Distinct Impact of Processing on Cross-Order Cry1I Insecticidal Activity
The insecticidal Cry proteins from <i>Bacillus thuringiensis</i> are used in biopesticides or transgenic crops for pest control. The Cry1I protein family has unique characteristics of being produced during the vegetative rather than sporulation phase, its protoxins forming dimers in solu...
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2025-02-01
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| author | Dafne Toledo Yolanda Bel Stefanie Menezes de Moura Juan Luis Jurat-Fuentes Maria Fatima Grossi de Sa Aida Robles-Fort Baltasar Escriche |
| author_facet | Dafne Toledo Yolanda Bel Stefanie Menezes de Moura Juan Luis Jurat-Fuentes Maria Fatima Grossi de Sa Aida Robles-Fort Baltasar Escriche |
| author_sort | Dafne Toledo |
| collection | DOAJ |
| description | The insecticidal Cry proteins from <i>Bacillus thuringiensis</i> are used in biopesticides or transgenic crops for pest control. The Cry1I protein family has unique characteristics of being produced during the vegetative rather than sporulation phase, its protoxins forming dimers in solution, and exhibiting dual toxicity against lepidopteran and coleopteran pests. The Cry1Ia protoxin undergoes sequential proteolysis from the N- and C-terminal ends, producing intermediate forms with insecticidal activity, while in some cases, the fully processed toxin is inactive. We investigated the oligomerization and toxicity of Cry1Ia intermediate forms generated through trypsinization (T-Int) and larval gut fluid (GF-Int) treatments, as well as the fully trypsinized protein (toxin). Heterologously expressed intermediate forms assembled into oligomers and showed similar toxicity to Cry1Ia protoxin against <i>Ostrinia nubilalis</i> (European corn borer) larvae, while the toxin form was ~30 times less toxic. In contrast, bioassays with <i>Leptinotarsa decemlineata</i> (Colorado potato beetle) larvae did not show significant differences in toxicity among Cry1Ia protoxin, T-Int, GF-Int, and fully processed toxin. These results suggest that the Cry1I mode of action differs by insect order, with N-terminal cleavage affecting toxicity against lepidopteran but not coleopteran larvae. This knowledge is essential for designing pest control strategies using Cry1I insecticidal proteins. |
| format | Article |
| id | doaj-art-6b4b5beb303048ea91061dbe26ebad8d |
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| publishDate | 2025-02-01 |
| publisher | MDPI AG |
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| series | Toxins |
| spelling | doaj-art-6b4b5beb303048ea91061dbe26ebad8d2025-08-20T02:04:05ZengMDPI AGToxins2072-66512025-02-011726710.3390/toxins17020067Distinct Impact of Processing on Cross-Order Cry1I Insecticidal ActivityDafne Toledo0Yolanda Bel1Stefanie Menezes de Moura2Juan Luis Jurat-Fuentes3Maria Fatima Grossi de Sa4Aida Robles-Fort5Baltasar Escriche6Institute of Biotechnology and Biomedicine, University of Valencia, 46100 Valencia, SpainInstitute of Biotechnology and Biomedicine, University of Valencia, 46100 Valencia, SpainDepartment of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USADepartment of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USAEmbrapa Genetic Resources and Biotechnology, Brasília 70770-917, DF, BrazilDepartment of Genetics, University of Valencia, 46100 Valencia, SpainInstitute of Biotechnology and Biomedicine, University of Valencia, 46100 Valencia, SpainThe insecticidal Cry proteins from <i>Bacillus thuringiensis</i> are used in biopesticides or transgenic crops for pest control. The Cry1I protein family has unique characteristics of being produced during the vegetative rather than sporulation phase, its protoxins forming dimers in solution, and exhibiting dual toxicity against lepidopteran and coleopteran pests. The Cry1Ia protoxin undergoes sequential proteolysis from the N- and C-terminal ends, producing intermediate forms with insecticidal activity, while in some cases, the fully processed toxin is inactive. We investigated the oligomerization and toxicity of Cry1Ia intermediate forms generated through trypsinization (T-Int) and larval gut fluid (GF-Int) treatments, as well as the fully trypsinized protein (toxin). Heterologously expressed intermediate forms assembled into oligomers and showed similar toxicity to Cry1Ia protoxin against <i>Ostrinia nubilalis</i> (European corn borer) larvae, while the toxin form was ~30 times less toxic. In contrast, bioassays with <i>Leptinotarsa decemlineata</i> (Colorado potato beetle) larvae did not show significant differences in toxicity among Cry1Ia protoxin, T-Int, GF-Int, and fully processed toxin. These results suggest that the Cry1I mode of action differs by insect order, with N-terminal cleavage affecting toxicity against lepidopteran but not coleopteran larvae. This knowledge is essential for designing pest control strategies using Cry1I insecticidal proteins.https://www.mdpi.com/2072-6651/17/2/67<i>Bacillus thuringiensis</i>Cry1Ia processingMode of actionColorado potato beetle (CPB)<i>Leptinotarsa decemlineata</i>European corn borer (ECB) |
| spellingShingle | Dafne Toledo Yolanda Bel Stefanie Menezes de Moura Juan Luis Jurat-Fuentes Maria Fatima Grossi de Sa Aida Robles-Fort Baltasar Escriche Distinct Impact of Processing on Cross-Order Cry1I Insecticidal Activity Toxins <i>Bacillus thuringiensis</i> Cry1Ia processing Mode of action Colorado potato beetle (CPB) <i>Leptinotarsa decemlineata</i> European corn borer (ECB) |
| title | Distinct Impact of Processing on Cross-Order Cry1I Insecticidal Activity |
| title_full | Distinct Impact of Processing on Cross-Order Cry1I Insecticidal Activity |
| title_fullStr | Distinct Impact of Processing on Cross-Order Cry1I Insecticidal Activity |
| title_full_unstemmed | Distinct Impact of Processing on Cross-Order Cry1I Insecticidal Activity |
| title_short | Distinct Impact of Processing on Cross-Order Cry1I Insecticidal Activity |
| title_sort | distinct impact of processing on cross order cry1i insecticidal activity |
| topic | <i>Bacillus thuringiensis</i> Cry1Ia processing Mode of action Colorado potato beetle (CPB) <i>Leptinotarsa decemlineata</i> European corn borer (ECB) |
| url | https://www.mdpi.com/2072-6651/17/2/67 |
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