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 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.

VULNERABILITY OF THE FIR CONEWORM, DIORYCTRIAABIETIVORELLA (GROTE) (LEPIDOPTERA: PYRALIDAE), IN DIFFERENT LARVAL STAGES TO THE HD-1 STRAIN OF BACILLUS THURINGIENSIS

1997 ◽  
Vol 129 (1) ◽  
pp. 197-198 ◽  
Author(s):  
Richard Trudel ◽  
Éric Bauce ◽  
Jean Cabana ◽  
Claude Guertin
Keyword(s):  
Bacillus Thuringiensis ◽  
Insect Pest ◽  
Specific Effect ◽  
Young Tree ◽  
Seed Orchards ◽  
Larval Stages ◽  
Dioryctria Abietivorella ◽  
Lepidoptera Pyralidae ◽  
Natural Stands ◽  
The Impact

The fir coneworm, Dioryctria abietivorella (Grote), is a major insect pest in seed orchards across Canada and the adjoining eastern and western United States. Larvae feed principally on cones, but they can also feed on needles and occasionally on the bark of young tree trunks (Hedlin et al. 1980; Ruth 1980; Martineau 1985). The potential for a population of D. abietivorella to build up in seed orchards may be greater than in natural stands (Hedlin et al. 1980; Ruth et al. 1982). The use of entomopathogen in the management of fir coneworm could be an adequate measure to reduce the impact of this insect. Moreover, Bacillus thuringiensis ssp. kurstaki has a specific effect on Lepidoptera (Aronson et al. 1986; Gill et al. 1992). The purpose of our study was to determine the activity of the HD-1 strain of B. thuringiensis ssp. kurstaki (serotype H-3a:3b) to larvae D. abietivorella. Bioassays were conducted with first-, third-, and fifth-instar larvae of fir coneworm to determine whether or not the insect's vulnerability to B. thuringiensis varies with larval age.

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.

Characterization of Bacillus thuringiensis isolates and their differential toxicity against Helicoverpa armigera populations

2010 ◽  
Vol 51 (1) ◽  
pp. 107-114 ◽  
Author(s):  
Deepak Anitha ◽  
Nachimuthu Senthil Kumar ◽  
Deepu Vijayan ◽  
Kunhikrishnan Ajithkumar ◽  
Guruswami Gurusubramanian
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Armigera ◽  
Differential Toxicity ◽  
Helicoverpa Armígera

Characterization of new Bacillus thuringiensis strains from Iran, based on cytocidal and insecticidal activity, proteomic analysis and gene content

BioControl ◽  
2018 ◽  
Vol 63 (6) ◽  
pp. 807-818 ◽  
Author(s):  
Ayda Khorramnejad ◽  
Reza Talaei-Hassanloui ◽  
Vahid Hosseininaveh ◽  
Yolanda Bel ◽  
Baltasar Escriche
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Proteomic Analysis ◽  
Gene Content

scholarly journals Characterization of Bacillus thuringiensis isolates by their insecticidal activity and their production of Cry and Vip3 proteins

PLoS ONE ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. e0206813 ◽  
Author(s):  
Burcu Şahin ◽  
Joaquín Gomis-Cebolla ◽  
Hatice Güneş ◽  
Juan Ferré
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity

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.

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