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United States Department of Agriculture

Agricultural Research Service

Research Project: Identification and Validation of Insect and Disease Resistance Mechanisms to Reduce Mycotoxin Production in Midwest Corn

Location: Crop Bioprotection Research

Title: Expression of a wolf spider toxin in tobacco inhibits the growth of microbes and insects

Authors
item Johnson, Eric
item Dowd, Patrick
item Hughes, Stephen

Submitted to: Biotechnology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 19, 2014
Publication Date: July 7, 2014
Citation: Johnson, E.T., Dowd, P.F., Hughes, S.R. 2014. Expression of a wolf spider toxin in tobacco inhibits the growth of microbes and insects. Biotechnology Letters. 36(1):1735-1742.

Interpretive Summary: Insect pests of food crops and ornamentals cause billions of dollars of losses. Insects often can develop resistance to insecticides. For many lower value crops, resistance that is produced by the plant is more economically practical than insecticide use, but often requires the development of new plant resistance mechanisms. The gene coding for a small protein from the venom of the wolf spider, which has low human toxicity, was transferred into tobacco. Plants expressing the spider protein were more resistant than normal plants to pest insect caterpillars and beetle larvae, and two different pathogens of tobacco. This study demonstrated that this modified spider protein can protect plants from a broad spectrum of pests and could be utilized for protection of important crops and ornamentals.

Technical Abstract: Abstract Lycotoxin I, from the wolf spider (Lycosa carolinensis), is an amphipathic pore-forming peptide that has antimicrobial and anti-insect activity. Constitutive expression of a lycotoxin I odified for oral toxicity to insects in tobacco (Nicotiana abacum) conferred significantly enhanced resistance to larvae of the corn earworm (Helicoverpa zea) and cigarette beetle (Lasioderma serricorne). Gene expression levels of modified lycotoxin I were negatively correlated to the survival of corn earworm larvae. In addition, pathogenic symptoms caused by Pseudomonas syringae pathovar tabaci and Alternaria alternata on themodified lycotoxin I-expressing leaveswere significantly less severe than on wild type leaves. These results indicate that modified lycotoxin I expression in tobacco can potentially protect leaf tissue from a broad spectrum of pests and pathogens.

Last Modified: 8/29/2014
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