Dark nodules occurring in Hypericum perforatum at defined locations in several tissues are the sites of hypericin accumulation and most likely hypericin synthesis. To identify transcripts of genes potentially in involved in hypericin synthesis, cDNA libraries from petal rims with dark nodules and petal centers without dark nodules (field grown plants) have been sequenced using a paired-end approach (2x 101 nt) on a HiSeq2000 sequencer.. Dark nodules in petals of Hypericum perforatum

Total RNAs were extracted using the InviTrap® Spin Plant RNA Mini Kit (STRATEC Biomedical, Birkenfeld, Germany) according to the manufacturer's instruction. RIN factors were determined using an Agilent2100 Bioanalyzer (Agilent Technologies, Santa Clara, CA, USA) and total RNAs with RIN >= 8 were used for the construction of cDNA libraries with the TruSeq RNA Library Prep Kit v2 (Illumina, San Diego, CA, USA). cDNA libraries were excised from preparative agarose gels to obtain an insert size of approx. 180 bp, which was controlled with an Agilent 2100 Bioanalyzer. Library concentrations were measured by qPCR with previously sequenced libraries as standard and sequenced with a paired-end approach (2x 101 nt) using a HiSeq2000 instrument (Illumina).