Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/16/2005
Publication Date: 7/21/2005
Citation: Xin, Z., Chen, J., Mandaokar, A., Last, R., Browse, J. 2005. Esk1 encodes a novel regulator of freezing tolerance[abstract]. American Society of Plant Biology. Paper No. 31001.
Technical Abstract: Many temperate plants acquire an increased freezing tolerance in response to a period of low nonfreezing temperatures through an adaptive process known as cold acclimation. Like many other temperate plants, Arabidopsis improves its freezing tolerance from -5 to -12C after 2d acclimation at 4C. To study the mechanisms of cold acclimation, we have carried out a genetic screen to isolate constitutively freezing tolerant mutants that bypass the requirement for a prior exposure to low nonfreezing temperatures. A constitutively freezing tolerant mutant, esk1, could survive -10C in the absence of cold acclimation. Transcriptome analysis in a missense allele and a knockout allele of the esk1 mutants revealed that 169 genes were up-regulated and 137 genes were down-regulated for two-fold or more in the esk1 mutants. The ESK1-mediated genes overlapped with that induced by cold acclimation and ABA treatment. Some were also regulated by overexpressing CBF/DREB transcription factors at warm temperatures. Positional cloning of ESK1 gene uncovered a large family of plant-specific proteins whose function has not been characterized previously. The recessive nature of esk1 mutations and the wide-spectrum of genes altered in the mutants suggest that the ESK1 protein may be a novel negative regulator of cold acclimation.