Cold Influence on the Content of Dehydrins in Scots Pine’s Callus

Dehydrins (DHN) are protective proteins acting at the cellular level and increasing the resistance of plants to cold and water-deficient conditions. The DHN of gymnosperms remain poorly studied. Scots pine is adapted to cold conditions and moisture deficiency, which points to DHN importance for the stability of this species at the cellular level. To identify the DHN of Scots pine that are regulated by cold stress, callus lines were obtained on vegetative branches and buds of five Scots pine trees (Pinus sylvestris L.) and exposed to low positive temperatures. In response to cold treatment, there was an accumulation of superoxide anion, an increase in the level of lipid peroxidation and in the activity of peroxidase and superoxide dismutase enzymes, which indicates damage of membranes and the activation of protective mechanisms in the callus cells. When exposed to cold, there was an increase in the expression of six of the studied DHN genes, which had individual characteristics for each tree. Callus lines obtained on different Scots pine trees showed differences in the content and in the composition of DHN. In the calluses of the two lines a previously unidentified DHN with molecular weight 24 kDa appeared in response to cold. The content of DHN 70 kDa, which also accumulates in response to water deficiency, increased. The study indicates that P. sylvestris has DHN that are regulated with cold exposure, and DHN that can be regulated by both cold exposure and water deficiency.