American Journal of Plant Sciences, 2014, 5, 3440-3455 Published Online November 2014 in SciRes. http://www.scirp.org/journal/ajps http://dx.doi.org/10.4236/ajps.2014.522360 How to cite this paper: Amara, I., Zaidi, I., Masmoudi, K., Ludevid, M.D., Pagès, M., Goday, A. and Brini, F. (2014) Insights into Late Embryogenesis Abundant (LEA) Proteins in Plants: From Structure to the Functions. American Journal of Plant Sciences, 5, 3440-3455. http://dx.doi.org/10.4236/ajps.2014.522360 Insights into Late Embryogenesis Abundant (LEA) Proteins in Plants: From Structure to the Functions Imen Amara 1,2 , Ikram Zaidi 2 , Khaled Masmoudi 2,3 , M. Dolors Ludevid 1 , Montserrat Pagès 1 , Adela Goday 1 , Faiçal Brini 2* 1 Department of Molecular Genetics, Center for Research in Agricultural Genomics (CSIC-IRTA-UABUB), Campus Universitat Autonoma de Barcelona, Bellatera (Cerdanyola Del Valles), Barcelona, Spain 2 Plant Protection and Improvement Laboratory, Centre of Biotechnology of Sfax (CBS)/University of Sfax, Sfax, Tunisia 3 International Center for Biosaline Agriculture (ICBA), Dubai, UAE Email: * faical.brini@cbs.rnrt.tn Received 23 September 2014; revised 22 October 2014; accepted 8 November 2014 Copyright © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ 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 sig- nificant 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. * Corresponding author.