Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: January 5, 2000
Publication Date: N/A
Technical Abstract: One of the most devastating pests of sugarbeet in the U.S. is the root maggot (Tetanops myopaeformis Roder). Losses can be higher than 20% in infested fields and are speculated to increase in the next few years due to the anticipated removal of all chemical pesticides effective against the maggot from EPA approved registrations. Currently no biological control measures are available. Introduction of multiple resistance genes into transgenic plants will most likely prove to be the most effective and perhaps sustained means of controlling diseases and insect infestations. Stable incorporation of beneficial genes into sugarbeet has been hampered by a lack of reproducible transformation methods. We are employing one of two transformation methods developed in this laboratory to introduce beneficial genes for insect control into sugarbeet. Two approaches are being undertaken for management of the sugarbeet root maggot (SBRM). One approach involves the expression in transgenic sugarbeet plants of proteinase inhibitor genes to specifically target the digestive proteases leading to inhibition of catalysis of dietary proteins essential for normal insect growth and development. Another approach being evaluated is the effect of cytokinin-induced insecticidal compounds on the SBRM larvae. Leaf surface extracts of Nicotiana plumbaginifolia plants transformed with a cytokinin biosynthesis gene induced a twitching response and death of more than 90% of first instar larvae as compared to about 25% of the controls at 5 days. Sugarbeet plants transformed with a cytokinin biosynthesis gene have been regenerated for further analysis of the effect of cytokinins on defense responses.