Molecular identificationMycelia were scraped from colonies of six isolates (Phoma2, 3,4, 5, 6, 8) and used for DNA extraction. In addition, two isolates originating from blackleg-affected canola (Brassica napus)plants were also included; isolate L3 (Leptosphaeria biglobosa)is weakly virulent on canola cultivar Westar (Shoemaker &Brun, 2001) and isolate K135 (Leptosphaeria maculans ‘brassicae’) is highly virulent on Westar (Chen & Fernando, 2006)(isolates were provided by W. D. G. Fernando, University ofManitoba, Canada). The mycelium was transferred into a1.5 mL tube, kept on ice, and ground using a sterile pestle for20 s. Buffer (450 lL of 2 9 STE (0.1 M NaCl, 10 mM Tris-HCl(pH 8.0), 1 mM EDTA (pH 8.0) and 50 lL 10% SDS) wasadded, mixed, and left at room temperature for 20 min. A mixture of 500 lL chloroform:isoamyl alcohol (24:1) was addedand incubated at room temperature for 20 min. The mixturewas centrifuged at 9300 g for 10 min and 400 lL of the supernatant was transferred to a new tube. One millilitre of 95%ethanol and 40 lL 3 M sodium acetate was added and the mixture was kept at 20 °C overnight or at 80 °C for 30 min.After centrifugation at 15 800 g for 15 min, the pellet waswashed with 70% ethanol, centrifuged at 15 800 g for 5 minand left at room temperature for 30 min. The DNA was redissolved in 20 lL elution buffer (EB; QIAGEN) or DNAse/RNAse-free water. For PCR, primers ITS2 (50-GCTGCGTTCTTCATCGATGC-30) and ITS5 (50-GGAAGTAAAAGTCGTAACAAGG-30) were used to amplify the ITS1-5.8S-ITS2region (White et al., 1990). DNA (100 ng) and 0.5 lL 10 mMITS2 and ITS5 primers were added to the reaction buffer withTaq DNA polymerase (5 U; QIAGEN) in 25 lL total volume.The PCR conditions were 94 °C for 4 min; followed by 35cycles of 94 °C for 50 s, 58 °C for 1 min, 72 °C for 1 min; andextension at 72 °C for 7 min. For electrophoresis, 8 lL of PCRproduct was run on a 1% agarose gel. Fragments of 0.3–0.7 kbin size were collected using the MinElute gel extraction kit(QIAGEN) and sent for sequencing directly or the fragmentswere cloned into pUC19 (Invitrogen) or pGEM-T Easy (Promega) following the manufacturer’s protocols. Single white colonies were transferred into 3 mL Luria broth with 100 mg L1ampicillin or 50 mg L1 kanamycin and incubated at 37 °Covernight with vigorous shaking. The plasmid DNA wasextracted using the Wizard Plus Midiprep kit (Promega) anddigested with EcoRI to confirm the insertion. A sample (10 ng)of the plasmid with correct size insertions was sent to MacrogenInc. for sequencing using M13 forward and reverse primers forpUC19 constructs or T7 and SP6 primers for pGEM-T Easyconstructs.