Green-Tissue-Specific Expression of a Reconstructedcry1CGene Encoding the Active Fragment ofBacillus thuringiensisδ-Endotoxin in Haploid Tobacco Plants Conferring Resistance toSpodoptera litura

Christov, N.; Imaishi, Hiromasa; Ohkawa, Hideo

doi:10.1271/bbb.63.1433

Cited by 15 publications

(9 citation statements)

References 34 publications

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“…The successful expression of cry1B and cry1C genes in transgenic plants has been previously reported to confer resistance for larvae of Lepidopteran insects. Expression of a cry1C gene provided effective control of diamondback moth, cabbage worm and cabbage looper in transgenic vegetable brassicas (Cao et al 1999;Cho et al 2001) and tobacco cutworm in transgenic tobacco (Christov et al 1999). Furthermore, cry genes identical to those used in this study have been previously shown to confer resistance to Lepidopteran larvae.…”

Section: Discussionmentioning

confidence: 67%

Transgenic Potato Lines Expressing cry1Ba1 or cry1Ca5 Genes are Resistant to Potato Tuber Moth

et al. 2007

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Modified cry1Ca5 and cry1Ba1 genes, under the transcriptional control of a CaMV 35S promoter, were individually transferred into potato (Solanum tuberosum L.) cv. Iwa using Agrobacterium-mediated transformation. Thirty-six and thirty-eight independently derived cry1Ca5-and cry1Ba1-transgenic plants were regenerated respectively. Multiplex-PCR confirmed the presence of the nptII selectable marker gene and the specific cry gene in all regenerated lines. In greenhouse experiments, approximately 90% of each transgenic population produced phenotypically normal plants. More than 90% of the cry1Ca5-transgenic lines gave 100% larval mortality of potato tuber moth (PTM), Phthorimaea operculella (Zeller), on excised greenhousegrown leaf and tuber bioassays. In contrast, only 40-50% of the cry1Ba1-transgenic lines gave 50 to 100% of larval mortality of PTM using the same bioassays, although all lines except one significantly inhibited larval growth. Southern blot analysis for eight selected cry1Ca5-transgenic lines revealed that they contained 1 to 6 copies of the cry gene. The amount of Cry1C protein, quantified by ELISA, ranged from 0.26 to 8.42 μg per g of leaf tissue and from 0.23 to 1.02 μg per g of tuber tissue. No relationship was apparent between cry1Ca5 gene copy number and amount of Cry protein expressed in leaves and tubers. Southern blot analysis for seven selected cry1Ba1-transgenic lines revealed that they contained 2 to 8 copies of the cry1Ba1 gene. Both the cry1Ca5 and cry1Ba1 genes offer additional sources of resistance that can be deployed with other effective cry genes to control tuber moth in potatoes.

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Section: Discussionmentioning

confidence: 67%

Transgenic Potato Lines Expressing cry1Ba1 or cry1Ca5 Genes are Resistant to Potato Tuber Moth

et al. 2007

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“…Christov et al . () reported that truncated cryIC encoding N‐terminal 655 aa is active against S . litura .…”

Section: Resultsmentioning

confidence: 97%

Synergistic activity of Bacillus thuringiensis δ‐endotoxin and TMOF against Culex pipiens and Spodoptera littoralis larvae

Mohammed

Diab

Khalil

2017

Entomological Research

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Trypsin Modulating Oostatic Factor (TMOF) is a decapeptide hormone that inhibits the biosynthesis of digestive enzymes in the mosquito midgut. The hormone inhibits food digestion and ultimately leads to starvation and death. It has been used as a biological insecticide to control mosquitoes. In an attempt to increase the insecticidal activity of TMOF, a combination of CryIC (δ‐endotoxin from Bacillus thuringiensis) and TMOF was determined. Eight recombinant proteins fused with GST (glutathione‐S‐transferase) were expressed in Escherichia coli cells. Their insecticidal activities were determined against Culex pipiens and Spodoptera littoralis larvae. Purified GST‐TMOF and its analogue GST‐YDPAS exhibited a moderate toxicity on C. pipiens larvae with LC50 of 145.9 and 339.9 μg/mL, respectively. Unexpectedly, no mortality was observed in first instar larvae of S. littoralis. Puirified GST‐TMOF and GST‐YDPAS together with Bt toxin showed a synergistic toxic effect on both Culex and Spodoptera larvae. In the presence of 100 μg/mL GST‐TMOF and GST‐YDPAS, the median lethal concentration of entomocidus on culex larvae decreased from 52.1 to 16.7 and 31.9 μg/mL, respectively. Likewise, GST‐TMOF and GST‐YDPAS incorporated with 0.07 μg/cm2 of enotmocidus showed insecticidal activity against S. littoralis with LC50 of 16.4 and 21.9 μg/cm2. The E. coli lysates containing GST‐CryIC and its 3′‐truncated version showed low toxicity against the lepidopteran insect (10.8 and 16.6 μg/cm2) compared to 0.15 μg/cm2 of the native crystalline form of CryIC. Similarly, the mosquitocidal activity of the recombinant Bt toxins was low.

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“…tobacco by Christov et al (1999) using the (rbcS) gene promoter. The ST-LS1 and rbcS genes belong to the same class of genes.…”

Section: Discussionmentioning

confidence: 99%

“…The intrinsic specificity of the latter group of promoters limits their application to monocots and phloem. The ribulose-bisphosphate carboxylase small subunit gene promoter (rbcS) has been shown to drive green tissue specific expression of Bt protein in tobacco but at low levels (Christov et al, 1999). The same promoter from Chrysanthemum, on the other hand, has been reported as a strong promoter for a hybrid Bt gene in potato (Naimov et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

The Bt gene cry2Aa2 driven by a tissue specific ST-LS1 promoter from potato effectively controls Heliothis virescens

et al. 2005

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Expression of the Cry2Aa2 protein was targeted specifically to the green tissues of transgenic tobacco Nicotiana tabacum cv. Xanthi plants. This deployment was achieved by using the promoter region of the gene encoding the Solanum tuberosum leaf and stem specific (ST-LS1) protein. The accumulated levels of toxin in the leaves were found to be effective in achieving 100% mortality of Heliothis virescens larvae. The levels of Cry2Aa2 expression in the leaves of these transgenic plants were up to 0.21% of the total soluble proteins. Bioassays with R 1 transgenic plants indicated the inheritance of cry2Aa2 in the progeny plants. Tissue-specific expression of the Bt toxin in transgenic plants may help in controlling the potential occurrence of insect resistance by limiting the amount of toxin to only predated tissues. The results reported here validate the use of the ST-LS1 gene promoter for a targeted expression of Bt toxins in green tissues of plants.

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Green-Tissue-Specific Expression of a Reconstructedcry1CGene Encoding the Active Fragment ofBacillus thuringiensisδ-Endotoxin in Haploid Tobacco Plants Conferring Resistance toSpodoptera litura

Cited by 15 publications

References 34 publications

Transgenic Potato Lines Expressing cry1Ba1 or cry1Ca5 Genes are Resistant to Potato Tuber Moth

Transgenic Potato Lines Expressing cry1Ba1 or cry1Ca5 Genes are Resistant to Potato Tuber Moth

Synergistic activity of Bacillus thuringiensis δ‐endotoxin and TMOF against Culex pipiens and Spodoptera littoralis larvae

The Bt gene cry2Aa2 driven by a tissue specific ST-LS1 promoter from potato effectively controls Heliothis virescens

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