Ectopic expression of common bean ERF transcription factor PvERF35 promotes salt stress tolerance in tobacco

In the present study, a TINY-like AP2/ERF gene, PvERF35i, was amplified from common bean (Phaseolus vulgaris L.), cloned and functionally characterized by overexpressing in tobacco cv. Petite havana. Transgenic plants overexpressing PvERF35 were generated using Agrobacterium-mediated transformation and used to evaluate the possible roles of the transgene under salt stress conditions. Evaluation of transgenics was completed using both molecular and biochemical analysis. PCR, Southern blot and RT-qPCR assays revealed the correct integration and enhanced expression of the transgene. Physiological and biochemical analysis of transgenic plants showed their better performance compared to the wild type in terms of germination and survival rates and root and shoot growth under salt stress treatment (200 mM NaCl). Having a high concentration of proline, APX and POX, the PvERF35 overexpressed plants were physiologically and morphologically less affected by salt stress application. In silico promoter analysis of the PvERF35 gene led to identification of important cis-regulatory elements, MYB, MYC and TGACG-motif, annotated with salt response of plants. The protein-protein interaction network showed that there was a strong association between ABC transporter proteins and PvERF35 protein. Salt stress-related miRNA, miRNA156 and miRNA159, targeting PvERF35 were identified using in silico target finding analysis. These findings suggest that PvERF35 functions as a stress-responsive transcription factor in differential modulation of salt stress tolerance and may have applications in the engineering of economically important crops.