Effects of cold stress on protein metabolism of certain walnut cultivars

Abstract

To investigate the effects of heat shock proteins (HSPs) on walnut (Juglans regia L.) plants under low-temperature stress, first of all, low-temperature tolerances of ten walnut cultivars (Chandler, Fernor, Franquette, Pedro, Bilecik, Kaman-I, Kaman-II, Kaman-III, Sebin, and Yalova I) were determined. One-year-old shoot samples were taken from the plants in two different periods, cold-acclimated (CA) and non-acclimated (NA), and were exposed to +5°C, -5°C, -15°C and -25°C for 12 h. Cold injury was determined by ion leakage analysis in the thawed bark tissues. According to the results of this analysis, two cultivars were determined as cold-sensitive (Chandler) and cold-tolerant (Fernor) in terms of low-temperature tolerance. To examine the effects of HSPs on cold tolerance in walnut plants, the protein profiles, the amount of total protein, and the HSPs of these two cultivars were determined. As a result of the immunoblot analysis, it was determined that 44 kDa HSP23 and 59 kDa HSP60 are responsible for low-temperature tolerance in walnut plants.