Expression of Synthetic hsr1 Gene in Transgenic Tobacco (Nicotiana tabacum) for Enhanced Tolerance to Drought and Salt Stresses

Drought and salinity are causing significant loss in crop yield worldwide. Genetically engineered salt and drought tolerant crop varieties can be a potential remedy for the recovery of lost uncultivated saline and low rain fall areas. In eukaryotes, transcription factors are involved in gene expression which activate or repress the transcription under specific conditions. Hence, the present study has been designed to characterize a fully modified synthetic hsr1 gene. This gene encodes for a transcription factor of heat shock family and has been found to be involved in drought and salinity tolerance in yeast. The synthetic hsr1 gene was cloned under double 35S promoter and CaMV terminator for high level of expression in the transgenic plants. Initially the gene was cloned into pJIT163 and then into expression vector pGreen0029. Agrobacterium tumefaciens strain GV was used as a vector for transformation into tobacco. In three different experiments about 34.5% transformation efficiency was observed. Putative transgenic plants were confirmed by PCR analysis using hsr1 gene specific primers. Further screening of these putative transgenic plants against different salinity levels and drought stress showed that transgenic plants were tolerant to drought and salinity conditions. Transformation in the model plant paves the way to genetically engineer vital crops for the development of drought and salinity resistant genotypes. (C) 2015 Friends Science Publishers