Submitted to: Environmental Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/4/2001
Publication Date: N/A
Citation: Interpretive Summary: The Angoumois grain moth is a major storage pest of cereals, particularly in developing countries, and no resistance to this insect has been identified to date. This work identified the enzymes that digest proteins in the gut of this insect and showed the genes for naturally occurring inhibitors of these enzymes can be used to confer resistance in the seeds of cereals to the insect. Additionally, a mathematical model was develope that allows scientists to evaluate how seed resistance in conjunction with biological control would control population growth of the Angoumois grain moth and protect cereals in storage. This information will benefit farmers both in developing countries as well as in the United States and aid scientists working to use genetic engineering to increase insect resistance in crops.
Technical Abstract: The Angoumois grain moth, Sitotroga cerealella (Oliver), is one of the major storage pests of cereals, and no antibiotic resistance in wheat against this insect has been identified to date. Midgut proteases are vital to insects that digest ingested food in the midgut and have been considered as targets for the control of insect pests. Protease inhibitors sare attractive for their potential use in developing insect-resistant plan varieties via genetic engineering. Characterization of the midgut proteases of S. cerealella larvae revealed the major digestive proteases were trypsin-like and ?-chymotrypsin-like serine proteases. The partial inhibition of proteolytic activity by pepstatin A, however, suggested the presence of another protease in the midgut sensitive to this inhibitor. The potential value of naturally occurring plant protease inhibitors as resistance factors for S. cerealella was assessed in bioassays using artificial seeds. Soybean trypsin inhibitor (Kunitz inhibitor) had an adverse effect on the development of the insect. To evaluate the potential value of a protease inhibitor as a resistance factor and the value of seed resistance in conjunction with an egg parasitoid on S. cerealella population dynamics a predictive model was developed. Outputs from the model supported the hypotheses that some protease inhibitors can be used as resistance factors to control S. cerealella and the use of resistant seed in conjunction with parasitoids would be of benefit in controlling the population growth of S. cerealella in a seed storage room.