Expression of Different Types of Dehydrins during Low-Temperature Exposure and Dehardening in Winter Wheat Crowns

The expression of dehydrin genes in crowns of winter wheat (Triticum aestivum L.) cultivars differing in frost resistance was studied according to the scheme: cold acclimation, freezing, and dehardening. It has been shown for the first time that, in addition to the previously described WCS120 dehydrins, some genes encoding proteins with the Y segment also play an equally important role in the frost resistance of winter wheat plants. The number of transcripts of these genes increased no less when exposed to negative temperatures after cold acclimation than in the case of WCS genes, and one of these genes, DHN3–B9 (wzy1-1), was activated 10 times more strongly than other highly inducible dehydrin genes. The dynamics of changes in the content of DHN mRNAs activated by cold and freezing were similar in winter wheat lines differing in frost resistance, but the number of transcripts of certain genes in the more resistant wheat cultivar increased more strongly. As shown by a comparative analysis of the profiles of changes in the mRNA content of dehydrin genes and their protein products, with the experimental scheme used in this work in the crowns of winter wheat during dehardening, the number of transcripts of dehydrin genes is significantly reduced to a level comparable to the level at the cold acclimation stage or even to the level of control values, and the degradation of protein products of genes is significantly suppressed—the content of proteins remains high at this stage.