Abstract
To identify key proteins in the regulation of salt tolerance in mangrove plant Bruguiera gymnorhiza, proteome analysis of samples grown under conditions of salt stress was performed. Comparative two-dimensional electrophoresis revealed that two, three and one proteins were differentially expressed in main root, lateral root and leaf, respectively, in response to salt stress. Among these, three proteins were identified by internal peptide sequence analysis: fructose-1,6-bisphosphate aldolase (FBP aldolase) in main root, osmotin in lateral root, and a novel protein in main root. These results suggest that FBP aldolase and osmotin play roles in salt-tolerance mechanisms common to both glycophytes and mangrove plants. Amounts of these proteins were not correlated to those of the respective mRNAs, as determined by microarray analysis. A novel salt-responsive protein, not previously detected by EST analysis, was also identified in this proteomic approach, and may provide insight into the salt-tolerance mechanism of the mangrove plant.
