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

Abstract

Late Embryogenesis Abundant (LEA) proteins, a group of hydrophilic proteins, have been linked to survival in plants and animals in periods of stress, putatively through safeguarding enzymatic function and prevention of aggregation in times of dehydration/heat. Yet despite decades of effort, the molecular-level mechanisms defining this protective function remain unknown. In this paper, we summarize and review research discoveries of the classification of the LEA protein groups based on their amino acid sequence similarity and on the presence of distinctive conserved motifs. Moreover, we focus on high correlation between their accumulation and water deficit, reinforcing their functional relevance under abiotic stresses. We also discuss the biochemical properties of LEA proteins arising from their hydrophilic nature and by amino acid composition. Although significant similarities have not been found between the members of the different groups, a unifying and outstanding feature of most of them is their high hydrophilicity and high content of glycine. Therefore, we have highlighted the biotechnological applications of LEA genes, and the effects of over-expressing LEA genes from all LEA groups from different species of origin into different plant hosts. Apart from agronomical purposes, LEA proteins could be useful for other biotechnological applications in relation to their capacity to prevent aggregation of proteins.

High Level of Nonsynonymous Changes in Common Bean Suggests That Selection under Domestication Increased Functional Diversity at Target Traits

“…In particular, AN-Pv18 is a late embryogenesis abundant protein, and high levels of these proteins accumulate in plants under environmental stress. In several studies, AN-Pv18 and AN-DNAJ have been shown to have roles in cellular protection during abiotic stress tolerance, and especially during drought (for review see Amara et al, 2014). AN-DNAJ belongs to the DNAJ heat-shock family of proteins that regulate the folding, localization, accumulation, and degradation of proteins, stabilize proteins and membranes, and can assist in protein refolding under stress conditions.…”

PREPARATION OF PLANT VECTOR CONSTRUCT CONTAINING DEHYDRIN GENE At2g21490

“…Among the proteins that are significantly accumulated during the stress caused by dehydration, osmoticum and/or a low temperature are LEA proteins ("Late embryogenesis abudant proteins") (Amara et al, 2014). They are hydrophilic molecules whose role probably is to protect biomolecules and cell membranes (Candat et al, 2014).…”

Synteny-based phylogenomic networks for comparative genomics

“…In plants, the group of Late Embryogenesis Abundant (LEA) proteins, composed of eight multi-gene families (Dehydrin, LEA_1, LEA_2, LEA_3, LEA_4, LEA_5, LEA_6 and SMP), have been shown to play roles in water stress tolerance, and may represent a conserved and indispensable component of regulatory networks involved in environmental stress adaptation that allowed plants to endure the constraints associated with land adaptation (Shih et al, 2008;Hincha and Thalhammer, 2012;Amara, 2014). Evidences suggest that there is functional variability between and within each of the eight families (Hundertmark and Hincha, 2008), what raises questions such as what are the sources of functional variations, what are the precise biological functions of each family, if and how LEA families work as one entity, and which LEA genes are involved in plant development and stress tolerance.…”

“…LEAs were originally associated with the acquisition of DT in plant embryos due to the high gene expression and protein accumulation in the later stages of seed maturation (Galau et al, 1986;Dure et al, 1989;Espelund et al, 1992;Manfre et al, 2006;Delahaie et al, 2013). In vegetative tissues, LEAs were found to accumulate upon abiotic stresses such as drought, salinity, heat and freezing, and under desiccation in resurrection plants (Hoekstra et al, 2001;Cuming et al, 2007;Amara, 2014;Stevenson et al, 2016). Interestingly, LEA genes are also found outside the plant kingdom, suggesting a common mechanism of DT across distinct life forms (Browne et al, 2002;Tunnacliffe et al, 2005;Kikawada et al, 2006;Gusev et al, 2014).…”

“…Several studies have attempted to identify, classify, and access LEAs function in plants (Battaglia et al, 2008;Hundertmark and Hincha, 2008;Shih et al, 2008;Amara, 2014), however, a comprehensive understanding of the evolutionary history and its relationship with the high diversification of protein sequence and function of LEAs in plants is still elusive.…”