Cloning And Functional Analysis Of Transcription Factor Gene TaMyb2s Associated With Drought Resistance In Wheat (Triticum Aestivum L.)

Drought stress is one environmental factor that greatly impacts plant distribution as well as crop production. Mining and utilizing the genes involved in drought toleranc is an effective approach to improve the characteristic for drought tolerance in plants.To further understand the molecular basis of wheat responses to drought stress, three members of TaMyb2 were isolated, which showed high homologous at amino acid level, and designated TaMyb2-â… , TaMyb2-â…¡and TaMyb2-â…¢, respectively. Phynogenetic analysis results indicated that the three members were close to HvMYB4 and OsMYB4, which were involved in drought or low temperature resistance. Yet no corresponding relationships were observed between the TaMyb2s and A, B, D genomes of common wheat.The expression patterns of TaMyb2s were detected using real-time quantitative PCR methods. All of the three members were up-regulated by stresses of PEG, NaCl and low temperature, and ABA treatment, implying that TaMyb2s involved in different signal transductions. Among them, TaMyb2-â…¢was most sensitive to PEG stress. Under cold stress, the response peak of three members, TaMyb2-â… , TaMyb2-â…¡and TaMyb2-â…¢appeared at late, middle and early stage in turn. The expression patterns of the three members induced by salt stress are quite similar, but the expression levels of them were different. TaMyb2-â…¢showed much more sensitive to salt stress. The expression patterns of TaMyb2-â… and TaMyb2-â…¢are similar under ABA treatment; the highest peak of both appeared at 12h, yet the peak for TaMyb2-â…¡apperared at 24h. Comparing the expression levels of the three members, TaMyb2-â…¢was the most sensitive to the four stresses, followed by TaMyb2-â… , TaMyb2-â…¡was the last one and had the lowest expression level.Transgenic Arabidopsis plants over-expressing TaMyb2 exhibited more tolerance to abiotic stresses, including drought, salt and other osmotic stresses, than wild type both at seedling and mature stages. In addition, the roots of transgenic lines were much longer than wild type under ABA treatment. These results indicated that TaMyb2 can improve the tolerance to drought and salt stress in transgenic Arabidopsis. All these results demonstrated that the TaMyb2s played an important role in plant responses to drought, salt and cold, and ABA treatment.