Agrobacterium-transformed rice plants expressing synthetic cryIA(b) and cryIA(c) genes are highly toxic to striped stem borer and yellow stem borer.
Over 2,600 transgenic rice plants in nine strains were regenerated from >500 independently selected hygromycin-resistant calli after Agrobacterium-mediated transformation. The plants were transformed with fully modified (plant codon optimized) versions of two synthetic cryIA(b) and cryIA(c) coding sequences from Bacillus thuringiensis as well as the hph and gus genes, coding for hygromycin phosphotransferase and beta-glucuronidase, respectively. These sequences were placed under control of the maize ubiquitin promoter, the CaMV35S promoter, and the Brassica Bp10 gene promoter to achieve high and tissue-specific expression of the lepidopteran-specific delta-endotoxins. The integration, expression, and inheritance of these genes were demonstrated in R0 and R1 generations by Southern, Northern, and Western analyses and by other techniques. Accumulation of high levels (up to 3% of soluble proteins) of CryIA(b) and CryIA(c) proteins was detected in R0 plants. Bioassays with R1 transgenic plants indicated that the transgenic plants were highly toxic to two major rice insect pests, striped stem borer (Chilo suppressalis) and yellow stem borer (Scirpophaga incertulas), with mortalities of 97-100% within 5 days after infestation, thus offering a potential for effective insect resistance in transgenic rice plants.
Cheng
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Agricultural Biotechnology Laboratories, Department of Biochemistry, Faculty of Medicine, University of Ottawa, 40 Marie Curie Private, Ottawa, Ontario, K1N 6N5 Canada.
Sardana
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R
Kaplan
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H
Altosaar
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D001413:Bacillus thuringiensis / Q000235:genetics; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics / Q000494:pharmacology*; D001427:Bacterial Toxins; D004731:Endotoxins / Q000235:genetics / Q000494:pharmacology*; D005798:Genes, Bacterial; D006460:Hemolysin Proteins; D007300:Insect Control; D007306:Insecticides / Q000494:pharmacology*; D012275:Oryza / Q000235:genetics* / Q000469:parasitology; D010572:Pest Control, Biological; D030821:Plants, Genetically Modified / Q000469:parasitology; D012231:Rhizobium / Q000235:genetics; D014170:Transformation, Genetic
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis