Short- and long-term effects of surface fires on heat stress protein content in Scots pine needles

Abstract

Plants can minimise the damaging effects of high temperatures through numerous protective mechanisms; however, it is largely unknown how these mechanisms respond to extreme temperatures associated with wildfire. We investigated the effect of experimental burning (EB) on the accumulation of stress heat shock proteins (Hsps), which are one of the factors of thermotolerance in plants, in the needles of Scots pine (Pinus sylvestris L.). Previous fire exposure led not only to short- and long-term changes in the content of stress proteins in needles but also to changes in the accumulation of these proteins in response to reheating. The content of Hsp 101, Hsp 70 and Hsp 17.6 in the needles increased on the second day after EB (short-term effect of fire). Three years after EB, the content of Hsps in the fire-exposed needles was lower compared with the control needles. When these needles were subjected to the heat stress test at 45°C, the content of Hsps increased, whereas the content of Hsps in control needles decreased. Our results suggest that Scots pine needles retain a fairly long-term ‘stress memory’, expressed through proteomic defence mechanisms, to wildfire heat-induced damage.