Gene Expression Profile Of Maize Seedling Under PEG Stress

Drought is one of the unavoidable agricultural stresses in the world for the most serious losses amongvarious agricultural stresses. Maize is an important food, feed and cash crops, and also is one kind of mostwater demanding and more sensitive to drought crops in dry land. Plants execute a number of physiologicaland metabolic responses to adapt to environmental stress during the long evolution process. Understandingthe molecular basis of maize reaction to water stress might provide new strategies to improve the stresstolerance of agriculturally important plants. With the development of modern bioinformatics and genomics,DGE has gradually become an important tool for the studies of expression filings of genes. In this study,the differential expression of genes in the maize seedlings under drought stress were investigated by DGEand its results were verified-based on real time fluorescence quantitative PCR technology. The main resultsare as follows:1. The corn seedlings can almost withstand under25%PEG stress, and maize seedlings maintain theirgrowth although the their morphology indexes of maize seedlings were affected. So20%PEG6000wasused to stress maize seeding in this study.2. Sequencing of hybrid maize Zheng dan958seedlings under20%PEG6000at0.5h、6h、48h byDGE technology, These results indicated that683、2857、1438genes expressed differentially in maizeseedling under20%PEG6000stress and control at0.5h、6h、48h and286、1524、801genes wereup-regulated among these differentially expressed genes, and397、13336、37genes were down-regulatedexpression among them. The up-regulated differentially expressed genes were less than the down-regulatedones at0.5h, however the up-regulated differentially expressed genes were more than the down-regulatedones at6h and48h. The differential expression genes are the most at6h among the3stressed time underPEG stress.3. The differentially expressed genes were categorized into three main categories at0.5h、6h、48h withmaize Gene Ontology database, cellular component, molecular function and biological process. A largeproportion of differentially expressed genes involved in cellular components, cell membrane and organelles;main genes function are related to ion binding, catalytic activity, cation binding, transfer enzyme activity,small molecules and hydrolase activity; response to cell processes, cell metabolism, macromolecularprimary metabolic process, metabolic process, response to stimulus, and nitrogen metabolism.4. Pathway enrichment analysis indicated that402、1704and796differential genes were found withannotation in Pathway at0.5h、6h and48h, respectively. Pathways with more genes involved were themetabolic Pathway, production of secondary metabolites, plant pathogen interactions, plant hormone signaltransduction, phenylpropanoid biosynthesis, phenylalanine metabolism, stilbenoid、diarylheptanoid andgingerol biosynthesis, starch and sucrose metabolism, biosynthesis of flavonoids, and protein processing inthe endoplasmic reticulum. Many genes involved in the response of maize seedling many and regulated byseveral collaborative biological processes, and changes of these genes expression levels maybe play important roles in regulation process under PEG stress,. And many candidate genes which maybe werecrucial for maize to endure drought stress were found, such as regulating factor, drought induced protein, etal, and the work will help to reveal and understand the mechanism of maize seedling under drought stress.5. The12randomly selected significant differentially expressed genes in digital gene expressionsequencing were verified by quantitative PCR method,the result showed that the genes expression tendencywere the same between digital gene expression and quantitative PCR. Thus the expression profiles of thesequencing results were accurate and reliable.Many genes were found by DGE sequencing and GO terms and enrichment Pathway responded todrought stress in maize seedling were understood. And plant response network to drought stress isdiscussed, which will provide some theoretical basis for further study on drought tolerance gene, and toreveal the molecular mechanisms of plant responses to drought stress. The work also provides a number ofcandidate genes for the cloning of plant response to drought stress in the future.