Spatio-temporal expression dynamics differ between flowering time gene homologues in the allopolyploid Brassica napus

First author: D. Marc Jones; Affiliations: John Innes Centre (约翰英纳斯中心): Norwich, UK

Corresponding author: Richard J. Morris

Polyploidy is a recurrent feature of eukaryotic evolution and has been linked to increases in complexity, adaptive radiation, and speciation. Within angiosperms, such events have occurred repeatedly in many plant lineages. Here we investigate the retention and spatio‐ emporal expression dynamics of duplicated genes predicted to regulate the floral transition in Brassica napus (oilseed rape 欧洲油菜, OSR). We show that flowering time genes are preferentially retained relative to other genes in the OSR genome. Using a transcriptome time series in two tissues (leaf and shoot apex 茎尖) across development, we show that 67% of these retained flowering time genes are expressed. Furthermore, between 64% (leaf) and 74% (shoot apex) of the retained gene homologues show diverged expression patterns relative to each other across development, suggesting neo‐ or subfunctionalisation. A case study of homologues of the shoot meristem identity gene TFL1 genes reveals differences in cis‐r egulatory elements that could explain this divergence. Such differences in the expression dynamics of duplicated genes highlight the challenges for translating gene regulatory networks from diploid model systems to more complex polyploid crop species.

多倍化是真核生物演化过程中反复出现的特性，与基因组复杂性，适应性辐射及物种形成的增加相关。在被子植物中，在许多植物支系中发生过多次多倍化事件。本文研究了欧洲油菜中与成花转变相关复制基因的保留和时空表达动态。结果显示开花基因相比于其他基因更容易在油菜基因组中保留下来。叶和茎尖在不同发育阶段的转录组时间序列数据显示67%的保留下来的开花时间相关基因表达。此外，64%的叶片和74%的茎尖组织保留的同源基因在不同发育阶段显示出不同的表达模式，说明这些基因存在新功能或者亚功能化。茎分生组织决定基因TFL1同源基因的研究显示在顺式元件上存在差异，可能能够解释同源基因之间的分化。复制基因表达模式的差异突出了将二倍体模式系统中的基因调控网络应用到更加复杂的多倍体作物物种的挑战。

通讯：Richard J. Morris (https://www.jic.ac.uk/directory/richard-morris/)

doi: https://doi.org/10.1111/tpj.14020

Journal: the plant journal

First Published: 10 July, 2018

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