Submitted to: Biotechnology Letters
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/12/2005
Publication Date: 4/1/2006
Citation: Lawrence, S.D., Novak, N.G. 2006. Expression of poplar chitinase in tomato leads to inhibition of development in colorado potato beetle.. Biotechnology Letters. Vol. 28, no.#8 pg. 593-599 Interpretive Summary: Colorado potato beetle (CPB) is a serious insect pest of tomatoes. Finding genes that confer resistance to CPB would be a boon to American agriculture. To speed up the screening of potential resistance genes, we have used the plant virus potato virus X (PVX) to express a gene in tomato plants. This allows testing of the putative resistance gene within 1 month rather than 6 months, which is required for standard plant cloning experiments. Using PVX we have inserted a plant chitinase gene into the leaves of tomato and used the plant material to feed CPB. Chitinases digest a component of the insect stomach resulting in the inhibition of feeding. It is thought that they are present in plants as a defense against insect pests. CPB development was inhibited in 48.7% of the insect larvae feeding on tomato leaves expressing the chitinase. This is the first example of a transgenic plant chitinase affecting insects and suggests a gene that might be useful in breeding CPB resistance in tomatoes for American agriculture.
Technical Abstract: The Colorado potato beetle (CPB; Leptinotarsa decemlineata (Say)) is a serious pest of tomatoes and other crops. We used potato virus X (PVX) to produce recombinant tomato seedlings to test the insecticidal quality of a recombinant protein on CPB larvae. Plant material is ready for insect bioassay within 3-4 weeks of constructing the recombinant virus. Considering that production of transgenic tomato seedlings using Agrobacterium takes at least 6 months, this hastens the rate at which genes can be examined. We tested a previously-described wound-induced chitinase, WIN6. Only 51.3% of CPB neonates feeding on leaves containing WIN6 developed to 2nd instar. To our knowledge this is the first plant chitinase that deters an insect pest.