Exploring the Genus Peltigera: A Metagenomic Perspective on Lichen Biology

Many fungi engage in symbiotic relationships that span from pathogenic and commensalistic to mutualistic interactions. Lichens are one of the most successful examples of complex mutualistic symbiotic systems, comprising an association predominantly between fungal (mycobiont) and one or more photosynthetic organism(s) (photobiont), including green algae and/or cyanobacteria. Additionally, diverse fungal and bacterial communities occur in the lichen association. Lichens can serve as long term air pollution indicators and 50% of lichen species exhibit antibiotic properties, with many metabolites holding promise as potential antibiotic agent.

The genus Peltigera is widespread across several continents and serves as a representative of cyanolichens, through its symbiotic association with a cyanobacterial photobiont of the genus Nostoc. Although lichens have been studied for at least 200 years, they remain poorly understood, despite the increasing interest in their properties. This is largely reflected in the absence in reliable genomic reference data until recently, as lichen genomic characterization is taking off.

To address this issue, here we present several metagenome assemblies of the lichen genus Peltigera found in North-Rhine Westphalia, Germany. These genomic assemblies of both photo- and mycobiont were derived using advanced long-read sequencing methodologies. Our analysis shows that the mycobiont genomes are near complete in terms of gene content as measured by BUSCO analysis. Moreover, our metagenomic analyses uncovered additional organisms associated within the lichen community, which will be reported.

Our study offers the possibility to gain new insights into the intricate genomic characteristics of lichens, advancing our understanding of these remarkable organisms and make a significant contribution to the upcoming golden age of lichen research.

Keywords: Lichen, Metagenome, Symbiosis, Oxford Nanopore Sequencing