Mechanism of insect resistance to the microbial insecticide Bacillus thuringiensis

Science ◽  
1990 ◽  
Vol 247 (4938) ◽  
pp. 72-74 ◽  
Author(s):  
J Van Rie ◽  
W. McGaughey ◽  
D. Johnson ◽  
B. Barnett ◽  
H Van Mellaert
Keyword(s):  
Bacillus Thuringiensis ◽  
Insect Resistance ◽  
Microbial Insecticide

Distribution of Toxin Genes and Enterotoxins in Bacillus thuringiensis Isolated from Microbial Insecticide Products

2015 ◽  
Vol 25 (12) ◽  
pp. 2043-2048 ◽  
Author(s):  
Seung-Hak Cho ◽  
Suk-Ho Kang ◽  
Yea-Eun Lee ◽  
Sung-Jo Kim ◽  
Young-Bin Yoo ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Toxin Genes ◽  
Microbial Insecticide

scholarly journals Evolution of Insect Resistance to Bacillus thuringiensis-Transformed Plants

Science ◽  
1996 ◽  
Vol 273 (5280) ◽  
pp. 1412-1413 ◽  
Author(s):  
A. R. Ives; ◽  
D. N. Alstad ◽  
D. A. Andow
Keyword(s):  
Bacillus Thuringiensis ◽  
Insect Resistance ◽  
Transformed Plants

scholarly journals Insecticidal Effects of Organotin(IV) Compounds on Plutella Xylostella (L.) Larvae. II. Inhibitory Potencies Against Acetylcholinesterase and Evidence for Synergism in Tests With Bacillus Thuringiensis(BER.) and Malathion

1994 ◽  
Vol 1 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Nazni W. Ahmad ◽  
Tay Siew Huang ◽  
S. Balabaskaran ◽  
K. M. Lo ◽  
V. G. Kumar Das
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Resistant Strain ◽  
Synergistic Effects ◽  
Diamondback Moth ◽  
Ache Inhibition ◽  
Microbial Insecticide ◽  
In Vitro Inhibition ◽  
Sublethal Concentrations

Features of pesticide synergism and acetylcholinesterase (AChE) inhibition (in vitro) were studied using a selected range of organotin compounds against the early 4th instar larvae of a highly resistant strain of the diamondback moth (DBM), Plutella xylostella, a major universal pest of cruciferous vegetables.Fourteen triorganotin compounds were evaluated for their ability to enhance the toxicity of the microbial insecticide, Bacillus thuringiensis (BT) and of the commercial insecticide, Malathion to Plutella xylostella larvae. Supplemental synergism was observed with triphenyl- and tricyclopentyltin hydroxides in combinations with Bacillus thuringiensis. Increased synergism was observed with an increase in the number of cyclopentyl groups on tin in the mixed series, CypnPh3-n SnX, where X = OH, and 1-(1,2,4-triazolyl). The combination of (p-chlorophenyl)diphenyltin N,N-dimethyldithiocarbamate at LD10 and LD25 concentrations with sublethal concentrations of Malathion as well as of tricyclohexyltin methanesulphonate at the 0.01% (w/v) concentration with Malathion exerted strong synergistic effects (supplemental synergism) with toxicity index (T.I) values of 7.2, 19.8 and 10.1, respectively.Studies on the in vitro inhibition of acetylcholinesterase prepared from the DBM larvae showed that while most of the triorganotin Compounds tested were without effect on the enzyme, compounds containing the thiocarbamylacetate or the dithiocarbamylacetate moieties demonstrated appreciable levels of inhibition, being comparable in efficacy to commercial grades of Malathion and Methomyl.

scholarly journals An ABC Transporter Mutation Is Correlated with Insect Resistance to Bacillus thuringiensis Cry1Ac Toxin

PLoS Genetics ◽  
2010 ◽  
Vol 6 (12) ◽  
pp. e1001248 ◽  
Author(s):  
Linda J. Gahan ◽  
Yannick Pauchet ◽  
Heiko Vogel ◽  
David G. Heckel
Keyword(s):  
Bacillus Thuringiensis ◽  
Insect Resistance ◽  
Abc Transporter ◽  
Cry1ac Toxin

scholarly journals Research and development of genetically engineered soybean using insect-resistance genes derived from Bacillus thuringiensis

2020 ◽  
Vol 18 (1) ◽  
pp. 1-21
Author(s):  
Le Thi Thu Hien ◽  
Pham Le Bich Hang ◽  
Nguyen Tuong Van ◽  
Le Thi Minh Thanh ◽  
Dao Thi Hang ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Insect Resistance ◽  
Resistance Genes ◽  
Insect Pests ◽  
Economic Value ◽  
Herbicide Tolerance ◽  
Genetically Engineered ◽  
Pests And Diseases ◽  
Good Ability ◽  
The World

Soybean (Glycine max) is one of the crops which have high economic value and serve for food, feed and process of many countries around the world. However, there are many factors affecting the productivity of soybean, of which insect pests and diseases are the most harmful agents. Therefore, an application of biotechnology to transfer insect resistance genes derived from a species of bacteria Bacillus thuringiensis can contribute to increase soybean yield and significantly reducing pesticide use. Currently, there are many insecticidal proteins detected from B. thuringiensis such as Cry, Cyt and Vip with a broad and specific spectrum belonged to several orders Lepidoptera, Diptera, Coleoptera, Homopera, and Nematoda. Numerous studies have been implemented over the world to transfer genes encoding these proteins in combination or modified forms to increase their toxicity. Several events of genetically engineered soybean with stacked traits of insect resistance and herbicide tolerance are commercialized and approved to be cultured in many countries such as MON 87701 × MON 89788 or DAS-81419-2. In Vietnam, studies on genetically engineered soybean with insect resistance trait has been carried out. Moreover, the exploitation, screening and selection of high biodiversity and indigenous B. thuringiensis strains which habors specific genes capable of killing targeted insects and serve as materials for plant transformation are great scientific meaning and potential practical application. This will be an important source of materials to create many soybean cultivars with good ability of insect resistance in order to meet specific needs.

scholarly journals MAPK-activated transcription factor PxJun suppresses PxABCB1 expression and confers resistance to Bacillus thuringiensis Cry1Ac toxin in Plutella xylostella (L.)

2021 ◽  
Author(s):  
Jianying Qin ◽  
Le Guo ◽  
Fan Ye ◽  
Shi Kang ◽  
Dan Sun ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcriptional Regulation ◽  
Bacillus Thuringiensis ◽  
Insect Resistance ◽  
Plutella Xylostella ◽  
Molecular Basis ◽  
Luciferase Reporter ◽  
Regulation Mechanism ◽  
Cry Toxins ◽  
Regulation Mechanisms

Deciphering the molecular mechanisms underlying insect resistance to Cry toxins produced by Bacillus thuringiensis (Bt) is pivotal for the sustainable utilization of Bt biopesticides and transgenic Bt crops. Previously, we identified that MAPK-mediated reduced expression of the PxABCB1 gene is associated with Bt Cry1Ac resistance in the diamondback moth, Plutella xylostella (L.). However, the underlying transcriptional regulation mechanism remains enigmatic. Herein, the PxABCB1 promoter in Cry1Ac-susceptible and Cry1Ac-resistant P. xylostella strains was cloned and analyzed and found to contain a putative Jun binding site (JBS). A dual-luciferase reporter assay and yeast one-hybrid assay (Y1H) demonstrated that the transcription factor PxJun repressed PxABCB1 expression by interacting with this JBS. The expression levels of PxJun were increased in the midguts of all resistant strains compared to the susceptible strain. Silencing of PxJun expression significantly elevated PxABCB1 expression and Cry1Ac susceptibility in the resistant NIL-R strain, and silencing of PxMAP4K4 expression decreased PxJun expression and also increased PxABCB1 expression. These results indicate that MAPK-activated PxJun suppresses PxABCB1 expression to confer Cry1Ac resistance in P. xylostella, deepening our understanding of the transcriptional regulation of midgut Cry receptor genes and the molecular basis of insect resistance to Bt Cry toxins. Importance The transcriptional regulation mechanisms underlying reduced expression of Bt toxin receptor genes in Bt-resistant insects remain elusive. This study unveils that a transcription factor PxJun activated by the MAPK signaling pathway represses PxABCB1 expression and confers Cry1Ac resistance in P. xylostella. Our results provide new insights into the transcriptional regulation mechanisms of midgut Cry receptor genes and deepen our understanding of the molecular basis of insect resistance to Bt Cry toxins. To our knowledge, this study identified the first transcription factor that can be involved in the transcriptional regulation mechanisms of midgut Cry receptor genes in Bt-resistant insects.

Germination and multiplication of Bacillus thuringiensis var. kurstaki in the midgut of Pieris canidia larva: An Electron Microscopic study

1990 ◽  
Vol 48 (3) ◽  
pp. 634-635
Author(s):  
Wilkin W.K. Cheung ◽  
Yui F. Lam
Keyword(s):  
Bacillus Thuringiensis ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Filter Paper ◽  
Bacterial Cells ◽  
Electron Microscopic ◽  
Time Intervals ◽  
Microbial Insecticide ◽  
Petri Dishes

Presently Bacillus thuringiensis var. kurstaki (Btk, thuricide) is a popular microbial insecticide on market for controlling lepidopterous pests. The damage of Btk on lepidopterous larvae have been well documented. However, practically few references give sufficient ultrastructural details on the germination and multiplication of Bt spores and bacterial cells after infecting the larvae. The present study is aimed to fill the gap of the necessary information.Pieris canidia L. larvae were immersed in 2.5% (w/v) thuricide (40,000 IU, Sandoz Co.) spore-crystal suspension for 5 sec. dip and were put onto petri dishes for observation in various time intervals after blotted dry with filter paper. Control larvae had not been treated with Btk.

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