Functional Analysis Of Maize Transcription Factor ZmDi19-7 In Drought Response

Maize is the world’s largest food and feed crop,and it is vulnerable to a variety of biological and abiotic stresses during its growth process.Drought-induced 19 protein(Di19)has been reported to be widely involved in plant growth and development and in the regulation of response to stress,but little is known about its function in maize.Based on previous studies,a Di19 family gene ZmDi19-7 was cloned from maize to respond to drought stress.Its basic molecular characteristics were analyzed by subcellular localization,transcriptional activity and binding characteristics.The biological function of ZmDi19-7 gene in response to drought stress in maize was clarified through overexpression analysis of drought resistance phenotype and physiological and biochemical indexes related to drought resistance of transgenic plants.Meanwhile,transcriptome sequencing technology was used to identify and analyze the signals of differentially expressed genes and their pathway genes in transgenic plants.The main results obtained are as follows:1.Evolutionary analysis of seven Di19 genes identified in maize revealed that ZmDi19-7 was clustered in the second subgroup.Amino acid sequence alignment analysis showed that the gene contained conserved C2H2 zinc finger domain and Di19_C domain.2.The analysis of expression thermogram of Maize during the whole growth period showed that the gene was highly expressed in many periods.The expression of ZmDi19-7 in maize tissues was analyzed by fluorescence quantitative PCR,the results showed that ZmDi19-7 was highly expressed in maize stems and leaves.The expression of ZmDi19-7 increased significantly under drought and high salt stress.3.The subcellular localization of ZmDi19-7-GFP fusion protein in tobacco was analyzed,the results showed that ZmDi19-7 protein was localized in the nucleus and cell membrane.4.Yeast transcriptional activity showed that ZmDi19-7 had no transcriptional activity in yeast.Luciferase activity analysis showed that ZmDi19-7 could specifically bind to conserved TACA(A/G)T motif.5.After drought treatment,ZmDi19-7 transgenic Arabidopsis thaliana plants had stronger drought resistance than wild type.By measuring the content of malondialdehyde,relative water content and peroxidase,it was concluded that ZmDi19-7 transgenic lines had lower malondialdehyde content,higher water content and higher peroxidase content than wild-type lines under drought treatment.6.The transcriptome sequencing analysis showed that there were 1894 differentially expressed genes in ZmDi19-7 after drought stress compared with wild type lines,of which 667 genes were significantly up-regulated.Further annotation of these differentially expressed genes revealed that the highly expressed genes mainly encode a variety of transcription factors,protein kinases and hormone-related regulatory genes.