Total RNA of flower buds and vegetative buds were extracted as above and the first strand cDNA was synthesized using PrimeScript RT reagent Kit With gDNA Eraser (Takara Bio Inc.). All primers used in this study were designed by the Primer 5 software according to the RNA-Seq data. CfGAPDH (JX560732) was selected as an internal reference (Additional file 1: Table S1).