Changes in Protein Patterns and Translatable Messenger RNA Populations during Cold Acclimation of Alfalfa

Changes in the rate and pattern of protein synthesis and in translatable mRNA population during cold acclimation of alfalfa (Medicago falcata cv Anik) seedlings have been examined. There appears to be a positive correlation between the increase in ability to synthesize proteins at 4 degrees C and the increase in freezing resistance (survival at -10 degrees C). Results obtained with three different approaches using sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern visualized by (a) staining, (b) immunoblotting and autoradiography, and (c) fluorography of in vivo labeled proteins, show that at least eight polypeptides are newly synthesized during cold acclimation. Results of analysis of in vitro translation products of mRNA from nonacclimated and acclimated seedlings show the appearance of new translatable mRNAs. It is concluded that changes in gene expression occur during cold acclimation, most probably at the transcriptional level.