*4.3. RNA Extraction and Transcriptome Sequencing*

For the RNA-seq study, the petals of each variety were completely cut and mixed (including the deep-color blotches in the centers of the petals), and three biological replicates were conducted. Total RNA extraction was completed using the RNA simple Total RNA Kit (Tiangen, Shanghai, China) from petals following the manufacturer's instructions. Extracted RNA purity was determined in a Nanodrop spectrophotometer (Thermo Scientific, Waltham, MA, USA), and RNA integrity was assessed using the Agilent 2100 Bioanalyzer (Agilent Technologies, Santa Clara, CA, USA). RNA-seq libraries were generated using the TruSeq RNA Sample Preparation Kit (Illumina, San Diego, CA, USA). After preparation, twelve libraries were sequenced on the Illumina HiSeq platform [52]. The RNA-seq analysis was performed by Panomix Biomedical Tech Co., Ltd. (Suzhou, China).
