Transcriptome library of Korean fir
RNA samples were extracted from the needles of 7days drought-treated plants. Total RNA was isolated using TRIzol reagent according to the manufacturers protocol (GibcoBRL, Cleveland, OH, USA). The RNA was analysed for quality and concentration using a 2100 Bioanalyzer (Agilent Technologies, Palo Alto, CA, USA). A total of 3 g of RNA for each sample was used in library construction with the Illumina Truseq RNA sample Preparation Kit (Illumina, Inc. San Diego, CA, USA) per the manufacturers instructions. Briefly, mRNA was enriched using magnetic beads containing poly-T molecules. Following purification, the enriched mRNA was broken into small fragments. Random oligonucleotides and SuperScript II were used to synthesise the first-strand cDNA. The second-strand cDNA was subsequently synthesised using DNA Polymerase I and RNase H. Finally, end repair was carried out on these cDNA fragments, and they were ligated with Illumina adapters. Libraries were amplified using PCR according to Illumina guidelines. Libraries with insert sizes of 200 bp were constructed and then sequenced using the Illumina HiSeq 2000. Transcriptome assembly was accomplished using Trinity software, which first combined reads with certain lengths of overlap to form longer fragments without ambiguous bases, named as contigs. Contigs were then connected by Trinity to generate sequences that could not be extended on either end. These sequences were named as transcripts.