Biocenter Klein Flottbek, University of Hamburg, 22609 Hamburg, Germany.
Theor Appl Genet. 2010 Jan;120(2):401-13. doi: 10.1007/s00122-009-1189-9. Epub 2009 Nov 4.
Heterosis is widely exploited in plant breeding, although its molecular basis is still not fully understood. For the characterization of this phenomenon and the development of transcriptome-based methods to predict hybrid performance (HP), we applied a microarray (46k) analysis of 21 European maize (Zea mays L.), 14 dent and 7 flint parental inbred lines. Expression profiles of the parental inbreds at the seedling stage were correlated with grain yield (GY) and grain dry matter content (GDMC) of 98 flint x dent factorial crosses at six locations. We observed highly significant correlations of the parental expression levels of certain differentially expressed genes with heterosis and HP for GY and also with HP for GDMC. This strong correlation provided first evidence toward a prediction potential of the genes and their expression levels. The identified gene set based on the parental transcriptome data revealed functional characteristics of HP and heterosis. Gene ontology (GO) analyses were performed to compare genes correlated with their expression pattern to HP for GY and GDMC, respectively. Between these gene groups, mostly different functional classes of genes were found to be enriched or underrepresented. The phenomenon of heterosis was characterized by the over- and underrepresentation of specific GO terms among heterosis-correlated genes.
杂种优势在植物育种中得到了广泛应用，尽管其分子基础仍未完全理解。为了对这种现象进行表征，并开发基于转录组的方法来预测杂种表现（HP），我们对 21 个欧洲玉米（Zea mays L.）、14 个齿形和 7 个燧石亲本自交系进行了微阵列（46k）分析。在幼苗期，亲本自交系的表达谱与 98 个燧石 x 齿形因子杂交在六个地点的粒重（GY）和籽粒干物质含量（GDMC）相关。我们观察到，某些差异表达基因的亲本表达水平与 GY 的杂种优势和 HP 以及 GDMC 的 HP 高度显著相关。这种强相关性为基因及其表达水平的预测潜力提供了初步证据。基于亲本转录组数据确定的基因集揭示了杂种优势和杂种优势的功能特征。进行了基因本体论（GO）分析，以比较与 GY 和 GDMC 的 HP 分别相关的基因及其表达模式。在这些基因组之间，发现富集或代表性不足的基因主要是不同的功能类别。杂种优势的特点是杂种优势相关基因中特定 GO 术语的过度表达和不足表达。
