scholarly journals Bacillus thuringiensis kurstaki strains produce vegetative insecticidal proteins (Vip 3) with high potential

2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Ebru Güney ◽  
Aysun Adıgüzel ◽  
Zihni Demirbağ ◽  
Kazım Sezen
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Bacterial Isolate ◽  
Insect Pest ◽  
Screening Tests ◽  
Pest Species ◽  
Insecticidal Proteins ◽  
Protein Coding ◽  
Median Lethal Concentrations ◽  
Polymerase Chain

AbstractBacillus thuringiensis (Bt) produces vegetative insecticidal proteins (Vip) during its vegetative growth stage. Vip3 proteins have a significant role in insecticidal activity of this bacterium. Each new bacterial isolate may encode Vip with different significance. The Vip protein coding by vip genes of two Bt strains (BnBt and MnD) with high insecticidal activity was characterized in this study. Polymerase chain reaction (PCR)-based screening for Vip genes of these Bt isolates expressed the detected Vip gene and tested the protein for insecticidal activity against the cotton leafworm, Spodoptera littoralis larvae. As a result of the screening tests, Vip3 genes were determined in MnD and BnBt isolates. Vip3 genes of both isolates were expressed and confirmed by 90 kDa proteins. Partially purified and trypsin-activated protein samples of BnBt and MnD isolates were tested against the second instar larvae of S. littoralis. The results showed that the highest insecticidal activity of the Vip3 proteins of BnBt and MnD was 86.66% and 83.33% mortality in 10 days, respectively. The median lethal concentrations (LC50) of BnBt and MnD were determined as 41.860 and 55.154 ng/μl, respectively. The results suggest that Vip3 protein is effective for preventing resistance in various insect-pest species. The expressed proteins may be utilized as a biopesticide against nocuous insects.

scholarly journals Characterization of Two Novel Bacillus thuringiensis Cry8 Toxins Reveal Differential Specificity of Protoxins or Activated Toxins against Chrysomeloidea Coleopteran Superfamily

Toxins ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 642
Author(s):  
Changlong Shu ◽  
Guixin Yan ◽  
Shizhi Huang ◽  
Yongxin Geng ◽  
Mario Soberón ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Genome Sequencing ◽  
Insecticidal Activity ◽  
Insect Pest ◽  
Anoplophora Glabripennis ◽  
Insecticidal Proteins ◽  
Holotrichia Parallela ◽  
Larval Stages ◽  
Differential Toxicity

Scarabaeoidea and Chrysomeloidea insects are agriculture-destructive coleopteran pests. Few effective Bacillus thuringiensis (Bt) insecticidal proteins against these species have been described. Bt isolate BtSU4 was found to be active against coleopteran insects. Genome sequencing revealed two new cry8 genes in BtSU4, designated as cry8Ha1 and cry8Ia1. Both genes expressed a 135 kDa protoxin forming irregular shape crystals. Bioassays performed with Cry8Ha1 protoxin showed that it was toxic to both larvae and adult stages of Holotrichia parallela, also to Holotrichia oblita adults and to Anoplophora glabripennis larvae, but was not toxic to larval stages of H. oblita or Colaphellus bowringi. The Cry8Ia1 protoxin only showed toxicity against H. parallela larvae. After activation with chymotrypsin, the Cry8Ha1 activated toxin lost its insecticidal activity against H. oblita adults and reduced its activity on H. parallela adults, but gained toxicity against C. bowringi larvae, a Chrysomeloidea insect pest that feeds on crucifer crops. The chymotrypsin activated Cry8Ia1 toxin did not show toxicity to any one of these insects. These data show that Cry8Ha1 and Cry8Ia1 protoxin and activated toxin proteins have differential toxicity to diverse coleopteran species, and that protoxin is a more robust protein for the control of coleopteran insects.

scholarly journals Bacillus thuringiensis Vip1 Functions as a Receptor of Vip2 Toxin for Binary Insecticidal Activity against Holotrichia parallela

Toxins ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 440 ◽  
Author(s):  
Jianxun Geng ◽  
Jian Jiang ◽  
Changlong Shu ◽  
Zeyu Wang ◽  
Fuping Song ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Affinity Chromatography ◽  
Insecticidal Activity ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Lethal Concentration ◽  
Insecticidal Proteins ◽  
Vegetative Phase ◽  
Holotrichia Parallela ◽  
Weak Binding

Bacillus thuringiensis is a well-known entomopathogenic bacterium that produces vegetative insecticidal proteins (Vips, including Vip1, Vip2, Vip3, and Vip4) during the vegetative phase. Here, we purified Vip1 and Vip2 from B. thuringiensis and characterized the insecticidal effects of these protoxins. Bioassay results showed that a 1:1 mixture of Vip1Ad and Vip2Ag, purified by ion-affinity chromatography independently, exhibited insecticidal activity against Holotrichia parallela larvae, with a 50% lethal concentration value of 2.33 μg/g soil. The brush border membrane (BBM) in the midgut of H. parallela larvae was destroyed after feeding the Vip1Ad and Vip2Ag mixture. Vacuolization of the cytoplasm and slight destruction of BBM were detected with Vip2Ag alone, but not with Vip1Ad alone. Notably, Vip1Ad bound to BBM vesicles (BBMVs) strongly, whereas Vip2Ag showed weak binding; however, binding of Vip2Ag to BBMV was increased when Vip1Ad was added. Ligand blotting showed that Vip2Ag did not bind to Vip1Ad but bound to Vip1Ad-t (Vip1Ad was activated by trypsin), suggesting the activation of Vip1Ad was important for their binary toxicity. Thus, our findings suggested that Vip1Ad may facilitate the binding of Vip2Ag to BBMVs, providing a basis for studies of the insecticidal mechanisms of Vip1Ad and Vip2Ag.

scholarly journals Oligomer Formation and Insecticidal Activity of Bacillus thuringiensis Vip3Aa Toxin

Toxins ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 274 ◽  
Author(s):  
Ensi Shao ◽  
Aishan Zhang ◽  
Yaqi Yan ◽  
Yaomin Wang ◽  
Xinyi Jia ◽  
...  
Keyword(s):  
Amino Acid ◽  
Bacillus Thuringiensis ◽  
Complex Formation ◽  
Insecticidal Activity ◽  
Spodoptera Litura ◽  
Insecticidal Proteins ◽  
Proteolytic Activation ◽  
Oligomer Formation ◽  
Lepidopteran Insects ◽  
Substitution Mutations

Bacillus thuringiensis (Bt) Vip3A proteins are important insecticidal proteins used for control of lepidopteran insects. However, the mode of action of Vip3A toxin is still unclear. In this study, the amino acid residue S164 in Vip3Aa was identified to be critical for the toxicity in Spodoptera litura. Results from substitution mutations of the S164 indicate that the insecticidal activity of Vip3Aa correlated with the formation of a >240 kDa complex of the toxin upon proteolytic activation. The >240 kDa complex was found to be composed of the 19 kDa and the 65 kDa fragments of Vip3Aa. Substitution of the S164 in Vip3Aa protein with Ala or Pro resulted in loss of the >240 kDa complex and loss of toxicity in Spodoptera litura. In contrast, substitution of S164 with Thr did not affect the >240 kDa complex formation, and the toxicity of the mutant was only reduced by 35%. Therefore, the results from this study indicated that formation of the >240 kDa complex correlates with the toxicity of Vip3Aa in insects and the residue S164 is important for the formation of the complex.

scholarly journals Bacillus thuringiensis as microbial biopesticide: uses and application for sustainable agriculture

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Pradeep Kumar ◽  
Madhu Kamle ◽  
Rituraj Borah ◽  
Dipendra Kumar Mahato ◽  
Bharti Sharma
Keyword(s):  
Bacillus Thuringiensis ◽  
Plant Growth ◽  
Sustainable Agriculture ◽  
Insect Pest ◽  
High Specificity ◽  
Environmental Safety ◽  
Main Body ◽  
Cry Protein ◽  
Insecticidal Proteins ◽  
Toxic Activity

Abstract Background Bacillus thuringiensis (Bt) has been used in agriculture for a long time because of its insecticidal proteins which make it a valuable environment-friendly biopesticide. However, its use is not only limited to insecticidal properties. Current and previous studies indicate its potential as a biofertilizer for promoting plant growth, the development of transgenic plants, and others. It is the presence of δ-endotoxins, especially cry protein, which attributes the insecticidal property to the bacteria. Besides, there are some vegetative and secreted insecticidal proteins that exert their toxic activity towards specific species. Main body of abstract The present review briefly provides an overview of the Bt uses and application as a biocontrol agent against insect pest for sustainable agriculture. Historical development of Bt as biocontrol, classification of various cry proteins, their mechanisms of actions against different insect-pest, and incorporation of cry genes in the plant for developing transgenic Bt plants such as Bt cotton, potato, and maize. Applications of Bt as biofertilizer and the various bioformulations as biopesticide are also described. Short conclusion Uses of harmful pesticides and chemical cause various health issues and environmental problem; therefore, the Bt served as the best alternative to overcome the above issue. Also, we aim to explore the potential as plant growth-promoting potential and solubilization of minerals and the uses as a biofertilizer, keeping the high specificity and environmental safety of Bt. Its various formulations are commercially available and considered an efficient alternative to chemical pesticides.

scholarly journals Novel Bacillus thuringiensis Binary Insecticidal Crystal Proteins Active on Western Corn Rootworm, Diabrotica virgifera virgifera LeConte

2002 ◽  
Vol 68 (3) ◽  
pp. 1137-1145 ◽  
Author(s):  
R. Tracy Ellis ◽  
Brian A. Stockhoff ◽  
Lisa Stamp ◽  
H. Ernest Schnepf ◽  
George E. Schwab ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Diabrotica Virgifera Virgifera ◽  
Bacillus Sphaericus ◽  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Sequence Comparisons ◽  
Insecticidal Proteins ◽  
Crystal Proteins ◽  
Insecticidal Crystal Proteins

ABSTRACT A new family of insecticidal crystal proteins was discovered by screening sporulated Bacillus thuringiensis cultures for oral activity against western corn rootworm (WCR) larvae. B. thuringiensis isolates PS80JJ1, PS149B1, and PS167H2 have WCR insecticidal activity attributable to parasporal inclusion bodies containing proteins with molecular masses of ca. 14 and 44 kDa. The genes encoding these polypeptides reside in apparent operons, and the 14-kDa protein open reading frame (ORF) precedes the 44-kDa protein ORF. Mutagenesis of either gene in the apparent operons dramatically reduced insecticidal activity of the corresponding recombinant B. thuringiensis strain. Bioassays performed with separately expressed, biochemically purified 14- and 44-kDa polypeptides also demonstrated that both proteins are required for WCR mortality. Sequence comparisons with other known B. thuringiensis insecticidal proteins failed to reveal homology with previously described Cry, Cyt, or Vip proteins. However, there is evidence that the 44-kDa polypeptide and the 41.9- and 51.4-kDa binary dipteran insecticidal proteins from Bacillus sphaericus are evolutionarily related. The 14- and 44-kDa polypeptides from isolates PS80JJ1, PS149B1, and PS167H2 have been designated Cry34Aa1, Cry34Ab1, and Cry34Ac1, respectively, and the 44-kDa polypeptides from these isolates have been designated Cry35Aa1, Cry35Ab1, and Cry35Ac1, respectively.

scholarly journals Impacts of three pesticides on arthropod biodiversity in brinjal agro-ecosystem

2018 ◽  
Vol 8 (1) ◽  
pp. 55-61
Author(s):  
S Akter ◽  
MZ Alam ◽  
MS Rana ◽  
HB Saif
Keyword(s):  
Bacillus Thuringiensis ◽  
Natural Enemies ◽  
Insect Pest ◽  
Pest Species ◽  
Arthropod Species ◽  
Surface Dwelling ◽  
Arthropod Biodiversity ◽  
Searching Method ◽  
The Impact ◽  
Arthropod Pest

A field study was conducted to find out the impact of three selected pesticides on arthropod biodiversity in brinjal agro-ecosystem during 2011-2012 at Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU). Twenty-six arthropod species were observed through visual searching method out of which 18 were insect pest species (from 14 families under 8 orders) and 8 were natural enemies (from 8 families under 6 families). Twenty one species of surface dwelling arthropods were caught in pitfall traps method, 12 of them were insect pest species (from 11 families under 8 orders) and 9 were natural enemies (from 9 families under 5 orders). Formicidae was the most abundant family among them. Bacillus thuringiensis (Bt) and Tracer 45SC (Spinosad) were less harmful to arthropod pest species as well as natural enemies in the brinjal agro-ecosystem. Proclaim 5SG reduced the overall abundance of arthropod species. Bacillus thuringiensis (Bt) and Tracer 45SC were relatively safe for natural enemies and therefore would be fit well into integrated pest management (IPM) against BSFB of brinjal crop.Int. J. Agril. Res. Innov. & Tech. 8 (1): 55-61, June, 2018

scholarly journals Current Insights on Vegetative Insecticidal Proteins (Vip) as Next Generation Pest Killers

Toxins ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 522
Author(s):  
Tahira Syed ◽  
Muhammad Askari ◽  
Zhigang Meng ◽  
Yanyan Li ◽  
Muhammad Ali Abid ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Mechanism Of Action ◽  
Insecticidal Activity ◽  
Binding Sites ◽  
Growth Phases ◽  
Cry Proteins ◽  
Insecticidal Proteins ◽  
Gram Negative ◽  
Vip Proteins ◽  
Evolution Of Resistance

Bacillus thuringiensis (Bt) is a Gram negative soil bacterium. This bacterium secretes various proteins during different growth phases with an insecticidal potential against many economically important crop pests. One of the important families of Bt proteins is vegetative insecticidal proteins (Vip), which are secreted into the growth medium during vegetative growth. There are three subfamilies of Vip proteins. Vip1 and Vip2 heterodimer toxins have an insecticidal activity against many Coleopteran and Hemipteran pests. Vip3, the most extensively studied family of Vip toxins, is effective against Lepidopteron. Vip proteins do not share homology in sequence and binding sites with Cry proteins, but share similarities at some points in their mechanism of action. Vip3 proteins are expressed as pyramids alongside Cry proteins in crops like maize and cotton, so as to control resistant pests and delay the evolution of resistance. Biotechnological- and in silico-based analyses are promising for the generation of mutant Vip proteins with an enhanced insecticidal activity and broader spectrum of target insects.

scholarly journals Characterization of Long Non-Coding RNAs in the Bollworm, Helicoverpa zea, and Their Possible Role in Cry1Ac-Resistance

Insects ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 12
Author(s):  
Roger D. Lawrie ◽  
Robert D. Mitchell ◽  
Jean Marcel Deguenon ◽  
Loganathan Ponnusamy ◽  
Dominic Reisig ◽  
...  
Keyword(s):  
Gene Expression ◽  
Helicoverpa Zea ◽  
Insect Pest ◽  
Field Resistance ◽  
Pest Species ◽  
Chemical Insecticide ◽  
Significant Differential Expression ◽  
Protein Coding ◽  
Non Coding Rnas

Multiple insect pest species have developed field resistance to Bt-transgenic crops. There has been a significant amount of research on protein-coding genes that contribute to resistance, such as the up-regulation of protease activity or altered receptors. However, our understanding of the role of non-protein-coding mechanisms in Bt-resistance is minimal, as is also the case for resistance to chemical pesticides. To address this problem relative to Bt, RNA-seq was used to examine statistically significant, differential gene expression between a Cry1Ac-resistant (~100-fold resistant) and Cry1Ac-susceptible strain of Helicoverpa zea, a prevalent caterpillar pest in the USA. Significant differential expression of putative long non-coding RNAs (lncRNAs) was found in the Cry1Ac-resistant strain (58 up- and 24 down-regulated gene transcripts with an additional 10 found only in resistant and four only in susceptible caterpillars). These lncRNAs were examined as potential pseudogenes and for their genomic proximity to coding genes, both of which can be indicative of regulatory relationships between a lncRNA and coding gene expression. A possible pseudogenic lncRNA was found with similarities to a cadherin. In addition, putative lncRNAs were found significantly proximal to a serine protease, ABC transporter, and CYP coding genes, potentially involved in the mechanism of Bt and/or chemical insecticide resistance. Characterization of non-coding genetic mechanisms in Helicoverpa zea will improve the understanding of the genomic evolution of insect resistance, improve the identification of specific regulators of coding genes in general (some of which could be important in resistance), and is the first step for potentially targeting these regulators for pest control and resistance management (using molecular approaches, such as RNAi and others).

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