ABSTRACT
Dehydrins are highly hydrophilic, well-soluble proteins which belong to a large family of Late embryogenesis-abundant (LEA) proteins whose name comes from Galau et al. (1986) who studied them for the first time in cotton (Gossypium hirsutum L.) embryos (Dure et al., 1981; Galau and Dure, 1981). They are classified as group 2 LEA (or LEA II) proteins (Bray, 1993; Ingram and Bartels, 1996) or LEA-D11 proteins according to one dehydrin member in a cotton embryo (Dure et al., 1989). In the Pfam database of protein domains (https://www.sanger.ac.uk/Software/Pfam">https://www.sanger.ac.uk/Software/Pfam; Bateman et al., 2004), they are simply named dehydrins and have a Pfam number – PF00257. They have a relatively high glycine content (greater than 6%) and a hydrophilicity index (Kyte and Doolittle, 1982) greater than 1, thus they can be classified as hydrophilins (Garay-Arroyo et al., 2000; Battaglia et al., 2008). The first reported dehydrin proteins were RAB21, a protein induced by salt and osmotic stress in rice (Oryza sativa L.) (Mundy and Chua, 1988), and D-11, a protein accumulating in maturating embryo of cotton (Gossypium hirsutum L.) (Baker et al., 1988). At the end of the 1980s, dehydrins were defined as ‘dehydration-induced proteins’ according to their mode of expression (Close et al., 1989). Later, as their sequence characteristics became available, dehydrins were re-defined on the basis of their sequentional motifs. They were newly defined 176as proteins possessing at least one copy of a conserved lysine-rich amino acid sequence, a K-segment, in their molecules (Close, 1996,1997). Due to this definition, based on the presence of a unique amino acid motif, dehydrins can be easily detected by a specific primary antibody raised against the K-segment (Close et al.,1993).
