Characterization of Lepidoptera-active cry and vip genes in Iranian Bacillus thuringiensis strain collection

Seifinejad, Ali; Jouzani, G.R. Salehi; Hosseinzadeh, Abbas; Abdmishani, C.

doi:10.1016/j.biocontrol.2007.09.010

Cited by 38 publications

(44 citation statements)

References 30 publications

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“…Similarly, the low occurrence of cry1B (one isolate) among the 31 isolates was consistent with similar findings in Korean and Iranian collections 27,30 . The results reported here differ from the results of a recent survey of Bt isolates obtained in Thailand by Thammasittirong and Attathom 12 in which cry1A, found at a relatively low frequency in the current work, was the most prevalent type.…”

Section: Discussionsupporting

confidence: 89%

“…The prevalence of cry1 gene type 1C and 1D found in the present study was not surprising, since they have been noted earlier in Asian Bt collections [26][27][28][29][30] . Similarly, the low occurrence of cry1B (one isolate) among the 31 isolates was consistent with similar findings in Korean and Iranian collections 27,30 .…”

Section: Discussionsupporting

confidence: 86%

“…This suggests some genetic linkage between cry1Cb and 1D (Fig. 2b) as has been previously reported 30,35 . The JC 291 isolate showed high toxicity to O. furnacalis, but differed in its cry1 PCR-RFLP pattern in the collection from the current study, as it contained three different cry1 type genes: cry1C, cry1Cb and cry1D.…”

Section: Discussionsupporting

confidence: 85%

“…Although possessing several cry-type genes was not considered to directly reflect the toxic level of Bt strains 28,30 , harbouring different cry gene types can give the isolates a broader spectrum of insect specificity. The toxicity level depends more on the level of gene expression and the synergism between different cry-type genes 33,34 , as well as on the copy number of plasmid templates for toxin production.…”

Section: Discussionmentioning

confidence: 99%

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Lertwiriyawong¹,

Pinthong²,

Chanpaisaeng³

et al. 2010

ScienceAsia

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ABSTRACT:The novel δ-endotoxin from Bacillus thuringiensis (Bt) is one of the alternative measures for lepidopteran pest control. A survey of 31 Bt isolates, obtained from Thailand and previously screened for their toxicity to lepidopterans, was conducted to determine the presence of cry1-type genes, using polymerase chain reaction -restriction fragment length polymorphism analysis. Seven distinct types of cry1 genes: cry1Aa, cry1B, cry1C, cry1Cb, cry1D, cry1E, and cry1F, were identified. The most common of the cry1-type genes was cry1Cb, followed by cry1C and cry1D, which covered 64.6, 48.4, and 25.8%, respectively. Besides cry1C and cry1Cb, two candidate cry genes, cry1E and cry1D, of isolate JC 190 (harbouring cry1C/1E), with cotton bollworm toxin specificity, showed 99% amino acid sequence identity to Cry1Ea of B. thuringiensis subsp. kenyae, while isolate JC 291 (containing cry1C/1Cb/1D), with Asian corn borer toxin specificity, harboured Cry1Dc, which exhibited only 84% amino acid sequence identity to Cry1Da of B. thuringiensis subsp. aizawai. The C-terminus of the JC291Cry1Dc possessed a unique sequence, 812-NVPIIPIISPW-822. Furthermore, the major differences between the 3D structure of Cry1Dc and Cry1Aa were confined to Domain II as three loop structures.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 86%

Section: Discussionsupporting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

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Lertwiriyawong¹,

Pinthong²,

Chanpaisaeng³

et al. 2010

ScienceAsia

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“…The results showed that all 5 isolates exhibited strong toxicity to C. pipiens and C. maculatus while, 2 isolates (YD10 and YH18) had larvicidal against S. littoralis. These results confirmed the results of microscopic examination of isolates no YD10 and YH18 which showed bipyramidal parasporal inclusions and exhibited strong toxicity to Lepidoptera [22,32,40,45].…”

Section: Discussionsupporting

confidence: 86%

Occurrence of Bacillus thuringiensis and their phages in Yemen soil

El–Didamony

2013

VirusDis.

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Bacillus thuringiensis (Bt) isolates were found in all samples of soil in nine Governorates of Yemen. From 384 isolates of Bacillus recovered from these soil samples after acetate selection, 104 isolates (27.1 %) were Bt. Five isolates of Bt were selected and insecticidal activity was tested against Culex pipiens, Callosobruchus maculatus and Spodoptera littoralis. The Bt isolate YH18 gave toxicity to all tested insects larvae. This study extended to isolate phages active against the selected Bt isolates. Five phages were isolated and classified into two groups of tailed phages. Four phages with long non-contractile tails and hexagonal heads (Siphoviridae) and one phage with very short tail and isometric head (Podoviridae). Susceptibility of selected Bt to infect by these phages was studied by spot-test technique. Also the Bt isolate no YH18 was resistant to all tested phages. This is the first report illustrates the diversity and the abundance of Bt and Bt phage in Yemen soil.

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Selection and characterization of Bacillus thuringiensis strains from northwestern Himalayas toxic against Helicoverpa armigera

2017

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In this study, we present the selection and the characterization of Bacillus thuringiensis (Bt) strains with respect to their cry/cyt gene content and toxicity evaluation toward one of the most important polyphagous lepidopteran pest, Helicoverpa armigera. Fifty‐six Bt isolates were obtained from 10 different regions of northwestern Himalayas, recording a total B. thuringiensis index of 0.62. Scanning electron microscopy revealed presence of bipyramidal, spherical, flat and irregular crystal shapes; SDS‐PAGE analysis of spore‐crystal mixtures showed the prominence of 130, 70, and 100 kDa protein bands in majority of the isolates; PCR analysis with primers for eight cry and cyt gene families and 13 cry gene subfamilies resulted in isolates showing different combinations of insecticidal genes. Strains containing cry1 were the most abundant (57.1%) followed by cyt2 (46.42%), cry11 (37.5%), cry2 (28.57%), cry4 (21.42%), cyt1 (19.64%), cry3 (8.9%), and cry7, 8 (7.14%). A total of 30.35% of the strains did not amplify with any of the primers used in this study. Median lethal concentration 50 (LC50) estimates of spore‐crystal mixtures of Bt‐JK12, 17, 22, 48, and 72 against second instar larvae of H. armigera was observed to be 184.62, 275.39, 256.29, 259.93 μg ml−1, respectively. B. thuringiensis presents great diversity with respect to the presence of crystal protein encoding genes and insecticidal activity. Four putative toxic isolates identified in this study have potential application in insect pest control. B. thuringiensis isolate JK12 exhibited higher toxicity against H. armigera than that of B. thuringiensis HD1, hence can be commercially exploited to control insect pest for sustainable crop production. The results of this study confirm the significance of continuous exploration of new Bt stains from different ecological regions of the world.

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Characterization of Lepidoptera-active cry and vip genes in Iranian Bacillus thuringiensis strain collection

Cited by 38 publications

References 30 publications

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Occurrence of Bacillus thuringiensis and their phages in Yemen soil

Selection and characterization of Bacillus thuringiensis strains from northwestern Himalayas toxic against Helicoverpa armigera

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