Molecular phylogeny and symbiotic selectivity of the green algal genus Dictyochloropsis s.l. (Trebouxiophyceae): a polyphyletic and widespread group forming photobiont-mediated guilds in the lichen family Lobariaceae.
Dictyochloropsis s.l. is an ecologically important, common but little-studied genus of green algae. Here, we examined the diversity and host selectivity of algae attributed to this genus at both species-to-species and species-to-community levels. We conducted a molecular investigation of 15 cultured strains and several lichen photobionts, using 18S rRNA, rbcL and ITS sequence data. We further used seven alga-specific microsatellite markers to study algal sharing among fungi of the family Lobariaceae in two populations in Madeira and Taiwan (454 lichens). We found that the genus Dictyochloropsis s.l. is polyphyletic. Dictyochloropsis clade 1 comprises only free-living algae whereas Dictyochloropsis clade 2 includes lichenized algae as well as free-living algae. Fungal selectivity towards algae belonging to Dictyochloropsis clade 2 is high. Selectivity varies geographically, with photobionts being restricted to a single region. Finally, we showed that Dictyochloropsis clade 2 individuals are shared among different fungal hosts in communities of lichens of the Lobariaceae. As for other green algal lineages, there is a high amount of cryptic diversity in Dictyochloropsis. Furthermore, co-evolution between Dictyochloropsis clade 2 algae and representatives of the Lobariaceae is manifested at the community level, with several unrelated fungal species being horizontally connected by shared photobiont clones.
Biodiversity and Conservation Biology, Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland.
Francesco
F
Dal Grande
Department of Lichenology and Bryology, Botanische Staatssammlung München, 80638, München, Germany.|GeoBio-Center, Ludwig-Maximilians Universität München, Richard-Wagner-Str. 10, D-80333, München, Germany.
Andreas
A
Beck
Biodiversity and Conservation Biology, Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland.
Carolina
C
Cornejo
Biodiversity and Conservation Biology, Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland.|Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe Universität, Max-von-Laue-Str. 13, D-60438, Frankfurt, Germany.
Garima
G
Singh
Biodiversity and Conservation Biology, Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland.
Saran
S
Cheenacharoen
Committee on Evolutionary Biology, University of Chicago, 1025 E. 57th Street, Chicago, IL, 60637, USA.|Department of Botany, The Field Museum, 1400 S. Lake Shore Drive, Chicago, IL, 60605, USA.
Matthew P
MP
Nelsen
Biodiversity and Conservation Biology, Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland.
Christoph
C
Scheidegger
D001203:Ascomycota; D005075:Biological Evolution; D000460:Chlorophyta / Q000235:genetics*; D048028:DNA, Algal / Q000032:analysis*; D021903:DNA, Ribosomal Spacer; D005060:Europe; D005658:Fungi; D014644:Genetic Variation; D008011:Lichens / Q000235:genetics*; D018895:Microsatellite Repeats; D010788:Photosynthesis; D010802:Phylogeny; D012335:RNA, Ribosomal; D017422:Sequence Analysis, DNA; D013559:Symbiosis; D013624:Taiwan
D048028:DNA, Algal; D021903:DNA, Ribosomal Spacer; D012335:RNA, Ribosomal
18S; Dictyochloropsis; Lobariaceae; internal transcribed spacer (ITS); lichen; microsatellite; photobiont; rbcL