TMOF: A Protein That Could Prevent Crop Loss

One reason for genetically engineered (GE) cotton’s dramatic and rapid acceptance by farmers is its improved control of three major insect pests: tobacco budworm, cotton bollworm and pink bollworm.

Cotton and other crop plants that are genetically engineered to make Bacillus

Budworm Moth

Budworm Moth

thuringensis (Bt) proteins become resistant to damaging crop pests (see Promising Results in the Fight Against Rice Stem Borer Moths). Unfortunately, as with any pesticide, insects develop tolerance to Bt over time, so it is important to investigate other proteins that might have efficacy as biopesticides. One such protein is Trypsin Modulating Oostatic Factor (TMOF).

Tobacco Budworm Larvae

Tobacco Budworm Larvae

TMOF is a protein that prevents insects from synthesizing the digestive enzyme trypsin, which is critical for digestion. TMOF was first developed for use on mosquitoes. Mosquito larvae that eat TMOF die because they cannot digest their food.

TMOF can have a similar effect on crop pests. In articles published in 2002 and 2003, a research group from the University of Napoli in Italy generated GE plants that produce TMOF. The researchers then tested the effect of the TMOF-producing GE plants on insect pests. Tobacco budworm larvae that ate leaves from these plants developed at an abnormally slow rate. Later studies, which I will cover in a future post, also showed that TMOF reduced the number of larvae that survive to adulthood. Taken together, these reports show that TMOF-producing GE plants protect themselves against damage from tobacco budworm.


Tortiglione C, Fanti P, Pennacchio F, Malva C, Breuer M, De Loof A, Monti L, Tremblay E, Rao R. The expression in tobacco plants of Aedes aegypti trypsin modulating oostatic factor (Aea-TMOF) alters growth and development of the tobacco budworm, Heliothis virescens. Molecular Breeding 2002; 9: 159 – 169. DOI: 10.1023/A:1019785914424.

Tortiglione C, Fogliano V, Ferracane R, Fanti P, Pennacchio F, Maria Monti L, Rao R. An insect peptide engineered into the tomato prosystemin gene is released in transgenic tabacco plants and exerts biological activity. Plant Molecular Biology 2003; 53: 891 – 902. DOI: 10.1023/B:PLAN.0000023667.62501.ef.


I also have researched the use of TMOF as a biopesticide, although not via GE plants. See one of my articles at Thompson DM, Young HP, Edens FW, Olmstead AW, LeBlanc GA, Hodgson E, Roe RM. Non-target toxicology of a new mosquito larvicide, trypsin modulating oostatic factor. Pesticide Biochemistry and Physiology 2004; 80: 131-142. DOI: 10.1016/j.pestbp.2004.06.009.


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