Single-Parent Expression Is a General Mechanism Driving Extensive Complementation of Non-syntenic Genes in Maize Hybrids
Single-Parent Expression Is a General Mechanism Driving Extensive Complementation of Non-syntenic Genes in Maize Hybrids
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DOI：
10.1016/j.cub.2017.12.027
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发表时间：
2018-02-05
期刊：
影响因子：
9.2
通讯作者：
Hochholdinger, Frank
中科院分区：
文献类型：
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作者：
Baldauf, Jutta A.;Marcon, Caroline;Hochholdinger, Frank
玉米（Zea mays L.）显示出异常程度的结构基因组多样性[1，2]。此外，基因表达的变化进一步有助于玉米非凡的表型多样性和可塑性。本研究系统地研究了远缘纯合玉米自交系对其高度杂合杂种F1代转录组可塑性的影响。杂种优势的经典显性模型解释了杂种植物的优势是通过第二亲本的上级等位基因在许多位点上对有害亲本等位基因的互补作用[3]。在一个近交系中有活性但在另一个近交系中无活性的基因代表了定义为单亲表达的等位基因多样性的极端实例[4]。我们观察到平均类似的1,000个这样的基因在所有自交系组合在主根发育。这些基因一致地显示表达互补（即，活性）在其杂交后代中。因此，极端表达互补是一种一般机制，平均导致近似600个额外的活性基因及其编码的生物学功能的杂交。现代玉米基因组由一组非同线基因补充，这些基因在玉米和高粱谱系分离后出现，并且在任何其他草物种中缺乏同线直系同源物[5]。我们证明了非同线基因是杂种中基因表达互补的驱动力。其中，高度多样化的bZIP和bHLH转录因子家族[6]系统性地过度代表。总之，极端基因表达互补广泛塑造了玉米杂种的转录组可塑性，因此可能是控制杂种发育可塑性的因素之一。
Maize (Zea mays L.) displays an exceptional degree of structural genomic diversity [1, 2]. In addition, variation in gene expression further contributes to the extraordinary phenotypic diversity and plasticity of maize. This study provides a systematic investigation on how distantly related homozygous maize inbred lines affect the transcriptomic plasticity of their highly heterozygous F-1 hybrids. The classical dominance model of heterosis explains the superiority of hybrid plants by the complementation of deleterious parental alleles by superior alleles of the second parent at many loci [3]. Genes active in one inbred line but inactive in another represent an extreme instance of allelic diversity defined as single-parent expression [4]. We observed on average similar to 1,000 such genes in all inbred line combinations during primary root development. These genes consistently displayed expression complementation (i.e., activity) in their hybrid progeny. Consequently, extreme expression complementation is a general mechanism that results on average in similar to 600 additionally active genes and their encoded biological functions in hybrids. The modern maize genome is complemented by a set of non-syntenic genes, which emerged after the separation of the maize and sorghum lineages and lack syntenic orthologs in any other grass species [5]. We demonstrated that non-syntenic genes are the driving force of gene expression complementation in hybrids. Among those, the highly diversified families of bZIP and bHLH transcription factors [6] are systematically overrepresented. In summary, extreme gene expression complementation extensively shapes the transcriptomic plasticity of maize hybrids and might therefore be one factor controlling the developmental plasticity of hybrids.