title: Ecological Specialization of Two Photobiont-Specific Maritime Cyanolichen Species of the Genus Lichina.
abstract: All fungi in the class Lichinomycetes are lichen-forming and exclusively associate with cyanobacteria. Two closely related maritime species of the genus Lichina (L. confinis and L. pygmaea) show similar distribution ranges in the Northeast Atlantic, commonly co-occurring at the same rocky shores but occupying different littoral zones. By means of 16S rRNA and phycocyanin operon markers we studied a) the phylogenetic relationships of cyanobionts associated with these species, b) the match of divergence times between both symbionts, and c) whether Lichina species differ in photobiont association and in how geography and ecology affect selectivity. The cyanobionts studied are closely related to both marine and freshwater strains of the genus Rivularia. We found evidence of a high specificity to particular cyanobiont lineages in both species: Lichina pygmaea and L. confinis incorporate specific lineages of Rivularia that do not overlap at the haplotype nor the OTU levels. Dating divergences of the fungal and cyanobacterial partners revealed an asynchronous origin of both lineages. Within each fungal species, selectivity varied across the studied area, influenced by environmental conditions (both atmospheric and marine), although patterns were highly correlated between both lichen taxa. Ecological speciation due to the differential association of photobionts to each littoral zone is suspected to have occurred in marine Lichina.
authors.affiliation: Integrative Freshwater Ecology Group, Center of Advanced Studies of Blanes, Spanish Council for Research (CEAB-CSIC), Blanes, Girona, Spain.
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Ortiz-Álvarez
authors.affiliation: Department of Biogeochemistry and Microbial Ecology, Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain.
authors.forename: Asunción
authors.initials: A
authors.lastname: de Los Ríos
authors.affiliation: Institute of Botany, Karl-Franzens-Universität Graz, A-8010, Graz, Austria.
authors.forename: Fernando
authors.initials: F
authors.lastname: Fernández-Mendoza
authors.affiliation: Biosfera Consultoría Medioambiental, Candamo, 5 Bajos, 33012, Oviedo, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Torralba-Burrial
authors.affiliation: Department of Biogeochemistry and Microbial Ecology, Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Pérez-Ortega
mesh_terms: D001203:Ascomycota / Q000145:classification / Q000235:genetics*; D001483:Base Sequence; D001499:Bayes Theorem; D000458:Cyanobacteria / Q000145:classification / Q000235:genetics*; D017753:Ecosystem; D005618:Fresh Water; D049810:Genetic Speciation; D006239:Haplotypes; D008011:Lichens / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D009876:Operon; D010798:Phycocyanin / Q000096:biosynthesis; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012623:Seawater; D013030:Spain; D013559:Symbiosis / Q000502:physiology
chemical_list: D012336:RNA, Ribosomal, 16S; D010798:Phycocyanin