Data from: Draft assembly of elite inbred line PH207 provides insights into genomic and transcriptome diversity in maize

Intense artificial selection over the last 100 years has produced elite maize (Zea mays) inbred lines that combine to produce high-yielding hybrids. To further our understanding of how genome and transcriptome variation contribute to the production of high-yielding hybrids, we generated a draft genome assembly of the inbred line PH207 to complement and compare with the existing B73 reference sequence. B73 is a founder of the Stiff Stalk germplasm pool, while PH207 is a founder of Iodent germplasm, both of which have contributed substantially to the production of temperate commercial maize and are combined to make heterotic hybrids. Comparison of these two assemblies revealed over 2,500 genes present in only one of the two genotypes and 136 gene families that have undergone extensive expansion or contraction. Transcriptome profiling revealed extensive expression variation, with as many as 10,564 differentially expressed transcripts and 7,128 transcripts expressed in only one of the two genotypes in a single tissue. Genotype-specific genes were more likely to have tissue/condition-specific expression and lower transcript abundance. The availability of a high-quality genome assembly for the elite maize inbred PH207 expands our knowledge of the breadth of natural genome and transcriptome variation in elite maize inbred lines across heterotic pools.

过去百余年的高强度人工选择，培育出了优异的玉米（Zea mays）自交系，此类自交系配组后可获得高产杂交种。为进一步解析基因组与转录组变异对高产杂交种形成的贡献机制，我们构建了自交系PH207的草图基因组组装，以与现有B73参考基因组序列进行互补比对。B73是硬秆种质类群（Stiff Stalk germplasm pool）的奠基自交系，而PH207则是碘型种质类群（Iodent germplasm）的奠基自交系；二者均为温带商用玉米育种做出了重要贡献，且二者配组可产生强优势杂交种。对两份基因组组装的比较分析显示，仅存在于两份基因型之一的基因超过2500个，另有136个基因家族发生了大规模的扩张或收缩。转录组表征（transcriptome profiling）显示存在广泛的表达差异：在单一组织中，多达10564个差异表达转录本（differentially expressed transcripts），以及7128个仅在两份基因型之一中表达的转录本。基因型特异性基因更倾向于具备组织/条件特异性表达模式，且转录本丰度更低。优异玉米自交系PH207的高质量基因组组装的发布，拓展了我们对不同杂种优势种质类群内优异玉米自交系自然基因组与转录组变异范围的认知。