Search Narrows for Plant Gene That Starves Worms

A search for genes that enable a corn plant to “starve” leaf-eating fall armyworms has been narrowed by scientists at the Agricultural Research Service and Mississippi State University.

Their ultimate goal is to genetically engineer commercially available corn hybrids so they too can have this built-in pest protection.

Recently, the scientists determined that the gene they seek is Mir1, responsible for making the protein 33 kD cysteine proteinase. When hungry armyworms munch corn leaves and ingest the protein, they may stop growing or starve.

The scientists hope to insert the protein-making gene into susceptible corn hybrids or other crops harried by armyworms and other destructive caterpillar pests.

The researchers isolated Mir1 from tissue of a worm-resistant corn line, Mp 708. They then made millions of copies of the Mir1 segment. This helped them identify nearly all the nucleotides--or individual chemical constituents--comprising Mir1. The scientists then inserted the Mir1 segment into bacteria for use as microbial workhorses in studies of the protein’s effectiveness.

Besides armyworms that attack corn, the genes may someday quell the appetite of other lepidopteran pests of other crops.

Scientific contact: W. Paul Williams, Corn Host Plant Resistance Research Unit, Agricultural Research Service, Mississippi State, Miss., phone (601) 324-2735.