CHARACTERIZATION OF CHILLING-ACCLIMATION-RELATED PROTEINS IN SOYBEAN AND IDENTIFICATION OF ONE AS A MEMBER OF THE HEAT-SHOCK PROTEIN (HSP-70) FAMILY

Through a 5-d exposure at 14-degrees-C/8-degrees-C (day/night), soybea n (Glycine max [L.] Merr.) was acclimated to a lower temperature of 8- degrees-C. In order to assess changes in protein synthesis related to chilling acclimation, proteins were labeled in vivo with [S-35]methion ine, separated by two-dimensional gel electrophoresis, and the derived autoradiograms were subjected to computer analysis. Two sets of chill ing-acclimation-related proteins were characterized following exposure and labeling at 8-degrees-C. One set corresponded to proteins whose s ynthesis was stimulated in acclimated plants in comparison with non-ac climated plants after transfer to 8-degrees-C for 2 d. The other set a lso displayed an enhanced synthesis in the acclimated plants versus th e non-acclimated plants but after 7 d of exposure at 8-degrees-C. Most of these chilling-acclimation-related proteins were not increased dur ing the acclimation period at 14-degrees-C. Using microsequence analys is, one of these proteins was shown to have a high sequence homology w ith members of the heat-shock protein (HSP 70) family.