A rapid and cost-efficient DMSO-based method for isolating DNA from cultured lichen photobionts

We have developed a simple and fast procedure for the purification of PCR-quality DNA from cultured lichen photobionts. This new one-step method uses the solvent dimethyl sulfoxide (DMSO) combined with heat treatment to chemically breakdown algal and plant tissues. The DMSO-DNA extracts may be directly precipitated and purified by standard techniques in a total time of approximately 30 min. Compared to other DNA extraction protocols, the DMSO-based method suppresses the need for liquid nitrogen, any extraction buffer, grinding, phenol, and long incubation or centrifugation steps, thereby considerably reducing the possibility of contamination. In addition, minimal amounts of starting material (5 × 10⁶–20 × 10⁶ cells from liquid or agarized cultures) produce sufficient DNA for 200 PCR reactions approximately, making this protocol a practical option for colony screening. This method works well in a wide range of cultured lichen photobionts and reduces the amount of labor-intensive steps and time consumed by other multi-step procedures, allowing for efficient processing of an increased number of samples.