Rapid change in global environmental conditions will increase the severity of salinity and drought stresses. Wheat (Triticum aestivum L.) is a major staple crop worldwide and its production is affected by these two major abiotic stresses. Use of breeding and transgenic techniques facilitated the development of tolerant varieties able to withstand in drought and saline environments. This work investigated the role of Solanum lycopersicum proteinase inhibitor II (PI-II), SlPI-II, gene for mounting tolerance under salinity and drought stress in transgenic wheat. Significant increase of 6.41-fold (TL1) was observed in transgenic plants at 1 day post 100m NaCl treatment. A gradual increase in the expression was observed at 200 mM NaCl treatment. At 300mM treatment, 3.78-fold (TL5) increase in the expression level was recorded. The maximum fold change of 5.01 and 3.99 was observed in 6 days post treatment at 100 mM and 200 mM in TL1, respectively. The extended saline treatment (14 days post treatment) in transgenic lines resulted the higher SlPI-II induction than control wheat plants which showed the efficacy of this gene in salinity tolerance. SlPI-II expression in 15% PEG treated plants showed transcript up to 7.31 fold increase during 1 day post treatment, while at 25% PEG transgene expression ranged from 3.45 to 2.27 fold increase. Conclusively, the role of SlPI-II gene in drought tolerance was due to sustained transcript increment during PEG treatment. We demonstrated that modern day transgenic approaches utilizing plant-based proteinase inhibitors will provide the new opportunities for the development of tolerant varieties in future.
