Studies On Cloning,Expression And Characterization Of NtWRKY8 In Tobacco

Plant was always exposed to a variety of adverse envirment in life of which serious harmful to plant growth, development, yield and quality, and even lead to death. Thus, plant generated series mechanisms to resist these damage and these regulations to various stress stimuli are always not a single pathway but always multi-pathways, coordinated with multiple genes from different levels response to stresses.Transcription factors play an important role in the regulation of plant growth and development, as well as their response to environment. A typical plant transcription factor usually contains a DNA binding domain, a transcription regulation domain, an oligomerization site and a nuclear localization domain. WRKY transcription factor that is discovered in plants is one of transcriptional regulatory factors in which N-terminal ends contain a conserved WRKYGQR amino acids sequences. Therefore, the WRKY transcription factor participates in the plant various kinds physiological and biochemical responses and has become one of the key point in the gene function research. WRKY transcription factor involved not only in plant growth and development, metabolic control, and it is also involved in the regulation to the process of plants to biotic stress and abiotic stress. The following progresses were gain in this study:1. The NtWRKY8 gene has an ORF of 1551 bp and encodes a 516 amino acids protein. It belongs to the WRKY transcription factor and contains two conserved WRKYGQR amino acids sequences, located in 201?265,360?425 amino acids, containing C2H2 zinc finger motif (C-X4-5-C-X22-23-H-X1-H), belongs to the first class I WRKY transcription factors.2. The transcript analysis revealed that the NtWRKY8 transcript is higher in leaves than in roots and stems while the expression quantity of flowers is in the lower of roots, stems and leafs in mature plant. Under various abiotic stress and biological stress in tobacco NtWRKY8 expression pattern analysis indicated that NtWRKY8 after induced by high salt, low temperature and high temperature is lowered to express, which was cut after the drought induced expressions; NtWRKY8 by ABA, ET, GA, MeJA and SA induced expression, which is regulated by the ABA of rendering first mode of raised, lowered after induced by ethylene is a first cut after the expression pattern of raising, MeJA regulation is not obvious.(3) Fusion proteins consisting of NtWRKY8 coupled to the GAL4 DNA binding domain strongly activated transcription in yeast.(4) Transient expression analysis using NtWRKY8-green fluorescent protein fusions showed that NtWRKY8 proteins were targeted to the onion epidermal cells nucleus.Above all, NtWRKY8 participated in the tobacco to a variety of biological and abiotic stress response, the study of NtWRKY8 modified theory basis for the art of tobacco.