Heterologous expression of a plant WRKY protein confers multiple stress tolerance in E. coli

Objective: OsWRKY71, a WRKY protein from rice, is reported to function during biotic stresses. It is requisite to further enquire the efficiency and mechanism of OsWRKY71 under various environmental stresses. Stress indicators such as salt, cold, heat, and drought were studied by overexpressing the OsWRKY71 in E. coli. Materials and methods: DNA binding domain containing region of OsWRKY71 was cloned and expressed in E. coli followed by exposure to stress conditions. OsWRKY71 was also assessed for its role in abiotic stresses in rice by qPCR. Results: Recombinant E. coli expressing OsWRKY71 was more tolerant to stresses such as heat, salt and drought in spot assay. The tolerance was further confirmed by monitoring the bacterial growth in liquid culture assay demonstrating that it encourages the E. coli growth under salt, drought, and heat stresses. This tolerance may be the consequence of OsWRKY71 interaction with the promoter of stress related genes or with other proteins in bacteria. The RT-qPCR analysis revealed the up-regulation of OsWRKY71 gene in rice upon interaction to cold, salt, drought and wounding with maximum up-regulation against salinity. Conclusion: Thus, the defensive role of OsWRKY71 may accord to the development and survival of plants during different environmental stresses.