Molecular Characterization of a MYB Protein from Oryza sativa for its Role in Abiotic Stress Tolerance

ABSTRACT

The MYB family represents one of the most abundant classes of transcriptional regulators that perform pivotal role under different developmental processes and abiotic stresses. In present study, a MYB gene from Oryza sativa was selected for functional characterization. Bioinformatics analysis revealed that OsMYB1 cDNA encodes R2-R3 type DNA binding domain consisting of 413 amino acids having size of 44 kDa and pI of 6.24. DNA binding domain containing region was cloned and over-expressed in E. coli. Then, the survival of pGEX-OsMYB1 transformed E. coli cells was compared with control plasmid under different concentrations of NaCl, mannitol, high and low temperature. pGEX-OsMYB1 enhanced the survival of cells at high temperature and salinity. Electrophoretic mobility shift assays (EMSAs) have shown that recombinant OsMYB1 protein was able to bind with DIG labeled probe containing MYB binding site. RT-qPCR analysis revealed high MYB1 expression under wounding, salt, drought and heat stresses in rice. Expression was 23 fold higher in response to wounding demonstrating the worth of OsMYB1 up-regulation in wounding. Intrinsic disorder profile predicted that OsMYB1 exhibits 60% degree of intrinsic disorder proposing that these regions might be involved in DNA binding specificity and protein-protein interaction. The positive response of OsMYB1 suggests that its over-expression in crop plants may help in providing protection to plants to grow under abiotic stresses.

Keywords:
abiotic stress; E. coli; Oryza sativa; OsMYB1; pGEX; Real time qPCR