Overexpression of OsMLD Encoding MYB-like DNA Binding Domain Increases Tolerance to Salt Stress in Rice (Oryza sativa L.)

MYB-like domain (MLD) gene is a transcription factor that plays a diverse role in plant development and in response to abiotic stresses. In this study, we isolated and developed CaMV35S::OsMLD rice lines and determined its expression pattern under abiotic stresses. The MLD has Myb_CC_LHEQLE superfamily similar to most transcription factor genes but with a very unique binding domain of SHLQKYR in the C-terminal region. Overexpressing rice lines showed enhanced tolerance to salinity with elevated mRNA transcript. Additionally, mRNA transcripts were up-regulated by ABA, H2O2 and dehydration stresses. Further investigation in the enhanced tolerance to salinity showed an increased accumulation of proline and a decreased in malondialdehyde contents indicating that OsMLD gene may be involved in the regulation of proline and osmolytes during abiotic stresses. These results showed that OsMLD gene could be used in the development of rice intended for soil with salinity-related problem.