When Vernalization Makes Sense

摘要

Many plants flower in the spring after exposure to low winter temperatures to ensure reproductive success and maximize seed production. This response to cold, called vernalization, overcomes a block that prevents premature flowering in autumn. The molecular mechanisms underlying vernalization are fascinating because they must induce flowering only after a plant has been exposed to cold for several weeks, but not after short exposures characteristic of autumn, and must allow flowering to proceed stably after temperatures rise in spring (see the figure). On page 76 in this issue, Heo and Sung (7) describe how a temporal cascade of RNA transcripts generated from a single genomic locus regulates this response. In the model plant species Arabidopsis thaliana, the FLOWERING LOCUS C (FLQ gene is the major target of vernalizaton (2, 3). FLC encodes a transcription factor that blocks flowering before winter by repressing key genes required for flowering (4).