Biotechnology may keep head scab disease from infesting barley seeds. That would alleviate barley growers' economic woes from the disease caused by the fungus Fusarium graminearum in the upper Midwest. ARS researchers have cloned two barley genes associated with production of two antifungal proteins, permatin and hordothionin. These proteins are only found inside the barley seed and may play a role in slowing fusarium's entry into the seed. Next, the researchers will redesign barley to produce the proteins on the leaflike structures surrounding the seed, where fusarium infection begins. In the spring of 1999, they'll determine if the transformed barley expressing these genes has an increased resistance to the disease-causing fungus. Head scab disease causes millions of dollars in crop losses of barley, wheat, oats, rye and corn.
Cereal Crops Research Unit, Madison, WI
Ron Skadsen, (608) 262-3672.

Brazil has partially lifted its 3-year-old prohibition on U.S. wheat imports, thanks in part to an ARS scientist's survey. His nationwide polling of nematologists confirmed that the wheat seed gall nematode no longer occurs in the United States, a result of improved seed-cleaning procedures that disrupt the pest's life cycle. U.S. wheat had been exported to Brazil for decades, but in 1995 Brazil halted shipments of the commodity, chiefly because of the wheat seed gall nematode. The pest was once widespread throughout the southeastern United States and often caused total crop loss. Last June, the ARS researcher presented survey results and related information to a Brazilian administrative and scientific delegation. The meeting included representatives of U.S. Wheat Associates (USWA) and USDA's Animal and Plant Health Inspection Service (APHIS) and Foreign Agriculture Service. An APHIS fungus expert addressed Brazil's concern about the wheat-borne fungi and USWA representatives described how wheat is processed, stored and shipped to eliminate these pests. Before the ban went into effect, U.S. growers sold wheat valued at more than $50 million a year to Brazil, one of the world's largest wheat importers.
Nematology Laboratory, Beltsville, MD
David J. Chitwood, (301) 504-5660.

New information about the anatomy of a microscopic worm, the lesion nematode, will help scientists identify weak links in this worm's reproductive process. After its cousins—the soybean cyst and root-knot nematodes—the lesion nematode ranks as the world's third worst parasite of crop plants. Species of plant-parasitic nematodes infect nearly every important U.S. crop and horticultural plant, causing huge economic losses. For its part, the lesion nematode—besides damaging plants—exposes them to other destructive soilborne microorganisms. But with a powerful instrument known as a transmission electron microscope, ARS scientists for the first time studied and mapped the structure of the male lesion nematode's reproductive system. This knowledge will help scientists gain the upper hand on this destructive plant pest and could lead to new alternatives to chemical nematicides. Today, only a few chemical controls for lesion nematodes are available, and they often are inadequate, unsuitable or too costly.
Nematology Laboratory, Beltsville, MD
Burt Endo, (301) 504-8046.