Submitted to: Polish Genetics Society Conference
Publication Type: Abstract Only
Publication Acceptance Date: 9/22/1998
Publication Date: N/A
Technical Abstract: The only commercially available insect tolerant transgenic plants express the Bacillus thuringiensis endotoxin gene, but other genes that code for cholesterol oxidase, a-amylase inhibitor, lectins, chitinases, peroxidases and vegetative insecticidal proteins are being evaluated. Additionally, genes for proteinase inhibitors and enzymes involved in the synthesis of the plant growth hormone cytokinin and secondary metabolities are being evaluated as novel approaches for insect control and will be further discussed here as they relate to the work being done in this laboratory. Cytokinins regulate normal plant growth and development and appear to have a role in plant defense mechanisms. Regulated overexpression of a gene involved in cytokinin biosynthesis was correlated with insect resistance in transgenic plants. We demonstrated that the higher levels of cytokinin increased production or secretion of a secondary metabolite with insecticidal activity. Present focus is on purifying and identifying the active compound(s) to gain a better understanding of cytokinin's role in its production and for possible direct genetic manipulation of the corresponding biosynthetic pathway as a means of enhancing natural plant defense mechanisms. We have also cloned a cytokinin modulated gene for cytochrome P450 monooxygenase that is likely to be involved in the biosynthesis of secondary metabolites many of which are insecticidal. The expression of this gene is upregulated by insect chewing and wounding. The possible role of P450 in defense responses in transgenic plants will be reported.