The characterization of the heat-shock response in the arctic plant Saxifraga cernua

• Published in: Canadian Journal of Botany
• Main Authors: Mason-Apps, Susan, Cummins, W. R., Filion, W. Gary
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1990
• Subjects: Plant Science; Arctic; Saxifraga cernua
• Online Access: http://dx.doi.org/10.1139/b90-009; http://www.nrcresearchpress.com/doi/pdf/10.1139/b90-009

A rapid increase in the incubation temperature of whole leaves of the arctic plant Saxifraga cernua, grown at 10 or 20 °C, resulted in the noncoordinate expression of 21 novel and (or) enhanced heat-shock polypeptides. Unlike other organisms, the expression of most of the normal polypeptides was not reduced. Incorporation of radioactivity during hyperthermic shifts was similar in both groups of plants at all temperatures investigated, with peak incorporation recorded at 33 °C. The temperature at which the expression of the heat-shock polypeptides was at a maximum level was also 33 °C. Protein synthesis was reduced after a heat shock at 35 °C and completely inhibited at 38 °C. These data suggest that the preshock growth temperature had no effect on the temperature of maximum expression of the heat-shock polypeptides nor the level of protein synthesis during heat shock. Recovery at 10 °C from a 33 °C heat shock was complete within 7–9 h. Extended time periods (up to 24 h) at the shock temperature of 33 °C demonstrated that the heat-shock response in this arctic plant was multiphasic, consisting of an early group and five sets of late heat-shock polypeptides