Protective role of exogenously supplied salicylic acid and PGPB (Stenotrophomonas sp.) on spinach and soybean cultivars grown under salt stress

Managing sustainable crop production under escalating soil salinity will be a great challenge in coming years. Exogenous application of protectants has been recognized to ameliorate the adverse effects of salinity through better growth performance of plant. Present study was conducted to assess the potential role of salicylic acid (SA) and PGPB (Stenotrophomonas sp.) on spinach and soybean cultivars grown under the two variable salt concentrations. The result of the study showed that the 100 ppm salt caused more severe effects than 50 ppm salt on both selected crops and their cultivars. Salt stress induced H2O2 generation and MDA accumulation, developed ionic imbalance, increased electrolyte leakage, and decreased biomass and yield. However, exogenous supply of protectants improves plant growth and yield, enhanced RWC, accumulated osmolytes, and increased enzymatic and non-enzymatic antioxidants with both the level of salinity. Moreover, applied protectants induced new protein bands and disappearance of some other expressed protein with different molecular weight provides a purpose for bearing more salt under salt stress conditions. Study concluded that the exogenously supplied PGPB and SA manage salinity-induced yield loss through increased growth, osmotic adjustment, protein accumulation, and APX activity. However, ionic balance does not have major role in protectant induced salinity tolerance. Study also finds PGPB more effective protectant than SA for reducing the salinity induced yield loss due to strong low molecular weight protein profiling, higher strength of ionic homeostasis and higher APX activity.