Abstract
Overwintering temperate plants can enhance freezing tolerance in response to low, non-freezing temperatures (cold acclimation, CA). When cold-acclimated plants are transferred to a warm temperature, they reversibly lose their freezing tolerance rather quickly (deacclimation, DA). Particularly, DA is important under oscillatory temperature conditions in early spring in the field but has not been studied in detail. Thus, the purpose of this study is to accumulate fundamental knowledge of DA to explore possibilities to reduce freezing injury occurring in the DA period. First, we verified changes of freezing tolerance in Arabidopsis thaliana during CA and DA periods: acquired freezing tolerance after 1 week of CA at 2℃ was lost after 2 days of DA. Next, we focused on proteomic changes of the plasma membrane that is considered to be the primary site for determination of freezing tolerance. Proteome analysis identified 647 CA and/or DA responsive-proteins with different patterns of alternations during CA and DA periods and these proteins were categorized into specific functional categories. With these results, we discussed the function of CA and DA responsive-proteins in detail.
