Structural Properties of Intrinsically Disordered Dehydrins Underlying Their Protective Role in Desiccation Tolerance

Abstract

Drought is a major threat to global food security, presenting a critical challenge for agriculture. Resurrection plants exhibit extraordinary desiccation tolerance, surviving the loss of up to 98 % of their water content for extended periods and fully recovering metabolic function upon rehydration. Investigating the molecular mechanisms underlying this adaptation can offer valuable insights for enhancing crop resilience to drought. Dehydrins, a subclass of late embryogenesis abundant (LEA) proteins, accumulate in resurrection plant leaves during desiccation. Although they have been implicated in the protection of proteins, membranes, and nucleic acids, their precise physiological function remains unknown. In this study, we recombinantly produced DHN152, a desiccation-induced dehydrin from Ramonda serbica, an ancient resurrection species, and analysed its structural and functional properties. DHN152 is a highly hydrophilic protein (GRAVY index: –1.29) with a high glycine content (22.6%) and abundant charged residues (lysine, glutamate, and aspartate). In silico analyses of DHN152 revealed high disorder propensity, which was confirmed by circular dichroism (CD) spectroscopy under physiological conditions. Upon exposure to 2,2,2-trifluoroethanol (a desiccation-mimicking agent) and lipid-mimetic detergents, DHN152 partially adopted an α-helical conformation, highlighting its structural plasticity. Given its lysine- rich composition and predicted nuclear localisation, we examined its effect on DNA under desiccation conditions. Additionally, we assessed its protective effects on enzyme activity and Escherichia coli growth under osmotic and salt stress. Taken together, our findings provide novel insights into the structure- function relationship of dehydrins in resurrection plants, laying the groundwork for bioengineering strategies aimed at improving drought resistance in crops.Book of abstract: 15th EBSA Congress in Rome, Italy, from the 30th of June to the 4th of July 2025