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Keywords:

  • calcium;
  • chilling;
  • freezing;
  • gene expression;
  • low temperature;
  • plants;
  • sensing;
  • transcription

Contents

 Summary737
I.Chilling and freezing: two different stresses requiring different solutions738
II.Identification of a major cis-element in the control of cold gene expression739
III.The CBF transcription factors (TFs) and their regulation739
IV.Events downstream of CBFs740
V.A post-genomic view on global transcript changes in response to low temperature741
VI.The effect of light and circadian signals on cold gene expression742
VII.Post-transcriptional regulation742
VIII.A receptor for cold?742
IX.What are the characteristics of plant cell thermometer(s)?744
X.Low-temperature signalling downstream of perception744
XI.Unresolved questions747
 Acknowledgements748
 References748

Summary

Plant species exhibit a range of tolerances to low temperatures, and these constitute a major determinant of their geographical distribution and use as crops. When tolerance is insufficient, either chilling or freezing injuries result. A variety of mechanisms are employed to evade the ravages of extreme or sub-optimal temperatures. Many of these involve cold-responsive gene expression and require that the drop in temperature is first sensed by the plant. Despite intensive research over the last 100 yr or longer, we still cannot easily answer the question of how plants sense low temperature. Over recent years, genomic and post-genomic approaches have produced a wealth of information relating to the sequence of events leading from cold perception to appropriate and useful responses. However, there are also crucial and significant gaps in the pathways constructed from these data. We describe the literature pertaining to the current understanding of cold perception, signalling and regulation of low-temperature-responsive gene expression in higher plants, raising some of the key questions that still intrigue plant biologists today and that could be targets for future work. Our review focuses on the control of gene expression in the pathways leading from cold perception to chilling and freezing tolerance.