Expression of dehydrins, HSP70, Cu/Zn SOD, and RuBisCO in leaves of tobacco (Nicotiana tabacum L.) dihaploids under salt stress

Salinity is an abiotic factor that has a negative impact on plant growth and seed germination, leading to limited crop production. The effect of salt stress (100 and 200 mM NaCl) on the expression of dehydrins (DHNs), heat-shock protein 70 (HSP70), superoxide dismutase (Cu/Zn SOD), and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) was investigated in leaves of tobacco (Nicotiana tabacum L.) F-1 hybrid DH10 and four dihaploid lines (207B, 238C, 239K, 244B) under in vitro conditions. After 33 d, the dihaploid lines as well as DH10 showed enhanced expression of 70-kDa DHN in response to 200 mM NaCl stress. This was especially evident in line 207B, which previously proved to be tolerant to salt stress, suggesting that DHNs have an important role in salt stress tolerance. Also, line 207B as well as lines 238C and 244B responded to 200 mM NaCl stress by increased expression of Cu/Zn SOD, indicating its possible role in providing salt stress tolerance. On the other hand, salt stress induced in line 239K resulted in a significantly higher expression of RuBisCO, indicating that differential susceptibility of dihaploids to increased levels of NaCl might be the result of their different genetic traits. Decreased expression of HSP70 in salt-treated tobacco dihaploids indicates that HSP70 is not included in protection against salt stress.