Cloning And Characterization Of ZmWRKY33, A WRKY Transcription Factor In Maize(Zea Mays L.)

Drought, high-salinity and low temperature are major abiotic stress factors to plant growth and development. Study the mechanisms of plant anti-stress are very important to yield of crops. Transcription factor is a crucial factor which can transduct and amplify the stess signal, then regulation gene expression downstream. Transcription factors can be divided into different types according to their DNA binding domain. WRKY transcription factor family plays an important role in abiotic stress response. Under abiotic stress, WRKY transcription factor can bind to the W-box which appears in the promoter sequence of functional genes, and regulate the functional genes’ specific expression in plants, then improve the resist ability of plants to abiotic stress.Here, we obtained a transcription factor gene ZmWRKY33which related to abiotic stress by in silico cloning and reverse transcription PCR (RT-PCR). ZmWRKY33encode a498amino acid protein which possesses two WRKY domain, belongs to group I WRKY transcription factor. Real-time RT-PCR analyses were performed to determine the expression profiles of ZmWRKY33. The expression of ZmWRKY33was strongly induced by dehydration (20%PEG6000), high salt (250mM NaCl), cold (4℃) and ABA (100μM) in five-leaf stage maize seedlings. In addition, we examined tissue-specific expression of ZmWRKY33, and found ZmWRKY33was highly expressed in roots than other tested tissues. These results suggest that ZmWRKY33is likely involved in the abiotic stresses response in maize through the ABA-dependent signaling transducation pathway.For further verified the gene function of ZmWRKY33, we transferred ZmWRKY33into Arabidopsis, and got Ti generation transgenic positive seedlings. Functional analysis indicated that transgenic positive seedlings showed higher salt stress tolerance than the wild type plants.