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European phylogeography of the epiphytic lichen fungus L obaria pulmonaria and its green algal symbiont
Author(s) -
Widmer Ivo,
Dal Grande Francesco,
Excoffier Laurent,
Holderegger Rolf,
Keller Christine,
Mikryukov Vladimir S.,
Scheidegger Christoph
Publication year - 2012
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.12051
Subject(s) - biology , epiphyte , lichen , phylogeography , fungus , ecology , botany , phylogenetics , gene , biochemistry
In lichen symbiosis, fungal and algal partners form close associations, often codispersed by vegetative propagules. Due to the particular interdependence, processes such as colonization, dispersal or genetic drift are expected to result in congruent patterns of genetic structure in the symbionts. To study the population structure of an obligate symbiotic system in E urope, we genotyped the fungal and algal symbionts of the epiphytic lichen L obaria pulmonaria at eight and seven microsatellite loci, respectively, and analysed about 4300 L . pulmonaria thalli from 142 populations from the species' E uropean distribution range. Based on a centroid approach, which localizes centres of genetic differentiation with a high frequency of geographically restricted alleles, we identified the South I taly– B alkan region as the primary glacial refugial area of the lichen symbiosis. Procrustean rotation analysis and a distance congruence test between the fungal and algal population graphs indicated general concordance between the phylogeographies of the symbionts. The incongruent patterns found in areas of postglacial recolonization may show the presence of an additional refugial area for the fungal symbiont, and the impact that horizontal photobiont transmission and different mutation rates of the symbionts have on their genotypic associations at a continental scale.