title: Transcriptome analysis of alfalfa under cold and freezing stress
design: To investigate the potential target mRNAs, two degradome libraries from cold stress and freezing stress samples were constructed, as previously described. In brief, poly(A)-enriched RNA were isolated and ligated to an RNA oligo-nucleotide adaptor containing a 3’MmeI recognition site, and the ligated products were used to synthetize first-strand cDNA. Then a short PCR (five cycles) was employed to amplify the cDNA, and the product was ligated to a double-stranded DNA adaptor, and subjected to gel purification again for PCR amplification. The final cDNA library was purified and sequenced on Illumina GAII by BGI-Shenzhen Co. Ltd (Shenzhen, China).