Metabolic profiling as a tool for understanding defense response of Taxus cuspidata cells to shear stress.

To obtain a better understanding of responsive mechanism of plant cells in response to hydrodynamic mechanical stress, a metabolic profiling approach was used to profile metabolite changes of Taxus cuspidata cells under laminar shear stress. A total of 65 intracellular metabolites were identified and quantified, using gas chromatography coupled to time-of-flight mass spectrometry. Potential biomarkers were found by the principal component analysis as well as partial least squares combined with variable influence in the projection. Trehalose, sorbitol, ascorbate, sucrose, and gluconic acid were mainly responsible for the discrimination between shear stress induced cells and control cells. Further analysis by mapping measured metabolite concentrations onto the metabolic network revealed that shear stress imposed restrictions on primary metabolic pathways by inhibiting tricarboxylic acid cycle, glycolysis, and N metabolism. To adapt to the shear condition, cells responded by starting defensive programs. These defensive programs included coinduction of glycolysis and sucrose metabolism, accumulation of compatible solutes, and antioxidative strategy. A strategy of defense mechanisms at the level of metabolites for T. cuspidata cells when challenged with the shear stress was proposed.