Compositional changes of plasma membrane proteins of Brachypodium distachyon during cold acclimation

Abstract

To survive at freezing temperatures, temperate plants increase their freezing tolerance by cold acclimation, during which changes of protein and lipid compositions of the plasma membrane (PM) play a key role. Brachypodium distachyon, a temperate grass species, has been recognized as a model plant and is evolutionarily closer to temperate cereals than rice. These facts suggest that B. distachyon could serve as a good system to study freezing tolerance mechanism of temperate cereals. In the present study, using non-acclimated (NA) and cold-acclimated (CA, 2℃) B. distachyon, we performed freezing tolerance test and PM proteome analysis. When freezing tolerance was evaluated by measurement of electrolyte leakage, the temperature at which 50% electrolyte leakage occurs after freezing (T_<EL50>) was lowered from -3.9℃ to -6.9℃ by cold acclimation. Furthermore based on the proteome analysis, PM proteins were found to be changed considerably by cold acclimation and the changes were similar in some parts to those found in oat and rye during cold acclimation. These results suggest that B. distachyon has an ability of cold acclimation and some common pathways responding to cold as shown in temperate cereals.