Combining Genes to Increase Crop Protection: TMOF and ChitinasePosted: May 13, 2011
Genetic engineering of plants can reduce the need for chemical insecticides. This, in turn, can improve food safety, and reduce energy inputs and cost. In recent posts I described genetically engineering plants to produce their own pesticides, specifically TMOF and chitinase. I also discussed the effects that the pesticides created by those plants had on insect larvae. Savvy readers would have noticed that the effects on insects have been promising, but not stellar. It’s hard to get very enthusiastic about delayed weight gain as a measure of success!
That’s the reason the Rao research group at Università di Napoli took their project one step further and combined two biopesticides into a single plant. In a paper published in the 2010 Insect Biochemistry and Molecular Biology journal, these researchers tested the combination of plant-made TMOF and plant-made chitinase against larvae of the tobacco budworm.
Classical methods were used to breed genetically engineered (GE) plants producing TMOF with GE plants producing chitinase. The hybrid offspring produced both pesticidal proteins. Tobacco budworm (Heliothis virescens) larvae were fed leaves from the hybrid plants, or from GE plants producing either TMOF or chitinase, or from non-GE plants. The insects that were fed leaves from the TMOF-producing plants or the chitinase-producing plants developed more slowly than those fed with leaves from non-GE plants. But insects that were fed leaves from the dual-biopesticide plants developed even more slowly than the insects fed with leaves from plants producing either TMOF or chitinase alone. Most important for crop protection, approximately 75% of larvae fed on hybrid plants died. This suggests that GE plants producing both TMOF and chitinase protect themselves better against damage from insect larvae than plants producing only one of the proteins.
L Fiandra, I Terracciano, P Fanti, A Garonna, L Ferracane, V Fogliano, M Casartelli, B Giordana, R Rao and F Pennacchio. 2010. A viral chitinase enhances oral activity of TMOF. Insect Biochemistry and Molecular Biology 40: 533 – 540. DOI:10.1016/j.ibmb.2010.05.001