title: GBS of Phytophthora spp.
design: GBS libraries were prepared from Phytophthora isolates according to the method described by Poland et al. (2012), with some modifications. Approximately 100 ng DNA of each sample was digested with 1 l PstI FastDigest, and 1 l HpaII FastDigest. The PstI adapter containing the barcodes and the HpaII Y-shaped adapter were ligated to the restriction sites with T4 ligase. The ligate was cleaned up using Sera-Mag SpeedBeads. In total, 10 l DNA was used in a PCR mix containing Taq 2x Master Mix (NEB) and 0.75 M each of primer IlluminaF_PE and IlluminaR_PE in a total volume of 50 L. The fragments were PCR-amplified and subsequently 25 l of each sample were cleaned using Sera-Mag SpeedBeads and eluted in 30 l 0.1x TE. Library quality was assessed by quantifying the DNA with a Quantus Fluorometer and by visualizing the fragment length profile using a QIAxcel Advanced System (Qiagen). In total, 96 samples with 96 unique barcodes were pooled for one lane of Illumina HiSeq3000 sequencing. The libraries were paired-end sequenced on an Illumina HiSeq3000 instrument (2x150 bp) at the Oklahoma Medical Research Foundation Genomics Facility (Oklahoma City, OK, USA). All read data were demultiplexed.