Metabolome and water homeostasis analysis of Thellungiella salsuginea suggests that dehydration tolerance is a key response to osmotic stress in this halophyte

Abstract

Metabolome and water homeostasis analysis of Thellungiella salsuginea suggests that dehydration tolerance is a key response to osmotic stress in this halophyte SUMMARYThellungiella salsuginea, a Brassicaceae species closely related to Arabidopsis thaliana, is tolerant to high salinity. The two species were compared under conditions of osmotic stress to assess the relationships between stress tolerance, the metabolome, water homeostasis and growth performance. A broad range of metabolites were analysed by metabolic fingerprinting and profiling, and the results showed that, despite a few notable differences in raffinose and secondary metabolites, the same metabolic pathways were regulated by salt stress in both species. The main difference was quantitative: Thellungiella had much higher levels of most metabolites than Arabidopsis whatever the treatment. Comprehensive quantification of organic and mineral solutes showed a relative stability of the total solute content regardless of the species or treatment, meaning that little or no osmotic adjustment occurred under stress. The reduction in osmotic potential observed in plants under stress was found to result from a passive loss of water. Thellungiella shoots contain less water than Arabidopsis shoots, and have the ability to lose more water, which could contribute to maintain a water potential gradient between soil and plant. Significant differences between Thellungiella and Arabidopsis were also observed in terms of the physicochemical properties of their metabolomes, such as water solubility and polarity. On the whole, the Thellungiella metabolome appears to be more compatible with dehydration. Osmotic stress was also found to impact the metabolome properties in both species, increasing the overall polarity. Together, the results suggest that Thellungiella copes with osmotic stress by tolerating dehydration, with its metabolic configuration lending itself to osmoprotective strategies rather than osmo-adjustment.

Integrated proteomics and metabolomics for dissecting the mechanism of global responses to salt and alkali stress in Suaeda corniculata

“…7). This results is consistent with findings in S. salsa and Thellungiella salsuginea (Lugan et al 2010;Wu et al 2012). These results suggest that salinity restrain amino acid metabolism in S. corniculata which may lead to a reduction of organic acids because it would lessen the capacity of osmotic adjustment under salt stress.…”

Plant Metabolomics: A Characterisation of Plant Responses to Abiotic Stresses

“…To elucidate the function of a single compound, it is also important to be aware that compensatory mechanisms are commonplace and that a change in the content of a single metabolite may have no effects on the phenotype, because of compensative modulation of other components of the same family of compounds. The original approach proposed by Lugan et al (2010), considering the metabolome as a single "virtual molecule" whose physicochemical properties are the weighted averages of www.intechopen.com the properties of individual metabolites, also appears to be quite promising both to investigate the global metabolic strategies of a species to maintain cell function under stress and to evaluate differences among species. In addition, further efforts to make stress treatment conditions more relevant to plant growth outside of the lab are required.…”

“…Metabolome data, together with transcriptome results, have pointed towards the presence of a stress anticipatory strategy in Thellungiella as responsible for its "extremophile" characteristics. More recently, Arabidopsis and Thellungiella responses to salinity and osmotic stress have been compared with an analogous approach by Lugan et al (2010). The authors found that, apart from a few differences in raffinose and secondary metabolites, salt stress affected the same metabolic pathways in the two species, the main differences being quantitative.…”

“…A very original contribution to the metabolomic analysis approach that was provided by this study is represented by the idea of considering the metabolome of each species as a single "virtual molecule", the physicochemical properties of which are the weighted averages of the properties of the individual metabolites. Therefore, based on this idea, the significant differences between the two species can be summarised as follows: i) under both standard and stressed conditions, the Thellungiella metabolome was more soluble, polar, massive and reduced than the Arabidopsis metabolome; ii) osmotic and salinity stresses changed the metabolome biophysical properties in a different way, depending on the stress and on the species; iii) both stresses induced more dramatic changes in Arabidopsis than in Thellungiella; iv) in Arabidopsis, salt affected the metabolome biophysical properties more than osmotic treatment and v) in Thellungiella, water stress induced more dramatic changes than salt stress (Lugan et al, 2010).…”

Docking Studies of Stress Tolerant Proteins With Protective Molecules

“…The auxin synthesis and transport offered the plant to adapt various stress [13]. Amino acids deposition has been observed in many plants exposed to abiotic stress [14]. Citrate synthase is an enzyme responsible for the catalyzing the reaction of the citric acid cycle the condensation of acetyl-coA and oxaloacetate to form citrate [15].…”