The tissues were then homogenized with appropriate volume of Trizol reagent (Invitrogen, USA) in independent bead containing safe lock tubes. After Trizol/chloroform extraction, the aqueous phase was mixed with 100% EtOH, and then loaded onto RNeasy column (Qiagen, USA). The RNA extraction process was continued according to the manufacturer's protocol. The libraries were prepared for 151bp paired-end sequencing using TruSeq stranded mRNA Sample Preparation Kit (Illumina, USA)