Specifics of stress proteins-dehydrins of birch Betula L. in the conditions of cryolithozone

Abstract

The compositional features of stressful dehydrin proteins of some species of Betula L.: silver birch B. pendula Roth, dwarf bog birch B. fruticosa Pall., dwarf birch B. nana L., growing under extreme climate conditions in the cryolithozone of Central Yakutia were studied using specific antibodies. The composition of birch dehydrins hanging from regions differing in more moderate climatic indices (South Yakutia and Pribaikalye) was studied for comparison. The composition of dehydrins in different species of birch under the conditions of cryolithozone has significant similarities. Low molecular weight dehydrins, mainly 17 kDa from two groups of identified dehydrins in the range with mol. m. 15–21 and 56–73 kDa, regardless of the species characteristics of birch, are subject to the greatest seasonal changes. These proteins in shoots and buds, as well as in the tissues of the bark and xylem of silver birch, have a high level during winter dormancy at the lowest negative temperatures, when frost resistance of plants reached maximum values, while they almost disappeared in the summer period. Dehydrins in the region of 15–21 kDa in birch shoots and buds were characterized by more pronounced intraspecific polymorphism in the conditions of Central Yakutia, their content, predominantly 17 kDa of dehydrin, significantly exceeded that of birches of the South Yakutia and Irkutsk populations. The middle molecular weight dehydrins of birch 66–69 kDa are presented round whole year at almost the same level. These dehydrins in leaves, male inflorescences, pollen and seedlings from silver birch seeds were observed during the growing season, although they were found in smaller quantities. Significant similarities in the composition and representation of dehydrins in the organs and tissues of the studied birch populations may indicate their important role in the general mechanisms of the formation of the low-temperature resistance of Betula L. plants to the conditions of Northeast Eurasia.

Keywords

• birch
• organs
• tissues
• low temperatures
• resistance
• permafrost
• yakutia