A new study by CRI Research Fellows Bastian Greshake Tzovaras and his collaborators in Mainz, Frankfurt and Leiden was published in the journal Genome Biology & Evolution! The paper lays some groundwork for further genomic studies of lichens.
Lichens are symbiotic organisms that consist of one or multiple fungal species that live in a close symbiosis with either green algae or photosynthesizing bacteria. This symbiosis is so successful that it is not only evolutionary old – with first lichen symbioses appearing at least 300 million years ago – but also happened independently at many different points in time. This turns lichens into interesting models to study how the individual symbiont genomes evolve in response to joining a symbiosis.
This potential could so far not be fully realized, as sequencing the genomes of lichens is rendered complex by various factors: Lichens grow notoriously slowly, making it hard to get enough biomaterial. Furthermore, in many cases it so far has been impossible to grow the individual symbionts outside their symbiosis. Due to these factors lichens are often sequenced as a whole, leading to highly diverse and complex sequencing data sets, which usually render the creation of high-quality reconstructions impossible. In this new study, the authors demonstrate a workflow that allows for such high-quality reconstructions of whole lichen genomes, making so-far understudied lichens available for further genome evolution work. In the future, this work will hopefully help to unleash the full potential of lichens as model organisms.
The graphs included here shows the individual symbiont genomes of the lichen Umbilicaria pustulata and the varying proportions to which they contribute to the lichen symbiosis.
You can find the full text of the study here.