Flower morphology is a vital ornamental characteristic. A single flower is the main floral pattern for lily, and rare double-flowered lily has extremely high ornamental and commercial value. However, the genetic basis underlying the double flowering of lily remains unknown. Here, with Lilium lancifolium and a double-flowered lily mutant used as experimental materials, RNA-seq was performed to elucidate the molecular mechanism of double-flowered lily. DEG enrichment highlighted the effect of hormone signal transduction pathways on stamen petaloidy. A large number of genes and TFs involved in hormone signal transduction pathways were identified. In particular, in the auxin biosynthesis and signaling pathway, most of the key genes were upregulated in double-flowered lily. In addition, comparative transcriptome and gene expression pattern analyses revealed that two MADS family members and a C2H2 gene may play vital roles in the transformation from single- to double-flowered lily. This study provides insights into the complex molecular networks underlying floral organ development in double-flowered lily.

花的形态是重要的观赏特征。单花是百合的主要花型，稀有的重瓣百合具有极高的观赏价值和商业价值。然而，百合双花的遗传基础仍然未知。在这里，与百合以重瓣百合突变体为实验材料，进行RNA-seq，阐明重瓣百合的分子机制。DEG富集突出了激素信号转导途径对雄蕊花瓣状的影响。鉴定出大量参与激素信号转导途径的基因和TF。特别是在生长素生物合成和信号通路中，重瓣百合的大部分关键基因上调。此外，比较转录组和基因表达模式分析表明，两个 MADS 家族成员和一个 C2H2 基因可能在百合从单花到重瓣的转化中起重要作用。本研究提供了对重瓣百合花器官发育的复杂分子网络的深入了解。