1
|
Hu Y, Tian C, Feng Y, Ma W, Zhang Y, Yang Q, Zhang X. Transgenic early japonica rice: Integration and expression characterization of stem borer resistance Bt gene. Gene 2024; 927:148753. [PMID: 38972556 DOI: 10.1016/j.gene.2024.148753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 06/22/2024] [Accepted: 07/04/2024] [Indexed: 07/09/2024]
Abstract
BACKGROUND Transgenic insect-resistant rice offers an environmentally friendly approach to mitigate yield losses caused by lepidopteran pests, such as stem borers. Bt (Bacillus thuringiensis) genes encode insecticidal proteins and are widely used to confer insect resistance to genetically modified crops. This study investigated the integration, inheritance, and expression characteristics of codon-optimised synthetic Bt genes, cry1C* and cry2A*, in transgenic early japonica rice lines. METHODS The early japonica rice cultivar, Songgeng 9 (Oryza sativa), was transformed with cry1C* or cry2A*, which are driven by the ubi promoter via Agrobacterium tumefaciens-mediated transformation. Molecular analyses, including quantitative PCR (qPCR), enzyme-linked immunosorbent assay (ELISA), and Southern blot analysis were performed to confirm transgene integration, inheritance, transcriptional levels, and protein expression patterns across different tissues and developmental stages. RESULTS Stable transgenic early japonica lines exhibiting single-copy transgene integration were established. Transcriptional analysis revealed variations in Bt gene expression among lines, tissues, and growth stages, with higher expression levels observed in leaves than in other organs. Notably, cry2A* exhibited consistently higher mRNA and protein levels than cry1C* across all examined tissues and developmental time points. Bt protein accumulation followed the trend of leaves > stem sheaths > young panicles > brown rice, with peak expression during the filling stage in the vegetative tissues. CONCLUSIONS Synthetic cry2A* displayed markedly elevated transcription and translation compared to cry1C* in the transgenic early japonica rice lines examined. Distinct spatiotemporal patterns of Bt gene expression were elucidated, providing insights into the potential insect resistance conferred by these genes in rice. These findings will contribute to the development of insect-resistant japonica rice varieties and facilitate the rational deployment of Bt crops.
Collapse
Affiliation(s)
- Yueting Hu
- Rice Research Institute, Heilongjiang Academy of Agricultural Sciences, Jiamusi 154026, China.
| | - Chongbing Tian
- Rice Research Institute, Heilongjiang Academy of Agricultural Sciences, Jiamusi 154026, China
| | - Yanjiang Feng
- Rice Research Institute, Heilongjiang Academy of Agricultural Sciences, Jiamusi 154026, China
| | - Wendong Ma
- Rice Research Institute, Heilongjiang Academy of Agricultural Sciences, Jiamusi 154026, China
| | - Yunjiang Zhang
- Rice Research Institute, Heilongjiang Academy of Agricultural Sciences, Jiamusi 154026, China
| | - Qing Yang
- Rice Research Institute, Heilongjiang Academy of Agricultural Sciences, Jiamusi 154026, China
| | - Xirui Zhang
- Rice Research Institute, Heilongjiang Academy of Agricultural Sciences, Jiamusi 154026, China
| |
Collapse
|
2
|
Meng M, Shen C, Lin M, Jin J, Chen W, Zhang X, Xu C, Hu X, Zhu Q, Chen C, Xie Y, Jacob Pooe O, Crickmore N, Liu X, Lü P, Liu Y. Characterization of the individual domains of the Bacillus thuringiensis Cry2Aa implicates Domain I as a possible binding site to Helicoverpa armigera. J Invertebr Pathol 2024; 205:108129. [PMID: 38754546 DOI: 10.1016/j.jip.2024.108129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 05/09/2024] [Accepted: 05/13/2024] [Indexed: 05/18/2024]
Abstract
Bacillus thuringiensis (Bt) Cry2Aa is a member of the Cry pore-forming, 3-domain, toxin family with activity against both lepidopteran and dipteran insects. Although domains II and III of the Cry toxins are believed to represent the primary specificity determinant through specific binding to cell receptors, it has been proposed that the pore-forming domain I of Cry2Aa also has such a role. Thus, a greater understanding of the functions of Cry2Aa's different domains could potentially be helpful in the rational design of improved toxins. In this work, cry2Aa and its domain fragments (DI, DII, DIII, DI-II and DII-DIII) were subcloned into the vector pGEX-6P-1 and expressed in Escherichia coli. Each protein was recognized by anti-Cry2Aa antibodies and, except for the DII fragment, could block binding of the antibody to Cry2Aa. Cry2Aa and its DI and DI-II fragments bound to brush border membrane vesicles (BBMV) from H. armigera and also to a ca 150 kDa BBMV protein on a far western (ligand) blot. In contrast the DII, DIII and DII-III fragments bound to neither of these. None of the fragments were stable in H. armigera gut juice nor showed any toxicity towards this insect. Our results indicate that contrary to the general model of Cry toxin activity domain I plays a role in the binding of the toxin to the insect midgut.
Collapse
Affiliation(s)
- Meng Meng
- School of Life Sciences, Jiangsu University, Zhenjiang 212013, China; Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Cheng Shen
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Manman Lin
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Jiafeng Jin
- School of Life Sciences, Jiangsu University, Zhenjiang 212013, China; Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Wei Chen
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Xiao Zhang
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Chongxin Xu
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Xiaodan Hu
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Qing Zhu
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Chengyu Chen
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Yajing Xie
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Ofentse Jacob Pooe
- School of Life Sciences, University of KwaZulu-Natal, Durban 4000, South Africa
| | - Neil Crickmore
- School of Biological Sciences, University of Sussex, Brighton BN1 9RH, United Kingdom
| | - Xianjin Liu
- School of Life Sciences, Jiangsu University, Zhenjiang 212013, China; Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China
| | - Peng Lü
- School of Life Sciences, Jiangsu University, Zhenjiang 212013, China.
| | - Yuan Liu
- School of Life Sciences, Jiangsu University, Zhenjiang 212013, China; Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing 210014, China.
| |
Collapse
|
3
|
Ay Alzahrani F, Crickmore N. N-terminal proteolysis determines the differential activity of Bacillus thuringiensis Cry2A toxins towards Aedes aegypti. J Invertebr Pathol 2024; 204:108100. [PMID: 38561070 DOI: 10.1016/j.jip.2024.108100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 03/25/2024] [Accepted: 03/29/2024] [Indexed: 04/04/2024]
Abstract
It has long been known that while both the Bacillus thuringiensis pesticidal proteins Cry2Aa and Cry2Ab have wide-ranging activities against lepidopteran insects only the former has activity against the mosquito Aedes aegypti. We have previously shown that this differential specificity is influenced by the N-terminal region of these proteins and here demonstrate that this is due to these sections affecting proteolytic activation. Enzymes from the midgut of A. aegypti cleave Cry2Aa at the C-terminal side of amino acid 49 resulting in a 58 kDa fragment whereas these enzymes do not cleave Cry2Ab at this position. The 58 kDa, but not the protoxin, form of Cry2Aa is capable of interacting with brush border membrane vesicles from A. aegypti.
Collapse
Affiliation(s)
- Faisal Ay Alzahrani
- Department of Chemistry, College of Sciences and Arts, King Abdulaziz University, Rabigh 21911, Saudi Arabia; School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Neil Crickmore
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK.
| |
Collapse
|
4
|
Shikov AE, Savina IA, Nizhnikov AA, Antonets KS. Recombination in Bacterial Genomes: Evolutionary Trends. Toxins (Basel) 2023; 15:568. [PMID: 37755994 PMCID: PMC10534446 DOI: 10.3390/toxins15090568] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/02/2023] [Accepted: 09/07/2023] [Indexed: 09/28/2023] Open
Abstract
Bacterial organisms have undergone homologous recombination (HR) and horizontal gene transfer (HGT) multiple times during their history. These processes could increase fitness to new environments, cause specialization, the emergence of new species, and changes in virulence. Therefore, comprehensive knowledge of the impact and intensity of genetic exchanges and the location of recombination hotspots on the genome is necessary for understanding the dynamics of adaptation to various conditions. To this end, we aimed to characterize the functional impact and genomic context of computationally detected recombination events by analyzing genomic studies of any bacterial species, for which events have been detected in the last 30 years. Genomic loci where the transfer of DNA was detected pertained to mobile genetic elements (MGEs) housing genes that code for proteins engaged in distinct cellular processes, such as secretion systems, toxins, infection effectors, biosynthesis enzymes, etc. We found that all inferences fall into three main lifestyle categories, namely, ecological diversification, pathogenesis, and symbiosis. The latter primarily exhibits ancestral events, thus, possibly indicating that adaptation appears to be governed by similar recombination-dependent mechanisms.
Collapse
Affiliation(s)
- Anton E. Shikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (I.A.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Iuliia A. Savina
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (I.A.S.); (A.A.N.)
| | - Anton A. Nizhnikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (I.A.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Kirill S. Antonets
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (I.A.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| |
Collapse
|
5
|
Shen C, Li YH, Lin MM, Zhang JZ, Wang J, Gao MJ, Zhang X, Hu XD, Liu Y, Liu XJ. Identifying the Epitopes of Bacillus thuringiensis Cry2Aa Toxin Involved in Cadherin Interaction by a Monoclonal Antibody. Appl Biochem Biotechnol 2022; 195:2709-2718. [PMID: 36074237 DOI: 10.1007/s12010-022-04162-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2022] [Indexed: 11/26/2022]
Abstract
Antibodies are a useful tool for assistance to map the binding epitopes in Bacillus thuringiensis Cry toxins and their receptors, and even determine how receptors promote toxicity. In this work, a monoclonal antibody (mAb-1D2) was produced by the hybridoma cell line raised against Cry2Aa toxins, with a half inhibition concentration (IC50) of 9.16 μg/mL. The affinity constant of two recombinant toxin-binding fragments derived from Helicoverpa armigera and Plutella xylostella cadherin-like protein (HaCad-TBR or PxCad-TBR) to Cry2Aa toxin was measured to be 1.21 μM and 1.24 μM, respectively. Competitive ELISA showed that mAb-1D2 competed with HaCad-TBR or PxCad-TBR binding to Cry2Aa. Meanwhile, the toxicity of the Cry2Aa toxin to the H. armigera and P. xylostella larvae were greatly reduced when the toxin was mixed with mAb-1D2, which indicated that cadherin may play an important functional role in the toxicity of Cry2Aa. After transforming mAb-1D2 to a single-chain variable fragment (scFv), the hot spot residues of Cry2Aa with 1D2-scFv, PxCad-TBR, and HaCad-TBR were analyzed by molecular docking. It was demonstrated that the hot spot residues of Cry2Aa involving with 1D2-scFv interaction were mainly in Domain II, and some residues in Domain I. Moreover, mAb-1D2 and the two cadherin fragments shared the common hot spot residues on Cry2Aa, which could explain mAb-1D2 inhibited Cry2Aa binding with cadherin fragments. This monoclonal antibody could be a useful tool for identifying the binding epitopes between Cry2Aa and cadherin, and even assist to analyze the roles of cadherin in Cry2Aa toxicity.
Collapse
Affiliation(s)
- Cheng Shen
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing, 210014, China
| | - Yi-Hang Li
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing, 210014, China
| | - Man-Man Lin
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing, 210014, China
| | - Jiang-Zhao Zhang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing, 210014, China
| | - Jing Wang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing, 210014, China
| | - Mei-Jing Gao
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing, 210014, China
| | - Xiao Zhang
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing, 210014, China
| | - Xiao-Dan Hu
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing, 210014, China
| | - Yuan Liu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing, 210014, China.
| | - Xian-Jin Liu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
- Key Laboratory of Food Quality and Safety of Jiangsu Province, Nanjing, 210014, China.
| |
Collapse
|
6
|
Potential for Bacillus thuringiensis and Other Bacterial Toxins as Biological Control Agents to Combat Dipteran Pests of Medical and Agronomic Importance. Toxins (Basel) 2020; 12:toxins12120773. [PMID: 33291447 PMCID: PMC7762171 DOI: 10.3390/toxins12120773] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 11/24/2020] [Accepted: 12/03/2020] [Indexed: 11/16/2022] Open
Abstract
The control of dipteran pests is highly relevant to humans due to their involvement in the transmission of serious diseases including malaria, dengue fever, Chikungunya, yellow fever, zika, and filariasis; as well as their agronomic impact on numerous crops. Many bacteria are able to produce proteins that are active against insect species. These bacteria include Bacillus thuringiensis, the most widely-studied pesticidal bacterium, which synthesizes proteins that accumulate in crystals with insecticidal properties and which has been widely used in the biological control of insects from different orders, including Lepidoptera, Coleoptera, and Diptera. In this review, we summarize all the bacterial proteins, from B. thuringiensis and other entomopathogenic bacteria, which have described insecticidal activity against dipteran pests, including species of medical and agronomic importance.
Collapse
|
7
|
Goje LJ, Elmi ED, Bracuti A, Courty T, Rao T, Alzahrani FA, Crickmore N. Identification of Aedes aegypti specificity motifs in the N-terminus of the Bacillus thuringiensis Cry2Aa pesticidal protein. J Invertebr Pathol 2020; 174:107423. [PMID: 32525026 DOI: 10.1016/j.jip.2020.107423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/21/2020] [Accepted: 06/04/2020] [Indexed: 10/24/2022]
Abstract
One advantage of using the Cry proteins of Bacillus thuringiensis as pesticides is their relatively narrow spectrum of activity, thus reducing the risk of non-target effects. Understanding the molecular basis of specificity has the potential to help us design improved products against emerging pests, or against pests that have developed resistance to other Cry proteins. Many previous studies have associated specificity with the binding of the Cry protein, particularly through the apical regions of domain II, to particular receptors on the midgut epithelial cells of the host insect. We have previously found that the specificity of Cry2A proteins against some insects is associated with domain I, which is traditionally associated with pore-formation but not receptor binding. In this work we identify four amino acids in the N-terminal region that, when mutated, can confer activity towards Aedes aegypti to Cry2Ab, a protein known to lack this toxicity. Intriguingly these amino acids are located in the region (amino acids 1-49) that is believed to be removed during proteolytic activation of the Cry protein. We discuss how the motifs containing these amino acids might be involved in the toxic process.
Collapse
Affiliation(s)
| | - Elmi Dahir Elmi
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Anthony Bracuti
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Thomas Courty
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Tejas Rao
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | | | - Neil Crickmore
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK.
| |
Collapse
|
8
|
Wang Y, Zhang X, Xie Y, Wu A, Zai X, Liu X. High-affinity phage-displayed peptide as a recognition probe for the detection of Cry2Ad2-3. Int J Biol Macromol 2019; 137:562-567. [PMID: 31238073 DOI: 10.1016/j.ijbiomac.2019.06.164] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/21/2019] [Accepted: 06/21/2019] [Indexed: 11/25/2022]
Abstract
Cry2A is widely used in transgenic crops in combination with Cry1A toxins. The sensitive and robust detection of Cry2A toxin in food and the environment is necessary to monitor the safety of biopesticides. Here, we describe an approach that involves the use of phage-displayed peptide for the detection of Cry2Ad2-3-the main area of Cry2Ad2 insecticidal activity. After four rounds of panning, six positive monoclonal phage particles were obtained. Pep5 with a sequence of ACSYNHNSKCGGG displayed low cross-reactivity with other Cry toxins. The working range of detection for Cry2Ad2-3 toxin standards in the brush border membrane vesicle (BBMV)-peptide sandwich ELISA was 10-50.625 ng mL-1 and the detection limit (LOD) was 8 ng mL-1. Molecular insight into the interaction of pep5 with Cry2Ad2-3 was gleaned using homology modeling and docking. Molecular docking results showed that high-affinity peptide tended to dock in the groove between the two domains of Cry2Ad2-3. The interactions within the toxin-pep5 complex were due to hydrogen bond and hydrophobic interaction. Pep5 also lead us to trap the binding region. Therefore, peptides may be a cost-efficient alternative for detecting Cry toxins and studying their mechanisms.
Collapse
Affiliation(s)
- Yun Wang
- College of Horticulture, Jinling Institute of Technology, 210038 Nanjing, PR China
| | - Xiao Zhang
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Jiangsu Academy of Agricultural Sciences, 210014 Nanjing, PR China
| | - Yajing Xie
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Jiangsu Academy of Agricultural Sciences, 210014 Nanjing, PR China
| | - Aihua Wu
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Jiangsu Academy of Agricultural Sciences, 210014 Nanjing, PR China
| | - Xueming Zai
- College of Horticulture, Jinling Institute of Technology, 210038 Nanjing, PR China
| | - Xianjin Liu
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Jiangsu Academy of Agricultural Sciences, 210014 Nanjing, PR China.
| |
Collapse
|
9
|
Expression of
cry
genes in
Bacillus thuringiensis
biotechnology. Appl Microbiol Biotechnol 2019; 103:1617-1626. [DOI: 10.1007/s00253-018-9552-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 01/03/2023]
|