library_construction_protocol: Approximately 1 ug of total RNA was used to remove ribosomal RNA according to the manuscript of the Epicentre Ribo-Zero Gold Kit (Illumina, San Diego, USA). Following purification, the ribo-minus RNA fractions is fragmented into small pieces using divalent cations under elevated temperature. Then the cleaved RNA fragments were reverse-transcribed to create the final cDNA library in accordance with a strand-specific library preparation by dUTP method. The average insert size for the paired-end libraries was 300±50 bp. And then we performed the pair-end 2×150bp sequencing on an Illumina Hiseq 4000 platform housed in the LC Sciences (Hangzhou, China) following the vendor's recommended protocol.