Secret to "Winterizing" Wheat Plants Revealed

By Marcia Wood
March 12, 2004

Much of the flour that goes into breads, pasta, cakes, breakfast cereals and other foods comes from so-called "winter wheats," planted in fall and harvested in spring.

A mostly mysterious network of genes orchestrates the growth of winter wheat seeds to ensure that wheat plants won't flower and form grain until the greatest danger of killer frosts has passed. This is accomplished through a natural mechanism known as "vernalization," during which the developing seedling must undergo several weeks of exposure to cold temperatures of 40 to 50 degrees F before it can resume developing into stems, leaves and flowers.

Now, Agricultural Research Service scientists have helped colleagues at the University of California at Davis and elsewhere develop the best-yet evidence of the role of a gene called vrn2 in vernalizing wheat plants. The Davis team is the first to isolate and copy--or clone--vrn2 from wheat. The researchers report their discoveries in today's issue of Science, one of the world's leading research journals.

Plant geneticist Ann E. Blechl of the ARS Western Regional Research Center provided the highly sought-after expertise necessary to successfully insert genes into wheat plants. Those plants were essential for proving vrn2's role.

Several years ago, Blechl and her Albany colleagues were among the first in the world to use tools of modern biotechnology to introduce genes into wheat. Wheat's recalcitrance to accept new genes had greatly slowed the progress of research designed to give this grain crop new genes to boost tolerance to drought or to improve its nutritional value, for instance.

Currently, Blechl is investigating ways to genetically improve wheat to reduce stickiness of wheat dough. Stickiness causes problems in commercial bakeries as well as home kitchens.

At UC-Davis, the vrn2 research is led by Jorge Dubcovsky, a professor of agronomy and range science, whose team had earlier isolated, cloned and established the identity of vrn1, a wheat gene that also has a role in vernalization.