| Drought tolerance in plant is the physiological and metabolic continuous adjustment that response to the environment. The mechanism is very complex, involving many genetic networks. Abundant data had been accumulated by different researchers using different methods during the past two decades. However, for a long time, the works including the clones of the tolerance genes in maize, the research of the gene expressions and the analysis of the QTL are independent. The designs of the experiments are different, so as the materials and the statistical methods. How to integrate all these important data for analysis of drought tolerance in maize has been a pursuit of researchers. A large number of genes regulated by drought stress have already been identified but it still has a long way to figure out the molecular mechanism of drought-tolerance in maize. Based on the above reasons, in this study, drought tolerance genes for breeding were investigated by integrating drought QTL, gene expression data and the resource of EST. The major contents and the findings of the research are as follows:Nineteen consensus QTL were acquired by meta-analysis integrating and refining the 362 QTL from different environments in this study. The genes in consensus QTL were located in silicon map of B73. Drought tolerance genes were investigated by local blast between EST related to drought and the full-length cDNA. The abundance of drought tolerance genes in water stress was calculated by the number of EST located in full-length cDNA. The density of drought tolerance genes distributing in chromosomes was obtained based on the alignment between drought tolerance genes and genome sequence. Comprehensive analysis of the data including the QTL related to drought, EST and the chips under water stress, platform related to drought tolerance in maize was built to discover 1285 candidate genes in the consensus QTL. Meanwhile, according to the gene ontology analysis, candidate genes mostly take part in the biological progress and the development of cells, minor genes in responses and transcriptions. Based on the transcriptional regulation analysis, TF have a lower rate in candidate genes than genome. One or more cis-element of the TF related to drought stress were found in the promoter region of candidate genes. The candidate genes play a role in metabolic progress which the plant need such as CO2 fixation, glucose metabolism, amino acid metabolism and secondary substance metabolism.82 important drought tolerance genes were selected through all the analysis above which would be used in further functional verification. |
