Expression of a Bacillus thuringiensis cryIA(c) gene in transgenic peanut plants and its efficacy against lesser cornstalk borer

• Published in: Transgenic research 1997-03, Vol.6 (2), p.169-176
• Main Authors: SINGSIT, C, ADANG, M. J, LYNCH, R. E, ANDERSON, W. F, WANG, A, CARDINEAU, G, OZIAS-AKINS, P
• Format: Article
• Language: English
• Subjects: Animals; Arachis - genetics; Arachis hypogaea; Bacillus thuringiensis; Bacillus thuringiensis - genetics; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - immunology; Bacterial Toxins; Bioassays; Biological and medical sciences; Biological Assay; Biological control; Biotechnology; Blotting, Southern; Cells, Cultured; Cloning, Molecular; Control; Elasmopalpus lignosellus; Endotoxins - genetics; Endotoxins - immunology; Enzyme-Linked Immunosorbent Assay; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial; Genes; Genetic engineering; Genetic technics; Genetic Therapy - methods; Genetic Vectors; Hemolysin Proteins; Hygromycin B; Insecta; Methods. Procedures. Technologies; Mutagenesis, Insertional; Phytopathology. Animal pests. Plant and forest protection; Plant Proteins - immunology; Plants, Genetically Modified; Plasmids; Polymerase Chain Reaction; Promoter Regions, Genetic; Protozoa. Invertebrates; Pyralidae; Seeds - genetics; Transformation, Genetic; Transgenic animals and transgenic plants; Transgenic plants
• ISSN: 0962-8819; 1573-9368
• DOI: 10.1023/A:1018481805928

The invasion of peanut (Arachis hypogaea L.) pods and seeds by aflatoxin-forming species of Aspergillus is linked to injury by the lesser cornstalk borer and frequently causes a severe reduction in crop quality. The lesser cornstalk borer is susceptible to the lepidopteran-active Bacillus thuringiensis insecticidal crystal protein. We have introduced a codon-modified Bacillus thuringiensis cryIA(c) gene into peanut using microprojectile bombardment. The toxin-coding region of a Bt cryIA(c) gene was reconstructed for expression in plants and the resulting 3.4 kb gene cassette (promoter: 1.8 kb coding: 3') was directly cloned into the BglII site of plant transformation vectors. The vectors contained the hph gene, conferring resistance to the antibiotic hygromycin. Somatic embryos initiated from immature peanut cotyledons of two cultivars were used as the target for bombardment. DNA from hygromycin-resistant embryogenic cell lines, regenerated plants, and a progeny plant showed the presence and integration of hph and Bt genes by PCR and/or Southern blot analyses. ELISA immunoassay of the CryIA(c) protein from the hygromycin-selected plants showed the expression of CryIA(c) protein up to 0.18% of total soluble protein. Insect feeding bioassay of transformed plants indicated various levels of resistance to the lesser cornstalk borer, from complete larval mortality to a 66% reduction in larval weight. A negative correlation between percent survival or larval weight and the amount of Bt CryIA(c) protein was recorded indicating in general that the higher the protein level the lower the survival or larval weight of the insect. Based on leaf bioassay, transformation of peanut with vectors containing the Bt cryIA(c) gene may be effective in protecting the peanut plants from damage by lepidopteran insect larvae of lesser cornstalk borer.