Modification of the coding sequence enhances plant expression of insect control protein genes

• Published in: Proceedings of the National Academy of Sciences - PNAS 1991-04, Vol.88 (8), p.3324-3328
• Main Authors: Perlak, F.J. (Monsanto Company, Chesterfield, MO), Fuchs, R.L, Dean, D.A, McPherson, S.L, Fischhoff, D.A
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Amino acids; BACILLUS THURINGIENSIS; Bacillus thuringiensis - genetics; Bacillus thuringiensis Toxins; Bacterial Proteins - genetics; Bacterial Toxins; Base Sequence; Biological and medical sciences; Cloning, Molecular; Codon; CONTROL DE INSECTOS; CONTROL GENETICO; DNA Mutational Analysis; Endotoxins; EXPRESION GENICA; EXPRESSION DES GENES; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; Genetic Engineering; Genetics and breeding of economic plants; Hemolysin Proteins; Insect control; Insect genetics; Invertebrates; LUTTE ANTIINSECTE; LUTTE GENETIQUE; LYCOPERSICON ESCULENTUM; Messenger RNA; Molecular Sequence Data; Nicotiana - genetics; NICOTIANA TABACUM; NUCLEOTIDE; Nucleotide sequences; Nucleotides; NUCLEOTIDOS; Oligonucleotides; Pest animals; Pest resistance; Plants; Plants - genetics; Plants, Toxic; Protein Biosynthesis; Proteins; Regulatory Sequences, Nucleic Acid; RNA, Messenger - genetics; Transcription, Genetic; TRANSFORMACION GENETICA; TRANSFORMATION GENETIQUE; Transgenic insects; Varietal selection. Specialized plant breeding, plant breeding aims
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.88.8.3324

Increased expression of the insect control protein genes of Bacillus thuringiensis in plants has been critical to the development of genetically improved plants with agronomically acceptable levels of insect resistance. The expression of the cryIA(b) gene was compared to partially modified (3% nucleotide difference) and to fully modified (21% nucleotide difference) cryIA(b) and cryIA(c) genes in tobacco and tomato. The modified genes increased the frequency of plants that produced the proteins at quantities sufficient to control insects and dramatically increased the levels of these proteins. Among the most highly expressing transformed plants for each gene, the plants with the partially modified cryIA(b) gene had a 10-fold higher level of insect control protein and plants with the fully modified cryIA(b) had a 100-fold higher level of CryIA(b) protein compared with the wild-type gene. Similar results were obtained with the fully modified cryIA(c) gene in plants. Specific sequences of the partially modified cryIA(b) gene were analyzed for their ability to affect cryIA(b) gene expression in tobacco. The DNA sequence of a single region was identified as important to the improvement of plant expression of the cryIA(b) gene. The increased levels of cryIA(b) mRNA were not directly proportional to the increased levels of CryIA(b) protein in plants transformed with the modified cryIA(b) genes, indicating that the nucleotide sequence of these genes had an effect in improving their translational efficiency in plants.