【摘要】 玉米(Zea mays)杂交种隆平206是黄淮海地区推广的重要玉米品种,具有显著生长优势以及产量优势,为研究杂种优势提供了极好的材料。为了从分子生物学的角度解析隆平206相对于父母本(父本:L7221;母本:L239)具有良好杂种优势的原因,本研究利用RNA-Seq技术,从转录组水平对其进行相关分析。结果表明,在杂交种与父母本之间共检测出3 005个差异表达基因(differentially expressed genes,DEGs),其中1 788个基因在杂交子代中上调表达,925个下调表达。通过对这些差异基因进行基因本体(Gene Ontology,GO)分析和通路富集分析,发现5.88%差异表达的基因参与到碳代谢途径,8.24%的DEGs参与到植物信号转导途径,并且这些DEGs在杂交子代中的表达量显著升高。结果显示,碳代谢途径以及植物信号转导途径在隆平206杂种优势的形成过程中具有重要的意义。研究结果可以为后续研究玉米杂种优势的分子机制提供重要的数据支持。更多还原

【Abstract】 Longping206(Zea mays), a spreading hybrid in south areas of the Yellow River, Huai and Hai Rivers, with conspicuous growth heterosis and higher yield production, provides us an opportunity to explore the potential molecular mechanism for heterosis. In this study, the new technology Illumina Hiseq2500 was applied to explore the transcription level in sixth leaves stage between Longping206 and its parents(L7221and L239). Gene expression level and function prediction were analysed with a lot of bioinformatic methods.From the comparison of phenogram, the hybrid was stronger than its paternal line in sixth leaves stage. The measurement of biomass had the same results with the phenogram. After the RNA-Seq sequencing,approximately 12.52 Gb clean data was generated after removing low-quality read. At least 69% read could be mapped into the reference genome of maize B73 with the software Tophat2. With the module Cuffdiff of Cufflinks, gene expression quantity was obtained. Then EBSeq software was used to calculate the differential expression. A total of 3 005 differentially expressed genes(DEGs) was discovered between Longping206 and its parental lines.All 1 788 DEGs were up-regulated in hybrid with 925 DEGs were down-regulated.To calculate the gene expression level in heterosis,traditional quantitative genetic parameters were used as the quantitative traits.To classify the function of DEGs,Gene Ontology(GO)analysis was used.In total,2 399 of3 005 DGHP(different expression genes in hybrid and parents)were assigned to at least one term in GO database including molecular function,biological process and cellular component.Most of important biological processes were enriched in hybrid such as hormone signal conditioning,energy metabolism,materials transport,stress threaten etc.To identify the metabolic pathways which the DGHP were involved and enriched,Kyoto Encyclopedia of Genes and Genomes(KEGG)database was performed to analyze the pathway.The results showed that at least 255 DGHP were classified into one functional category.5.88%and8.24%of these DEGs were involved in the carbon metabolism and plant signal transduction pathways,respectively.Interestingly,most of the DEGs were up-regulated,which revealed that the two ways were important to the formation of heterosis.qRT-PCR was performed to validate the consistence of transcriptome analysis with 10 random different expression genes.The extensive transcriptome data which was obtained from high-throughput sequencing given the comprehensive overview of the leaf transcriptomes at Longping206 and its parents in a heterotic maize cross.This study provides a useful resource for molecular mechanisms of the maize heterosis research.更多还原