DNA extraction, PCR amplification and DNA sequencing.
Samples of pure cultures from 3-day-old CYA agar plates were added
to 1.5 ml tubes containing TE buffer [10 mM Tris/HCl (pH 8.0),
1 mM EDTA (pH 4.5)], gently homogenized and then lysed by either
sonication or enzymic digestion. For physical disruption, tubes were
placed in a sonicator (ultrasonic bath LBS2; Falc Instruments) at 60
KHz for 3–5 min then heated at 100 uC for 5–10 min. Samples were
centrifuged in a micro-centrifuge for 2 min at 14 000 r.p.m. at room
temperature, and the supernatant extracts containing unpurified
fungal DNA were then stored at 220 uC for subsequent PCR analysis.
Enzymic digestion was instead initially performed with lyticase
(20 mg ml21; Sigma) at 40 uC for 1 h, and then by incubating with
proteinase K (20 mg ml21; Sigma) at 50–60 uC for several hours
followed by phenol/chloroform extraction and alcohol precipitation
to yield PCR-amplifiable genomic DNA; the resulting DNA pellets
were dissolved in 50–100 ml TE buffer and stored at 220 uC.