title: Transgenic rice expressing the cry2AX1 gene confers resistance to multiple lepidopteran pests.
abstract: A chimeric Bacillus thuringiensis toxin (Bt) gene, cry2AX1was cloned in a bi-selectable marker free binary vector construct. The cry2AX1 gene, driven by the Chrysanthemum rbcS1 promoter, was introduced into JK1044R, the restorer line (Oryza sativa L. ssp. Indica) of a notified commercially grown rice hybrid in India, by Agrobacterium-mediated transformation. Its effect against two major lepidopteran insect pests viz., yellow stem borer (YSB) Scirpophaga incertulas, rice leaf folder (RLF) Cnaphalocrocis medinalis and one minor insect pest, oriental army worm (OAW) Mythimna separata was demonstrated through bioassays of transgenic rice plants under laboratory and greenhouse conditions. The rbcS1 promoter with chloroplast signal peptide was used to avoid Cry2AX1 protein expression in rice seed endosperm tissue. A total of 37 independent transformants were generated, of which after preliminary molecular characterization and YSB bioassay screening, five events were selected for their protein expression and bioefficacy against all three rice insect. One elite transgenic rice line, BtE15, was identified with Cry2AX1 expression ranging from 0.68 to 1.34 µg g(-1) leaf fresh weight and with 80-92 % levels of resistance against rice pests at the vegetative and reproductive stages. Increase in Cry2AX1 protein concentration was also observed with crop maturity. The Cry2AX1protein concentration in the de-husked seeds was negligible (as low as 2.7-3.6 ng g(-1)). These results indicate the potential application of cry2AX1 gene in rice for protection against YSB, RLF and OAW.
authors.affiliation: Biotechnology Division, J.K Agri. Genetics Pvt. Ltd., Hyderabad, 500016, India. mithun@jkseeds.net.|Department of Biotechnology, Jawaharlal Nehru Technological University (JNTU), Hyderabad, 500072, India. mithun@jkseeds.net.
authors.forename: M
authors.initials: M
authors.lastname: Chakraborty
authors.affiliation: Biotechnology Division, J.K Agri. Genetics Pvt. Ltd., Hyderabad, 500016, India.
authors.forename: P Sairam
authors.initials: PS
authors.lastname: Reddy
authors.affiliation: Biotechnology Division, J.K Agri. Genetics Pvt. Ltd., Hyderabad, 500016, India.
authors.forename: G
authors.initials: G
authors.lastname: Mustafa
authors.affiliation: Biotechnology Division, J.K Agri. Genetics Pvt. Ltd., Hyderabad, 500016, India.
authors.forename: G
authors.initials: G
authors.lastname: Rajesh
authors.affiliation: Department of Biotechnology, Jawaharlal Nehru Technological University (JNTU), Hyderabad, 500072, India.
authors.forename: V M Laxmi
authors.initials: VM
authors.lastname: Narasu
authors.affiliation: Department of Plant Molecular Biology and Biotechnology, Centre for Plant Molecular Biology, Tamil Nadu Agricultural University, Coimbatore, 641 003, India.
authors.forename: V
authors.initials: V
authors.lastname: Udayasuriyan
authors.affiliation: Biotechnology Division, J.K Agri. Genetics Pvt. Ltd., Hyderabad, 500016, India.|Bayer CropScience-Seeds, Bayer (South East Asia) Pte Ltd, Singapore, Singapore.
authors.forename: Debashis
authors.initials: D
authors.lastname: Rana
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics*; D004731:Endotoxins / Q000235:genetics*; D006460:Hemolysin Proteins / Q000235:genetics*; D007313:Insecta / Q000472:pathogenicity; D007915:Lepidoptera / Q000472:pathogenicity; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000235:genetics* / Q000469:parasitology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development; D011401:Promoter Regions, Genetic
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Agrobacterium mediated transformation; Chrysanthemum rbcS1 promoters; Cnaphalocrocis medinalis; Mythimna separata; Scirpophaga incertulas; Transgenic rice (Oryza sativa); cry2AX1