| WRKY transcription factor family has been extensively studied in recent years. The WRKY protein has a zinc-finger-like motif and the conserved amino acid sequence WRKYGQR at its N-terminal end. WRKY protein can specifically bind to the DNA sequence motif (T)(T)TGAC(C/T) which is called W-box. Recent studies show that WRKY transcription factors are involved in plant biotic and abiotic stress responses and signal transduction, plant growth and development, morphogenesis and a variety of physiological metabolism.In this research, PeWRKY1 gene was cloned from Populus euphrutica and constucted to a plants-over-expression vector. The constructed gene was transfered to tobacco using Agrobacterium-mediated method,8 tans genic lines were obtained. After a week treatment of 100mM NaCl, Pn and Gs values significantly decreased in both the wildtype and transgenic plants. After 3 days of salt relief, Pn and Gs of previously salinised plants markedly recovered in transgenic lines whereas there were no corresponding changes in the wildtype, Result indicate that PeWRKY1 contributed to salinity tolerance of tabacoo plants.The promoter of PeWRKY1 gene was cloned respectively from P.euphratica and P.canescens. Sequense alignment showed that both have a variety of plant stress-related components. For example, they both contains a W-box, indicating that the promoter may be regulated by the upstream WRKY family members.The two promoters was transferred to tobacoo respectively together with GUS gene. GUS staining show that the expression of two promoters were tissue-specific. In transgenic tobacoo with PeWRKY1 promoter, GUS activity was found in root, vascular cambium of stem and mesophyll cells. However, GUS activity was not found in vascular cambium of stem in transgenic tobacoo with PpWRKY1 promoter, in addition to a lower expression in root and mesophyll cells. Our data indicate that the two promoters may regulate different responses upon abiotic stress. |
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