ScienceDaily (Mar. 8, 2004) — A genetic fingerprinting technique developed by Agricultural Research Service scientists could point the way to new strains of Pasteuria bacteria with potential to biologically control soybean cyst nematodes.

ARS nematologist Greg Noel and colleagues developed the method to help resolve confusion surrounding Pasteuria's taxonomic classification and clarify its parasite-host relationship with soil-dwelling roundworms like the soybean cyst nematode, a crop pest that costs $324 million to $1.4 billion annually in U.S. soy losses.

Since Pasteuria can't be cultured in the lab, researchers seeking to determine its genetic affiliation must resort to extracting DNA from the spore-infected bodies of nematodes. It's a laborious, time-consuming affair that's sometimes prone to DNA contamination by other microbes, according to Noel. He is in the ARS Soybean/Maize Germplasm, Pathology and Genetics Research Unit at Urbana, Ill.

There, rather than using centrifuging, heat and chemicals to obtain Pasteuria DNA, Noel resorted to "glass bead beating." The procedure involves grinding spore-infected nematodes so that any DNA within them is released into a sterile solution. Lab-built molecules called primers are then added. These bind only with Pasteuria DNA--if it's present--and ready the material for amplification by polymerase chain reaction. The DNA can then be cloned and sequenced as Pasteuria's unique, genetic fingerprint.

According to Noel, the method is fast, easy to use, and highly specific. Besides its taxonomic applications, it should aid scientists in identification of Pasteuria species that attack different nematode species. Some of these Pasteuria also complete their life cycles in juvenile nematodes, while others do so in female nematodes.

Either way, the pests face a grisly demise. Within a month, for example, infected soybean cyst nematode females become fragile to the point of crumbling apart, a fate that diminished the pest's population by 87 percent in Noel's field studies at Urbana.

Read more about this research in the March issue of Agricultural Research magazine.

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

Related Stories

Techniques Available To Detect Soil That Inhibits Destructive Soybean Pest (July 4, 2005) — Identification of soils that inhibit a tiny soybean-destroying organism is an important tool in reducing yield losses, according to a Purdue University plant ...  > read more

Soy Scientists To Fill 'Library' With Genetic Bookmarks (Mar. 28, 2008) — Soybean varieties with improved yield, pest resistance, protein and oil quality and quantity and other traits are among the benefits expected of a new project in which Agricultural Research Service ...  > read more

First Soybeans With Complete Nematode Resistance Developed (June 9, 2000) — The soybean farmer's biggest enemy – a tiny parasitic worm known as the soybean cyst nematode – will soon not be a worry, thanks to Purdue University scientists and Midwestern plant ...  > read more

Soybean Varieties Viable In Southern Indiana, Resistant To Root-knot Nematode (Mar. 25, 2008) — Researchers have identified several soybean varieties that grow well in areas of the Midwest like southern Indiana, US and are resistant to root-knot nematodes, a plant-destroying parasite with a ...  > read more

Search ScienceDaily

Natural Pest Control