Correlation between serovars of Bacillus thuringiensis and type I β-exotoxin production

Hernández, Carmen Sara; Martı́nez, Clara; Porcar, Manuel; Caballero, Primitivo; Ferré, Juan

doi:10.1016/s0022-2011(02)00199-4

Cited by 18 publications

(11 citation statements)

References 30 publications

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“…There are different methods to determine which B. thuringiensis strains produce β‐exotoxins (hereafter βEx + ), including high‐performance liquid chromatography (HPLC), bioassays with susceptible insects, spectrophotometry, enzyme‐linked immunosorbent assay and polymerase chain reaction (Gohar and Perchat ; Hernández et al . ; Liu et al . ).…”

Section: Introductionmentioning

confidence: 99%

Detection of β-exotoxin synthesis in Bacillus thuringiensis using an easy bioassay with the nematode Caenorhabditis elegans

Sánchez-Soto¹,

Saavedra-González²,

Ibarra³

et al. 2015

Lett Appl Microbiol

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In this work, we implemented a qualitative and fast bioassay using the nematode Caenorhabditis elegans to detect the production of β-exotoxin in different strains of Bacillus thuringiensis. We show that this assay is useful to detect β-exotoxin in B. thuringiensis with high reliability, helping to discriminate strains that could not be used as bioinsecticides because of their putative risk to humans. Data show that qualitative bioassay with nematodes is a potential alternative to fly larvae bioassays, and correlated with the determination of β-exotoxin by HPLC.

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Section: Introductionmentioning

confidence: 99%

Detection of β-exotoxin synthesis in Bacillus thuringiensis using an easy bioassay with the nematode Caenorhabditis elegans

Sánchez-Soto¹,

Saavedra-González²,

Ibarra³

et al. 2015

Lett Appl Microbiol

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“…B. thuringiensis subsp. thuringiensis strains (like 4A4) that contain Cry1 toxins very often also produce plasmid-encoded β-exotoxin [13,14,15]. Analysis of the 4A4 genome revealed that this strain indeed has all genes necessary for β-exotoxin production, all of which are located on a plasmid right next to Cry1Ba1.…”

Section: Resultsmentioning

confidence: 99%

“…In contrast, some B. thuringiensis strains secrete toxins during vegetative growth, which are called vegetative insecticidal proteins (Vip) [10,11,12]. Another secreted toxin of B. thuringiensis is the thermostable secondary metabolite β-exotoxin, which has a wide range of insecticidal activity [13,14,15]. …”

Section: Introductionmentioning

confidence: 99%

Identification of Distinct Bacillus thuringiensis 4A4 Nematicidal Factors Using the Model Nematodes Pristionchus pacificus and Caenorhabditis elegans

Iatsenko

Nikolov

Sommer

2014

Toxins

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Bacillus thuringiensis has been extensively used for the biological control of insect pests. Nematicidal B. thuringiensis strains have also been identified; however, virulence factors of such strains are poorly investigated. Here, we describe virulence factors of the nematicidal B. thuringiensis 4A4 strain, using the model nematodes Pristionchus pacificus and Caenorhabditis elegans. We show that B. thuringiensis 4A4 kills both nematodes via intestinal damage. Whole genome sequencing of B. thuringiensis 4A4 identified Cry21Ha, Cry1Ba, Vip1/Vip2 and β-exotoxin as potential nematicidal factors. Only Cry21Ha showed toxicity to C. elegans, while neither Cry nor Vip toxins were active against P. pacificus, when expressed in E. coli. Purified crystals also failed to intoxicate P. pacificus, while autoclaved spore-crystal mixture of B. thuringiensis 4A4 retained toxicity, suggesting that primary β-exotoxin is responsible for P. pacificus killing. In support of this, we found that a β-exotoxin-deficient variant of B. thuringiensis 4A4, generated by plasmid curing lost virulence to the nematodes. Thus, using two model nematodes we revealed virulence factors of the nematicidal strain B. thuringiensis 4A4 and showed the multifactorial nature of its virulence.

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“…Several other studies (Cantwell et al, 1964;Mohd-Salleh et al, 1980;Ohba et al, 1981;Levinson et al, 1990;Hernández et al, 2001) showed that -exotoxin was associated with certain Bt serovars, including;aizawai, alesti, darmstadiensis, galleriae, kenyae, kurstaki, morrisoni, sotto, tenebrionis, tolworthi, and thuringiensis. However, Ohba et al (1981) and Hernández et al (2001Hernández et al ( , 2003 demonstrated that β-exotoxin production is a strain-specific property rather than a serovar-specific property. This is in agreement with the present study.…”

Section: Discussionmentioning

confidence: 99%

Toxicity of Bacillus thuringiensis d-exotoxins and b-endotoxins to Drosophila melanogaster, Ephestia kuhniella and human erythrocytes

Obeidat¹,

Khyami-Horani

Al-Momani³

2012

Afr. J. Biotechnol.

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A total of 73 Bacillus thuringiensis (Bt) strains were screened for the presence of non-hemolytic insecticidal -exotoxin-free -endotoxins. Out of them, 45 Bt strains produced -endotoxins with specific insecticidal activity against Drosophila melanogaster and/or Ephestia kuhniella larvae. The thermostable -exotoxin was observed only in 15 Bt strains and appeared to exhibit dual non-specific insecticidal activity against both D. melanogaster and E. kuhniella larvae and showed in vitro hemolysis for human erythrocytes. It was found that -exotoxin was produced by Bt strains belonging to five serovars (israelensis, kenyae, kurstaki, pakistani, and tohokuensis) and two non-serotypable strains. This result suggests that β-exotoxin production is a strain-specific property rather than a serovarspecific property. To our knowledge, this is the first study that demonstrates -exotoxins production association with Bt strains belonging to serovars israelensis, pakistani, and tohokuensis. The plasmid DNA profiles of some -exotoxin producing Bt strains shared large plasmid patterns which may have the common -exotoxin regulatory gene(s). It was found that 16 local Bt strains, 15 of which belonged to five serovars (aizawai, israelensis, kurstaki, morrisoni, and pakistani) and one was autoagglutinated strain, produced non-hemolytic insecticidal -exotoxin-free -endotoxins. Based on random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR), the genotypic relatedness among these 16 Bt strains was investigated. The strains were grouped into two clusters. Bt strains within serovars israelensis were grouped in two subclusters, Bt strains within serovars aizawai were genomically homogeneous and clustered together, while the other serovars were grouped together in one subcluster. The autoagglutinated strain was clustered within serovar israelensis. Thus, these endotoxins can be developed for the use in Bt-based insecticidal preparations.

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Correlation between serovars of Bacillus thuringiensis and type I β-exotoxin production

Cited by 18 publications

References 30 publications

Detection of β-exotoxin synthesis in Bacillus thuringiensis using an easy bioassay with the nematode Caenorhabditis elegans

Detection of β-exotoxin synthesis in Bacillus thuringiensis using an easy bioassay with the nematode Caenorhabditis elegans

Identification of Distinct Bacillus thuringiensis 4A4 Nematicidal Factors Using the Model Nematodes Pristionchus pacificus and Caenorhabditis elegans

Toxicity of Bacillus thuringiensis d-exotoxins and b-endotoxins to Drosophila melanogaster, Ephestia kuhniella and human erythrocytes

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