cry proteins
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2022 ◽  
Author(s):  
Yang Liu ◽  
Siping Han ◽  
Shuo Yang ◽  
Ziqi Chen ◽  
Yuejia Yin ◽  
...  

Abstract Though cry gene transformed crops have successfully revolutionized modern agriculture, it is still necessary to discover new Cry proteins to overcome potential threatens from the development of resistant insect populations. We swapped domain-IIIs with various Cry proteins and engineered seven chimeric proteins, aiming to produce new engineered hybrid insecticidal proteins. Seven recombinant proteins were expressed in Escherichia coli. Three proteins exhibited high toxicity against Asian corn borer in dietary exposure assays. Three hybrid proteins were further transformed to rice (cv. Jijing88) to determine their insecticidal activity. Cry1Ab/Gc hybrid proteins, Cry1Ab being replaced by the domain-III of Cry1Gc, showed significantly more toxic against rice stem borer than others. Furthermore, Cry1Ab/Gc gene was transformed into maize (cv. HiII), then backcrossed into commercial maize inbred lines (cv. Ji853 and Y822), and formulated into Xiangyu 998 hybrid to evaluate their commercial value. Transgenic maize performed significant resistance improvement to the Asian corn borer without affecting the yield, and this new protein did not have adverse effects on the environment. Our result proved domain-swapped could be used as an efficient method for exploring new cry genes and engineered hybrid insecticidal protein. Cry1Ab/Gc provides a new tool for Lepidopteran insects resistant management in rice and maize.


Toxins ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 55
Author(s):  
Minghui Jin ◽  
Yinxue Shan ◽  
Yan Peng ◽  
Ping Wang ◽  
Qi Li ◽  
...  

The insecticidal Vip3 proteins, secreted by Bacillus thuringiensis (Bt) during its vegetative growth phase, are currently used in Bt crops to control insect pests, and are genetically distinct from known insecticidal Cry proteins. Compared with Cry toxins, the mechanisms of Vip3 toxins are still poorly understood. Here, the responses of Spodoptera frugiperda larvae after Vip3Aa challenge are characterized. Using an integrative analysis of transcriptomics and proteomics, we found that Vip3Aa has enormous implications for various pathways. The downregulated genes and proteins were mainly enriched in metabolic pathways, including the insect hormone synthesis pathway, whereas the upregulated genes and proteins were mainly involved in the caspase-mediated apoptosis pathway, along with the MAPK signaling and endocytosis pathways. Moreover, we also identified some important candidate genes involved in apoptosis and MAPKs. The present study shows that exposure of S. frugiperda larvae to Vip3Aa activates apoptosis pathways, leading to cell death. The results will promote our understanding of the host response process to the Vip3Aa, and help us to better understand the mode of action of Vip3A toxins.


Author(s):  
America S. Gaona‐Mendoza ◽  
Martha C. Bravo Rivas ◽  
José E. Barboza‐Corona ◽  
Julio A. Massange‐Sánchez ◽  
Luz E. Casados‐Vázquez

Insects ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 27
Author(s):  
Álvaro Rodríguez-González ◽  
Alejandra J. Porteous-Álvarez ◽  
Marcos Guerra ◽  
Óscar González-López ◽  
Pedro A. Casquero ◽  
...  

The beetle Xylotrechus arvicola is a destructive pest in vineyards (Vitis vinifera) in the main wine-producing areas of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood-making galleries, thus damaging the plant both directly and indirectly; the latter through the proliferation of wood fungi, which can invade the inside of the plant, decreasing the quality and quantity of its production. The susceptibility of X. arvicola larvae to five coleopteran toxic Cry proteins (Cry1B, Cry1I, Cry3A, Cry7A, and Cry23/37) was evaluated under laboratory conditions in order to deepen the knowledge of the effect of these proteins on this insect throughout its biological development.


2021 ◽  
Author(s):  
Semih Yilmaz ◽  
Abeer Babiker Idris ◽  
Abdurrahman Ayvaz ◽  
Aysun Cetin ◽  
Funda Ulgen ◽  
...  

Aims: This study aimed to analyze the evolutionary relationship between Bacillus species isolated from agricultural soil using in-silico tools. Methods and Results: A cross-sectional study was conducted in Adana province, in Turkey. A total of 120 Bacillus species were isolated from 80 soil samples. However, the phylogenetic tree diverged into two lineages; one belongs to B. subtilis group while the other belongs to B. cereus group. Interestingly, three native strains (SY27.1A, SY35.3A, and SY58.5A), which produce Cry proteins, shared high similarity with B. subtilis group (over 99%) and less than 95% similarity with known B. thuringiensis and other species of B. cereus group. Furthermore, 11 canonical SNPs (canSNPs) were identified in strains that belong to B. pumilus group when compared with B. subtilis reference sequences. Conclusions: Phylogenetic analysis of 16S rRNA sequences was found valuable for differentiation between Bacillus species isolated from soil samples. In addition, SNPs analysis provided more intra-specific information in the cases of B. subtilis group. Significance and Impact of Study: A detailed analysis was provided for the SNPs present in a conserved region of 16S rRNA gene of Bacillus species. Also, we proposed three novel Bacillus strains that produce Cry proteins and belong to B. subtilis group.


Author(s):  
Yudong Quan ◽  
Maria Lázaro-Berenguer ◽  
Patricia Hernández-Martínez ◽  
Juan Ferré

Vegetative insecticidal proteins (Vip3) from Bacillus thuringiensis have been used, in combination with Cry proteins, to better control insect pests and as a strategy to delay the evolution of resistance to Cry proteins in Bt crops (crops protected from insect attack by the expression of proteins from B. thuringiensis ). In this study, we have set up the conditions to analyze the specific binding of 125 I-Vip3Af to Spodoptera frugiperda and Spodoptera exigua brush border membrane vesicles (BBMV). Heterologous competition binding experiments revealed that Vip3Aa shares the same binding sites with Vip3Af, but that Vip3Ca does not recognize all of them. As expected, Cry1Ac and Cry1F did not compete for Vip3Af binding sites. By trypsin treatment of selected alanine-mutants, we were able to generate truncated versions of Vip3Af. Their use as competitors with 125 I-Vip3Af indicated that only those molecules containing domains I to III (DI-III and DI-IV) were able to compete with the trypsin-activated Vip3Af protein for binding, and that molecules only containing either domain IV or domains IV and V (DIV and DIV-V) were unable to compete with Vip3Af. These results were further confirmed with competition binding experiments using 125 I-DI-III. In addition, the truncated protein 125 I-DI-III also bound specifically to Sf21 cells. Cell viability assays showed that the truncated proteins DI-III and DI-IV were as toxic to Sf21 cells as the activated Vip3Af, suggesting that domains IV and V are not necessary for the toxicity to Sf21 cells, in contrast to their requirement in vivo. IMPORTANCE This study shows that Vip3Af binding sites are fully shared with Vip3Aa, only partially shared with Vip3Ca, and not shared with Cry1Ac and Cry1F in two Spodoptera spp. Truncated versions of Vip3Af revealed that only domains I to III were necessary for the specific binding, most likely because they can form the functional tetrameric oligomer and because domain III is supposed to contain the binding epitopes. In contrast to results obtained in vivo (bioassays against larvae), domains IV and V are not necessary for the ex vivo toxicity to Sf21 cells.


Life ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 999
Author(s):  
Maria Cristina Gonzalez-Vazquez ◽  
Ruth Abril Vela-Sanchez ◽  
Norma Elena Rojas-Ruiz ◽  
Alejandro Carabarin-Lima

A hallmark of Bacillus thuringiensis bacteria is the formation of one or more parasporal crystal (Cry) proteins during sporulation. The toxicity of these proteins is highly specific to insect larvae, exerting lethal effects in different insect species but not in humans or other mammals. The aim of this review is to summarize previous findings on Bacillus thuringiensis, including the characteristics of the bacterium, its subsequent contribution to biotechnology as a bioinsecticide due to the presence of Cry proteins, and its potential application as an adjuvant. In several studies, Cry proteins have been administered together with specific antigens to immunize experimental animal models. The results have shown that these proteins can enhance immunogenicity by generating an adequate immune response capable of protecting the model against an experimental infectious challenge, whereas protection is decreased when the specific antigen is administered without the Cry protein. Therefore, based on previous results and the structural homology between Cry proteins, these molecules have arisen as potential adjuvants in the development of vaccines for both animals and humans. Finally, a model of the interaction of Cry proteins with different components of the immune response is proposed.


2021 ◽  
Vol 12 ◽  
Author(s):  
Mamta Gupta ◽  
Harish Kumar ◽  
Sarvjeet Kaur

Bacillus thuringiensis (Bt) bacterium is found in various ecological habitats, and has natural entomo-pesticidal properties, due to the production of crystalline and soluble proteins during different growth phases. In addition to Cry and Cyt proteins, this bacterium also produces Vegetative insecticidal protein (Vip) during its vegetative growth phase, which is considered an excellent toxic candidate because of the difference in sequence homology and receptor sites from Cry proteins. Vip proteins are referred as second-generation insecticidal proteins, which can be used either alone or in complementarity with Cry proteins for the management of various detrimental pests. Among these Vip proteins, Vip1 and Vip2 act as binary toxins and have toxicity toward pests belonging to Hemiptera and Coleoptera orders, whereas the most important Vip3 proteins have insecticidal activity against Lepidopteran pests. These Vip3 proteins are similar to Cry proteins in terms of toxicity potential against susceptible insects. They are reported to be toxic toward pests, which can’t be controlled with Cry proteins. The Vip3 proteins have been successfully pyramided along with Cry proteins in transgenic rice, corn, and cotton to combat resistant pest populations. This review provides detailed information about the history and importance of Vip proteins, their types, structure, newly identified specific receptors, and action mechanism of this specific class of proteins. Various studies conducted on Vip proteins all over the world and the current status have been discussed. This review will give insights into the significance of Vip proteins as alternative promising candidate toxic proteins from Bt for the management of pests in most sustainable manner.


2021 ◽  
Vol 4 (2) ◽  
pp. 1708-1714
Author(s):  
Daniele Tasior ◽  
Adriana Micheli ◽  
Elderson Ruthes

Bacillus thuringiensis, apresenta atividade tóxica contra espécies das ordens Lepidoptera, Diptera, Hymenoptera e Coleoptera, dentre outras. Dentre as principais características das toxinas produzidas pelo B. thuringiensis tem-se a especificidade aos insetos e biodegradação, tornando a utilização deste microrganismo viável economicamente e ecologicamente, uma vez que evita a contaminação do meio ambiente, e adicionalmente, preserva os inimigos naturais. De acordo com a literatura especializada, estirpes de B. thuringiensis apresentam grande variabilidade genética e neste sentido a utilização da PCR (Polymerase Chain Reaction) apresenta grande destaque, pois auxilia na identificação e caracterização de genes codificadores de δ-endotoxinas, direcionando os trabalhos de bioensaios. Desta forma, o presente trabalho tem como objetivo desenvolver uma metodologia de identificação das principais proteínas (Cry) que compõem os produtos comerciais. Para isso foram selecionados dois produtos comerciais (P1 e P2). Cerca de 1 ml de cada produto foi depositado em placas de petri contendo meio de cultura, e espalhados com uma alça de Drigalski, estas placas foram acondicionadas a temperatura de 28°C por um período de 3 dias para crescimento das colônias bacterianas. Em seguida, realizou-se a obtenção de DNA para identificação das proteínas Cry. Seis proteínas Cry de B. thuringiensis (Cry1Aa, Cry1Ab, Cry1Ac, Cry1C, Cry1D e Cry1F) foram selecionadas para identificação nos bioinseticidas escolhidos. Quando submetidos ao teste com o primer geral Gray-cry1, o qual confirma a presença de genes Cry1, somente o P1 apresentou amplificação molecular, ou seja, presença de proteínas Cry em sua formulação. Diferentemente, de P1, P2 não demostrou presença de nenhuma banda em gel de agarose, o que nos permite concluir que não há presença de proteínas Cry, mesmo estas estando teoricamente presentes na formulação de P2. Este dado é de extrema importância uma vez que molecularmente foi possível comprovar a formulação proteica do bioinseticida P1, pois o perfil molecular foi condizente com a presença/ausência de bandas referentes as proteínas do produto. Os resultados deste trabalho vêm somar com predição de resultados a campo no que diz respeito a efetividade do bioinseticida.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Sujit Kumar Das ◽  
Sukanta Kumar Pradhan ◽  
Kailash Chandra Samal ◽  
Nihar Ranjan Singh

Abstract Background Bacillus thuringiensis (Bt) is a gram-positive spore-forming soil bacterium that synthesizes crystalline (Cry) protein, which is toxic and causing pathogenicity against mainly three insect orders: Coleoptera, Diptera, and Lepidoptera. These crystalline protein inclusions, i.e., δ-endotoxins are successfully used as a bio-control agent against insect pests. Main body A total of 58 various Cry proteins belonging to these 3 insect orders were retrieved from SwissProt database and are categorized into different groups. Structural and functional analysis were performed to understand the functional domain arrangements at sequence level as well as at structural level involving both experimental and predicted 3-dimensional models. Besides, the analysis of evolutionary relationship involving all 58 observed Cry proteins at the sequence, domain, and structural levels were done using different bioinformatics tools. Evolutionary analysis revealed that some Cry proteins having toxicity for a specific insect order are found to be clustered for another different insect order, which concludes that they might have toxicity for more than one insect order. Three-dimensional (3D) structure analysis of both experimental and predicted models revealed that proteins might have toxicity for a specific insect order differ in their structural arrangements and was observed in Cry proteins belonging to 3 different insect orders. Conclusions It could be hypothesized that an inner-molecular domain shift or domain insertion/deletion might have taken place during the evolutionary process, which consequently causes structural and functional divergence of Bt. The study output may be helpful for understanding the diversity as well as specificity of the analyzed insecticidal proteins and their application as a biopesticide in the field of agriculture.


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