Dissecting the cryoprotection mechanisms for dehydrins.

Cesar L Cuevas-Velazquez,David F Rendã³N-Luna,Alejandra A Covarrubias

doi:10.3389/fpls.2014.00583

Cesar L Cuevas-Velazquez, David F Rendã³N-Luna + Show 1 more

Open Access

https://doi.org/10.3389/fpls.2014.00583

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Abstract

One of the common responses of plants to water deficit is the accumulation of the so-called late embryogenesis abundant (LEA) proteins. In vitro studies suggest that these proteins can protect other macromolecules and cellular structural components from the impairments caused by water limitation. Their binding to phospholipids, nucleic acids and/or to divalent cations has suggested multi-functionality. Genetic analyses indicate that these proteins are required for an optimal adjustment of plants to this insult. This diverse information has conducted to propose different models for LEA proteins action mechanisms. Many of these properties are shared by group 2 LEA proteins or dehydrins (DHNs), one of the LEA protein families for which large amount of data is available. This manuscript focuses on the different mechanisms proposed for this LEA protein group by analyzing published data derived from in vitro cryoprotection assays. We compared the molar ratio of protectant:enzyme needed to preserve 50% of the initial activity per enzyme monomer to assess different mechanisms of action. Our results add evidence for protein–protein interaction as a protection mechanism but also indicate that some DHNs might protect by different means. The strength and weakness of the proposed protection mechanisms are discussed.

Highlights

One of the common responses of plants to water deficit is the accumulation of the socalled late embryogenesis abundant (LEA) proteins
DEHYDRINS, A PLANT SPECIFIC GROUP OF LEA PROTEINS Late embryogenesis abundant (LEA) proteins are a group of enigmatic proteins that have been strongly associated with plant responses to water deficit (Battaglia et al, 2008; Hincha and Thalhammer, 2012)
Due to the vast majority of DHNs reports over other LEA proteins, people not familiar with these proteins assume that all LEA proteins are DHNs; this is not the case, LEA proteins represent a rather large group of diverse proteins

Summary

Introduction

One of the common responses of plants to water deficit is the accumulation of the socalled late embryogenesis abundant (LEA) proteins. Those cases with a high MR50, where many DHN molecules are required for cryoprotection, suggest a mechanism where DHN molecules would not necessarily need to contact the cryosusceptible target protein but rather stay localized near the enzyme and, because their hydrophilic and highly disordered characteristics, they may provide an appropriate environment to stabilize a native and functional structure, a mechanism that has been referred as molecular shield (Tunnacliffe and Wise, 2007; Chakrabortee et al, 2012; Hughes et al, 2013).

Results

Conclusion