Total RNA of flower and vegetative buds were extracted using EASYspin plant RNA rapid extraction kit according to the manufacturer’s protocol (Yuan Ping Hao Biotechnology Co. Ltd, Beijing, China). Then, the concentration was detected by a NanoDrop 2000™ micro-volume spectrophotometer (Thermo Scientific, Waltham, MA, USA) and the quality was tested by gel electrophoresis. cDNA library construction for the flower and vegetative buds and Illumina deep sequencing were performed on the HiSeq™ 2000 platform according to the manufacturer’s instructions at Hangzhou Woosen Biotechnology Co. Ltd. (Hangzhou, Zhejiang, China). The Illumina reads were assembled to obtain the contigs and unigenes using Trinity software and Cap3 after removing the short raw reads and quality inspection by fastQC (Grabherr et al. 2011).