ºÙºÙÊÓƵ

The gene that controls "vernalization," the biological process that requires cold temperatures to trigger flower formation in some plants, has been isolated and cloned in wheat for the first time by a team of researchers at the University of California, Davis.

"We are hopeful that this discovery, combined with existing biotechnological methods, will facilitate better manipulation of flowering time in wheat," said the team's lead researcher, Jorge Dubcovsky, a professor and wheat breeder in ºÙºÙÊÓƵ' agronomy and range science department. "It also should open the way to a better understanding of the complex network of genes responsible for determining flowering time in temperate cereal crops."

Some plants, including certain wheat varieties, will not flower until they have been exposed to a certain period of cold temperatures. For example, winter wheat requires several weeks at low temperature, usually in the range of 40-50 F, in order to flower and eventually produce grain. It is thought that the plants evolved this vernalization mechanism to prevent the cold-sensitive flowering parts of the plants from developing during winter when they might be damaged by extremely cold winter temperatures.

Previously, the VRN1 gene was known to largely control the vernalization process in wheat, but researchers didn't know a lot about it, other than its general location on three wheat chromosomes. To better identify the gene, Dubcovsky and colleagues used thousands of plants to develop detailed genetic and physical maps for the VRN1 region in wheat and for the same region in rice and sorghum. By comparing the maps, the researchers determined that the AP1 gene, which belongs to a family of genes known to be important to the regulation of flower development, is the VRN1 gene that regulates vernalization.

Funding for the study, published recently in the Proceedings of the National Academy of Sciences, was provided by a U.S. Department of Agriculture National Research Initiative Grant and by the National Science Foundation.