Proteomic Analysis of Ginseng (Panax ginseng C. A. Meyer) Fluid Proteins under Salt Stress

Ginseng (Panax ginseng C. A. Meyer), due to its relatively longer cultivation time, is often exposed to environmental stresses such as heat, salt, and drought. Particularly, salt-stress-derived oxidative damages greatly affect photosynthetic efficiency and consequently cause reduction of growth, development, and yield of ginseng. Thus, efforts have been made to understand the salt-stress-induced changes at proteome levels; however, the overall understanding of possible salt-responsive proteins in ginseng is still limited because of their low-abundance. A growing body of evidence suggests that plants secrete various low-abundant proteins localized in the intra- and extracellular spaces during stress conditions, and those proteins may have a key role for salt tolerance. Therefore, here, we report the ginseng fluids proteome to identify the potential salt-responsive proteins. This approach led to the identification of 261 secreted fluid proteins, and functional categorization revealed that identified proteins were majorly associated with photosynthesis, protein synthesis, cell binding, and various metabolisms. Further validation using qRT-PCR analysis showed similar expression profiles of heat-shock protein 70, glycosyl hydrolase 17, and fructose-bisphosphate aldolase class-I with proteome results. Overall, ginseng fluid proteomic analysis successfully identified the potential salt-responsive proteins, which might be helpful for understanding of salt-tolerance mechanisms in ginseng.