Isolation And Characterization Of Maize Transcription Factor ZmWRKY19 Gene

Maize is one of the major crops in China. Its yield is limited by all kinds of stresses such as drought, salinity, cold and fungal pathogens. Molecular breeding explores defense genes to improve the biotic stress tolerance for crops. Most members of WRKY family are involved in plant growth, development and plant response to abiotic and biotic stresses. We cloned the ZmWRKY19 gene by the homology-based cloning method and characterized its function in biotic stress in Arabidopsis.The main results:1.The ZmWRKY19 gene was cloned using the PCR mehod. The gene ID is GRMZM2G382350 in the Maize Gene Data Base. The full length of the genomic DNA is 5212 bp. The coding sequence is 723 bp coding a protein consists of 240 amino acids. Conserved WRKY domain and C2 HC finger are found in the protein sequence. The relative molecular mass of the protein is 26.8 KD and isoelectric point is 6.23.2.The response to abiotic and biotic stresses was measured by qRT-PCR. The expression of ZmWRKY19 gene is induced by SA, salinity and 42℃ heat shock.3.ZmWRKY19 gene is a transcription factor. We constructed an expression vector of WRKY fused to the GFP protein and a dual luciferase control vector. The green fluorescence signal only exist in the nucleus in onion epidermal cells and tobacco cells. Using maize callus protoplast system to detect the transactivity, the results indicate that the WRKY protein regulate the gene expression through binding to the W-box element.4.A GUS expressing vector driven by the promoter of ZmWRKY19 was cloned and transformed into Arabidopsis. The GUS staining results reveal that the gene express only in leaf vein. Morever, its expression mainly present in mature leaf.5. The ZmWRKY19 expression vector was constructed and transformed into Arabidopsis. A number of transgenic plants were screened by RT-PCR, then the plants were tested for response to pathogens infection. The relative electrical conductivity show that overexpression lines enhanced its ability to defend the fungal pathogens infection compared to the vector control and wield type.6.The full length of ZmWRKY19 genomic DNA was cloned. The expression vector driven by the ubiquitin promoter was constructed and transformed into maize. A number of regenerated plants were obtained.