RNA helicase-like protein as an early regulator of
transcription factors for plant chilling and freezing tolerance.
Gong Z, Lee H, Xiong L, Jagendorf A, Stevenson B, Zhu JK.
Department of Plant Sciences, University of Arizona, Tucson, AZ 85721; and
Department of Plant Biology, Cornell University, Ithaca, NY 14853.
Susceptibility to chilling injury prevents the cultivation of many important
crops and limits the extended storage of horticultural commodities. Although
freezing tolerance is acquired through cold-induced gene expression changes
mediated in part by the CBF family of transcriptional activators, whether plant
chilling resistance or sensitivity involves the CBF genes is not known. We
report here that an Arabidopsis thaliana mutant impaired in the cold-regulated
expression of CBF genes and their downstream target genes is sensitive to
chilling stress. Expression of CBF3 under a strong constitutive promoter
restores chilling resistance to the mutant plants. The mutated gene was cloned
and found to encode a nuclear localized RNA helicase. Our results identify a
regulator of CBF genes, and demonstrate the importance of gene regulation and
the CBF transcriptional activators in plant chilling resistance.