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Douris V, Papapostolou KM, Ilias A, Roditakis E, Kounadi S, Riga M, Nauen R, Vontas J. Investigation of the contribution of RyR target-site mutations in diamide resistance by CRISPR/Cas9 genome modification in Drosophila. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 87:127-135. [PMID: 28669775 DOI: 10.1016/j.ibmb.2017.06.013] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/22/2017] [Accepted: 06/26/2017] [Indexed: 06/07/2023]
Abstract
Diamide insecticides are used widely against lepidopteran pests, acting as potent activators of insect Ryanodine Receptors (RyRs) and thus inducing muscle contraction and eventually death. However, resistant phenotypes have recently evolved in the field, associated with the emergence of target site resistance mutations (G4946E/V and I4790M). We investigated the frequency of the mutations found in a resistant population of Tuta absoluta from Greece (G4946V ~79% and I4790M ~21%) and the associated diamide resistance profile: there are very high levels of resistance against chlorantraniliprole (9329-fold) and flubendiamide (4969-fold), but moderate levels against cyantraniliprole (191-fold). To further investigate functionally the contribution of each mutation in the resistant phenotype, we used CRISPR/Cas9 to generate genome modified Drosophila carrying alternative allele combinations, and performed toxicity bioassays against all three diamides. Genome modified flies bearing the G4946V mutation exhibited high resistance ratios to flubendiamide (91.3-fold) and chlorantraniliprole (194.7-fold) when compared to cyantraniliprole (5.4-fold). Flies naturally wildtype for the I4790M mutation were moderately resistant to flubendiamide (15.3-fold) but significantly less resistant to chlorantraniliprole (7.5-fold), and cyantraniliprole (2.3-fold). These findings provide in vivo functional genetic confirmation for the role and relative contribution of RyR mutations in diamide resistance and suggest that the mutations confer subtle differences on the relative binding affinities of the three diamides at an overlapping binding site on the RyR protein.
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Affiliation(s)
- Vassilis Douris
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13 Heraklion, Crete, Greece; Laboratory of Molecular Entomology, Department of Biology, University of Crete, GR-700 13 Heraklion, Crete, Greece.
| | - Kyriaki-Maria Papapostolou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13 Heraklion, Crete, Greece; Laboratory of Molecular Entomology, Department of Biology, University of Crete, GR-700 13 Heraklion, Crete, Greece
| | - Aris Ilias
- Hellenic Agricultural Organisation - 'Demeter', Institute of Olive Tree, Subtropical Crops and Viticulture, Heraklion, Crete, Greece
| | - Emmanuel Roditakis
- Hellenic Agricultural Organisation - 'Demeter', Institute of Olive Tree, Subtropical Crops and Viticulture, Heraklion, Crete, Greece
| | - Styliani Kounadi
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13 Heraklion, Crete, Greece; Laboratory of Molecular Entomology, Department of Biology, University of Crete, GR-700 13 Heraklion, Crete, Greece
| | - Maria Riga
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13 Heraklion, Crete, Greece; Laboratory of Molecular Entomology, Department of Biology, University of Crete, GR-700 13 Heraklion, Crete, Greece
| | - Ralf Nauen
- Bayer AG, Crop Science Division, R&D Pest Control Biology, Alfred Nobel Str. 50, D-40789 Monheim, Germany
| | - John Vontas
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13 Heraklion, Crete, Greece; Laboratory of Pesticide Science, Department of Crop Science, Agricultural University of Athens, 75 Iera Odos Street, GR-11855, Athens, Greece.
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Wang J, Wang H, Liu S, Liu L, Tay WT, Walsh TK, Yang Y, Wu Y. CRISPR/Cas9 mediated genome editing of Helicoverpa armigera with mutations of an ABC transporter gene HaABCA2 confers resistance to Bacillus thuringiensis Cry2A toxins. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 87:147-153. [PMID: 28705634 DOI: 10.1016/j.ibmb.2017.07.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 07/07/2017] [Accepted: 07/09/2017] [Indexed: 05/29/2023]
Abstract
High levels of resistance to Bt toxin Cry2Ab have been identified to be genetically linked with loss of function mutations of an ABC transporter gene (ABCA2) in two lepidopteran insects, Helicoverpa armigera and Helicoverpa punctigera. To further confirm the causal relationship between the ABCA2 gene (HaABCA2) and Cry2Ab resistance in H. armigera, two HaABCA2 knockout strains were created from the susceptible SCD strain with the CRISPR/Cas9 genome editing system. One strain (SCD-A2KO1) is homozygous for a 2-bp deletion in exon 2 of HaABCA2 created by non-homologous end joining (NHEJ). The other strain (SCD-A2KO2) is homozygous for a 5-bp deletion in exon 18 of HaABCA2 made by homology-directed repair (HDR), which was produced to mimic the r2 resistance allele of a field-derived Cry2Ab-resistant strain from Australia. Both knockout strains obtained high levels of resistance to both Cry2Aa (>120-fold) and Cry2Ab (>100-fold) compared with the original SCD strain, but no or very limited resistance to Cry1Ac (<4-fold). Resistance to Cry2Ab in both knockouts is recessive, and genetic complementary tests confirmed Cry2Ab resistance alleles are at the same locus (i.e. HaABCA2) for the two strains. Brush border membrane vesicles (BBMVs) of midguts from both knockout strains lost binding with Cry2Ab, but maintained the same binding with Cry1Ac as the SCD strain. In vivo functional evidence from this study demonstrates knockout of HaABCA2 confers high levels of resistance to both Cry2Aa and Cry2Ab, confirming that HaABCA2 plays a key role in mediating toxicity of both Cry2Aa and Cry2Ab against H. armigera.
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Affiliation(s)
- Jing Wang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Huidong Wang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Shaoyan Liu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Laipan Liu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Wee Tek Tay
- CSIRO, Black Mountain Laboratories, Canberra, Australian Capital Territory, Australia.
| | - Thomas K Walsh
- CSIRO, Black Mountain Laboratories, Canberra, Australian Capital Territory, Australia.
| | - Yihua Yang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Yidong Wu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
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