Flowering and Freezing Tolerance Linked in Wheat

Understanding the flowering and freezing tolerance in wheat and barley varieties were the objectives of the study by University of California Davis wheat geneticist Jorge Dubcovsky and his colleagues from Ohio University and Hungary. Long exposures to non freezing cold temperatures accelerate flowering time in a process know as vernalization. These exposures also prepare the wheat to better tolerate freezing, a process known as cold acclimation.

Their study showed that when the main vernalization gene VRN1 is expressed in the leaves, it initiates a process that leads to decreased expression of the freezing tolerance gene. In the fall, when plants have low levels of the vernalization gene VRN1, it activates the freezing tolerance genes, helping to trigger the plants' acclimation to cold temperatures. This is essential in the fall, when cool temperatures are an indication that winter's freezing temperatures are approaching.

"However the same cool temperature in the spring, when high levels of the vernalization gene VRN1 are present in the leaves, results in a weaker response of the freezing tolerance genes," Dubcovsky said. "This avoids initiating the plants' cold-acclimation response, which requires a lot of the plants' energy and is unnecessary in the spring because warmer weather is approaching."

The study is published in the Journal of Plant Physiology. The news article can be viewed at http://www.news.ucdavis.edu/search/news_detail.lasso?id=9545