Cucumber (Cucumis sativus L.) is a typical monoecism vegetable with individual male and female flowers, which has been used as a plant model for sex determination. It is well known that light is one of the most important environmental stimuli, which control the timing of the transition from vegetative growth to reproductive development. However, whether light controls sex determination remains elusive. To unravel this problem, we performed high-throughput RNA-Seq analyses, which compared the transcriptomes of shoot apices between R2B1(Red light:Blue light = 2:1)-treated and R4B1(Red light:Blue light = 4:1)-treated cucumber seedlings. Results showed that the higher proportion of blue light in the R2B1 treatment significantly induced the formation of female flowers and accelerated female flowering time in this whole study. The genes related to flowering time, such as flowering locus T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CO1 (SOC1), were up-regulated after R2B1 treatment. Furthermore, the transcriptome analysis showed that up-regulation and down-regulation of specific DEGs (the differentially expressed genes) were primarily the result of plant hormone signal transduction after treatments. The specific DEGs related with auxin formed the highest percentage of DEGs in the plant hormone signal transduction. In addition, the expression levels of transcription factors also changed after R2B1 treatment. Thus, sex differentiation affected by light quality might be induced by plant hormone signal transduction and transcription factors. These results provide a theoretical basis for further investigation of the regulatory mechanism of female flower formation under different light qualities in cucumber seedlings.

中文翻译：

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比较RNA-Seq分析对不同比例的蓝光和红光下黄瓜性别分化的调控。

黄瓜（Cucumis sativus L.）是一种典型的单株蔬菜，具有雌雄同株的花朵，已被用作确定性别的植物模型。众所周知，光是最重要的环境刺激之一，它控制着从营养生长到生殖发育的过渡时间。但是，光线是否能控制性别决定仍然难以捉摸。为了解决这个问题，我们进行了高通量RNA-Seq分析，比较了R2B1（红光：蓝光= 2：1）处理和R4B1（红光：蓝光= 4：1）处理后的茎尖转录组。处理的黄瓜幼苗。结果表明，在整个研究中，R2B1处理中较高比例的蓝光显着诱导了雌花的形成并加快了雌花的开花时间。R2B1处理后，与开花时间相关的基因（例如开花基因座T（FT）和CO1过表达抑制因子（SOC1））被上调。此外，转录组分析表明，特定DEG（差异表达基因）的上调和下调主要是处理后植物激素信号转导的结果。在植物激素信号转导中，与植物生长素相关的特定DEGs形成了最高百分比的DEGs。另外，R2B1处理后，转录因子的表达水平也发生了变化。因此，受光质量影响的性别分化可能是由植物激素信号转导和转录因子诱导的。