Differential Proteomic Responses to Salinity Stress in Leaves and Roots of Creeping Bentgrass.

Knowledge of stress-responsive proteins is critical for further understanding of molecular mechanisms of stress tolerance.  The study was designed to determine differentially expressed proteins in leaves and roots for two creeping bentgrass cultivars. The study was conducted in a growth chamber with plants grown in sand culture. ‘Penn A-4’ and ‘Penncross’ plants were either watered daily with water (control) or NaCl solution at electrical conductivity of 12 ds m^-1 (salt stress). ‘Penn A-4’ maintained higher relative water content and lower electrolyte leakage under salt stress, suggesting that it exhibited better salt tolerance than ‘Penncross’. Proteins were extracted from leaves and roots and separated using two-dimensional electrophoresis.  A total of 148 leaf and 106 root protein spots were subjected to mass spectrometry analysis.  Totally 106 leaf protein spots and 90 root protein spots were successfully identified by mass spectrometry.  Leaves had more salt-responsive proteins than roots in both cultivars.  The better salt tolerance in ‘Penn-A4’ was mainly associated with its higher level of H⁺-ATPase in roots and the up-regulation of catalase and glutathione S-transferase in leaves.  In addition, higher levels of UDP-sulfoquinovose synthase, methionine synthase, and glucan exohydrolase were detected in ‘Penn-A4’ leaves, which may also contribute to its superior salinity tolerance compared to ‘Penncross’.