title: Microclimatic differentiation of gene pools in the Lobaria pulmonaria symbiosis in a primeval forest landscape.
abstract: Population genetics of the tree-colonizing lichen Lobaria pulmonaria were studied in the largest primeval beech forest of Europe, covering 10 000 ha. During an intensive survey of the area, we collected 1522 thallus fragments originating from 483 trees, which were genotyped with eight mycobiont- and 14 photobiont-specific microsatellite markers. The mycobiont and photobiont of L. pulmonaria were found to consist of two distinct gene pools, which are co-existing within small areas of 3-180 ha in a homogeneous beech forest. The small-scale distribution pattern of the symbiotic gene pools show habitat partitioning of lineages associated with either floodplains or mountain forests. Using approximate Bayesian computation (ABC), we dated the divergence of the two fungal gene pools of L. pulmonaria as the Early Pleistocene. Both fungal gene pools survived the Pleistocene glacial cycles in the Carpathians, although possibly in climatically different refugia. Fungal diversification prior to these cycles and the selection of photobionts with different altitudinal distributions explain the current sympatric, but ecologically differentiated habitat partitioning of L. pulmonaria. In addition, the habitat preferences of the mycobiont are determined by other factors and are rather independent of those of the photobiont at the landscape level. The distinct gene pools should be considered evolutionarily significant units and deserve specific conservation priorities in the future, for example gene pool A, which is a Pliocene relict.
authors.affiliation: Lichenology & Bryology, M. G. Kholodny Institute of Botany, Tereschenkivska str. 2, 01601, Kyiv, Ukraine; Botany, Kherson State University, 40 Rokiv Zhovtnya str. 27, 73000, Kherson, Ukraine.
authors.forename: Olga
authors.initials: O
authors.lastname: Nadyeina
authors.forename: Lyudmyla
authors.initials: L
authors.lastname: Dymytrova
authors.forename: Anna
authors.initials: A
authors.lastname: Naumovych
authors.forename: Sergyi
authors.initials: S
authors.lastname: Postoyalkin
authors.forename: Silke
authors.initials: S
authors.lastname: Werth
authors.forename: Saran
authors.initials: S
authors.lastname: Cheenacharoen
authors.forename: Christoph
authors.initials: C
authors.lastname: Scheidegger
mesh_terms: D000531:Altitude; D001499:Bayes Theorem; D005075:Biological Evolution; D000458:Cyanobacteria / Q000235:genetics; D029964:Fagus; D065928:Forests; D005658:Fungi / Q000235:genetics; D005788:Gene Pool; D014644:Genetic Variation; D008011:Lichens / Q000235:genetics*; D008834:Microclimate; D018895:Microsatellite Repeats; D008957:Models, Genetic; D017422:Sequence Analysis, DNA; D013559:Symbiosis / Q000235:genetics*; D014455:Ukraine
keywords: Dictyochloropsis reticulata; altitude; approximate Bayesian computation; epiphytic lichen; mycobiont; population genetics