RNA Degradation Mechanism in Arabidopsis Cold Stress Response

Abstract

Overwintering plants are capable of exhibiting high levels of cold tolerance, which is acquired through the process of cold acclimation. During the cold acclimation process, the expression of various cold responsive genes and proteins is altered. It is important to clarify the regulatory mechanism for expression of genes and proteins in order to understand the cold tolerance in plants. mRNA and protein levels are regulated by both synthesis such as transcription or translation and post-transcriptional or translational RNA regulation such as turnover or stabilization. In this study we focused on the turnover of RNA regulation during cold stress response.
We found that mutant of XRN4 which encodes a 5'-3' exoribonuclease exhibits freezing tolerant phenotype in non-acclimated condition. Detailed analysis of freezing tolerance and ion leakage tests revealed that xrn4 mutants show freezing tolerance in only non-acclimated condition but not in cold acclimated condition. This data indicates that regulation of RNA degradation plays an important role in plant cold stress response. Identification of the XRN4 targets using transcriptome and proteome analysis is in progress.