Extraction of DNA from Phytophthora infestans Using QIAGEN Columns

High molecular weight DNA of Phytophthora infestans was extracted using a modification of the commercial QIAGEN column procedure. Both a ʹmaxiʹ and ʹmini" procedure are described. The maxi procedure utilizes a QiAGEN-tip 500 column while the mini procedure utilizes a QIAGEN-tip 20 column. When fungal protoplasts were used as starting material from 9 g (fresh weight) of mycelium, nearly 500 /Ug of DNA in the size range of 20- 200 kb was obtained and the product was successfully used in construction of a lambda genomic library. The modified QIAGBN method can replace the more timeconsuming, and expensive cesium chloride density gradient centrifugation for extraction of ultra-pure DNA from P. infestans