The role of dehydrins in plant response to cold

Abstract

Dehydrins present a distinct biochemical group of late embryogenesis abundant (LEA) proteins characterised by the presence of a lysine-rich amino acid motif, the K-segment. They are highly hydrophilic, soluble upon boiling, and rich in glycine and polar amino acids. It is proposed that they can act as emulsifiers or chaperones in the cells, i.e., they protect proteins and membranes against unfavourable structural changes caused by dehydration. Cold usually precedes freezing in nature and induces many physiological and biochemical changes in the cells of freezing-tolerant plant species (cold-acclimation) that enable them to survive unfavourable conditions. It is demonstrated that the induction of dehydrin expression and their accumulation is an important part of this process in many dicotyledons (both herbaceous and woody species), and also in winter cultivars of cereals, especially wheat and barley. Some mechanisms which are proposed to be involved in regulation of dehydrin expression are discussed, i.e., endogenous content of abscisic acid, homologues of Arabidopsis C-repeat binding factor (CBF) transcriptional activators, the activity of vernalization genes and photoperiodic signals. Finally, we outline some new approaches emerging for the solution of the complex mechanisms involved in plant cold-acclimation, especially the methods of functional genomics that enable to observe simultaneously changes in the activity of many genes and proteins in a single sample. © 2007 Institute of Experimental Botany, ASCR.