Plant dehydrins and stress tolerance: versatile proteins for complex mechanisms

Abstract

Dehydrins (DHNs), or group 2 LEA (Late Embryogenesis Abundant) proteins, play a fundamental role in plant response and adaptation to abiotic stresses. They accumulate typically in maturing seeds or are induced in vegetative tissues following salinity, dehydration, cold, and freezing stress. The generally accepted classification of dehydrins is based on their structural features, such as the presence of conserved sequences, designated as Y, S, and K segments. The K segment representing a highly conserved 15 amino acid motif forming amphiphilic α-helix is especially important since it has been found in all dehydrins. Since more than 20 years, they are thought to play an important protective role during cellular dehydration but their precise function remains unclear. This review outlines the current status of the progress made towards the structural, physico-chemical and functional characterization of plant dehydrins and how these features could be exploited in improving stress tolerance in plants.

Figure 1

DHN-5 interferes with JA signaling pathway. Overexpression of DHN-5 causes decreased sensitivity to jasmonate (JA), and affects a subset of JA-responsive genes, downregulation of wound-induced genes and upregulation of pathogen-responsive genes in Arabidopsis thaliana. JAZ (jasmonate ZIM-domain) proteins are negative regulators of JA-signaling. JAI3 encodes a member of JAZ protein, JAZ3. Myc2 (JAI1) is a bHLH-type transcription factor. ERF1 is a transcription factor, which mediates responses to ethylene and JA, antagonistic to MYC2 function. How DHN-5 affects JA signaling is unknown. For details, see references –.