Previous studies have shown that high light intensity can induce anthocyanin synthesis (AS) in petunia plants. To identify which kind of light quality plays a role in inducing such metabolic process, and what transcripts participate in controlling it, we carried out whole-transcriptome sequencing and analysis of petunia petals treated with different light-quality conditions. Among the red and white light treatments, a total of 2 205 differentially expressed genes and 15, 22, and 20 differentially expressed circRNAs, miRNAs, and lncRNAs, were identified respectively. The AS-related genes, including the structural genes CHSj, F3′H, F3′5′H, DFR, and ANS, and the regulatory genes AN4, DPL, PHZ and MYBx were found to be downregulated under red light condition compared with their levels under white light condition. Furthermore, the light photoreceptor Cryptochrome 3 (CRY3) and a series of light-dependent genes, such as PIF, HY5, and BBXs, were also determined to respond to the light treatments. The anthocyanin contents in early petunia petals under red light were significantly lower than that under white and blue light. The results of qRT-PCR further confirmed the expression pattern of some AS-related and light-response genes in response to different light quality. Yeast two-hybrid results showed that the key elements in the light signal pathway, HY5 can interact with BBX19, BBX24 and BBX25. And PHZ, the important AS regulator can induce anthocyanin synthesis in response to blue light quality from transient expression analysis in petunia petals. These findings presented here not only deepen our understanding of how light quality controls anthocyanin synthesis, but also allow us to explore potential target genes for improving pigment production in petunia flower petals.

先前的研究表明，高光强度可以诱导矮牵牛植物中的花青素合成（AS）。为了确定哪种光质量在诱导这种代谢过程中起作用，以及哪些转录本参与控制这种代谢过程，我们对用不同光质量条件处理的矮牵牛花瓣进行了全转录组测序和分析。在红光和白光治疗中，分别鉴定出总共2205个差异表达的基因和15、22和20个差异表达的circRNA，miRNA和lncRNA。与AS相关的基因，包括结构基因CHSj，F3'H，F3'5'H，DFR和ANS，以及调控基因AN4，DPL，PHZ和MYBx与在白光条件下的水平相比，它们在红光条件下的水平被下调。此外，光感受器Cryptochrome 3（CRY3）和一系列光依赖基因，例如PIF，HY5和BBXs，也被确定对光疗做出反应。红光下矮牵牛花瓣中的花色苷含量明显低于白光和蓝光下。qRT-PCR的结果进一步证实了一些AS相关和光响应基因响应不同光质量的表达模式。酵母双杂交结果表明，HY5是光信号通路中的关键元素，可以与BBX19，BBX24和BBX25相互作用。PHZ是重要的AS调节剂，可通过矮牵牛花瓣的瞬时表达分析响应蓝光质量诱导花色苷合成。此处提出的这些发现不仅加深了我们对光质量如何控制花色苷合成的理解，还使我们能够探索潜在的靶基因以改善矮牵牛花瓣中色素的产生。