Robust CTAB-activated charcoal protocol for plant DNA extraction

DNA extracted from plants rich in polyphenols and/or polysaccharides is often problematic when subjected to polymerase chain reaction, especially when mature tissues are used for DNA extraction. In order to overcome the problems associated with poor-quality DNA extracted from such plant samples, a protocol has been developed, availing on a high salt concentration and on the combination of polyvinylpyrrolidone and activated charcoal in the extraction buffer, in order to prevent the solubilization of polysaccharides and polyphenols in the DNA extract. Mild temperature conditions during extraction and precipitation were also recognized as important parameters. Besides DNA purity, mild precipitation conditions were found to be beneficial in obtaining less low-molecular mass nucleic acids in the final DNA extract. The homogenization step and the amount of sample extracted were also found to be crucial in keeping the extraction procedure robust.