Extraction of high-quality metagenomic DNA from the lichens Flavoparmelia caperata and Peltigera membranacea

Abstract

Lichens are composite organisms found throughout temperate terrestrial forests, with species-specific associations with industrial air pollution. Metagenomic analysis of lichen samples requires robust nucleic acid extraction methodology, a process that is challenging due to the protective cortex layers, high polysaccharide content, and the vast diversity of the internal microbiome. Our method includes physical lysis through garnet bead beating, chemical lysis using a sodium dodecyl sulfate buffer, phenol:chloroform:isoamyl alcohol extraction, and ethanol precipitation. The method was tested on three different lichen samples from two distinct species and yielded metagenomic DNA suitable for sequencing and PCR amplification. This procedure addresses the issues associated with DNA extraction from lichen using common laboratory equipment and reagents without the utilization of liquid nitrogen. This paper presents a cost-effective and accessible DNA extraction method for obtaining high-quality genetic material from dried and preserved lichen specimens.