Salinity-induced metabolic profile changes in Nitraria tangutorum Bobr. suspension cells

Salinity is an important abiotic stress that severely depresses plant growth and development. Plants have evolved salinity tolerance mechanisms to enable adaptation to hostile environments. Generally, metabolic networks must be reconfigured to maintain metabolic homeostasis and to mitigate the stress. However, the mechanisms of plant stress-response systems are incompletely understood, which represents a bottleneck for further use of salinity-tolerant plants. Through its capability to provide both an overview and detailed analysis of changes in metabolic pathways, metabolomics has been widely applied to research plants' stress resistance. In this study a metabolomics approach was adopted to describe changes in the metabolic profile of Nitraria tangutorum Bobr. suspension cells under salinity stress. Four salinity treatments (100, 150, 200, and 250 mM NaCl) were applied and liquid medium lacking NaCl was used as the control. After culture for 4 days, salinity stress affected the biomass, cell morphology, and osmotic potential of the suspension cells. Totals of 373 and 629 peaks were detected by gas chromatography/time-of-flight mass spectrometry in the aqueous phase and organic phase, respectively. Metabolic profiling differences were visualized by partial least squares-discriminant analysis models to highlight the changes in metabolic pathways under salinity stress. Twenty-six metabolites that showed differences in content were identified, including sugars, amino acids, and fatty acids. This research provides novel insights into the complex of metabolic pathways involved in the synthesis of stress-related metabolites, and of the salinity-tolerance mechanism in N. tangutorum suspension cells.