Functional Characterization Of PtZFP103 Gene Of Populus Trichocarpa C2H2 Zinc-finger Protein

Zinc-finger proteins(ZFPs)are the family of transcription regulators in plants,which involved in the normal growth and development of plants in various processes,such as regulating the growth of plant organs,promoting the hairy body initialization and regulation of the root meristem tissue and leaf polarity.At the same time,zinc-finger proteins have many regulatory roles in response to biotic and abiotic stress,such as low temperature,drought,high salinity and pathogen defense.At present,there are few reports about the C2H2 zinc finger protein genes in woody plants.In our study,the function of PtZFP103 gene was indificated and the specific expression of promoter was analyzed indificated.The results are as follows:(1)We undertook the expression profiling of PtZFP103 in response to abiotic stress.The plantlets were treated with NaCl,mannitol,ABA,SA and MeJA for 0 h,3 h,6 h,12 h,24 h,7 d,respectively and the roots and leaves were collected as samples for qRT-PCR.We found that the PtZFP103 gene expression had substantial changes under NaCl and mannitol stresses.We cloned PtZFP103 from Populus trichocarpa cDNA library.Subcellular localization experiments in onion epidermal cells with the particle gun showed that PtZFP103 was located in the nuclear.Furthermore,transactivation assays proved that PtZFP103 functioned as a transcriptional activator and the PtZFP103 transactivation activity was conferred by its C-terminal domain,located at 379-507 aa using the domain deletion analysis.(2)We demonstrated the putative cis-acting regulatory DNA elements by analyzing the promoter sequences of PtZFP103 with the PlantCare.In the promoter region,we identified many key cis-elements that were concerned about environmental stress responsiveness,such as TC-rich repeats and ABRE.The tissue-specific expression analysis showed that the GUS genes was induced under NaCl,mannitol,ABA,SA and MeJA from the Agrobacterium mediated transformation of Arabidopsis thaliana,suggesting the PtZFP103 may be involved in stress response.(3)We transformed the plant expression vector of pBI121-PtZFP103 into Arabidopsis thaliana via the Agrobacterium mediated transformation.The analysis of seed germination rate and seedling root length and fresh weight under NaCl and mannitol stress disclosed that overexpression of PtZFP103 in Arabidopsis could improvr salt and drought tolerance.To further analyze of its salt resistance,we proformed the histochemical stain analysis(NBT,DAB and Evans Blue)and physiological index analysis(MDA,SOD,POD)between the overexpression of PtZFP103 gene and control in Arabidopsis.The transgenic Arabidopsis overexpressing PtZFP103 showed significant stress tolerance under salt stress than wild type.The results suggest that the overexpression of PtZFP103 gene may induced the antioxidant enzyme defense systems to improve salt resistance ability in plant.