is a major pest of corn in both North America and Europe and as such presents significant challenges for farmers. IPD079Ea protein is encoded by the ipd079Ea gene from Ophioglossum pendulum (a species of fern) and was found to have activity against western corn rootworm in multiple corn events transformed to express the IPD079Ea protein. In chronic laboratory hazard studies, IPD079Ea protein was fed to eleven species in the order Coleoptera and four species in the order Lepidoptera to assess the spectrum of activity. Activity was observed on certain species of the Chrysomelidae and Coccinellidae families, with western corn rootworm as the most sensitive insect tested. No adverse effects on mortality or other sublethal endpoints were observed on any species within Lepidoptera. Overall, IPD079Ea protein appears not to have broad insecticidal properties and has potential value as an effective trait to control western corn rootworm in agricultural systems.
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Affiliation(s)
| | - Stephan Ballou
- Corteva Agriscience, 8325 NW 62nd Ave., Johnston, IA 50131, USA
| | - Tim Gunderson
- Corteva Agriscience, 8325 NW 62nd Ave., Johnston, IA 50131, USA
| | - Emily Huang
- Corteva Agriscience, 8325 NW 62nd Ave., Johnston, IA 50131, USA
| | | | - Taylor Olson
- Corteva Agriscience, 8325 NW 62nd Ave., Johnston, IA 50131, USA
| | - Brian Stolte
- Corteva Agriscience, 8325 NW 62nd Ave., Johnston, IA 50131, USA
| | - Kristine LeRoy
- Corteva Agriscience, 8325 NW 62nd Ave., Johnston, IA 50131, USA
| | - Carl Walker
- Corteva Agriscience, 8325 NW 62nd Ave., Johnston, IA 50131, USA
| | - Yiwei Wang
- Corteva Agriscience, 8325 NW 62nd Ave., Johnston, IA 50131, USA
| | - Rachel Woods
- Corteva Agriscience, 8325 NW 62nd Ave., Johnston, IA 50131, USA
| | - John Zhang
- Corteva Agriscience, 8325 NW 62nd Ave., Johnston, IA 50131, USA
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Bio-fabricated zinc oxide and cry protein nanocomposites: Synthesis, characterization, potentiality against Zika, malaria and West Nile virus vector's larvae and their impact on non-target organisms. Int J Biol Macromol 2022; 224:699-712. [DOI: 10.1016/j.ijbiomac.2022.10.158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 09/29/2022] [Accepted: 10/18/2022] [Indexed: 11/05/2022]
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Towards Understanding the Function of Aegerolysins. Toxins (Basel) 2022; 14:toxins14090629. [PMID: 36136567 PMCID: PMC9505663 DOI: 10.3390/toxins14090629] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 09/04/2022] [Accepted: 09/09/2022] [Indexed: 11/17/2022] Open
Abstract
Aegerolysins are remarkable proteins. They are distributed over the tree of life, being relatively widespread in bacteria and fungi, but also present in some insects, plants, protozoa, and viruses. Despite their abundance in cells of certain developmental stages and their presence in secretomes, only a few aegerolysins have been studied in detail. Their function, in particular, is intriguing. Here, we summarize previously published findings on the distribution, molecular interactions, and function of these versatile aegerolysins. They have very diverse protein sequences but a common fold. The machine learning approach of the AlphaFold2 algorithm, which incorporates physical and biological knowledge of protein structures and multisequence alignments, provides us new insights into the aegerolysins and their pore-forming partners, complemented by additional genomic support. We hypothesize that aegerolysins are involved in the mechanisms of competitive exclusion in the niche.
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Dundas CM, Dinneny JR. Genetic Circuit Design in Rhizobacteria. BIODESIGN RESEARCH 2022; 2022:9858049. [PMID: 37850138 PMCID: PMC10521742 DOI: 10.34133/2022/9858049] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 07/31/2022] [Indexed: 10/19/2023] Open
Abstract
Genetically engineered plants hold enormous promise for tackling global food security and agricultural sustainability challenges. However, construction of plant-based genetic circuitry is constrained by a lack of well-characterized genetic parts and circuit design rules. In contrast, advances in bacterial synthetic biology have yielded a wealth of sensors, actuators, and other tools that can be used to build bacterial circuitry. As root-colonizing bacteria (rhizobacteria) exert substantial influence over plant health and growth, genetic circuit design in these microorganisms can be used to indirectly engineer plants and accelerate the design-build-test-learn cycle. Here, we outline genetic parts and best practices for designing rhizobacterial circuits, with an emphasis on sensors, actuators, and chassis species that can be used to monitor/control rhizosphere and plant processes.
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Affiliation(s)
| | - José R. Dinneny
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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Vinotha V, Yazhiniprabha M, Jeyavani J, Vaseeharan B. Synthesis and characterization of cry protein coated zinc oxide nanocomposites and its assessment against bacterial biofilm and mosquito vectors. Int J Biol Macromol 2022; 208:935-947. [PMID: 35364199 DOI: 10.1016/j.ijbiomac.2022.03.165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 03/03/2022] [Accepted: 03/25/2022] [Indexed: 11/05/2022]
Abstract
Mosquitoes need to be eradicated as they can spread deadly diseases. Cry toxic proteins from Bacillus and zinc oxide nanoparticles also can tremendously control pest and bacterial pathogens. With this reference, the Ac-ZnO NPs was effectively synthesized using Acorus calamus rhizomes extract where after incorporated with bacterial cry toxic protein (Btp) to produce Btp-Ac-ZnO nanocomposites. The XRD and FTIR, disclose the crystalline form with an average size of 17.47 nm and the possible biomolecules of Btp-Ac-ZnO NCs. SEM and TEM make known the well agglomerated and cone shape of Btp-Ac-ZnO NCs. The NCs show concentration-dependent antioxidant activity. Btp-Ac-ZnO NCs drastically arrest the formation of biofilm by the pathogenic bacteria such as E. faecalis, S. aureus, P. aeruginosa, and P. vulgaris at 100 μg/mL. All the above, the Btp-Ac-ZnO NCs exhibits superior larvicidal activity against three mosquito vectors namely Ae. aegypti, An. stephensi and Cx. quinquefasciatus with LC50 values of 43.76, 39.60 and 37.13 μg/mL respectively. Besides, the biological enzymes are significantly reduced in the treated larvae than that of untreated one, which indicates the effect of Btp-Ac-ZnO NCs. Since, the Btp-Ac-ZnO NCs could be utilized against the pathogenic bacteria, and its biofilm structure, and also in the vector control sectors.
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Affiliation(s)
- Viswanathan Vinotha
- Nanobioscience and Nanopharmacology Division, Biomaterials and Biotechnology in Animal Health Lab, Department of Animal Health and Management, Alagappa University, Karaikudi 630004, Tamil Nadu, India
| | - Mariappan Yazhiniprabha
- Nanobioscience and Nanopharmacology Division, Biomaterials and Biotechnology in Animal Health Lab, Department of Animal Health and Management, Alagappa University, Karaikudi 630004, Tamil Nadu, India
| | - Jeyaraj Jeyavani
- Nanobioscience and Nanopharmacology Division, Biomaterials and Biotechnology in Animal Health Lab, Department of Animal Health and Management, Alagappa University, Karaikudi 630004, Tamil Nadu, India
| | - Baskaralingam Vaseeharan
- Nanobioscience and Nanopharmacology Division, Biomaterials and Biotechnology in Animal Health Lab, Department of Animal Health and Management, Alagappa University, Karaikudi 630004, Tamil Nadu, India.
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Kuwar SS, Mishra R, Banerjee R, Milligan J, Rydel T, Du Z, Xie Z, Ivashuta S, Kouadio JL, Meyer JM, Bonning BC. Engineering of Cry3Bb1 provides mechanistic insights toward countering western corn rootworm resistance. CURRENT RESEARCH IN INSECT SCIENCE 2022; 2:100033. [PMID: 36003270 PMCID: PMC9387510 DOI: 10.1016/j.cris.2022.100033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 11/28/2022]
Abstract
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is an economically important pest of corn (maize) in North America and Europe. Current management practices for WCR involve transgenic expression of insecticidal proteins to minimize larval feeding damage to corn roots. The evolution of resistant WCR populations to transgenic corn expressing insecticidal proteins (e.g. Cry3Bb1, Gpp34Ab1/Tpp35Ab1) necessitates efforts to discover and deploy new modes of action for WCR control. Here, we tested the hypothesis that the addition of short peptides selected for binding to the WCR gut would restore insecticidal activity of Cry3Bb1 to resistant insects. Phage display technology coupled with deep sequencing was used to identify peptides selected for binding to WCR brush border membrane vesicles and to recombinant putative receptors aminopeptidase and cadherin. The binding and specificity of selected peptides was confirmed by ELISA and pull-down assays, and candidate gut surface binding partners were identified. Although production of 284 novel Cry3Bb1 variants with these peptides did not restore activity against resistant WCR in artificial diet bioassays, 112 variants were active against susceptible insects. These results provided insights for the mechanism of Cry3Bb1 activity and toward engineering a new mode-of-action via receptor re-targeting in the context of protein structure and function.
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Affiliation(s)
- Suyog S. Kuwar
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
| | - Ruchir Mishra
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
| | - Rahul Banerjee
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
| | - Jason Milligan
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Timothy Rydel
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Zijin Du
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Zhidong Xie
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Sergey Ivashuta
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Jean-Louis Kouadio
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Jason M. Meyer
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Bryony C. Bonning
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
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Basu D, South PF. Design and Analysis of Native Photorespiration Gene Motifs of Promoter Untranslated Region Combinations Under Short Term Abiotic Stress Conditions. FRONTIERS IN PLANT SCIENCE 2022; 13:828729. [PMID: 35251099 PMCID: PMC8888687 DOI: 10.3389/fpls.2022.828729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/18/2022] [Indexed: 05/09/2023]
Abstract
Quantitative traits are rarely controlled by a single gene, thereby making multi-gene transformation an indispensable component of modern synthetic biology approaches. However, the shortage of unique gene regulatory elements (GREs) for the robust simultaneous expression of multiple nuclear transgenes is a major bottleneck that impedes the engineering of complex pathways in plants. In this study, we compared the transcriptional efficacies of a comprehensive list of well-documented promoter and untranslated region (UTR) sequences side by side. The strength of GREs was examined by a dual-luciferase assay in conjunction with transient expression in tobacco. In addition, we created suites of new GREs with higher transcriptional efficacies by combining the best performing promoter-UTR sequences. We also tested the impact of elevated temperature and high irradiance on the effectiveness of these GREs. While constitutive promoters ensure robust expression of transgenes, they lack spatiotemporal regulations exhibited by native promoters. Here, we present a proof-of-principle study on the characterization of synthetic promoters based on cis-regulatory elements of three key photorespiratory genes. This conserved biochemical process normally increases under elevated temperature, low CO2, and high irradiance stress conditions and results in ∼25% loss in fixed CO2. To select stress-responsive cis-regulatory elements involved in photorespiration, we analyzed promoters of two chloroplast transporters (AtPLGG1 and AtBASS6) and a key plastidial enzyme, AtPGLP using PlantPAN3.0 and AthaMap. Our results suggest that these motifs play a critical role for PLGG1, BASS6, and PGLP in mediating response to elevated temperature and high-intensity light stress. These findings will not only enable the advancement of metabolic and genetic engineering of photorespiration but will also be instrumental in related synthetic biology approaches.
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Affiliation(s)
| | - Paul F. South
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
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Kouadio JL, Zheng M, Aikins M, Duda D, Duff S, Chen D, Zhang J, Milligan J, Taylor C, Mamanella P, Rydel T, Kessenich C, Panosian T, Yin Y, Moar W, Giddings K, Park Y, Jerga A, Haas J. Structural and functional insights into the first Bacillus thuringiensis vegetative insecticidal protein of the Vpb4 fold, active against western corn rootworm. PLoS One 2021; 16:e0260532. [PMID: 34928980 PMCID: PMC8687597 DOI: 10.1371/journal.pone.0260532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 11/11/2021] [Indexed: 01/09/2023] Open
Abstract
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is a major maize pest in the United States causing significant economic loss. The emergence of field-evolved resistant WCR to Bacillus thuringiensis (Bt) traits has prompted the need to discover and deploy new insecticidal proteins in transgenic maize. In the current study we determined the crystal structure and mode of action (MOA) of the Vpb4Da2 protein (formerly known as Vip4Da2) from Bt, the first identified insecticidal Vpb4 protein with commercial level control against WCR. The Vpb4Da2 structure exhibits a six-domain architecture mainly comprised of antiparallel β-sheets organized into β-sandwich layers. The amino-terminal domains 1-3 of the protein share structural homology with the protective antigen (PA) PA14 domain and encompass a long β-pore forming loop as in the clostridial binary-toxB module. Domains 5 and 6 at the carboxyl-terminal half of Vpb4Da2 are unique as this extension is not observed in PA or any other structurally-related protein other than Vpb4 homologs. These unique Vpb4 domains adopt the topologies of carbohydrate-binding modules known to participate in receptor-recognition. Functional assessment of Vpb4Da2 suggests that domains 4-6 comprise the WCR receptor binding region and are key in conferring the observed insecticidal activity against WCR. The current structural analysis was complemented by in vitro and in vivo characterizations, including immuno-histochemistry, demonstrating that Vpb4Da2 follows a MOA that is consistent with well-characterized 3-domain Bt insecticidal proteins despite significant structural differences.
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Affiliation(s)
| | - Meiying Zheng
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Michael Aikins
- Department of Entomology, Kansas State University, Manhattan, Kansas, United States of America
| | - David Duda
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Stephen Duff
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Danqi Chen
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jun Zhang
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jason Milligan
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Christina Taylor
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | | | - Timothy Rydel
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Colton Kessenich
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Timothy Panosian
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Yong Yin
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - William Moar
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Kara Giddings
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Yoonseong Park
- Department of Entomology, Kansas State University, Manhattan, Kansas, United States of America
| | - Agoston Jerga
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jeffrey Haas
- Bayer Crop Science, Chesterfield, Missouri, United States of America
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Castano-Duque L, Gilbert MK, Mack BM, Lebar MD, Carter-Wientjes CH, Sickler CM, Cary JW, Rajasekaran K. Flavonoids Modulate the Accumulation of Toxins From Aspergillus flavus in Maize Kernels. FRONTIERS IN PLANT SCIENCE 2021; 12:761446. [PMID: 34899785 PMCID: PMC8662736 DOI: 10.3389/fpls.2021.761446] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/15/2021] [Indexed: 06/14/2023]
Abstract
Aspergillus flavus is an opportunistic fungal pathogen capable of producing aflatoxins, potent carcinogenic toxins that accumulate in maize kernels after infection. To better understand the molecular mechanisms of maize resistance to A. flavus growth and aflatoxin accumulation, we performed a high-throughput transcriptomic study in situ using maize kernels infected with A. flavus strain 3357. Three maize lines were evaluated: aflatoxin-contamination resistant line TZAR102, semi-resistant MI82, and susceptible line Va35. A modified genotype-environment association method (GEA) used to detect loci under selection via redundancy analysis (RDA) was used with the transcriptomic data to detect genes significantly influenced by maize line, fungal treatment, and duration of infection. Gene ontology enrichment analysis of genes highly expressed in infected kernels identified molecular pathways associated with defense responses to fungi and other microbes such as production of pathogenesis-related (PR) proteins and lipid bilayer formation. To further identify novel genes of interest, we incorporated genomic and phenotypic field data from a genome wide association analysis with gene expression data, allowing us to detect significantly expressed quantitative trait loci (eQTL). These results identified significant association between flavonoid biosynthetic pathway genes and infection by A. flavus. In planta fungal infections showed that the resistant line, TZAR102, has a higher fold increase of the metabolites naringenin and luteolin than the susceptible line, Va35, when comparing untreated and fungal infected plants. These results suggest flavonoids contribute to plant resistance mechanisms against aflatoxin contamination through modulation of toxin accumulation in maize kernels.
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12
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Kouadio JL, Duff S, Aikins M, Zheng M, Rydel T, Chen D, Bretsnyder E, Xia C, Zhang J, Milligan J, Evdokimov A, Nageotte J, Yin Y, Moar W, Giddings K, Park Y, Jerga A, Haas J. Structural and functional characterization of Mpp75Aa1.1, a putative beta-pore forming protein from Brevibacillus laterosporus active against the western corn rootworm. PLoS One 2021; 16:e0258052. [PMID: 34634061 PMCID: PMC8504720 DOI: 10.1371/journal.pone.0258052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 09/16/2021] [Indexed: 12/16/2022] Open
Abstract
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is a major corn pest of significant economic importance in the United States. The continuous need to control this corn maize pest and the development of field-evolved resistance toward all existing transgenic maize (Zea mays L.) expressing Bacillus thuringiensis (Bt) insecticidal proteins against WCR has prompted the development of new insect-protected crops expressing distinct structural classes of insecticidal proteins. In this current study, we describe the crystal structure and functional characterization of Mpp75Aa1.1, which represents the first corn rootworm (CRW) active insecticidal protein member of the ETX_MTX2 sub-family of beta-pore forming proteins (β-PFPs), and provides new and effective protection against WCR feeding. The Mpp75Aa1.1 crystal structure was solved at 1.94 Å resolution. The Mpp75Aa1.1 is processed at its carboxyl-terminus by WCR midgut proteases, forms an oligomer, and specifically interacts with putative membrane-associated binding partners on the midgut apical microvilli to cause cellular tissue damage resulting in insect death. Alanine substitution of the surface-exposed amino acids W206, Y212, and G217 within the Mpp75Aa1.1 putative receptor binding domain I demonstrates that at least these three amino acids are required for WCR activity. The distinctive spatial arrangement of these amino acids suggests that they are part of a receptor binding epitope, which may be unique to Mpp75Aa1.1 and not present in other ETX_MTX2 proteins that do not have WCR activity. Overall, this work establishes that Mpp75Aa1.1 shares a mode of action consistent with traditional WCR-active Bt proteins despite significant structural differences.
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Affiliation(s)
- Jean-Louis Kouadio
- Bayer Crop Science, Chesterfield, Missouri, United States of America
- * E-mail:
| | - Stephen Duff
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Michael Aikins
- Department of Entomology, Kansas State University, Manhattan, Kansas, United States of America
| | - Meiying Zheng
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Timothy Rydel
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Danqi Chen
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Eric Bretsnyder
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Chunsheng Xia
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jun Zhang
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jason Milligan
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Artem Evdokimov
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jeffrey Nageotte
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Yong Yin
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - William Moar
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Kara Giddings
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Yoonseong Park
- Department of Entomology, Kansas State University, Manhattan, Kansas, United States of America
| | - Agoston Jerga
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jeffrey Haas
- Bayer Crop Science, Chesterfield, Missouri, United States of America
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13
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Panevska A, Glavan G, Jemec Kokalj A, Kukuljan V, Trobec T, Žužek MC, Vrecl M, Drobne D, Frangež R, Sepčić K. Effects of Bioinsecticidal Aegerolysin-Based Cytolytic Complexes on Non-Target Organisms. Toxins (Basel) 2021; 13:457. [PMID: 34208927 PMCID: PMC8310125 DOI: 10.3390/toxins13070457] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 01/05/2023] Open
Abstract
Aegerolysin proteins ostreolysin A6 (OlyA6), pleurotolysin A2 (PlyA2) and erylysin A (EryA) produced by the mushroom genus Pleurotus bind strongly to an invertebrate-specific membrane sphingolipid, and together with a protein partner pleurotolysin B (PlyB), form transmembrane pore complexes. This pore formation is the basis for the selective insecticidal activity of aegerolysin/PlyB complexes against two economically important coleopteran pests: the Colorado potato beetle and the western corn rootworm. In this study, we evaluated the toxicities of these aegerolysin/PlyB complexes using feeding tests with two ecologically important non-target arthropod species: the woodlouse and the honey bee. The mammalian toxicity of the EryA/PlyB complex was also evaluated after intravenous administration to mice. None of the aegerolysin/PlyB complexes were toxic against woodlice, but OlyA6/PlyB and PlyA2/PlyB were toxic to honeybees, with 48 h mean lethal concentrations (LC50) of 0.22 and 0.39 mg/mL, respectively, in their food. EryA/PlyB was also tested intravenously in mice up to 3 mg/kg body mass, without showing toxicity. With no toxicity seen for EryA/PlyB for environmentally beneficial arthropods and mammals at the tested concentrations, these EryA/PlyB complexes are of particular interest for development of new bioinsecticides for control of selected coleopteran pests.
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Affiliation(s)
- Anastasija Panevska
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (A.P.); (G.G.); (A.J.K.); (D.D.)
| | - Gordana Glavan
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (A.P.); (G.G.); (A.J.K.); (D.D.)
| | - Anita Jemec Kokalj
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (A.P.); (G.G.); (A.J.K.); (D.D.)
| | - Veronika Kukuljan
- Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia;
| | - Tomaž Trobec
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (T.T.); (M.C.Ž.); (M.V.)
| | - Monika Cecilija Žužek
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (T.T.); (M.C.Ž.); (M.V.)
| | - Milka Vrecl
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (T.T.); (M.C.Ž.); (M.V.)
| | - Damjana Drobne
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (A.P.); (G.G.); (A.J.K.); (D.D.)
| | - Robert Frangež
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (T.T.); (M.C.Ž.); (M.V.)
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (A.P.); (G.G.); (A.J.K.); (D.D.)
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14
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Milijaš Jotić M, Panevska A, Iacovache I, Kostanjšek R, Mravinec M, Skočaj M, Zuber B, Pavšič A, Razinger J, Modic Š, Trenti F, Guella G, Sepčić K. Dissecting Out the Molecular Mechanism of Insecticidal Activity of Ostreolysin A6/Pleurotolysin B Complexes on Western Corn Rootworm. Toxins (Basel) 2021; 13:toxins13070455. [PMID: 34209983 PMCID: PMC8310357 DOI: 10.3390/toxins13070455] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 02/04/2023] Open
Abstract
Ostreolysin A6 (OlyA6) is a protein produced by the oyster mushroom (Pleurotus ostreatus). It binds to membrane sphingomyelin/cholesterol domains, and together with its protein partner, pleurotolysin B (PlyB), it forms 13-meric transmembrane pore complexes. Further, OlyA6 binds 1000 times more strongly to the insect-specific membrane sphingolipid, ceramide phosphoethanolamine (CPE). In concert with PlyB, OlyA6 has potent and selective insecticidal activity against the western corn rootworm. We analysed the histological alterations of the midgut wall columnar epithelium of western corn rootworm larvae fed with OlyA6/PlyB, which showed vacuolisation of the cell cytoplasm, swelling of the apical cell surface into the gut lumen, and delamination of the basal lamina underlying the epithelium. Additionally, cryo-electron microscopy was used to explore the membrane interactions of the OlyA6/PlyB complex using lipid vesicles composed of artificial lipids containing CPE, and western corn rootworm brush border membrane vesicles. Multimeric transmembrane pores were formed in both vesicle preparations, similar to those described for sphingomyelin/cholesterol membranes. These results strongly suggest that the molecular mechanism of insecticidal action of OlyA6/PlyB arises from specific interactions of OlyA6 with CPE, and the consequent formation of transmembrane pores in the insect midgut.
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Affiliation(s)
- Matej Milijaš Jotić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Anastasija Panevska
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Ioan Iacovache
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (I.I.); (B.Z.)
| | - Rok Kostanjšek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Martina Mravinec
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Matej Skočaj
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (I.I.); (B.Z.)
| | - Ana Pavšič
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Jaka Razinger
- Agricultural Institute of Slovenia, 1000 Ljubljana, Slovenia; (J.R.); (Š.M.)
| | - Špela Modic
- Agricultural Institute of Slovenia, 1000 Ljubljana, Slovenia; (J.R.); (Š.M.)
| | - Francesco Trenti
- Bioorganic Chemistry Laboratory, Department of Physics, University of Trento, 38123 Trento, Italy; (F.T.); (G.G.)
| | - Graziano Guella
- Bioorganic Chemistry Laboratory, Department of Physics, University of Trento, 38123 Trento, Italy; (F.T.); (G.G.)
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
- Correspondence: ; Tel.: +386-1-320-3419
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15
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Pérez Ortega C, Leininger C, Barry J, Poland B, Yalpani N, Altier D, Nelson ME, Lu AL. Coordinated binding of a two-component insecticidal protein from Alcaligenes faecalis to western corn rootworm midgut tissue. J Invertebr Pathol 2021; 183:107597. [PMID: 33945817 DOI: 10.1016/j.jip.2021.107597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 04/08/2021] [Accepted: 04/20/2021] [Indexed: 12/19/2022]
Abstract
AfIP-1A/1B is a two-component insecticidal protein identified from the soil bacterium Alcaligenes faecalis that has high activity against western corn rootworm (WCR; Diabrotica virgifera virgifera LeConte). Previous results revealed that AfIP-1A/1B is cross-resistant to the binary protein from Bacillus thuringiensis (Bt), Cry34Ab1/Cry35Ab1 (also known as Gpp34Ab1/Tpp35Ab1; Crickmore et al., 2020), which was attributed to shared binding sites in WCR gut tissue (Yalpani et al., 2017). To better understand the interaction of AfIP-1A/1B with its receptor, we have systematically evaluated the binding of these proteins with WCR brush border membrane vesicles (BBMVs). Our findings show that AfIP-1A binds directly to BBMVs, while AfIP-1B does not; AfIP-1B binding only occurred in the presence of AfIP-1A which was accompanied by the presence of stable, high molecular weight oligomers of AfIP-1B observed on denaturing protein gels. Additionally, we show that AfIP-1A/1B forms pores in artificial lipid membranes. Finally, binding of AfIP-1A/1B was found to be reduced in BBMVs from Cry34Ab1/Cry35Ab1-resistant WCR where Cry34Ab1/Cry35Ab1 binding was also reduced. The reduced binding of both proteins is consistent with recognition of a shared receptor that has been altered in the resistant strain. The coordination of AfIP-1B binding by AfIP-1A, the similar structures between AfIP-1A and Cry34Ab1, along with their shared binding sites and cross-resistance, suggest a similar role for AfIP1A and Cry34Ab1 in receptor recognition and docking site for their cognate partners, AfIP-1B and Cry35Ab1, respectively.
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Affiliation(s)
| | - Chris Leininger
- Corteva Agriscience, 7300 NW 62(nd) Ave., Johnston, IA 50131, USA
| | - Jennifer Barry
- Corteva Agriscience, 7300 NW 62(nd) Ave., Johnston, IA 50131, USA
| | - Brad Poland
- Corteva Agriscience, 7300 NW 62(nd) Ave., Johnston, IA 50131, USA
| | - Nasser Yalpani
- Corteva Agriscience, 7300 NW 62(nd) Ave., Johnston, IA 50131, USA
| | - Dan Altier
- Corteva Agriscience, 7300 NW 62(nd) Ave., Johnston, IA 50131, USA
| | - Mark E Nelson
- Corteva Agriscience, 7300 NW 62(nd) Ave., Johnston, IA 50131, USA.
| | - Albert L Lu
- Corteva Agriscience, 7300 NW 62(nd) Ave., Johnston, IA 50131, USA
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16
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Branching out the aerolysin, ETX/MTX-2 and Toxin_10 family of pore forming proteins. J Invertebr Pathol 2021; 186:107570. [PMID: 33775676 DOI: 10.1016/j.jip.2021.107570] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/15/2020] [Accepted: 03/09/2021] [Indexed: 01/28/2023]
Abstract
Organisms have evolved mechanisms in which cellular membranes can both be targeted and punctured thereby killing the targeted cell. One such mechanism involves the deployment of pore forming proteins (PFPs) which function by oligomerizing on cell membranes and inserting a physical pore spanning the membrane. This pore can lead to cell death by either causing osmotic flux or allowing the delivery of a secondary toxin. Pore forming proteins can be broadly classified into different families depending on the structure of the final pore; either α-PFPs using channels made from α -helices or β-PFPs using channels made from β-barrels. There are many different β-PFPs and an emerging superfamily is the aerolysin-ETX/MTX-2 superfamily. A comparison between the members of this superfamily reveals the pore forming domain is a common module yet the receptor binding region is highly variable. These structural and architectural variations lead to differences in the target recognition and determine the site of activity. Closer investigation of the topology of the family also suggests that the Toxin_10 family of PFPs could be considered as part of the aerolysin-ETX/MTX-2 superfamily. Comparatively, far less is known about how Toxin_10 proteins assemble into the final pore structure than aerolysin-ETX/MTX-2 proteins. This review aims to collate the pore forming protein members and bridge the structural similarities between the aerolysin-ETX/MTX-2 superfamily and the insecticidal Toxin_10 subfamily.
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17
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Crystal structure of RahU, an aegerolysin protein from the human pathogen Pseudomonas aeruginosa, and its interaction with membrane ceramide phosphorylethanolamine. Sci Rep 2021; 11:6572. [PMID: 33753805 PMCID: PMC7985367 DOI: 10.1038/s41598-021-85956-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 03/08/2021] [Indexed: 12/15/2022] Open
Abstract
Aegerolysins are proteins produced by bacteria, fungi, plants and protozoa. The most studied fungal aegerolysins share a common property of interacting with membranes enriched with cholesterol in combination with either sphingomyelin or ceramide phosphorylethanolamine (CPE), major sphingolipids in the cell membranes of vertebrates and invertebrates, respectively. However, genome analyses show a particularly high frequency of aegerolysin genes in bacteria, including the pathogenic genera Pseudomonas and Vibrio; these are human pathogens of high clinical relevance and can thrive in a variety of other species. The knowledge on bacterial aegerolysin-lipid interactions is scarce. We show that Pseudomonas aeruginosa aegerolysin RahU interacts with CPE, but not with sphingomyelin-enriched artificial membranes, and that RahU interacts with the insect cell line producing CPE. We report crystal structures of RahU alone and in complex with tris(hydroxymethyl)aminomethane (Tris), which, like the phosphorylethanolamine head group of CPE, contains a primary amine. The RahU structures reveal that the two loops proximal to the amino terminus form a cavity that accommodates Tris, and that the flexibility of these two loops is important for this interaction. We show that Tris interferes with CPE-enriched membranes for binding to RahU, implying on the importance of the ligand cavity between the loops and its proximity in RahU membrane interaction. We further support this by studying the interaction of single amino acid substitution mutants of RahU with the CPE-enriched membranes. Our results thus represent a starting point for a better understanding of the role of P. aeruginosa RahU, and possibly other bacterial aegerolysins, in bacterial interactions with other organisms.
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18
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Yin Y, Flasinski S, Moar W, Bowen D, Chay C, Milligan J, Kouadio JL, Pan A, Werner B, Buckman K, Zhang J, Mueller G, Preftakes C, Hibbard BE, Price P, Roberts J. A new Bacillus thuringiensis protein for Western corn rootworm control. PLoS One 2020; 15:e0242791. [PMID: 33253273 PMCID: PMC7703998 DOI: 10.1371/journal.pone.0242791] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 11/09/2020] [Indexed: 11/23/2022] Open
Abstract
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.
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Affiliation(s)
- Yong Yin
- Bayer Crop Science, Chesterfield, Missouri, United States of America
- * E-mail:
| | | | - William Moar
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - David Bowen
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Cathy Chay
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jason Milligan
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | | | - Aihong Pan
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Brent Werner
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Karrie Buckman
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jun Zhang
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Geoffrey Mueller
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Collin Preftakes
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Bruce E. Hibbard
- USDA-ARS, Plant Genetics Research Unit, University of Missouri, Columbia, Missouri, United States of America
| | - Paula Price
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - James Roberts
- Bayer Crop Science, Chesterfield, Missouri, United States of America
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19
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Panevska A, Skočaj M, Modic Š, Razinger J, Sepčić K. Aegerolysins from the fungal genus Pleurotus - Bioinsecticidal proteins with multiple potential applications. J Invertebr Pathol 2020; 186:107474. [PMID: 32971130 DOI: 10.1016/j.jip.2020.107474] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 09/08/2020] [Accepted: 09/10/2020] [Indexed: 12/24/2022]
Abstract
The aegerolysin proteins ostreolysin A6, pleurotolysin A2 and erylysin A are produced by mushrooms of the genus Pleurotus. These aegerolysins can interact specifically with sphingolipid-enriched membranes. In particular, they strongly bind insect cells and to artificial lipid membranes that contain physiologically relevant concentrations of the main invertebrate-specific sphingolipid, ceramide phosphoethanolamine. Moreover, the aegerolysins permeabilise these membranes when combined with their protein partner pleurotolysin B, which contains a membrane-attack-complex/perforin domain. These aegerolysin/ pleurotolysin B complexes show strong and selective toxicity towards western corn rootworm larvae and adults and Colorado potato beetle larvae. Their insecticidal activities arise through aegerolysin binding to ceramide phosphoethanolamine in the insect midgut. This mode of membrane binding is different from those described for similar aegerolysin-based complexes of bacterial origin (e.g., Cry34Ab1/Cry35Ab1), or other Bacillus thuringiensis proteinaceous crystal toxins, which associate with protein receptors. The ability of Pleurotus aegerolysins to specifically interact with sphingolipid-enriched domains in mammalian cells can be further exploited to visualize lipid rafts in living cells, and to treat certain types of tumours and metabolic disorders. Finally, these proteins can strongly enhance fruiting initiation of P. ostreatus even when applied externally. In this review, we summarise the current knowledge of the potential biotechnological and biomedical applications of the Pleurotus aegerolysins, either alone or when complexed with pleurotolysin B, with special emphasis on their bioinsecticidal effects.
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Affiliation(s)
- Anastasija Panevska
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
| | - Matej Skočaj
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
| | - Špela Modic
- Plant Protection Department, Agricultural Institute of Slovenia, Hacquetova 17, 1000 Ljubljana, Slovenia.
| | - Jaka Razinger
- Plant Protection Department, Agricultural Institute of Slovenia, Hacquetova 17, 1000 Ljubljana, Slovenia.
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
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20
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Pereira AE, Huynh MP, Sethi A, Miles AL, Wade French B, Ellersieck MR, Coudron TA, Shelby KS, Hibbard BE. Baseline Susceptibility of a Laboratory Strain of Northern Corn Rootworm, Diabrotica barberi (Coleoptera: Chrysomelidae) to Bacillus thuringiensis Traits in Seedling, Single Plant, and Diet-Toxicity Assays. JOURNAL OF ECONOMIC ENTOMOLOGY 2020; 113:1955-1962. [PMID: 32789524 DOI: 10.1093/jee/toaa107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Indexed: 06/11/2023]
Abstract
The northern corn rootworm (NCR), Diabrotica barberi Smith & Lawrence, is an economic pest of maize in the U.S. Corn Belt. The objective of this study was to determine the baseline susceptibility of a laboratory NCR strain to Bt proteins eCry3.1Ab, mCry3A, Cry3Bb1, and Cry34/35Ab1 using seedling, single plant, and diet-toxicity assays. Plant assays were performed in greenhouse using corn hybrids expressing one of the Bt proteins and each respective near-isoline. Diet-toxicity assays, consisting of Bt proteins overlaid onto artificial diet were also conducted. In both plant assays, significantly more larvae survived Cry34/35Ab1-expressing corn compared with all other Bt-expressing corn, and larvae that survived eCry3.1Ab-expressing corn had significantly smaller head capsule widths compared with larvae that survived Cry34/35Ab1-expressing corn. In seedling assays, larvae surviving eCry3.1Ab-expressing corn also had significantly smaller head capsule widths compared with larvae that survived mCry3A-expressing corn. Additionally, larvae that survived mCry3A-expressing corn weighed significantly more than larvae surviving eCry3.1Ab- and Cry34/35Ab1-expressing corn. In single plant assays, no significant differences in larval dry weight was observed between any of the Bt-expressing corn. In diet assays, LC50s ranged from 0.14 (eCry3.1Ab) to 10.6 µg/cm2 (Cry34/35Ab1), EC50s ranged from 0.12 (Cry34/35Ab1) to 1.57 µg/cm2 (mCry3A), IC50s ranged from 0.08 (eCry3.1Ab) to 2.41 µg/cm2 (Cry34/35Ab1), and MIC50s ranged from 2.52 (eCry3.1Ab) to 14.2 µg/cm2 (mCry3A). These results establish the toxicity of four Bt proteins to a laboratory diapausing NCR strain established prior to the introduction of Bt traits and are important for monitoring resistance evolution in NCR field populations.
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Affiliation(s)
| | - Man P Huynh
- Division of Plant Sciences, University of Missouri, Columbia, MO
| | | | | | - B Wade French
- North Central Agricultural Research Laboratory, Brookings, SD
| | | | - Thomas A Coudron
- Biological Control Insect Research Laboratory, USDA-ARS, Columbia, MO
| | - Kent S Shelby
- Biological Control Insect Research Laboratory, USDA-ARS, Columbia, MO
| | - Bruce E Hibbard
- Plant Genetics Research Unit, USDA/ARS, University of Missouri, Columbia, MO
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21
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Insecticidal Activity of Bacillus thuringiensis Proteins Against Coleopteran Pests. Toxins (Basel) 2020; 12:toxins12070430. [PMID: 32610662 PMCID: PMC7404982 DOI: 10.3390/toxins12070430] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/25/2020] [Accepted: 06/25/2020] [Indexed: 12/17/2022] Open
Abstract
Bacillus thuringiensis is the most successful microbial insecticide agent and its proteins have been studied for many years due to its toxicity against insects mainly belonging to the orders Lepidoptera, Diptera and Coleoptera, which are pests of agro-forestry and medical-veterinary interest. However, studies on the interactions between this bacterium and the insect species classified in the order Coleoptera are more limited when compared to other insect orders. To date, 45 Cry proteins, 2 Cyt proteins, 11 Vip proteins, and 2 Sip proteins have been reported with activity against coleopteran species. A number of these proteins have been successfully used in some insecticidal formulations and in the construction of transgenic crops to provide protection against main beetle pests. In this review, we provide an update on the activity of Bt toxins against coleopteran insects, as well as specific information about the structure and mode of action of coleopteran Bt proteins.
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22
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Haque MS, Saha NR. Biosafety Measures, Socio-Economic Impacts and Challenges of Bt-brinjal Cultivation in Bangladesh. Front Bioeng Biotechnol 2020; 8:337. [PMID: 32528934 PMCID: PMC7247817 DOI: 10.3389/fbioe.2020.00337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/26/2020] [Indexed: 11/13/2022] Open
Abstract
This study surveyed the onsite biosafety measures adopted by the farmers cultivating Bt-brinjal, the socio-economic impact, and the challenges of Bt-brinjal cultivation in Bangladesh through interviews of 101 farmers from 26 Upazila (administrative region) under 20 Districts. Bt-brinjal 2, released by Bangladesh Agricultural Research Institute (BARI), is cultivated by 35% of the surveyed farmers. It was revealed that 52% of farmers maintained border crops. Among the growers, 52% informed that they disclose to the buyers that they are selling Bt-brinjal while selling in the open market where no product is traditionally labeled. Most of the farmers (71%) use Bt-brinjal plant debris as animal feed. Farmers (60%) received training on biosafety of Bt-brinjal cultivation. According to 85% of farmers, Bt-brinjal cultivation improved insect control. The farmers (77%) agreed that Bt-brinjal reduced labor and chemical costs and 75% of the farmers found increased yield and 72% of them found enhanced income by Bt-brinjal cultivation. However, 25% farmers informed that they did not get increased yield due to incidence of secondary insects. Most of the farmers (89%) perceive that cultivation of Bt-brinjal improved quality of brinjal. Furthermore, 59% of the farmers opined that price was reduced due to Bt-brinjal cultivation. The farmers also believe that Bt-brinjal cultivation reduced pesticide use (97%) and concern of insecticide use (96%) and hence they consider Bt-brinjal safer for human health (96%). However, to harvest the benefits of modern biotechnology, proper management of the biosafety in Bt-brinjal cultivation and labeling of Bt-brinjal during marketing should be maintained properly.
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Affiliation(s)
| | - Nihar Ranjan Saha
- Department of Biotechnology, Bangladesh Agricultural University, Mymensingh, Bangladesh
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Wang PH, Kumar S, Zeng J, McEwan R, Wright TR, Gupta M. Transcription Terminator-Mediated Enhancement in Transgene Expression in Maize: Preponderance of the AUGAAU Motif Overlapping With Poly(A) Signals. FRONTIERS IN PLANT SCIENCE 2020; 11:570778. [PMID: 33178242 PMCID: PMC7591816 DOI: 10.3389/fpls.2020.570778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/11/2020] [Indexed: 05/08/2023]
Abstract
The selection of transcription terminators (TTs) for pairing with high expressing constitutive promoters in chimeric constructs is crucial to deliver optimal transgene expression in plants. In this study, the use of the native combinations of four polyubiquitin gene promoters and corresponding TTs resulted in up to >3-fold increase in transgene expression in maize. Of the eight polyubiquitin promoter and TT regulatory elements utilized, seven were novel and identified from the polyubiquitin genes of Brachypodium distachyon, Setaria italica, and Zea mays. Furthermore, gene expression driven by the Cassava mosaic virus promoter was studied by pairing the promoter with distinct TTs derived from the high expressing genes of Arabidopsis. Of the three TTs studied, the polyubiquitin10 gene TT produced the highest transgene expression in maize. Polyadenylation patterns and mRNA abundance from eight distinct TTs were analyzed using 3'-RACE and next-generation sequencing. The results exhibited one to three unique polyadenylation sites in the TTs. The poly(A) site patterns for the StPinII TT were consistent when the same TT was deployed in chimeric constructs irrespective of the reporter gene and promoter used. Distal to the poly(A) sites, putative polyadenylation signals were identified in the near-upstream regions of the TTs based on previously reported mutagenesis and bioinformatics studies in rice and Arabidopsis. The putative polyadenylation signals were 9 to 11 nucleotides in length. Six of the eight TTs contained the putative polyadenylation signals that were overlaps of either canonical AAUAAA or AAUAAA-like polyadenylation signals and AUGAAU, a top-ranking-hexamer of rice and Arabidopsis gene near-upstream regions. Three of the polyubiquitin gene TTs contained the identical 9-nucleotide overlap, AUGAAUAAG, underscoring the functional significance of such overlaps in mRNA 3' end processing. In addition to identifying new combinations of regulatory elements for high constitutive trait gene expression in maize, this study demonstrated the importance of TTs for optimizing gene expression in plants. Learning from this study could be applied to other dicotyledonous and monocotyledonous plant species for transgene expression. Research on TTs is not limited to transgene expression but could be extended to the introduction of appropriate mutations into TTs via genome editing, paving the way for expression modulation of endogenous genes.
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Affiliation(s)
- Po-Hao Wang
- Applied Science & Technology, Corteva Agriscience, Johnston, IA, United States
| | - Sandeep Kumar
- Applied Science & Technology, Corteva Agriscience, Johnston, IA, United States
- *Correspondence: Sandeep Kumar,
| | - Jia Zeng
- Data Science & Informatics, Corteva Agriscience, Indianapolis, IN, United States
| | - Robert McEwan
- Applied Science & Technology, Corteva Agriscience, Johnston, IA, United States
| | - Terry R. Wright
- Trait Discovery, Corteva Agriscience, Indianapolis, IN, United States
| | - Manju Gupta
- Trait Product Development, Dow Agrosciences, Indianapolis, IN, United States
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Wang K, Shu C, Zhang J. Effective bacterial insecticidal proteins against coleopteran pests: A review. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2019; 102:e21558. [PMID: 31094011 DOI: 10.1002/arch.21558] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 04/02/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
Coleoptera, the order of insects commonly referred to as beetles, are able to survive in various environments, and thus, comprise the largest order in the animal kingdom. Coleopterans mainly include coprophagous and phytophagous lineages, and many species of the latter lineage are serious pests. In addition to traditional chemical methods, biocontrol measures using various bacterial insecticidal proteins have also gradually been developed to control these insect pests. In this review, we summarized the possible coleopteran-pest-specific bacteria and insecticidal proteins that have been reported in the literature thus far and have provided a comprehensive overview and long-term guidance for the control of coleopteran pests in the future.
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Affiliation(s)
- Kui Wang
- College of Life Sciences, Northeast Agricultural University, Harbin, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Changlong Shu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jie Zhang
- College of Life Sciences, Northeast Agricultural University, Harbin, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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25
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Zhao Y, Kim JY, Karan R, Jung JH, Pathak B, Williamson B, Kannan B, Wang D, Fan C, Yu W, Dong S, Srivastava V, Altpeter F. Generation of a selectable marker free, highly expressed single copy locus as landing pad for transgene stacking in sugarcane. PLANT MOLECULAR BIOLOGY 2019; 100:247-263. [PMID: 30919152 DOI: 10.1007/s11103-019-00856-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 03/15/2019] [Indexed: 05/23/2023]
Abstract
A selectable marker free, highly expressed single copy locus flanked by insulators was created as landing pad for transgene stacking in sugarcane. These events displayed superior transgene expression compared to single-copy transgenic lines lacking insulators. Excision of the selectable marker gene from transgenic sugarcane lines was supported by FLPe/FRT site-specific recombination. Sugarcane, a tropical C4 grass in the genus Saccharum (Poaceae), accounts for nearly 80% of sugar produced worldwide and is also an important feedstock for biofuel production. Generating transgenic sugarcane with predictable and stable transgene expression is critical for crop improvement. In this study, we generated a highly expressed single copy locus as landing pad for transgene stacking. Transgenic sugarcane lines with stable integration of a single copy nptII expression cassette flanked by insulators supported higher transgene expression along with reduced line to line variation when compared to single copy events without insulators by NPTII ELISA analysis. Subsequently, the nptII selectable marker gene was efficiently excised from the sugarcane genome by the FLPe/FRT site-specific recombination system to create selectable marker free plants. This study provides valuable resources for future gene stacking using site-specific recombination or genome editing tools.
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Affiliation(s)
- Yang Zhao
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida - IFAS, Gainesville, FL, 32611, USA
| | - Jae Y Kim
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida - IFAS, Gainesville, FL, 32611, USA
- Department of Plant Resources, College of Industrial Science, Kongju National University, Yesan, 32439, Republic of Korea
| | - Ratna Karan
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida - IFAS, Gainesville, FL, 32611, USA
| | - Je H Jung
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida - IFAS, Gainesville, FL, 32611, USA
- Smart Farm Research Center, Institute of Natural Products, Korea Institute of Science and Technology (KIST), Gangwon-do, 25451, Republic of Korea
| | - Bhuvan Pathak
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida - IFAS, Gainesville, FL, 32611, USA
| | - Bruce Williamson
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida - IFAS, Gainesville, FL, 32611, USA
| | - Baskaran Kannan
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida - IFAS, Gainesville, FL, 32611, USA
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Florida - IFAS, Gainesville, FL, 32611, USA
| | - Duoduo Wang
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida - IFAS, Gainesville, FL, 32611, USA
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Florida - IFAS, Gainesville, FL, 32611, USA
| | - Chunyang Fan
- Syngenta Crop Protection, LLC, Research Triangle Park, NC, 27709, USA
| | - Wenjin Yu
- Syngenta Crop Protection, LLC, Research Triangle Park, NC, 27709, USA
| | - Shujie Dong
- Syngenta Crop Protection, LLC, Research Triangle Park, NC, 27709, USA
| | - Vibha Srivastava
- Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Fredy Altpeter
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida - IFAS, Gainesville, FL, 32611, USA.
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Florida - IFAS, Gainesville, FL, 32611, USA.
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26
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Panevska A, Hodnik V, Skočaj M, Novak M, Modic Š, Pavlic I, Podržaj S, Zarić M, Resnik N, Maček P, Veranič P, Razinger J, Sepčić K. Pore-forming protein complexes from Pleurotus mushrooms kill western corn rootworm and Colorado potato beetle through targeting membrane ceramide phosphoethanolamine. Sci Rep 2019; 9:5073. [PMID: 30911026 PMCID: PMC6433908 DOI: 10.1038/s41598-019-41450-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 03/08/2019] [Indexed: 01/13/2023] Open
Abstract
Aegerolysins ostreolysin A (OlyA) and pleurotolysin A (PlyA), and pleurotolysin B (PlyB) with the membrane-attack-complex/perforin domain are proteins from the mushroom genus Pleurotus. Upon binding to sphingomyelin/cholesterol-enriched membranes, OlyA and PlyA can recruit PlyB to form multimeric bi-component transmembrane pores. Recently, Pleurotus aegerolysins OlyA, PlyA2 and erylysin A (EryA) were demonstrated to preferentially bind to artificial lipid membranes containing 50 mol% ceramide phosphoethanolamine (CPE), the main sphingolipid in invertebrate cell membranes. In this study, we demonstrate that OlyA6, PlyA2 and EryA bind to insect cells and to artificial lipid membranes with physiologically relevant CPE concentrations. Moreover, these aegerolysins permeabilize these membranes when combined with PlyB. These aegerolysin/PlyB complexes show selective toxicity toward western corn rootworm larvae and adults and Colorado potato beetle larvae. These data strongly suggest that these aegerolysin/PlyB complexes recognize CPE as their receptor molecule in the insect midgut. This mode of binding is different from those described for similar aegerolysin-based bacterial complexes, or other Bacillus thuringiensis Cry toxins, which have protein receptors. Targeting of Pleurotus aegerolysins to CPE and formation of transmembrane pores in concert with PlyB suggest the use of aegerolysin/PlyB complexes as novel biopesticides for the control of western corn rootworm and Colorado potato beetle.
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Affiliation(s)
- Anastasija Panevska
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - Vesna Hodnik
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - Matej Skočaj
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - Maruša Novak
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - Špela Modic
- Agricultural Institute of Slovenia, Hacquetova 17, 1000, Ljubljana, Slovenia
| | - Ivana Pavlic
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia.,Department of Biotechnology, University of Rijeka, Radmile Matejčić 2, 51000, Rijeka, Croatia
| | - Sara Podržaj
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - Miki Zarić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - Nataša Resnik
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia
| | - Peter Maček
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - Peter Veranič
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia
| | - Jaka Razinger
- Agricultural Institute of Slovenia, Hacquetova 17, 1000, Ljubljana, Slovenia.
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia.
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27
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Pereira AE, Coudron TA, Shelby K, French BW, Bernklau EJ, Bjostad LB, Hibbard BE. Comparative Susceptibility of Western Corn Rootworm (Coleoptera: Chrysomelidae) Neonates to Selected Insecticides and Bt Proteins in the Presence and Absence of Feeding Stimulants. JOURNAL OF ECONOMIC ENTOMOLOGY 2019; 112:842-851. [PMID: 30668732 DOI: 10.1093/jee/toy415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Indexed: 06/09/2023]
Abstract
The susceptibility of western corn rootworm, Diabrotica virgifera virgifera LeConte, larvae to nine insecticides from five different classes and to Bt proteins eCry3.1Ab and mCry3A in the presence or absence of feeding stimulants, was estimated in filter paper and diet toxicity assays, respectively. The use of a synthetic feeding stimulant blend of the sugars glucose, sucrose, and fructose plus linoleic acid at a ratio of 30:4:4:0.3 mg/ml of distilled water was evaluated to determine whether they increase the efficacy of insecticides and Bt proteins. The efficacy of thiamethoxam diluted in solutions with feeding stimulants was significantly increased when compared to thiamethoxam dilutions in water (>60-fold). Differences in the efficacy of the other insecticide classes when diluted in feeding stimulant solutions were no greater than fivefold when compared to the insecticides diluted in water. The presence of corn root juice as a natural feeding stimulant diminished toxicity of the insecticides, except for thiamethoxam, even though larval fresh weight was higher when fed on root juice compared to feeding stimulant or water. The use of feeding stimulants in diet toxicity assays did not enhance efficacy of eCry3.1Ab nor mCry3A proteins. Feeding stimulants can be recommended in combination with thiamethoxam to increase larval mortality. These results are discussed in terms of applicability of feeding stimulants to improve susceptibility of western corn rootworm larvae to pesticides in general.
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Affiliation(s)
| | - Thomas A Coudron
- Biological Control of Insect Research Laboratory, USDA/ARS, Columbia, MO
| | - Kent Shelby
- Biological Control of Insect Research Laboratory, USDA/ARS, Columbia, MO
| | - B Wade French
- North Central Agricultural Research Laboratory, USDA/ARS, Brookings, SD
| | - Elisa J Bernklau
- Department of Bioagricultural Sciences & Pest Management, Colorado State University, Fort Collins, CO
| | - Louis B Bjostad
- Department of Bioagricultural Sciences & Pest Management, Colorado State University, Fort Collins, CO
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28
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Hou J, Cong R, Izumi-Willcoxon M, Ali H, Zheng Y, Bermudez E, McDonald M, Nelson M, Yamamoto T. Engineering of Bacillus thuringiensis Cry Proteins to Enhance the Activity against Western Corn Rootworm. Toxins (Basel) 2019; 11:toxins11030162. [PMID: 30875860 PMCID: PMC6468356 DOI: 10.3390/toxins11030162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/07/2019] [Accepted: 03/10/2019] [Indexed: 12/02/2022] Open
Abstract
A novel Bacillus thuringiensis Cry protein, Cry8Hb, active against Diabrotica virgifera virgifera (Western corn rootworm, WCRW) was discovered. Unexpectedly, the anti-rootworm activity of the Cry8Hb toxin was enhanced significantly by fusing Escherichia coli maltose binding protein (MBP) to this Cry toxin. While the exact mechanism of the activity enhancement remains indefinite, it is probable that the enhancement is a result of increased solubility of the MBP-Cry8Hb fusion in the rootworm midgut. This hypothesis was examined using a synthetic Cry3 protein called IP3-1, which was not soluble at a neutral pH like Cry8Hb and marginally active to WCRW. When IP3-1 was fused to MBP, its anti-WCRW activity was enhanced 13-fold. To further test the hypothesis, DNA shuffling was performed on IP3-1 to increase the solubility without MBP. Screening of shuffled libraries found six new IP3 variants showing very high anti-WCRW activity without MBP. Sequence and 3D structure analysis of those highly active, shuffled IP3 variants revealed several charge-altering mutations such as Lys to Glu on the putative MBP-attaching side of the IP3 molecule. It is likely that those mutations make the protein acidic to substitute the functions of MBP including enhancing the solubility of IP3 at a neutral pH.
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Affiliation(s)
- Jingtong Hou
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Ruth Cong
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Michi Izumi-Willcoxon
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Hana Ali
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Yi Zheng
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Ericka Bermudez
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Mark McDonald
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Mark Nelson
- Corteva Agrisciences, Agriculture Division of DowDuPont, Johnston, IA 50131, USA.
| | - Takashi Yamamoto
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
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29
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Susceptible and mCry3A resistant corn rootworm larvae killed by a non-hemolytic Bacillus thuringiensis Cyt1Aa mutant. Sci Rep 2018; 8:17805. [PMID: 30546034 PMCID: PMC6292897 DOI: 10.1038/s41598-018-36205-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 11/16/2018] [Indexed: 11/12/2022] Open
Abstract
The western corn rootworm (WCR) Diabrotica virgifera virgifera causes substantial damage in corn. Genetically modified (GM) plants expressing some Bacillus thuringiensis (Bt) insecticidal Cry proteins efficiently controlled this pest. However, changes in WCR susceptibility to these Bt traits have evolved and identification of insecticidal proteins with different modes of action against WCR is necessary. We show here for the first time that Cyt1Aa from Bt exhibits toxicity against WCR besides to the dipteran Aedes aegypti larvae. Cyt1Aa is a pore-forming toxin that shows no cross-resistance with mosquitocidal Cry toxins. We characterized different mutations in helix α-A from Cyt1Aa. Two mutants (A61C and A59C) exhibited reduced or absent hemolytic activity but retained toxicity to A. aegypti larvae, suggesting that insecticidal and hemolytic activities of Cyt1Aa are independent activities. These mutants were still able to form oligomers in synthetic lipid vesicles and to synergize Cry11Aa toxicity. Remarkably, mutant A61C showed a five-fold increase insecticidal activity against mosquito and almost 11-fold higher activity against WCR. Cyt1Aa A61C mutant was as potent in killing WCR that were selected for resistance to mCry3A as it was against unselected WCR indicating that this toxin could be a useful resistance management option in the control of WCR.
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30
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Geisert RW, Cheruiyot DJ, Hibbard BE, Shapiro-Ilan DI, Shelby KS, Coudron TA. Comparative Assessment of Four Steinernematidae and Three Heterorhabditidae Species for Infectivity of Larval Diabrotica Virgifera Virgifera. JOURNAL OF ECONOMIC ENTOMOLOGY 2018; 111:542-548. [PMID: 29365135 DOI: 10.1093/jee/tox372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Larval Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) were exposed to seven different entomopathogenic nematode species to test their potential infectivity in a laboratory setting. Known D. virgifera-infecting nematode species Heterorhabditis bacteriophora Poinar, Heterorhabditis megidis Poinar, Jackson & Klein, Steinernema feltiae Filipjev, and Steinernema carpocapsae Weiser were tested in a concerted experiment alongside Steinernema diaprepesi Nguyen & Duncan, Steinernema riobrave Cabanillas, Poinar & Raulston, and a Missouri wild-type H. bacteriophora which have not been previously tested on D. virgifera. The species S. rarum Doucet was tested separately for D. virgifera infectivity. Third-instar D. virgifera were exposed to either 60 or 120 nematodes per larva for 6 d. Following exposure, mortality was recorded and larvae were examined to determine the presence of active nematode infections. Results indicated a significantly higher proportion of larvae with active infections from the Heterorhabditidae species and S. diaprepesi than the other Steinernematidae species for both exposure rates; mortality data indicated a similar trend. Steinernema rarum showed almost no infectivity in laboratory experiments.
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Affiliation(s)
- Ryan W Geisert
- Biological Control of Insects Research Laboratory, USDA-Agricultural Research Service, Columbia, MO
| | - Dorothy J Cheruiyot
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA
| | - Bruce E Hibbard
- Plant Genetics Research Unit, USDA-Agricultural Research Service, Columbia, MO
| | - David I Shapiro-Ilan
- Southeastern Fruit and Tree Nut Research Laboratory, USDA-Agricultural Research Service, Byron, GA
| | - Kent S Shelby
- Biological Control of Insects Research Laboratory, USDA-Agricultural Research Service, Columbia, MO
| | - Thomas A Coudron
- Biological Control of Insects Research Laboratory, USDA-Agricultural Research Service, Columbia, MO
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31
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Wei J, O'Rear J, Schellenberger U, Rosen BA, Park Y, McDonald MJ, Zhu G, Xie W, Kassa A, Procyk L, Perez Ortega C, Zhao J, Yalpani N, Crane VC, Diehn SH, Sandahl GA, Nelson ME, Lu AL, Wu G, Liu L. A selective insecticidal protein from Pseudomonas mosselii for corn rootworm control. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:649-659. [PMID: 28796437 PMCID: PMC5787824 DOI: 10.1111/pbi.12806] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/22/2017] [Accepted: 08/04/2017] [Indexed: 06/07/2023]
Abstract
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. Recombinant PIP-47Aa kills WCR, two other corn rootworm pests (Diabrotica barberi and Diabrotica undecimpunctata howardi) and two other beetle species (Diabrotica speciosa and Phyllotreta cruciferae), but it was not toxic to the spotted lady beetle (Coleomegilla maculata) or seven species of Lepidoptera and Hemiptera. Transgenic corn plants expressing PIP-47Aa show significant protection from root damage by WCR. PIP-47Aa kills a WCR strain resistant to mCry3A and does not share rootworm midgut binding sites with mCry3A or AfIP-1A/1B from Alcaligenes that acts like Cry34Ab1/Cry35Ab1. Our results indicate that PIP-47Aa is a novel insecticidal protein for controlling the corn rootworm pests.
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Affiliation(s)
| | | | - Ute Schellenberger
- DuPont PioneerHaywardCAUSA
- Present address:
TeneoBio Inc.1490 O'Brien DriveMenlo ParkCA94025USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Lu Liu
- DuPont PioneerHaywardCAUSA
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32
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A Maize Inbred Exhibits Resistance Against Western Corn Rootwoorm, Diabrotica virgifera virgifera. J Chem Ecol 2017; 43:1109-1123. [PMID: 29151152 DOI: 10.1007/s10886-017-0904-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 10/26/2017] [Accepted: 11/06/2017] [Indexed: 01/04/2023]
Abstract
Insect resistance against root herbivores like the western corn rootworm (WCR, Diabrotica virgifera virgifera) is not well understood in non-transgenic maize. We studied the responses of two American maize inbreds, Mp708 and Tx601, to WCR infestation using biomechanical, molecular, biochemical analyses, and laser ablation tomography. Previous studies performed on several inbreds indicated that these two maize genotypes differed in resistance to pests including fall armyworm (Spodoptera frugiperda) and WCR. Our data confirmed that Mp708 shows resistance against WCR, and demonstrates that the resistance mechanism is based in a multi-trait phenotype that includes increased resistance to cutting in nodal roots, stable root growth during insect infestation, constitutive and induced expression of known herbivore-defense genes, including ribosomal inhibitor protein 2 (rip2), terpene synthase 23 (tps23) and maize insect resistance cysteine protease-1 (mir1), as well high constitutive levels of jasmonic acid and production of (E)-β-caryophyllene. In contrast, Tx601 is susceptible to WCR. These findings will facilitate the use of Mp708 as a model to explore the wide variety of mechanisms and traits involved in plant defense responses and resistance to herbivory by insects with several different feeding habits.
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Head GP, Carroll MW, Evans SP, Rule DM, Willse AR, Clark TL, Storer NP, Flannagan RD, Samuel LW, Meinke LJ. Evaluation of SmartStax and SmartStax PRO maize against western corn rootworm and northern corn rootworm: efficacy and resistance management. PEST MANAGEMENT SCIENCE 2017; 73:1883-1899. [PMID: 28195683 DOI: 10.1002/ps.4554] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 02/02/2017] [Accepted: 02/09/2017] [Indexed: 05/08/2023]
Abstract
BACKGROUND Cases of western corn rootworm (WCR) field-evolved resistance to Cry3Bb1 and other corn rootworm (CRW) control traits have been reported. Pyramid products expressing multiple CRW traits can delay resistance compared to single trait products. We used field studies to assess the pyramid CRW corn products, SmartStax (expressing Cry3Bb1 and Cry34Ab1/Cry35Ab1) and SmartStax PRO (expressing Cry3Bb1, Cry34Ab1/Cry35Ab1 and DvSnf7), at locations with high WCR densities and possible Cry3Bb1 resistance, and to assess the reduction in adult emergence attributable to DvSnf7 and other traits. Insect resistance models were used to assess durability of SmartStax and SmartStax PRO to WCR resistance. RESULTS SmartStax significantly reduced root injury compared to non-CRW-trait controls at all but one location with measurable WCR pressure, while SmartStax PRO significantly reduced root injury at all locations, despite evidence of Cry3Bb1 resistance at some locations. The advantage of SmartStax PRO over SmartStax in reducing root damage was positively correlated with root damage on non-CRW-trait controls. DvSnf7 was estimated to reduce WCR emergence by approximately 80-95%, which modeling indicated will improve durability of Cry3Bb1 and Cry34Ab1/Cry35Ab1 compared to SmartStax. CONCLUSION The addition of DvSnf7 in SmartStax PRO can reduce root damage under high WCR densities and prolong Cry3Bb1 and Cry34Ab1/Cry35Ab1 durability. © 2017 Society of Chemical Industry.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Lance J Meinke
- Department of Entomology, University of Nebraska, Lincoln, NE, USA
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Yalpani N, Altier D, Barry J, Kassa A, Nowatzki TM, Sethi A, Zhao JZ, Diehn S, Crane V, Sandahl G, Guan R, Poland B, Perez Ortega C, Nelson ME, Xie W, Liu L, Wu G. An Alcaligenes strain emulates Bacillus thuringiensis producing a binary protein that kills corn rootworm through a mechanism similar to Cry34Ab1/Cry35Ab1. Sci Rep 2017; 7:3063. [PMID: 28596570 PMCID: PMC5465095 DOI: 10.1038/s41598-017-03544-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 04/28/2017] [Indexed: 11/15/2022] Open
Abstract
Crops expressing Bacillus thuringiensis (Bt)-derived insecticidal protein genes have been commercially available for over 15 years and are providing significant value to growers. However, there remains the need for alternative insecticidal actives due to emerging insect resistance to certain Bt proteins. A screen of bacterial strains led to the discovery of a two-component insecticidal protein named AfIP-1A/1B from an Alcaligenes faecalis strain. This protein shows selectivity against coleopteran insects including western corn rootworm (WCR). Transgenic maize plants expressing AfIP-1A/1B demonstrate strong protection from rootworm injury. Surprisingly, although little sequence similarity exists to known insecticidal proteins, efficacy tests using WCR populations resistant to two different Cry proteins show that AfIP-1A/1B and mCry3A differ in their mode of action while AfIP-1A/1B and the binary Cry34Ab1/Cry35Ab1 protein share a similar mode. These findings are supported by results of competitive binding assays and the similarity of the x-ray structure of AfIP-1A to Cry34Ab1. Our work indicates that insecticidal proteins obtained from a non-Bt bacterial source can be useful for developing genetically modified crops and can function similarly to familiar proteins from Bt.
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Affiliation(s)
| | - Dan Altier
- DuPont Pioneer, Johnston, IA, 50131, USA
| | | | | | | | - Amit Sethi
- DuPont Pioneer, Johnston, IA, 50131, USA
| | | | | | | | | | - Rongjin Guan
- Nexomics Biosciences, Bordentown, NJ, 08505, USA
| | | | | | | | | | - Lu Liu
- DuPont Pioneer, Hayward, CA, 94545, USA
| | - Gusui Wu
- DuPont Pioneer, Johnston, IA, 50131, USA
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Butala M, Novak M, Kraševec N, Skočaj M, Veranič P, Maček P, Sepčić K. Aegerolysins: Lipid-binding proteins with versatile functions. Semin Cell Dev Biol 2017; 72:142-151. [PMID: 28506897 DOI: 10.1016/j.semcdb.2017.05.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 04/13/2017] [Accepted: 05/11/2017] [Indexed: 01/21/2023]
Abstract
Proteins of the aegerolysin family span many kingdoms of life. They are relatively widely distributed in bacteria and fungi, but also appear in plants, protozoa and insects. Despite being produced in abundance in cells at specific developmental stages and present in secretomes, only a few aegerolysins have been studied in detail. In particular, their organism-specific physiological roles are intriguing. Here, we review published findings to date on the distribution, molecular interactions and biological activities of this family of structurally and functionally versatile proteins, the aegerolysins.
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Affiliation(s)
- Matej Butala
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Maruša Novak
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Nada Kraševec
- National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Matej Skočaj
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Peter Veranič
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Peter Maček
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia.
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia.
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Bowling AJ, Pence HE, Li H, Tan SY, Evans SL, Narva KE. Histopathological Effects of Bt and TcdA Insecticidal Proteins on the Midgut Epithelium of Western Corn Rootworm Larvae (Diabrotica virgifera virgifera). Toxins (Basel) 2017; 9:toxins9050156. [PMID: 28481307 PMCID: PMC5450704 DOI: 10.3390/toxins9050156] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 04/20/2017] [Accepted: 04/28/2017] [Indexed: 01/21/2023] Open
Abstract
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. Cry34/35Ab1 is a pore forming toxin, but the specific effects of Cry34/35Ab1 on WCR cells and tissues have not been well characterized microscopically, and the overall histopathology is poorly understood. Using high-resolution resin-based histopathology methods, the effects of Cry34/35Ab1 as well as Cry3Aa1, Cry6Aa1, and the Photorhabdus toxin complex protein TcdA have been directly visualized and documented. Clear symptoms of intoxication were observed for all insecticidal proteins tested, including swelling and sloughing of enterocytes, constriction of midgut circular muscles, stem cell activation, and obstruction of the midgut lumen. These data demonstrate the effects of these insecticidal proteins on WCR midgut cells, and the collective response of the midgut to intoxication. Taken together, these results advance our understanding of the insect cell biology and pathology of these insecticidal proteins, which should further the field of insect resistance traits and corn rootworm management.
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Affiliation(s)
| | | | - Huarong Li
- Dow AgroSciences, Indianapolis, IN 46268, USA.
| | - Sek Yee Tan
- Dow AgroSciences, Indianapolis, IN 46268, USA.
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Wang H, Eyun SI, Arora K, Tan SY, Gandra P, Moriyama E, Khajuria C, Jurzenski J, Li H, Donahue M, Narva K, Siegfried B. Patterns of Gene Expression in Western Corn Rootworm (Diabrotica virgifera virgifera) Neonates, Challenged with Cry34Ab1, Cry35Ab1 and Cry34/35Ab1, Based on Next-Generation Sequencing. Toxins (Basel) 2017; 9:toxins9040124. [PMID: 28358336 PMCID: PMC5408198 DOI: 10.3390/toxins9040124] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 03/22/2017] [Accepted: 03/27/2017] [Indexed: 11/16/2022] Open
Abstract
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. No DETs were identified in the Cry35Ab1 treatment. Putative Bt binding receptors previously identified in other insect species were not identified in DETs in this study. The majority of DETs (75% with Cry34Ab1 and 68.3% with Cry34/35Ab1 treatments) had no significant hits in the NCBI nr database. In addition, 92 DETs were shared between Cry34Ab1 and Cry34/35Ab1 treatments. Further analysis revealed that the most abundant DETs in both Cry34Ab1 and Cry34/35Ab1 treatments were associated with binding and catalytic activity. Results from this study confirmed the nature of these binary toxins against WCR larvae and provide a fundamental profile of expression pattern of genes in response to challenge of the Cry34/35Ab1 toxin, which may provide insight into potential resistance mechanisms.
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Affiliation(s)
- Haichuan Wang
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE 68583-0915, USA.
| | - Seong-Il Eyun
- Center for Biotechnology, School of Biological Sciences, UNL, Lincoln, NE 68583, USA.
| | | | - Sek Yee Tan
- Dow AgroSciences, Indianapolis, IN 46268, USA.
| | | | - Etsuko Moriyama
- Center for Biotechnology, School of Biological Sciences, UNL, Lincoln, NE 68583, USA.
| | | | - Jessica Jurzenski
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE 68583-0915, USA.
| | - Huarong Li
- Dow AgroSciences, Indianapolis, IN 46268, USA.
| | | | - Ken Narva
- Dow AgroSciences, Indianapolis, IN 46268, USA.
| | - Blair Siegfried
- Entomology and Nematology Department, University of Florida, Gainesville, FL 32611-0620, USA.
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Sampson K, Zaitseva J, Stauffer M, Vande Berg B, Guo R, Tomso D, McNulty B, Desai N, Balasubramanian D. Discovery of a novel insecticidal protein from Chromobacterium piscinae , with activity against Western Corn Rootworm, Diabrotica virgifera virgifera. J Invertebr Pathol 2017; 142:34-43. [DOI: 10.1016/j.jip.2016.10.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 09/19/2016] [Accepted: 10/17/2016] [Indexed: 02/06/2023]
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Graser G, Walters FS, Burns A, Sauve A, Raybould A. A General Approach to Test for Interaction Among Mixtures of Insecticidal Proteins Which Target Different Orders of Insect Pests. JOURNAL OF INSECT SCIENCE (ONLINE) 2017; 17:3065810. [PMID: 28355479 PMCID: PMC5416900 DOI: 10.1093/jisesa/iex003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Indexed: 05/31/2023]
Abstract
A shift toward transgenic crops which produce combinations of insecticidal proteins has increased the interest (Syngenta Seeds, Inc., Minnetonka, MN) in studying the potential for interactions amongst those proteins. We present a general testing method which accommodates proteins with nonoverlapping spectrums of activity. Our sequential testing approach first investigates groups of the proteins with overlapping activity; e.g., proteins active against Lepidoptera or Coleoptera, respectively. The Colby method is used to test for interactions within each respective group. Subsequently, the mixture of proteins within each group is regarded as a single entity and tests for interactions between the groups (when combined) is conducted using analysis of variance. We illustrate the method using Cry1Ab, Vip3Aa20, and Cry1F (a mixture of proteins active against Lepidoptera), and mCry3A and eCry3.1Ab (a mixture of proteins active against Coleoptera). These insecticidal proteins are produced by Bt11 × MIR162 × TC1507 × MIR604 × 5307 maize. We detected no interactions between Cry1Ab, Vip3Aa20, and Cry1F in tests using larvae of two different lepidopteran species, and possible slight antagonism between mCry3A and eCry3.1Ab with a coleopteran test species. We detected no effect of (eCry3.1Ab + mCry3A) on the potency of (Cry1Ab + Vip3Aa20 + Cry1F) to lepidopteran larvae, and no effect of (Cry1Ab + Vip3Aa20 + Cry1F) on the potency of (mCry3A + eCry3.1Ab) to coleopteran larvae. We discuss implications of these results for characterization of Bt11 × MIR162 × TC1507 × MIR604 × 5307 maize, and the value of the method for characterizing other transgenic crops that produce several insecticidal proteins.
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Affiliation(s)
- Gerson Graser
- Syngenta Crop Protection, Product Safety, LLC, PO Box 12257, 9 Davis Drive, Durham, NC 27709, USA
| | - Frederick S. Walters
- Syngenta Crop Protection, Product Safety, LLC, PO Box 12257, 9 Davis Drive, Durham, NC 27709, USA
| | - Andrea Burns
- Syngenta Crop Protection, Product Safety, LLC, PO Box 12257, 9 Davis Drive, Durham, NC 27709, USA
| | - Alaina Sauve
- Syngenta Crop Protection, Product Safety, LLC, PO Box 12257, 9 Davis Drive, Durham, NC 27709, USA
| | - Alan Raybould
- Syngenta Crop Protection AG, Regulatory Affairs, Schwarzwaldallee 215, Basel, CH-4058, Switzerland
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Schellenberger U, Oral J, Rosen BA, Wei JZ, Zhu G, Xie W, McDonald MJ, Cerf DC, Diehn SH, Crane VC, Sandahl GA, Zhao JZ, Nowatzki TM, Sethi A, Liu L, Pan Z, Wang Y, Lu AL, Wu G, Liu L. A selective insecticidal protein from Pseudomonas for controlling corn rootworms. Science 2016; 354:634-637. [DOI: 10.1126/science.aaf6056] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 09/09/2016] [Indexed: 01/29/2023]
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Geisert RW, Hibbard BE. Evaluation of Potential Fitness Costs Associated With eCry3.1Ab Resistance in Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:1853-1858. [PMID: 27151470 DOI: 10.1093/jee/tow095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 04/10/2016] [Indexed: 06/05/2023]
Abstract
Both an eCry3.1Ab-selected and paired control western corn rootworm, Diabrotica virgifera virgifera LeConte, colony were tested for adult longevity, egg oviposition, egg viability, and larval development in order to evaluate the potential fitness costs associated with eCry3.1Ab resistance. Adult longevity experiments were conducted by pairing virgin males and females together in plastic boxes supplied with food, water, and ovipositional medium and observed for survival time. Eggs were also collected from the ovipositional medium once a week to determine average egg oviposition and egg viability. Larval development time experiments were conducted by infesting seedling assays with 25 neonate larvae and recording larval recovery after several days. Adult longevity, average egg oviposition, and larval development time results indicated a lack of fitness costs associated with eCry3.1Ab resistance in the western corn rootworm. Results of egg viability indicated a fitness advantage for the eCry3.1Ab-selected colony with a significantly higher egg hatch than the control.
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Affiliation(s)
- Ryan W Geisert
- USDA-ARS, 1503 S. Providence, Research PK, Columbia, MO 65211 ,
| | - Bruce E Hibbard
- USDA-ARS, 205 Curtis Hall, University of Missouri, Columbia, MO 65211
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Narva KE, Wang NX, Herman R. Safety considerations derived from Cry34Ab1/Cry35Ab1 structure and function. J Invertebr Pathol 2016; 142:27-33. [PMID: 27480405 DOI: 10.1016/j.jip.2016.07.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/15/2016] [Accepted: 07/28/2016] [Indexed: 11/16/2022]
Abstract
Insecticidal proteins developed for in-plant protection against crop pests undergo extensive safety testing during the product development process. Safety considerations for insecticidal proteins expressed in crops follow recommended, science-based guidelines and specific studies are conducted on a case by case basis. Corn events expressing Bacillus thuringiensis (Bt) Cry34Ab1 and Cry35Ab1 were developed to protect maize from Diabrotica virgifera virgifera (western corn rootworm) feeding damage. The protein crystal structures of Cry34Ab1 and Cry35Ab1 are different from the more common three-domain Cry or Vip3 proteins expressed in insect resistant maize varieties. Cry34Ab1 is a single domain protein that folds into a beta sandwich structure that resembles membrane-active proteins, including several cytolysins, from a variety of natural sources. Cry35Ab1 has two domains, one domain with structural relatedness to sugar binding motifs and a second domain with an extended beta sheet structure that is clearly related to beta pore forming proteins, some of which are insecticidal, e.g. B. sphaericus BinA/BinB. In this review we discuss Cry34Ab1/Cry35Ab1 structure and function in the context of protein safety studies for insect resistant crops.
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Affiliation(s)
- Kenneth E Narva
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN 46268, USA.
| | - Nick X Wang
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN 46268, USA
| | - Rod Herman
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN 46268, USA
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Conditions for homogeneous preparation of stable monomeric and oligomeric forms of activated Vip3A toxin from Bacillus thuringiensis. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 46:257-264. [DOI: 10.1007/s00249-016-1162-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/16/2016] [Accepted: 07/16/2016] [Indexed: 10/21/2022]
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Geisert RW, Ellersieck MR, Hibbard BE. Tolerance of eCry3.1Ab in Reciprocal Cross Offspring of eCry3.1Ab-Selected and Control Colonies of Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:815-820. [PMID: 26628501 DOI: 10.1093/jee/tov335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Two new insect colonies were created by separating virgin western corn rootworm, Diabrotica virgifera virgifera LeConte, males and females from both a selected laboratory colony that was being reared on eCry3.1Ab-expressing corn (Zea mays L.) and a control colony reared on its near-isoline corn. Females from the selected colony were paired with males of the control colony and vice versa to create both a selected female by control male colony (Sel♀) and control female by selected male colony (Con♀). Both colonies along with their parental colonies (eCry3.1Ab-selected and control) were evaluated on eCry3.1Ab-expressing corn and its near-isoline in seedling assays. Larvae from each colony were also used in diet toxicity experiments in order to determine the LC50 and EC50 values for the eCry3.1Ab toxin for each. Statistical analysis of seedling assay experiments did not indicate any significant colony×corn interaction but did show a significant main effect of corn type for both larval recovery and larval head capsule widths. Results from the diet toxicity assays showed the control colony to have a significantly lower LC50 value than the selected and cross colonies and a significantly lower EC50 than the selected and Con♀ colonies. Calculations of dominance values (h) of eCry3.1Ab resistance traits from seedling assays indicated that the two reciprocal cross colonies have a dominance value (h) of ∼1, suggesting dominance of the eCry3.1Ab resistance trait.
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Frank DL, Kurtz R, Tinsley NA, Gassmann AJ, Meinke LJ, Moellenbeck D, Gray ME, Bledsoe LW, Krupke CH, Estes RE, Weber P, Hibbard BE. Effect of Seed Blends and Soil-Insecticide on Western and Northern Corn Rootworm Emergence from mCry3A+eCry3.1Ab Bt Maize. JOURNAL OF ECONOMIC ENTOMOLOGY 2015; 108:1260-1270. [PMID: 26470254 DOI: 10.1093/jee/tov081] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 03/13/2015] [Indexed: 06/05/2023]
Abstract
Seed blends containing various ratios of transgenic Bt maize (Zea mays L.) expressing the mCry3A+eCry3.1Ab proteins and non-Bt maize (near-isoline maize) were deployed alone and in combination with a soil applied pyrethroid insecticide (Force CS) to evaluate the emergence of the western corn rootworm, Diabrotica virgifera virgifera LeConte, in a total of nine field environments across the Midwestern United States in 2010 and 2011. Northern corn rootworm, Diabrotica barberi Smith & Lawrence emergence was also evaluated in four of these environments. Both western and northern corn rootworm beetle emergence from all Bt treatments was significantly reduced when compared with beetle emergence from near-isoline treatments. Averaged across all environments, western corn rootworm beetle emergence from 95:5, 90:10, and 80:20 seed blend ratios of mCry3A+eCry3.1Ab: near-isoline were 2.6-, 4.2-, and 6.7-fold greater than that from the 100:0 ratio treatment. Northern corn rootworm emergence from the same seed blend treatments resulted in 2.8-, 3.2-, and 4.2-fold more beetles than from the 100:0 treatment. The addition of Force CS (tefluthrin) significantly reduced western corn rootworm beetle emergence for each of the three treatments to which it was applied. Force CS also significantly delayed the number of days to 50% beetle emergence in western corn rootworms. Time to 50% beetle emergence in the 100% mCry3A+eCry3.1Ab treatment with Force CS was delayed 13.7 d when compared with western corn rootworm beetle emergence on near-isoline corn. These data are discussed in terms of rootworm resistance management.
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Affiliation(s)
- Daniel L Frank
- USDA-ARS, Plant Genetics Research Unit, 205 Curtis Hall, University of Missouri, Columbia, MO 65211, USA Present address: Extension Service, Agriculture and Natural Resources Unit, West Virginia University, Morgantown, WV 26506, USA
| | - Ryan Kurtz
- Syngenta Biotechnology, Inc., 3054 E. Cornwallis Rd., Research Triangle Park, NC 27709, USA Present address: Cotton Incorporated, 6399 Weston Pkwy, Cary, NC 27513, USA
| | - Nicholas A Tinsley
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801, USA
| | - Aaron J Gassmann
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Lance J Meinke
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA
| | - Daniel Moellenbeck
- DM Crop Research Group, Inc., 700 North 3rd St., P.O. Box 53, Polk City, IA 50226, USA
| | - Michael E Gray
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801, USA
| | - Larry W Bledsoe
- Department of Entomology, Purdue University, West Lafayette, IN 47907, USA
| | - Christian H Krupke
- Department of Entomology, Purdue University, West Lafayette, IN 47907, USA
| | - Ronald E Estes
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801, USA
| | - Patrick Weber
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Bruce E Hibbard
- USDA-ARS, Plant Genetics Research Unit, 205 Curtis Hall, University of Missouri, Columbia, MO 65211, USA
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Kelker MS, Berry C, Evans SL, Pai R, McCaskill DG, Wang NX, Russell JC, Baker MD, Yang C, Pflugrath JW, Wade M, Wess TJ, Narva KE. Structural and biophysical characterization of Bacillus thuringiensis insecticidal proteins Cry34Ab1 and Cry35Ab1. PLoS One 2014; 9:e112555. [PMID: 25390338 PMCID: PMC4229197 DOI: 10.1371/journal.pone.0112555] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 10/07/2014] [Indexed: 11/18/2022] Open
Abstract
Bacillus thuringiensis strains are well known for the production of insecticidal proteins upon sporulation and these proteins are deposited in parasporal crystalline inclusions. The majority of these insect-specific toxins exhibit three domains in the mature toxin sequence. However, other Cry toxins are structurally and evolutionarily unrelated to this three-domain family and little is known of their three dimensional structures, limiting our understanding of their mechanisms of action and our ability to engineer the proteins to enhance their function. Among the non-three domain Cry toxins, the Cry34Ab1 and Cry35Ab1 proteins from B. thuringiensis strain PS149B1 are required to act together to produce toxicity to the western corn rootworm (WCR) Diabrotica virgifera virgifera Le Conte via a pore forming mechanism of action. Cry34Ab1 is a protein of ∼14 kDa with features of the aegerolysin family (Pfam06355) of proteins that have known membrane disrupting activity, while Cry35Ab1 is a ∼44 kDa member of the toxin_10 family (Pfam05431) that includes other insecticidal proteins such as the binary toxin BinA/BinB. The Cry34Ab1/Cry35Ab1 proteins represent an important seed trait technology having been developed as insect resistance traits in commercialized corn hybrids for control of WCR. The structures of Cry34Ab1 and Cry35Ab1 have been elucidated to 2.15 Å and 1.80 Å resolution, respectively. The solution structures of the toxins were further studied by small angle X-ray scattering and native electrospray ion mobility mass spectrometry. We present here the first published structure from the aegerolysin protein domain family and the structural comparisons of Cry34Ab1 and Cry35Ab1 with other pore forming toxins.
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Affiliation(s)
- Matthew S. Kelker
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Colin Berry
- Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Steven L. Evans
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Reetal Pai
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | | | - Nick X. Wang
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Joshua C. Russell
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Matthew D. Baker
- Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Cheng Yang
- Rigaku Americas Corporation, The Woodlands, Texas, United States of America
| | - J. W. Pflugrath
- Rigaku Americas Corporation, The Woodlands, Texas, United States of America
| | - Matthew Wade
- School of Optometry & Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Tim J. Wess
- School of Optometry & Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Kenneth E. Narva
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
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Validation of reference housekeeping genes for gene expression studies in western corn rootworm (Diabrotica virgifera virgifera). PLoS One 2014; 9:e109825. [PMID: 25356627 PMCID: PMC4214676 DOI: 10.1371/journal.pone.0109825] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 09/10/2014] [Indexed: 11/19/2022] Open
Abstract
Quantitative Real-time PCR (qRT-PCR) is a powerful technique to investigate comparative gene expression. In general, normalization of results using a highly stable housekeeping gene (HKG) as an internal control is recommended and necessary. However, there are several reports suggesting that regulation of some HKGs is affected by different conditions. The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a serious pest of corn in the United States and Europe. The expression profile of target genes related to insecticide exposure, resistance, and RNA interference has become an important experimental technique for study of western corn rootworms; however, lack of information on reliable HKGs under different conditions makes the interpretation of qRT-PCR results difficult. In this study, four distinct algorithms (Genorm, NormFinder, BestKeeper and delta-CT) and five candidate HKGs to genes of reference (β-actin; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; β-tubulin; RPS9, ribosomal protein S9; EF1a, elongation factor-1α) were evaluated to determine the most reliable HKG under different experimental conditions including exposure to dsRNA and Bt toxins and among different tissues and developmental stages. Although all the HKGs tested exhibited relatively stable expression among the different treatments, some differences were noted. Among the five candidate reference genes evaluated, β-actin exhibited highly stable expression among different life stages. RPS9 exhibited the most similar pattern of expression among dsRNA treatments, and both experiments indicated that EF1a was the second most stable gene. EF1a was also the most stable for Bt exposure and among different tissues. These results will enable researchers to use more accurate and reliable normalization of qRT-PCR data in WCR experiments.
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Gindin G, Mendel Z, Levitin B, Kumar P, Levi T, Shahi P, Khasdan V, Weinthal D, Kuznetsova T, Einav M, Kushmaro A, Protasov A, Zaritsky A, Ben-Dov E. The basis for rootstock resilient to Capnodis species: screening for genes encoding δ-endotoxins from Bacillus thuringiensis. PEST MANAGEMENT SCIENCE 2014; 70:1283-1290. [PMID: 24293325 DOI: 10.1002/ps.3694] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 10/22/2013] [Accepted: 11/29/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND Conventional methods often fail to control the flatheaded borers Capnodis spp., major pests of stone fruit trees; the larvae are protected from insecticides and predation because they feed deep in the roots. A potential solution is transgenic trees producing in their roots toxic compounds such as Cry proteins of Bacillus thuringiensis (Bt). RESULTS Toxicities against Capnodis larvae were demonstrated by exploiting a recently designed artificial larval diet and an available collection of field isolated Bt. An isolate of Bt tenebrionis (Btt) from commercial bioinsecticide (Novodor) displayed LC50 and LC95 values of 3.2 and 164 mg g(-1) , respectively, against neonates of Capnodis tenebrionis, whereas values of the most toxic field isolate K-7 were 1.9 and 25.6 mg g(-1) respectively. Weights of surviving larvae after 1 month on diets containing low concentrations of K-7 (0.1-1.0 mg g(-1) ) were lower than on Btt or untreated larvae. K-7 was also toxic against larvae of C. cariosa and C. miliaris and found to harbour genes encoding Cry9Ea-like and Cry23Aa/Cry37Aa binary toxins. CONCLUSION Larvae of Capnodis spp. are susceptible to Bt Cry toxins. Expressing cry genes active against these pests thus seems a feasible solution towards production of transgenic rootstock trees resilient to the pest.
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Affiliation(s)
- Galina Gindin
- Department of Entomology, Agricultural Research Organisation, The Volcani Centre, Bet Dagan, Israel
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Hiltpold I, Adamczyk JJ, Higdon ML, Clark TL, Ellersieck MR, Hibbard BE. Carbon isotope ratios document that the elytra of western corn rootworm (Coleoptera: Chrysomelidae) reflects adult versus larval feeding and later instar larvae prefer Bt corn to alternate hosts. ENVIRONMENTAL ENTOMOLOGY 2014; 43:840-848. [PMID: 24874160 DOI: 10.1603/en13248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In much of the Corn Belt and parts of Europe, the western corn rootworm, Diabrotica virgifera virgifera LeConte, is the most important insect pest of maize. The need for additional basic knowledge of this pest has been highlighted while developing resistance management plans for insecticidal genetically modified crops. This study evaluated the possibility of tracking feeding habits of western corn rootworm larvae using stable carbon isotope signatures. Plants accumulate different ratios of (13)C:(12)C isotopes, usually expressed as δ(13)C, according to whether they use the C3 or C4 photosynthetic pathway. Herbivore biomass is expected to reflect the δ(13)C of the food they eat. For the current experiment, western corn rootworm larvae were grown on different species of plants exhibiting different δ(13)C values. The δ(13)C values were then measured in elytra of emerged beetles. When beetles were unfed, biomass reflected larval feeding. When beetles were fed for 31 d postemergence, δ(13)C values of elytra almost exclusively reflected adult feeding. These results suggest the use of caution in the interpretation of δ(13)C data aiming to document larval diet history when adult feeding history is unknown. The technique was also used to evaluate western corn rootworm larval choice between alternate hosts and maize with and without genetically modified (Bt) traits aimed at their control. Propensity for feeding on alternate hosts versus maize was biased toward feeding on maize regardless whether the maize had Bt or not, suggesting western corn rootworm larvae were not repelled by Bt. These data will be helpful for regulators in interpreting western corn rootworm feeding data on Bt maize.
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Affiliation(s)
- Ivan Hiltpold
- Division of Plant Science, University of Missouri, 205 Curtis Hall, Columbia, MO 65211, USA
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Rudeen ML, Gassmann AJ. Effects of Cry34/35Ab1 corn on the survival and development of western corn rootworm, Diabrotica virgifera virgifera. PEST MANAGEMENT SCIENCE 2013; 69:709-716. [PMID: 23109348 DOI: 10.1002/ps.3425] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 08/24/2012] [Accepted: 09/19/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a major agricultural pest that is managed with transgenic corn, Zea mays L., expressing genes from Bacillus thuringiensis Berliner (Bt). The effects of Bt corn producing Cry34/35Ab1 (event DAS-59122-7) and entomopathogens on the survival and development of larval D. v. virgifera were examined in laboratory, field and greenhouse experiments. RESULTS Larvae preferred non-Bt over Bt corn in a laboratory experiment, and there was higher recovery from non-Bt corn than from Bt corn in a field experiment. In a greenhouse study, survival at 17 days did not differ significantly among non-Bt corn, Bt corn and a blend of Bt and non-Bt corn, but development was delayed on Bt corn. Older larvae fed non-Bt corn had lower survival when entomopathogenic nematodes were added, but no other effects of pathogen were detected. CONCLUSION Bt corn producing Cry34/35Ab1 delayed larval development of D. v. virgifera and deterred feeding. In a mixture of Bt and non-Bt corn, larval development and survival were similar to non-Bt corn alone, suggesting that non-Bt plants in a blended refuge or a pure stand may produce a similar number of adult insects, and that timing of adult emergence may also be similar.
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