Comparison of plasma membrane proteomic changes of Arabidopsis suspension-cultured cells (T87 Line) after cold and ABA treatment in association with freezing tolerance development.

The plasma membrane (PM) is the primary site of freezing injury in plants. To determine global changes in PM protein profiles in association with freezing tolerance development, proteome analysis of the purified PM of Arabidopsis suspension-cultured cells (T87 line) was conducted with label-free protein quantification technology. Freezing tolerance of Arabidopsis cells at the lag growth phase (8 d old) increased after cold acclimation (CA) or ABA treatment. Proteome analysis assigned 658 proteins in the PM in total, of which 45.3% (298 proteins) were predicted to have transmembrane domains. They were classified into several functional categories, with the primary categories being proteins in transporters, signal transduction, protein destination and storage, and cell structure. After CA, 271 proteins increased and 111 proteins decreased. ABA treatment resulted in 185 increased and 56 decreased proteins. Of these, 139 increased and 49 decreased proteins were identified in common after both CA and ABA treatment. In addition, there were proteins specifically expressed in cold- (132 increased and 62 decreased) or ABA- (46 increased and 7 decreased) treated cells. Collectively, our results clearly show that (i) responses of the PM proteome to CA and ABA treatment overlap substantially but, at the same time, some proteins exhibited different response patterns in each treatment; and (ii) the majority of ABA-responsive proteins are CA-responsive proteins but not vice versa, suggesting complex interactions of CA and ABA signaling pathways in the PM proteome responses.