Transcriptome Analysis of Apis cerana

After confirming the A. cerana species, 10 adult workers from each colony were pooled and homogenized using a mortar and pestle with liquid nitrogen. Total RNA was extracted using TRIzol Reagent (Invitrogen, Carlsband, CA, USA) according to the manufacturer’s instructions. The concentration of RNA was measured for absorbance at 260 nm (A260), and its purity was assessed at a ratio of A260/A280 using a BioDrop-DUO UV/Vis spectrophotometer (BioDrop, Cambridge, UK). Four micrograms of RNA was reverse-transcribed into cDNA using Tetro Reverse Transcriptase (Bioline, Memphis, TN, USA). Both oligo(dT) and random hexamer primers were used in the reaction. The mixture was incubated at 25 °C for 10 min, followed by 45 °C for 30 min, and then the reaction was terminated at 85 °C for 5 min. The cDNA was obtained and stored at −20 °C before proceeding to the next step.