Insecticidal Activity of Two 65 kDa Proteins from Crystal Proteins of Bacillus thuringiensis serovar kurstaki HD-I against the Smaller Tea Tortrix, Adoxophyes sp. and the Diamondback Moth, Plutella xylostella

1996 ◽  
Vol 31 (2) ◽  
pp. 330-334
Author(s):  
Hidetaka HORI ◽  
Masaki HIMEJIMA ◽  
Tomoko IWASA ◽  
Shoji ASANO
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Crystal Proteins

Integrative Model for Binding of Bacillus thuringiensis Toxins in Susceptible and Resistant Larvae of the Diamondback Moth (Plutella xylostella)

1999 ◽  
Vol 65 (4) ◽  
pp. 1413-1419 ◽  
Author(s):  
Victoria Ballester ◽  
Francisco Granero ◽  
Bruce E. Tabashnik ◽  
Thomas Malvar ◽  
Juan Ferré
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Binding Sites ◽  
Diamondback Moth ◽  
The Philippines ◽  
Competitive Binding ◽  
Single Mutation ◽  
Crystal Proteins ◽  
Mechanism Of Resistance ◽  
Resistant Strains

ABSTRACT Insecticidal crystal proteins from Bacillus thuringiensis in sprays and transgenic crops are extremely useful for environmentally sound pest management, but their long-term efficacy is threatened by evolution of resistance by target pests. The diamondback moth (Plutella xylostella) is the first insect to evolve resistance to B. thuringiensis in open-field populations. The only known mechanism of resistance to B. thuringiensis in the diamondback moth is reduced binding of toxin to midgut binding sites. In the present work we analyzed competitive binding of B. thuringiensis toxins Cry1Aa, Cry1Ab, Cry1Ac, and Cry1F to brush border membrane vesicles from larval midguts in a susceptible strain and in resistant strains from the Philippines, Hawaii, and Pennsylvania. Based on the results, we propose a model for binding of B. thuringiensis crystal proteins in susceptible larvae with two binding sites for Cry1Aa, one of which is shared with Cry1Ab, Cry1Ac, and Cry1F. Our results show that the common binding site is altered in each of the three resistant strains. In the strain from the Philippines, the alteration reduced binding of Cry1Ab but did not affect binding of the other crystal proteins. In the resistant strains from Hawaii and Pennsylvania, the alteration affected binding of Cry1Aa, Cry1Ab, Cry1Ac, and Cry1F. Previously reported evidence that a single mutation can confer resistance to Cry1Ab, Cry1Ac, and Cry1F corresponds to expectations based on the binding model. However, the following two other observations do not: the mutation in the Philippines strain affected binding of only Cry1Ab, and one mutation was sufficient for resistance to Cry1Aa. The imperfect correspondence between the model and observations suggests that reduced binding is not the only mechanism of resistance in the diamondback moth and that some, but not all, patterns of resistance and cross-resistance can be predicted correctly from the results of competitive binding analyses of susceptible strains.

scholarly journals Identification of a native Bacillus thuringiensis strain from Sri Lanka active against Dipel-resistant Plutella xylostella

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7535
Author(s):  
Rashini Yasara Baragamaarachchi ◽  
Jayanetti Koralage Ramani Radhika Samarasekera ◽  
Ovitigala Vithanage Don Sisira Jagathpriya Weerasena ◽  
Kurt Lamour ◽  
Juan Luis Jurat-Fuentes
Keyword(s):  
Bacillus Thuringiensis ◽  
Sri Lanka ◽  
Insecticidal Activity ◽  
Plutella Xylostella ◽  
Multilocus Sequence Typing ◽  
Diamondback Moth ◽  
Sustainable Use ◽  
Field Resistance ◽  
Protein Crystal ◽  
Isolation And Characterization

Background Biopesticides based on strains of the bacterium Bacillus thuringiensis (Bt) are used globally for effective and environmentally friendly pest control. The most serious threat to the sustainable use of these microbial pesticides is the development of resistance on targeted pests. Populations of Plutella xylostella (diamondback moth) have evolved field resistance to Bt pesticides at diverse locations worldwide. Discovery of novel Bt strains with varied toxin profiles that overcome resistance is one of the strategies to increase sustainability of Bt pesticides against P. xylostella. In this study, we report isolation and characterization of a Bt strain named AB1 from Sri Lanka displaying toxicity towards larvae of P. xylostella resistant to the commercial Bt pesticide Dipel. Methods Strains of Bt from diverse environments in Sri Lanka were evaluated for protein crystal production through Differential Interference Contrast (DIC) microscopic examination, and for insecticidal activity against P. xylostella in bioassays. The genome of the AB1 strain was sequenced by Hiseq Illumina sequencing to identify the insecticidal genes present in the genome and nano liquid chromatography followed by tandem mass spectrometry (nanoLC/MS/MS) of purified crystal proteins of AB1 was performed to identify the expressed insecticidal proteins. Multilocus sequence typing and Gyrase B gene sequence analyses were performed to identify the phylogenetic origin of the AB1 strain. Results The AB1 strain was identified as producing high levels of bipyramidal crystals and displaying insecticidal activity against susceptible and Dipel-resistant strains of P. xylostella. Multilocus sequence typing and phylogenetic analysis of the Gyrase B gene identified that AB1 belongs to the B. thuringiensis subsp. aizawai serotype. Comparative analysis of genomic and proteomic data showed that among the insecticidal protein coding genes annotated from the AB1 genome (cry1Aa, cry1Ca, cry1Da, cry1Ia, cry2Ab and cry9), Cry1Ca and Cry1Da toxins represented most of the toxin fraction in parasporal crystals from AB1. Overall findings warrant further development of B. thuringiensis subsp. aizawai AB1 strain as a pesticide to control P. xylostella.

Sign in / Sign up

Export Citation Format

Share Document