Evaluation of in Vitro Salt Tolerance in Cucumis prophetarum L., A Crop Wild Relative

Salinity is the major abiotic factor that limits plant growth and productivity. In this study, we present an in vitro propagation protocol for Cucumis prophetarum L. a crop wild relative to cucumber and to compare the effect of salinity on C. sativus and C. prophetarum. Results showed that Murashige and Skoog (MS) medium supplemented with 1 mg L^-1 Kin and 0.5 mg L^-1 NAA was the optimal medium for shoot proliferation and root induction, respectively. Interestingly, C. prophetarum plants showed better growth responses than C. sativus under low salinity stress. Higher levels of NaCl (100 and 150 mM) were lethal for C. sativus. Furthermore, 50 mM NaCl increased proline content in C. prophetarum and decreased lipid peroxidation content in C. sativus. In addition, C. sativus microshoots accumulated high amount of Na and showed higher K/Na ratio than C. prophetarum. In conclusion, this study showed that is more salt tolerant than C. sativus, which indicates the potential of using C. prophetarum to improve salt tolerance traits in cucumber.