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Davis, California
June 5, 2003
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 UC Davis' 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.
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