Plant dehydrins — Tissue location, structure and function

Abstract

Dehydrins (DHNs) are part of a large group of highly hydrophilic proteins known as LEA (Late Embryogenesis Abundant). They were originally identified as group II of the LEA proteins. The distinctive feature of all DHNs is a conserved, lysine-rich 15-amino acid domain, EKKGIMDKIKEKLPG, named the K-segment. It is usually present near the C-terminus. Other typical dehydrin features are: a track of Ser residues (the S-segment); a consensus motif, T/VDEYGNP (the Y-segment), located near the N-terminus; and less conserved regions, usually rich in polar amino acids (the Φ-segments). They do not display a well-defined secondary structure. The number and order of the Y-, S-and K-segments define different DHN sub-classes: Y n SK n , Y n Kn, SKn, K n and K n S. Dehydrins are distributed in a wide range of organisms including the higher plants, algae, yeast and cyanobacteria. They accumulate late in embryogenesis, and in nearly all the vegetative tissues during normal growth conditions and in response to stress leading to cellular dehydration (e.g. drought, low temperature and salinity). DHNs are localized in different cell compartments, such as the cytosol, nucleus, mitochondria, vacuole, and the vicinity of the plasma membrane; however, they are primarily localized to the cytoplasm and nucleus. The precise function of dehydrins has not been established yet, but in vitro experiments revealed that some DHNs (YSK n -type) bind to lipid vesicles that contain acidic phospholipids, and others (K n S) were shown to bind metals and have the ability to scavenge hydroxyl radicals [Asghar, R. et al. Protoplasma 177 (1994)

TrMADS3, a new MADS-box gene, from a perennial species Taihangia rupestris (Rosaceae) is upregulated by cold and experiences seasonal fluctuation in expression level

“…These results suggest that the transgenic plants appear primarily to tolerate osmotic stress exerted by NaCl and mannitol. When plants are subjected to stress leading to cellular dehydration, a number of hydrophilic proteins like lateembryogenesis-abundant (Rorat 2006) and antifreeze proteins (Griffith and Yaish 2004) are induced or upregulated. The hydrophilic C-terminal of TrMADS3 implies the activity of the protein under dehydration conditions in Taihangia.…”

Dehydrins expression related to timing of bud burst in Norway spruce

“…They are found to accumulate in seeds during late embryogenesis, in plant tissues by stresses and processes leading to water deWcit, and responsive to the abscisic acid (e.g. Ingram and Bartels 1996;Campbell and Close 1997;Rorat 2006). They may play a role in the development of freezing tolerance and cold acclimation (e.g.…”

Extreme climatic events: impacts of drought and high temperature on physiological processes in agronomically important plants

“…Arabidopsis dehydrins ERD10 and ERD14 fulfill protective functions acting as potent chaperones of broad substrate specificity and they also have membrane-binding capacity (Kovacs et al, 2008). It was also reported that both ERD10 and ERD14 can be phosphorylated at various sites, which promotes the binding of divalent metal ions, and this might be related to their ion-sequestering activity (Rorat, 2006). Drought tolerance is assessed as the ability of plants to maintain a certain level of production under water shortage, which is relevant for most economically important crops (Volaire and Lelievre, 2001).…”

“…Dehydrins belong to the group of Late Embryogenesis-Abundant (LEA) proteins which are expressed in late stages of seed maturation and/or upon water stress conditions in plants (Rorat, 2006). They constitute a highly divergent group of thermostable intrinsically disordered proteins that can be classified into different types according to the presence of distinct, short sequence motifs.…”

“…The number and order of the Y-, S-, and K-segments define the different dehydrin sub-classes: YnSKn, YnKn, SKn, Kn, and KnS, which may possess a specific function and tissue distribution (Close, 1997). As intrinsically disordered proteins dehydrins are characterized by high flexibility, structural adaptability, and extended conformational states (Tompa, 2009) which most probably contributes to conferring plant desiccation stress tolerance via various possible biochemical mechanismssequestering ions, stabilizing membranes, or acting as chaperones (Danyluk et al, 1998;Rorat, 2006;Tompa, 2009). Arabidopsis dehydrins ERD10 and ERD14 fulfill protective functions acting as potent chaperones of broad substrate specificity and they also have membrane-binding capacity (Kovacs et al, 2008).…”