Accumulation of an Acidic Dehydrin in the Vicinity of the Plasma Membrane during Cold Acclimation of Wheat

Abstract

Expression of the acidic dehydrin gene wcor410 was found to be associated with the development of freezing tolerance in several Gramineae species. This gene is part of a family of three homologous members, wcor410 , wcor410b , and wcor410c , that have been mapped to the long arms of the homologous group 6 chromosomes of hexaploid wheat. To gain insight into the function of this gene family, antibodies were raised against the WCOR410 protein and affinity purified to eliminate cross-reactivity with the WCS120 dehydrin-like protein of wheat. Protein gel blot analyses showed that the accumulation of WCOR410 proteins correlates well with the capacity of each cultivar to cold acclimate and develop freezing tolerance. Immunoelectron microscope analyses revealed that these proteins accumulate in the vicinity of the plasma membrane of cells in the sensitive vascular transition area where freeze-induced dehydration is likely to be more severe. Biochemical fractionation experiments indicated that WCOR410 is a peripheral protein and not an integral membrane protein. These results provide direct evidence that a subtype of the dehydrin family accumulates near the plasma membrane. The properties, abundance, and localization of these proteins suggest that they are involved in the cryoprotection of the plasma membrane against freezing or dehydration stress. We propose that WCOR410 plays a role in preventing the destabilization of the plasma membrane that occurs during dehydrative conditions.

Comparative analysis of Pinus pinea and Pinus pinaster dehydrins under drought stress

“…These proteins, characterised by the presence of highly conserved segments in amino acid sequence named Y-, Sand K-segments (Close 1996;Close 1997) or A-and Esegments specifically in Pinaceae (Perdiguero et al 2012a), have been proposed to play a key role in the response to drought stress in plants. This is because they are involved in preserving and maintaining cell functions during dehydration (Eriksson and Harryson 2011;Kosová et al 2010;Rorat 2006), probably via stabilisation of membranes by hydrophobic interactions (Campbell and Close 1997;Danyluk et al 1998;Koag et al 2003), chaperone activity (Kovacs et al 2008a;Kovacs et al 2008b) or antioxidant activity preventing excessive reactive oxygen species (ROS) formation (Hara et al 2005;Sun and Lin 2010). The overexpression of dehydrins in Arabidopsis or tobacco enhanced tolerance to drought and other stresses (Brini et al 2007;Hara et al 2003;Puhakainen et al 2004).…”

Accumulation of dehydrin-like proteins in the mitochondria of cereals in response to cold, freezing, drought and ABA treatment

“…Highly-conserved polar regions of dehydrins have been suggested to hydrogen-bond with polar regions of macromolecules, acting essentially as a surfactant, to prevent coagulation under conditions of cellular dehydration or low temperatures [18]. Immunolocalization and subcellular fractionation results have showed that members of the dehydrin family are present in the nucleus, cytoplasm, and plasma membrane [19,20]. Recently we have found that two dehydrin-like proteins (dlps) accumulated in mitochondria of Triticum aestivum (L.) (winter wheat), Secale cereale (L.) (winter rye), and in Zea mays (L.) (corn) in response to cold [21].…”

Insights into Late Embryogenesis Abundant (LEA) Proteins in Plants: From Structure to the Functions

“…Most of them accumulate in all tissues upon water deficit although there are those that preferentially respond to particular stress conditions. Some dehydrins are strongly accumulated in response to low-temperature treatments but not to drought or salinity [99]; other group 2 members are not induced in response to low temperatures, while a small number of dehydrins show an unusual constitutive expression [100]- [102]. However, it is not possible to assign a specific accumulation pattern to particular group or subgroup.…”

“…LEA proteins being highly hydrophilic are not expected to interact with cellular membranes in hydrated condi-tions, but interaction cannot be excluded through α-helices in a dehydrating cell. Among group 2 LEA proteins, wheat WCOR414 and Arabidopsis LTi29 acidic dehydrins were immunodetected in the vicinity of the plasma membrane during cold acclimation [100] [138] and maize dehydrins were observed in association to membranes of protein and lipid bodies [139]. Maize native and recombinant dehydrin DHN (Rab17) binds in vitro to anionic lipid vesicles and binding produces an increase in amphipathic α-helix (a structural element that interacts to membranes and proteins); both binding and gain in conformation were attributed to the K-segment [140] [141].…”