Abstract
Plants are exposed to many environmental stresses. To adjust to these environmental changes, plants developed various strategies for regulating gene expression. Recent discovery of small RNAs has enhanced the impact of mRNA stability control. We first investigated the change of mRNA half-lives in response to cold stress in Arabidopsis by doing microarray anayses over a time course following transcriptional inhibition. We used this strategy, "mRNA-decay array", with Arabidopsis cell culture to isolate genes which altered the level of mRNA stability after cold stress treatment. These microarray analyses revealed that majority of the transcripts are stabilized probably due to general decrease of enzymatic activity under low temperature. Compared to these average transcripts, more than a thousand of transcripts are either stabilized or destabilized in response to cold treatment, and functional category classification indicated that stress-related transcripts tend to be destabilized. By estimating the steady-state mRNA level and transcription rate under cold stress, it is suggested that several mRNAs are regulated by stability efficiently enough to change their steady-state levels.
