University of California Davis and The Ohio State University Wheat Research
In winter wheat and barley varieties, long exposures to non-freezing cold temperatures accelerate flowering time (vernalization) and improve freezing tolerance (cold acclimation). The two processes are interconnected, and when plants initiate their reproductive development, freezing tolerance decreases. Researchers at the University of California, The Ohio State University and their colleagues in Hungary demonstrated that when the main vernalization gene, VRN1, is expressed in the leaves it initiates a process that leads to the down-regulation of the freezing tolerance gene families CBF and COR. This system provides wheat and other temperate grasses the ability to respond differently to a cool temperature in the fall and the spring. A cool temperature in the fall, when plants have low VRN1 transcript levels, results in a strong induction of the freezing tolerance genes initiating the acclimation of the plants to cold. This is essential in the fall, when cool temperatures are an indication of the approaching freezing temperatures of the winter. The same cool temperature in the spring, when high levels of VRN1 transcripts are present in the leaves, results in a weaker response of the freezing tolerance genes, avoiding the initiation of an energetically-expensive and unnecessary response. The improved understanding of the connection between the vernalization and freezing tolerance pathways has the potential to contribute to the development of new strategies to improve freezing tolerance in wheat.
Work in Dr. Dubcovsky’s lab was supported by the National Research Initiative Competitive Grant no. 2008-35100-04562 from the USDA National Institute of Food and Agriculture.
The researchers published their findings in the June 22 Online First issue of Plant Physiology:
Dhillon, T., S.P. Pearce, E.J. Stockinger, A. Distelfeld, C. Li, A.K. Knox, I. Vashegyi, A. Vágújfalvi, G. Galiba, and J. Dubcovsky. Freezing tolerance and flowering regulation in cereals: the VRN-1 connection. Plant Physiology. DOI:10.1104/pp.110.159079
Plant Phys Stockinger Dubcovsky onlinre first.pdf
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