Accumulation of HSP70 in Deschampsia antarctica Desv. leaves under thermal stress

• Published in: Antarctic Science
• Main Authors: REYES, MARÍA ANTONIETA, CORCUERA, LUIS J., CARDEMIL, LILIANA
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2003
• Subjects: Geology; Ecology, Evolution, Behavior and Systematics; Oceanography; Antarctic; Antarc*; Antarctic Science; Antarctica
• Online Access: http://dx.doi.org/10.1017/s0954102003001366; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102003001366

The aim of this study was to evaluate the hypothesis that Deschampsia antarctica Desv., the only grass of the Maritime Antarctic, responds to temperatures higher or lower than its optimum for photosynthesis (13°C), with the accumulation of heat shock proteins. The LT 50 was determined in plants acclimated at 4°C (cold-acclimated plants) and in plants grown at 13°C (control plants) by membrane damage and by the activity of respiratory dehydrogenases. The LT 50 was 48.3°C in both groups of plants when determined by membrane damage. When the LT 50 was determined by the activity of respiratory dehydrogenases, this was, without significant difference, 47.8°C in cold-acclimated plants and 46.5°C in control plants. Western blot analyses were performed to investigate the accumulation of HSP70 at different temperatures. The optimal temperature for HSP70 accumulation was 35°C in cold-acclimated and control plants. Cold-acclimated plants subjected to a thermal stress of 35°C accumulated HSP70 protein more than control plants subjected to 35°C. After eight hours of continuous stress at 35°C, the maximum relative content of HSP70 in cold-acclimated plants was 1.9 fold higher than control plants. The threshold temperature for HSP70 accumulation was lower in cold-acclimated plants than in control plants. It is concluded that D. antarctica is able to tolerate heat stress with an LT 50 similar to those of heat tolerant plants and that the cold-acclimated plants accumulate higher levels of HSP70 than those grown at 13°C.