Cloning And Functional Analysis Of Abiotic Stress-Related Zinc Finger Protein Genes From Rice(Oryza Sativa L.)

Abiotic stresses such as cold, high salinity and drought are major obstacles affecting plant growth and crop productivity. Many researches have been focused on identifying abiotic stress-inducible genes in order to apply these genes in genetic improvement of crop tolerance to abiotic stress. Among products encoded by these genes, transcription factors play very important roles in plant responsiveness to stress because many aspects of the stress adaptation process are under transcriptional control, and they represent one of the best targets for engineering plants to achieve enhanced stress tolerance. The DREB subfamily of AP2/EREBP transcription factors play dominant roles in stress-responses.Zinc finger protein is one type of important transcription factors with finger domains, widely existing in eukaryotic organisms. The term "zinc finger" represents a sequence motif in which the Cys residues and/or the His residues coordinate a zinc atom(s) to form local peptide structures that are required for their specific functions. The zinc finger proteins can be divided into several types incuding TFâ…¢A-type, WRKY-type, GATA-type, DOF-type and so on, based on the differences of structure and function. With development of genome sequencing project, more and more zinc finger protein genes will be discovered, some of which may be novel type. This thesis aims to clone and function analyze the zinc finger proteins involved in abiotic stresses and some novel results are given as follows.We identified several abiotic stress related TFâ…¢A-type zinc finger protein genes for the first time in monocots. The expression analysis revealed ZFP18 gene was regulated by cold, drought, high salinity and ABA treatment, but ZFP245 was just transiently regulated by cold and drought stress. The 1400 bp promoter region was fused to GUS reporter gene in pBI121 and transformed into tobacco plants by Agrobacterial mediating method. The histochemical analysis revealed no any signal could be detected in unstressed tobacco plants, but strongly observed in NaCl or KCl treated tobacco leaves and NaCl treated roots. More treatments including cold and PEG6000, Zn²⁺, Mg²⁺, Cd²⁺ all could not result any detectable signals of GUS gene. To further research the cellular function of ZFP18 and ZFP245, we expected to generate transgenic plants overexpressing theses genes. Unfortunately, we could not obtain the transgenic plants overxpressing ZFP18 gene.