METHOD FOR EXTRACTION OF FRANKIA DNA FROM SOIL

Soil DNA extraction methods that rely on cell extraction prior to lysis are inefficient for filamentous organisms such as Frankia. Direct lysis with detergents and physical cell wall disruption increases yield but the DNA is still contaminated with humic substances. Our method used in situ lysozyme digestion and lysis with SDS and proteinase K followed by centrifugation/wash cycles to collect DNA in solution. Potassium acetate precipitated contaminants; DNA in the supernatant was concentrated by ethanol precipitation. DNA was separated from remaining humic contaminants by agarose gel electrophoresis then electroeluted, phenol/chloroform extracted and precipitated by ethanol. The purified DNA could be cut with restriction endonuclease for restriction fragment length analysis and amplified by polymerase chain reaction.