A simple method for extraction of fungal genomic DNA

We have developed a new, simple and effective method for extraction of fung al genomic DNA. The initial steps involved suspension of freeze-dried mycel ium in buffer containing sodium dodecyl sulphate, detachment of DNA from po lysaccharides by mild shearing, NaCl precipitation of polysaccharides and p rotein, chloroform extraction and ethanol precipitation. The ethanol precip itate was then subjected to a second round of mild shearing, NaCl precipita tion, chloroform extraction and ethanol precipitation. The procedure requir ed approximately 1 h to perform. The method yielded 8-32 mu g of high molec ular weight DNA per 30 mg of freeze-dried mycelium when tested on six funga l species: Aspergillus niger, A. flavus, Fusarium graminarum, Neotyphodium lolii, Penicillium citrinum and Rhizopus nigricanes. The DNA was digestible with EcoRI, HindIII, SalI and BamHI. For the slow-growing N. lolii, a modi fication of the method was developed that removed the agar residue from col onies grown on agar plates by centrifugation at 13 000 rev min(-1) in the p resence of CsCl. The modified method yielded 1.5-2 mu g of high molecular w eight DNA per colony.