The plant dehydrin LTI30 stabilizes lipid lamellar structures in varying hydration conditions

Abstract

A major challenge to plant growth and survival is changes in temperature and diminishing water supply. During acute temperature and water stresses, plants often express stress proteins, such as the dehydrins, which are intrinsically disordered hydrophilic proteins. In this paper, we investigated how the dehydrin Lti30 from Arabidopsis thaliana stabilizes membrane systems that are exposed to large changes in hydration, and we compared the effects of Lti30 on membranes with those of the simple osmolytes urea and trimethylamine N-oxide (TMAO). Using X-ray diffraction and solid-state NMR, we studied lipid–protein self-assembly at varying hydration levels. We made the following observations. 1) The association of Lti30 with anionic membranes relies on electrostatic attraction, and the protein is located in the bilayer interfacial membrane region. 2) Lti30 can stabilize the lamellar multilayer structure, making it insensitive to variations in water content. 3) In lipid systems with a composition similar to those present in some seeds and plants, dehydrin can prevent the formation of non-lamellar phases upon drying, which may be crucial for maintaining membrane integrity. 4) Lti30 stabilizes bilayer structures both at high and low water contents, whereas the small osmolyte molecules mainly prevent dehydration-induced transitions. These results corroborate the idea that dehydrins are part of a sensitive and multifaceted regulatory mechanism that protects plant cells against stress.