Format: ORAL

Edgar L.Y. Wong1,2, Henrique Valim1,2, Imke Schmitt1,2,3

1 Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany 2 LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Frankfurt am Main, Germany 3 Goethe University Frankfurt, Institute of Ecology, Evolution and Diversity, Frankfurt am Main, Germany

Lichens are known to withstand extreme environmental heterogeneity such as seasonal and diurnal temperature differences, and regular hydration-desiccation cycles. Many species also have a wide distribution range across multiple climate zones. However, little is known about the mechanisms and genomic basis of environmental adaptation in lichen-forming fungi. In this talk, we will present genomic work on Umbilicaria species, which are obligate lichen-forming fungi that grow on rocks. Using samples collected (1) from different mountainous gradients in Europe and USA; (2) from low-elevation Mediterranean zone to high-elevation cold temperate zones; and (3) with different reproductive modes (asexual or sexual), we compared patterns of genomic differentiation and signatures of adaptation to climate niches. Specifically, we ask: (1) How do population genomic features of different species vary along replicated elevational gradients? (2) Which genomic regions are associated with the climate niche transition from the Mediterranean to the cold temperate zone? (3) Which bioclimatic variables are important predictors of population genomic change at the boundary between the two climate zones? (4) Do species with contrasting reproductive modes show different genomic features? Some of our results include clear genomic differentiation between samples collected from the Mediterranean versus the cold temperate climate niche. Cline analyses showed one bioclimatic variable (winter temperature) as a strong selective pressure that led to allele fixation. Coupled with genomic scans for selective sweeps and subsequent gene ontology analyses, we will present strong evidence that this bioclimatic variable is a major driver of genomic differentiation and hence adaptation. Overall, our results enrich our knowledge of fungal genomic functions related to climatic niche, population genomics, and the response of long-lived, sessile species to environmental heterogeneity.