RNA-Seq of hairy root of Salvia miltiorrhiza
mRNA was isolated using magnetic beads conju-gated with oligo (dT) capture probes. First-strand cDNAwas synthesized from mRNA fragments by reverse tran-scriptase using random hexamers (Invitrogen, San Diego, CA, USA) as primers, and second-strand cDNA was then synthesized using reaction buffer, dNTPs, RNase H and DNA polymerase I (Amersham Biosciences, Piscataway, NJ, USA). The resulting cDNA fragments were puri- fied using a QIAquick PCR Purification Kit (Qiagen) and were then treated with T4 DNA polymerase (Illumina, San Diego, CA, USA), T4 PNK (Illumina), and Klenow DNA polymerase (Illumina) to convert the overhangs into blunt ends. The cDNAs were ligated to sequencing adapters (Illumina) and separated by agarose gel electrophoresis to select suitable fragments for PCR amplification.