Widespread green algae Chlorella and Stichococcus exhibit polar-temperate and tropical-temperate biogeography.
Chlorella and Stichococcus are morphologically simple airborne microalgae, omnipresent in terrestrial and aquatic habitats. The minute cell size and resistance against environmental stress facilitate their long-distance dispersal. However, the actual distribution of Chlorella- and Stichococcus-like species has so far been inferred only from ambiguous morphology-based evidence. Here we contribute a phylogenetic analysis of an expanded SSU and ITS2 rDNA sequence dataset representing Chlorella- and Stichococcus-like species from terrestrial habitats of polar, temperate and tropical regions. We aim to uncover biogeographical patterns at low taxonomic levels. We found that psychrotolerant strains of Chlorella and Stichococcus are closely related with strains originating from the temperate zone. Species closely related to Chlorella vulgaris and Muriella terrestris, and recovered from extreme terrestrial environments of polar regions and hot deserts, are particularly widespread. Stichococcus strains from the temperate zone, with their closest relatives in the tropics, differ from strains with the closest relatives being from the polar regions. Our data suggest that terrestrial Chlorella and Stichococcus might be capable of intercontinental dispersal; however, their actual distributions exhibit biogeographical patterns.
Experimental Phycology and Culture Collection of Algae (SAG), University of Göttingen, 37073 Göttingen, Germany Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Göttingen, 37073 Göttingen, Germany lhodac@uni-goettingen.de.
Ladislav
L
Hodač
Experimental Phycology and Culture Collection of Algae (SAG), University of Göttingen, 37073 Göttingen, Germany.
Christine
C
Hallmann
Experimental Phycology and Culture Collection of Algae (SAG), University of Göttingen, 37073 Göttingen, Germany.
Karolin
K
Spitzer
Centre for Polar Ecology, University of South Bohemia, 37005 České Budějovice, Czech Republic Institute of Botany, Phycology Centrum, Academy of Sciences of the Czech Republic, 37982 Třeboň, Czech Republic.
Josef
J
Elster
Experimental Phycology and Culture Collection of Algae (SAG), University of Göttingen, 37073 Göttingen, Germany.
Fabian
F
Faßhauer
Department of Forest Botany, University of Göttingen, 37077 Göttingen, Germany.
Nicole
N
Brinkmann
Experimental Phycology and Culture Collection of Algae (SAG), University of Göttingen, 37073 Göttingen, Germany.
Daniela
D
Lepka
Experimental Phycology and Culture Collection of Algae (SAG), University of Göttingen, 37073 Göttingen, Germany.
Vaibhav
V
Diwan
Experimental Phycology and Culture Collection of Algae (SAG), University of Göttingen, 37073 Göttingen, Germany.
Thomas
T
Friedl
D000864:Antarctic Regions; D001110:Arctic Regions; D018441:Biofilms / Q000145:classification; D048408:Chlorella vulgaris / Q000145:classification* / Q000235:genetics / Q000254:growth & development*; D000460:Chlorophyta / Q000145:classification* / Q000235:genetics / Q000254:growth & development*; D003081:Cold Climate; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D017753:Ecosystem; D010802:Phylogeny; D058974:Phylogeography
D021903:DNA, Ribosomal Spacer
Chlorella; SSU/ITS2; Stichococcus; biogeography; green algae; polar strains