OREGON STATE UNIVERSITY

OSU scientists clone Mendel's famous dwarfing gene

08/05/1997

CORVALLIS, Ore. - Oregon State University scientists announced today they have cloned one of the most famous genes in biology - the dwarfing "factor" Gregor Mendel, the father of genetics, first reported 130 years ago.

In a paper published in the Aug. 5 Proceedings of the National Academy of Sciences, OSU Agricultural Experiment Station researchers Bill Proebsting and David Martin tell how they isolated the gene that controls the final step in the production of "gibberellins."

Gibberellins are primary substances that control stem height, flowering and seed development in plants.

"The finding brings full circle Mendel's experiments with tall and dwarf peas that have been repeated in classrooms around the world," said Proebsting. "Now we understand genetically and biochemically why one form of the gene produces a tall plant and the other, a dwarf.

"The gene from dwarf plants contains a single mutation not found in the gene from tall plants," the OSU horticulture professor said. "As a result, dwarf plants make less gibberellin than tall ones."

The success in cloning the dwarfing factor should benefit biologists and farmers. "For biologists, it's one more piece of the puzzle of how plants work," Proebsting said.

"Plants can sense many factors in their environment such as day length, light quality, temperature, moisture and nutrients," he explained. "They integrate this information and alter their growth accordingly in order to adapt to growing conditions. As a result, isolation of this and other gibberellin genes helps us study plant development in new ways."

Farmers have learned that dwarf plants are more productive than tall plants, Proebsting said. Dwarf plants produce more seed or fruit and less stem. They also remain upright so they are easier to harvest.

"Dwarf grain varieties that are also resistant to some insect disease pests formed the basis of the 'Green Revolution' that raised living standards around the world," Proebsting noted.

The OSU researchers said fruit growers would be especially interested in the gene cloning.

"They want dwarf, compact trees because they are higher yielding, more manageable and easier to harvest," Proebsting said. "Dwarf trees are difficult to breed, however. Each generation is several years long, and trees often have complicated genetics.

"Fruit growers can use growth regulating chemicals," he added. "But these are expensive, don't always work as they should and have a poor public image."

The OSU accomplishment could help others to genetically engineer dwarf plants.

"Gibberellins are a likely target for dwarfing plants," Martin said. "Information like ours will help genetic engineers find similar genes in crop plants that are hard to breed using traditional techniques. Having such a gene, it will soon be possible to genetically alter its effects in order to reduce gibberellin and produce a smaller plant."