Polyploidy is widespread in angiosperms and has a significant impact on plant evolution, diversity, and breeding program. However, the changes in the flower development regulatory mechanism in autotetraploid plants remains relatively limited. In this study, RNA-seq analysis was used to investigate changes in signaling pathways at flowering in autotetraploid Brassica rapa. The study findings showed that the key genes such as CO, CRY2, and FT which promotes floral formation were down-regulated, whereas floral transition genes FPF1 and FD were up-regulated in autotetraploid B. rapa. The data also demonstrated that the positive regulators GA1 and ELA1 in the gibberellin’s biosynthesis pathway were negatively regulated by polyploidy in B. rapa. Furthermore, transcriptional factors (TFs) associated with flower development were significantly differentially expressed including the up-regulated CIB1 and AGL18, and the down-regulated AGL15 genes, and by working together such genes affected the expression of the down-stream flowering regulator FLOWERING LOCUS T in polyploid B. rapa. Compared with that in diploids autotetrapoid plants consist of differential expression within the signaling transduction pathway, with 13 TIFY gens up-regulated and 17 genes related to auxin pathway down-regulated. Therefore, polyploidy is more likely to integrate multiple signaling pathways to influence flowering in B. rapa after polyploidization. In general, the present results shed new light on our global understanding of flowering regulation in polyploid plants during breeding program.

中文翻译：

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比较转录组分析显示多倍体小白菜开花时多个信号通路中的差异基因表达

多倍体在被子植物中很普遍，并且对植物的进化，多样性和育种程序有重大影响。然而，同源四倍体植物中花发育调控机制的变化仍然相对有限。在这项研究中，RNA-seq分析用于研究芸苔四倍体开花时信号通路的变化。研究结果表明，在促进四倍体的B. rapa中，促进花形成的关键基因，如CO，CRY2和FT被下调，而花卉过渡基因FPF1和FD被上调。数据还表明，赤霉素的生物合成途径中的正调控因子GA1和ELA1受B. rapa的多倍体负调控。此外，与花发育相关的转录因子（TFs）显着差异表达，包括上调的CIB1和AGL18以及下调的AGL15基因，并且通过共同作用，这些基因影响下游开花调节因子FLOWERING LOCUS T的表达。多倍体B. rapa。与二倍体相比，四倍体植物在信号转导途径中差异表达，其中13个TIFY基因上调，17个与生长素途径相关的基因下调。因此，多倍体化更有可能整合多种信号通路，以影响多倍体化后B. rapa的开花。总的来说，目前的结果为我们对育种计划中多倍体植物开花调控的全球理解提供了新的思路。