Ectopic Expression of MdMYB121 Gene Enhances Tolerance to Abiotic Stresses in Tobacco

Apple MdMYB121(sequence ID MDP0000196982)protein has typical R2R3MYB domains. Semi-quantitative RT-PCR analysis showed that MdMYB121 gene was induced by various abiotic stresses and stress-related hormones to different extents. The full-cDNA of MdMYB121 gene was amplified with RT-PCR and inserted downstream Cauliflower mosaic virus 35S CaMV promoter into an expression vector pBI121. Subsequently,it was genetically transformed into tobacco. Three transgenic tobacco lines were used for further investigation. The result showed that the seed germination and seedling growth of transgenic lines were more insensitive to high salinity than the WT control. In addition,the growth of transgenic seedlings was also less insensitive to salicylic acid(SA)than the WT control,as indicated with longer roots,hypocotyls,and more lateral roots in transgenic lines than WT. Finally,abiotic stresses tolerance assays were conducted for transgenic plants in soil. The result showed that transgenicplants were more tolerant to high salinity,drought and cold than the WT control. Therefore,MdMYB121 is induced by multiple abiotic stresses,and is involved in the responses to and the fight against abiotic stresses.