Genetically engineered plants could thwart sucking insects

04/02/2012 03:53:00 PM
Vicky Boyd

Cornell University genetic researchCourtesy Cornell UniversityCornell University researcher Angela Douglas (left) dusts a tobacco plant for aphids as colleague Georg Jander watches.Researchers at Cornell University in Ithaca, N.Y., want to use the aphid's sweet tooth against it as a way to control the pest and the diseases it may carry.

Angela Douglas and Georg Jander plan to genetically engineer tobacco and Arabidopsis plants to disrupt crucial processes in insect guts that allow them to cope with high sugar concentrations, according to a news release.

The plant phloem on which many sucking insects feed is about twice as sweet as grape juice.

Without special evolutionary adaptations, the insect would die from dehydration while feeding; the sugar in the gut would draw water from surrounding tissues.

Douglas and Jander will work to identify genes in the peach-potato aphid, sweet potato whitefly and potato psyllid that modify and transport sugars as well as genes that control water transport.

They will then modify plants to produce double-stranded RNA of the targeted insect genes, enabling them to turn off these crucial genes.

When the insect feeds on these modified plants, its system interprets the RNA as an invader and blocks expression of that gene sequence.

The technique is called RNA interference (RNAi) or gene silencing.

The researchers expect to see the insects die of dehydration, but they will conduct assays to ensure that was the cause of death.

"The beauty of this approach is that we can specifically target genes in the insect without any side effect on the plants," Douglas said in the release.

Read more about using RNAi technology to help control citrus greening in February's Citrus + vegetable Magazine.

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