Genome-wide transcript analysis of maize hybrids: allelic additive gene expression and yield heterosis
Genome-wide transcript analysis of maize hybrids: allelic additive gene expression and yield heterosis
复制标题
DOI：
10.1007/s00122-006-0335-x
复制
发表时间：
2006-09-01
影响因子：
5.4
通讯作者：
Bowen, Ben
中科院分区：
文献类型：
--
作者：
Guo, Mei;Rupe, Mary A.;Bowen, Ben
杂种优势或杂种优势在植物育种中得到了广泛的应用，但其分子机制尚不清楚。在这项研究中，我们应用了全基因组转录谱分析，以获得在一系列16个不同杂种优势程度的玉米杂交种的未成熟耳部组织中大量基因表达方式的全局图像。主要观察结果包括：(1)等位基因加性表达比例与杂种产量和杂种优势呈正相关；(2)倾向于父本表达水平的基因比例与杂种产量和杂种优势呈负相关；(3)玉米杂交种中特定基因的过表达或过表达与产量或杂种优势均无相关性。通过分析在不同植物密度胁迫水平下生长的遗传改良现代杂交种先锋(R) 3394和遗传改良较差的老杂交种先锋(R) 3306，证实了表达模式与杂交种性能的关系。等位基因加性表达比例与现代高产杂交种、杂种优势和高产环境呈正相关，与父本偏倚基因表达比例相反。杂种基因表达对基因型和环境的动态变化可能与亲本等位基因的差异调控有关。本研究结果表明，差异等位基因调控可能在杂种产量或杂种优势中发挥重要作用，并为杂种优势的分子机制提供了新的认识。
Heterosis, or hybrid vigor, has been widely exploited in plant breeding for many decades, but the molecular mechanisms underlying the phenomenon remain unknown. In this study, we applied genome-wide transcript profiling to gain a global picture of the ways in which a large proportion of genes are expressed in the immature ear tissues of a series of 16 maize hybrids that vary in their degree of heterosis. Key observations include: (1) the proportion of allelic additively expressed genes is positively associated with hybrid yield and heterosis; (2) the proportion of genes that exhibit a bias towards the expression level of the paternal parent is negatively correlated with hybrid yield and heterosis; and (3) there is no correlation between the over- or under-expression of specific genes in maize hybrids with either yield or heterosis. The relationship of the expression patterns with hybrid performance is substantiated by analysis of a genetically improved modern hybrid (Pioneer (R) hybrid 3394) versus a less improved older hybrid (Pioneer (R) hybrid 3306) grown at different levels of plant density stress. The proportion of allelic additively expressed genes is positively associated with the modern high yielding hybrid, heterosis and high yielding environments, whereas the converse is true for the paternally biased gene expression. The dynamic changes of gene expression in hybrids responding to genotype and environment may result from differential regulation of the two parental alleles. Our findings suggest that differential allele regulation may play an important role in hybrid yield or heterosis, and provide a new insight to the molecular understanding of the underlying mechanisms of heterosis.