library_construction_protocol: RNA was prepared using the Maxwell RSC RNA kit (Promega) following the manufacturer's recommendations. 1μg total RNA or 10ng small RNA was used for library preparation. 3 ´SR Adaptor for Illumina was ligated to the small RNA using 3´ Ligation Enzyme. To prevent adaptor-dimer, the excess of 3 ´SR Adaptor were hybrid with SR RT Primer for Illumina. 5 ´SR Adaptor for Illumina was ligated to the small RNA using 5´ Ligation Enzyme and first strand cDNA was synthesized using ProtoScript II Reverse Transcriptase. Each sample was then amplified by PCR using P5 and P7 primers, the PCR product were purified by DNA clean beads.