Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 7, 2007
Publication Date: July 11, 2007
Citation: Xin, Z., Chen, J. 2007. ESK1 is a novel component of freezing tolerance[abstract]. Plant Biology Annual Meeting. Chicago, Illinois. July 7-11, 2007. Technical Abstract: Plants acquire a greater freezing tolerance through multiple mechanisms in response to a period of low nonfreezing temperatures through an adaptive process known as cold acclimation. The eskimo1 (esk1) mutant of Arabidopsis is constitutively freezing tolerant. The enhanced freezing tolerance is not associated with any increase in ability to survive drought or salt stresses, which are similar to freezing in their induction of cellular dehydration. Genome-wide comparisons of gene expression between esk1-1 and wild-type indicate that mutations at esk1 result in altered expression of transcription factors and signaling components, and of a set of stress-responsive genes. Interestingly, the list of 312 genes regulated by esk1 shows greater overlap with sets of genes regulated by salt, osmotic and abscisic acid treatments than with genes regulated by cold acclimation or by the transcription factors CBF3 and ICE1, which have been shown to control genetic pathways for freezing tolerance. Map-based cloning identified the esk1 locus as At3g55990. The wild-type ESK1 gene encodes a 57 kD protein and is a member of a large gene family of DUF231 domain proteins whose members encode a total of 45 proteins of unknown function. Our results indicate that ESK1 is a novel negative regulator of cold acclimation. Mutations in the ESK1 gene provide strong freezing tolerance through genetic regulation that is apparently very different from previously described genetic mechanisms of cold acclimation.