Proteomics-based investigation of salt-responsive mechanisms in plant roots

Salinity is one of the major abiotic stresses that limits agricultural productivity worldwide. Plant roots function as the primary site of salinity perception. Salt responses in roots are essential for maintaining root functionality, as well as for transmitting the salt signal to shoot for proper salt response and adaptation in the entire plant. Therefore, a thorough understanding of signaling and metabolic mechanisms of salt response in roots is critical for improving plant salt tolerance. Current proteomic studies have provided salt-responsive expression patterns of 905 proteins in 14 plant species. Through integrative analysis of salt-responsive proteins and previous physiological and molecular findings, this review summarizes current understanding of salt responses in roots and highlights proteomic findings on the molecular mechanisms in the fine-tuned salt-responsive networks. At the proteome level, the following processes become dominant in root salt response: (i) salt signal perception and transduction; (ii) detoxification of reactive oxygen species (ROS); (iii) salt uptake/exclusion and compartmentalization; (iv) protein translation and/or turnover dynamics; (v) cytoskeleton/cell wall dynamics; (vi) carbohydrate and energy metabolism; and (vii) other salt-responsive metabolisms. These processes work together to gain cellular homeostasis in roots and determine the overall phenotype of plant growth and development under salt stress.

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► Salt-responsive proteomes of plant roots (905 IDs in 14 species) are summarized.
► Salt signaling and ROS detoxification are dominant processes under salt stress.
► Salt uptake/exclusion and compartmentalization lead to ion homeostasis.
► Protein turnover and cytoskeleton/cell wall dynamics are critical for tolerance.
► Carbohydrate/energy metabolism and other metabolic changes play important roles.