"(Phys.org July 16, 2012) Researchers led by Professor Caroline Dean have uncovered the genetic basis for variations in the vernalization response shown by plants growing in very different climates, linking epigenetic mechanisms with evolutionary change.

Vernalization is a period of prolonged cold that some plants require before they will flower. This ensures that they only produce flowers after the damaging cold of winter has passed. The plant must have a way of ‘remembering’ how much cold weather it has endured and in 2011 the researchers uncovered the mechanism plants use. When sufficient time in the cold has passed, an epigenetic switch silences a flowering-repressor gene called FLC. These epigenetic changes are then passed on to daughter cells during the rest of the plants developmental cycle.

Different plants have different vernalization requirements, as the length of winter cold they experience varies with geography and climate. In new research published in the journal Science, Professor Dean’s team have worked out how different plants set the level at which this epigenetic switch is triggered. They looked at a variety of Arabidopsis thaliana derived from North Sweden (Lov-1), and compared it to the reference ‘Columbia’ variety. Columbia needs 4 weeks of cold to trigger the epigenetic switch. The Lov-1 variety needs 9 weeks of cold to achieve the same, a natural variation to cope with the longer winters at northern latitudes..."

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