Abstract
An application of low temperature or ABA induces freezing tolerance in Arabidopsis plants. In this study, we analyzed responses of Arabidopsis cultured cells (T87) to low temperature or ABA to understand molecular mechanisms of freezing tolerance acquisition at cellular level. Increase in freezing tolerance occurred only with cells at late lag phase when exposed to a low temperature for 2 days or ABA for 1 day. Osmotic concentration, sugar content and cold-inducible gene expression (COR15a and RD29A) had no apparent relationship with changes in freezing tolerance. Microarray analysis to determine the freezing-tolerance-associated genes of cultured cells revealed that there were 448 up- or 438 down-regulated genes after cold treatment. Among these genes, 17 and 14% were up- and down-regulated, respectively, only with cultured cells. These results suggest that perception and signal transduction of low temperature or ABA varies between at cellular and whole plant level.
