Peptide Discovery in Soybean Pest Could Lead to Controls

Compounds called peptides that may regulate insect feeding and movement have now been discovered in extracts of soybean cyst nematodes. The discovery, a scientific first, opens a new path for investigating nature-based controls for these microscopic wormlike pests.

Agricultural Research Service scientists reported the discovery in Volume 897 of Annals, published by the New York Academy of Sciences. They hope further studies will provide clues on how to turn the peptides against the pest, perhaps by disrupting its reproduction.

Soybean growers now ineffectively battle the soybean cyst nematode, their greatest foe, with resistant varieties and crop rotation. However, resistant varieties are not effective against all of the races of the nematode and usually do not yield as well as susceptible varieties when nematodes are absent.

Soybean cyst nematodes are the most destructive pests of U.S. soybeans, annually costing growers $1.5 billion.

The peptides discovered by the ARSscientists may have essential roles in controlling feeding and movement by regulating nervous transmission and muscle activity. The peptides in the soybean cyst nematode differ from those in non-parasitic species of nematodes, according to Edward P. Masler at the ARS Nematology Laboratory in Beltsville, Md.

Masler and colleagues detected at least three different peptides in extracts from the nematodes grown on soybean plants, by using a modified version of a standard test called an ELISA (enzyme-linked immunosorbent assay).

The peptide levels vary during the worms' development, but the researchers are focusing on those most active in female nematodes. The females lay the eggs that will yield new generations of hungry, root-eating offspring.

ARS is the chief scientific agency of the U.S. Department of Agriculture.

Scientific contact: Edward P. Masler, ARS Nematology Laboratory, Beltsville, Md., (301) 504-8732, fax (301) 504-5589, [email protected].