Over-expression of rice R1-type MYB transcription factor confers different abiotic stress tolerance in transgenic Arabidopsis

Among various abiotic stresses, water deficit hit the first in the list followed by heavy metal stresses as a serious environmental growth-limiting factor that restricts the global crop yield. Molecular approaches will help us to trace key regulators which are involved in stress-related phenomenon to enhance crop productivity. The present study functionally characterized one of the key regulators, OsMYB-R1 in Arabidopsis. Phylogenetic analyses indicated that OsMYB-R1 had a close relationship with Sorghum bicolour and Zea mays. Ectopic expression of OsMYB-R1 in Arabidopsis resulted in improved tolerance to PEG/drought and chromium stress in addition to conferring no tolerance to salinity stress. Further RNA seq. data revealed that OsMYB-R1 regulates the expression of key genes that improve the root architecture and maintain the cellular homeostasis of transgenic lines through an efficient anti-oxidant system. It also reveals the differential gene expression of stress-responsive and hormone-responsive genes, which indicate the intricate network of defense regulatory machinery activated in transgenic lines. Additionally, salicylic acid (SA) plays a significant role in promoting the growth of the OsMYB–R1 over-expressing plants and increased GUS intensity in SA treated OsMYB–R1 promoter plants demonstrate the explicit role of SA signaling in overcoming stress tolerance. Whereas no significant change was observed in OsMYB–R1 over-expressing plants after ABA and MeJA treatment. Overall, OsMYB-R1 is a promising gene resource for improving abiotic stress tolerance in other crops, especially in dicotyledon plants.