Bacillus thuringiensis Applications in Agriculture

George, Zenas Okon; Crickmore, N.

doi:10.1007/978-94-007-3021-2_2

Cited by 35 publications

(26 citation statements)

References 165 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Transgenic plants expressing different insecticidal genes are good alternatives to harmful chemical insecticides [1] and also led to the worldwide acceptance of Bt crystal proteins, synthesized by Bacillus thuringiensis , as a major insecticidal toxin against different insects [2]. B. thuringiensis , a gram positive soil bacterium [3], produces a number of protoxin proteins during sporulation that are deposited in the form of parasporal crystals and known as Bt toxin or δ-endotoxin [4].…”

Section: Introductionmentioning

confidence: 99%

New Insight to Structure-Function Relationship of GalNAc Mediated Primary Interaction between Insecticidal Cry1Ac Toxin and HaALP Receptor of Helicoverpa armigera

et al. 2013

View full text Add to dashboard Cite

Over the last few decades Cry1Ac toxin has been widely used in controlling the insect attack due to its high specificity towards target insects. The pore-forming toxin undergoes a complex mechanism in the insect midgut involving sequential interaction with specific glycosylated receptors in which terminal GalNAc molecule plays a vital role. Recent studies on Cry toxins interactions with specific receptors revealed the importance of several amino acid residues in domain III of Cry1Ac, namely Q509, N510, R511, Y513 and W545, serve as potential binding sites that surround the putative GalNAc binding pocket and mediate the toxin-receptor interaction. In the present study, alanine substitution mutations were generated in the Cry1Ac domain III region and functional significance of those key residues was monitored by insect bioassay on Helicoverpa armigera larvae. In addition, ligand blot analysis and SPR binding assay was performed to monitor the binding characteristics of Cry1Ac wild type and mutant toxins towards HaALP receptor isolated from Helicoverpa armigera. Mutagenesis data revealed that, alanine substitutions in R511, Y513 and W545 substantially impacted the relative affinity towards HaALP receptor and toxicity toward target insect. Furthermore, in silico study of GalNAc-mediated interaction also confirmed the important roles of these residues. This structural analysis will provide a detail insight for evaluating and engineering new generation Cry toxins to address the problem of change in insect behavioral patterns.

show abstract

Section: Introductionmentioning

confidence: 99%

New Insight to Structure-Function Relationship of GalNAc Mediated Primary Interaction between Insecticidal Cry1Ac Toxin and HaALP Receptor of Helicoverpa armigera

et al. 2013

View full text Add to dashboard Cite

show abstract

“…One of them might be the non-target nature of S. litura. Ruut et al (2001) and George & Crickmore (2012) found that the host-specific nature of Bt toxins, might induce the production of different toxins crystal, which might not be suitable for the non-target pests. The selectivity of Bt toxin is determined by toxin structure and other factors on the body of the target insects.…”

Section: The Effect Of Bt Toxin Cry2ab2 On Spodoptera Lituramentioning

confidence: 99%

“…Many control methods have been employed to keep this pest on check including biological control and synthetic chemical pestisides (Subiadi et al, 2014). One of the currently developed biological control method is the use of Bacilus thuringiensis (Bt), either conventionally by direct spraying or inserted within the transgenic maize crops throught genetically modification procedure (George & Crickmore, 2012). There are many toxins that have been used to create transgenic maize such as Cry1A.105, Cry1Ab, Cry2Ab2, Cry34Ab1, Cry35Ab1, Cry3Bb, Cry3Bb1, and Cry1F (Roh et al, 2007) (PSA, 2015).…”

Section: Introductionmentioning

confidence: 99%

THE EFFECT OF Bacillus thuringiensis TOXIN Cry1A.105 AND Cry2Ab2 ON THE SURVIVAL OF THE NON-TARGET PEST, Spodoptera litura (PENGARUH TOKSIN Bacillus thuringiensis Cry1A.105 DAN Cry2Ab2 TERHADAP KELANGSUNGAN HIDUP HAMA BUKAN SASARAN, Spodoptera litura)

Pratiwi

Trisyono

Martono

2017

JPTI

View full text Add to dashboard Cite

Spodoptera litura is one of the important insect pest of maize besides the notoriously damaging corn borer, Ostrinia furnacalis. S. litura has been the target of various controls including the use of Bacillus thuringiensis (Bt) toxin Cry1A.105 and Cry2Ab2. This study was conducted to evaluate the acute effect of Bt toxin Cry1A.105 and Cry2Ab2 on the growth and development of S. litura from larval to adult stages. Two sublethal concentrations were used; 0.1875 and 0.0469 ppm for Cry1A.105, and 0.0008 and 0.0003 ppm for Cry2Ab2. The bioassay using diet dipping was carried out on a CRD with three experiments and five repetitions. The observation was carried out on the mortality and survival rates of S. litura. The mortality reached 28% when the larvae were treated with 0.1875 ppm and 20% with 0.0469 ppm of Cry 1A.105. The exposed larvae and pupae were smaller than control. Larval and pupal weight were 117.0 and 165.6 g with 0.1875 ppm, while control were 212.9 and 211.2 g. Cry1A.105 also longer the larval stage, larval stage with higher and lower concentration were 24.5 and 22.3 day, while control was 20.5 day. The resulted pupae from larve which exposed by Cry1A.105 were less than control; there were 40% at concentration 0.1875 ppm and control 61%. The two concentration of Cry2Ab2 produced similar mortality of 20%. Similarly, Cry2Ab2 affected pupal to adult stages development. The longevity of pupal stage with concentration 0.0003 ppm was 9.5 days, followed by 0.0008 ppm (9.1 days) and control (10.1 days). The adult emerge on the highest concentration was 47.4% while control only 34.6%. There results showed that both Cry1A.105 and Cry2Ab2 were detrimental to the survival of S. litura which is the non-target insect of transgenic Bt maize.

show abstract

“…For example, "chitinases for enhancing the entomotoxicity of engineered Bt strains" are receiving considerable attention to develop "new strategies" for pest control (see Li and Yu, 2012 for references therein). Or as George and Crickmore (2012) put it "to boost the efficacy of Bt insecticidal toxins and overcome resistance posed by insect pests, the use of other proteins like cadherin fragments have been shown to be a successful strategy" or "also combinations of Cry toxins have proven to be a very useful strategy employed in boosting efficacy and hting resistance." For example, the secondary compound gossypol derived from the cotton has been applied in combination with Cry1Ac to boost its efficacy against a resistant population of Helicoverpa zea (Anilkumar et al, 2009).…”

Section: Combinatorial Cry Toxin Effects Commonly Knownmentioning

confidence: 99%

Specificity and Combinatorial Effects of Bacillus Thuringiensis Cry Toxins in the Context of GMO Environmental Risk Assessment

Hilbeck

Otto

2015

Front. Environ. Sci.

View full text Add to dashboard Cite

Stacked GM crops expressing up to six Cry toxins from Bacillus thuringiensis (Bt) are today replacing the formerly grown single-transgene GM crop varieties. Stacking of multiple Cry toxins not only increase the environmental load of toxins but also raise the question on how possible interactions of the toxins can be assessed for risk assessment, which is mandatory for GM crops. However, no operational guidelines for a testing strategy or testing procedures exist. From the developers point of view, little data testing for combinatorial effects of Cry toxins is necessary as the range of possibly affected organisms focuses on pest species and no evidence is claimed to exist pointing to combinatorial effects on non-target organisms. We have examined this rationale critically using information reported in the scientific literature. To do so, we address the hypothesis of narrow specificity of Cry toxins subdivided into three underlying different conceptual conditions (i) "efficacy" in target pests as indicator for "narrow specificity," (ii) lack of reported adverse effects of Cry toxins on non-target organisms, and (iii) proposed modes of action of Cry toxins (or the lack thereof) as mechanisms underlying the reported activity/efficacy/specificity of Cry toxins. Complementary to this information, we evaluate reports about outcomes of combinatorial effect testing of Cry toxins in the scientific literature and relate those findings to the practice of environmental risk assessment of Bt-crops in general and of stacked Bt-events in particular.

show abstract

Bacillus thuringiensis Applications in Agriculture

Cited by 35 publications

References 165 publications

New Insight to Structure-Function Relationship of GalNAc Mediated Primary Interaction between Insecticidal Cry1Ac Toxin and HaALP Receptor of Helicoverpa armigera

New Insight to Structure-Function Relationship of GalNAc Mediated Primary Interaction between Insecticidal Cry1Ac Toxin and HaALP Receptor of Helicoverpa armigera

THE EFFECT OF Bacillus thuringiensis TOXIN Cry1A.105 AND Cry2Ab2 ON THE SURVIVAL OF THE NON-TARGET PEST, Spodoptera litura (PENGARUH TOKSIN Bacillus thuringiensis Cry1A.105 DAN Cry2Ab2 TERHADAP KELANGSUNGAN HIDUP HAMA BUKAN SASARAN, Spodoptera litura)

Specificity and Combinatorial Effects of Bacillus Thuringiensis Cry Toxins in the Context of GMO Environmental Risk Assessment

Contact Info

Product

Resources

About