Abstract
Cold acclimation (CA) results in alterations of plasma membrane (PM) lipid composition in plants, which is critical to increase freezing tolerance. Recent studies indicate that PM is considered not homogeneous and contains sterol/sphingolipid-enriched microdomains (MD). In plant cells, however, the function of PM-MD is not yet fully understood. The present study aims to investigate lipid composition of PM-MD isolated from non-acclimated and cold-acclimated leaves of oat and rye that differ considerably in freezing tolerance. Lipid composition of MD is different from that of total PM in both species: sterol lipids are enriched in MD, the proportion of phospholipids is less in MD than in total PM, and the proportion of glucocerebrosides is similar in the both preparations. In rye and oat, CA resulted in an increase in free sterols, but other sterols lipids, glucocerebrosides and phospholipids changed only moderately. CA-induced changes in lipid compositions of MD are different from those observed in the total PM preparations. With information on lipid composition of PM-MD of Arabidopsis leaves, we will discuss the roles of PM-MD in plant cold acclimation and freezing tolerance.
