Terrestrial green algae show higher tolerance to dehydration than do their aquatic sister-species: Raw data and analysis files

Diverse algae possess the ability to recover from extreme desiccation
without forming specialized resting structures. Green algal genera such
as Tetradesmus (Sphaeropleales, Chlorophyceae) contain
temperate terrestrial, desert, and aquatic species, providing an
opportunity to compare physiological traits associated with the transition
to land in closely related taxa. We subjected six species from distinct
habitats to three dehydration treatments varying in relative humidity (RH
5%, 65%, 80%) followed by short- and long-term rehydration. We tested the
capacity of the algae to recover from dehydration using the effective
quantum yield of photosystem II as a proxy for physiological activity. The
degree of recovery was dependent both on the habitat of origin and the
dehydration scenario, with terrestrial, but not aquatic species,
recovering from dehydration. Distinct strains of each species responded
similarly to dehydration and rehydration, with the exception of one
aquatic strain that recovered from the mildest dehydration treatment. Cell
ultrastructure was uniformly maintained in both aquatic and desert species
during dehydration and rehydration, but staining with an amphiphilic
styryl dye indicated damage to the plasma membrane from
osmotically-induced water loss in the aquatic species. These analyses
demonstrate that terrestrial Tetradesmus possess a
vegetative desiccation tolerance phenotype, making these species ideal for
comparative omics studies.