Molecular taxonomy of Dunaliella (Chlorophyceae), with a special focus on D. salina: ITS2 sequences revisited with an extensive geographical sampling

Abstract

We used an ITS2 primary and secondary structure and Compensatory Base Changes (CBCs) analyses on new French and Spanish Dunallela salina strains to investigate their phylogenetic position and taxonomic status within the genus Dunaliella. Our analyses show a great diversity within D. salina (with only some clades not statistically supported) and reveal considerable genetic diversity and structure within Dunaliella, although the CBC analysis did not bolster the existence of different biological groups within this taxon. The ITS2 sequences of the new Spanish and French D. salina strains were very similar except for two of them: ITC5105 "Janubio" from Spain and ITC5119 from France. Although the Spanish one had a unique ITS2 sequence profile and the phylogenetic tree indicates that this strain can represent a new species, this hypothesis was not confirmed by CBCs, and clarification of its taxonomic status requires further investigation with new data. Overall, the use of CBCs to define species boundaries within Dunaliella was not conclusive in some cases, and the ITS2 region does not contain a geographical signal overall.

Assembling the challenging puzzle of algal biodiversity: species delimitation within the genus Asterochloris (Trebouxiophyceae, Chlorophyta)

“…, , Assunção et al. ). In particular, it was demonstrated that the CBCs are not diagnostic at the species level and that even genera, families, and orders of green algae can lack CBCs in such regions (Caisová et al.…”

Phylogenetic analysis of Dunaliella (Chlorophyta) emphasizing new benthic and supralittoral isolates from Great Salt Lake

“…Dunaliella parva UTEX 1983, which aligns in the D. viridis clade (Assunção et al. 2012a), falls within a diverse group of Chlorophyceae containing polyphyletic sarcinoid taxa (Watanabe et al. ), thus it is not surprising that this morphology would be common in Dunaliella .…”

Flagellate Green Algae

“…Two contractile vacuoles are located near the base of the flagella except for the saline and marine species, which lack contractile vacuoles. Saline and marine species, including type species (D. salina), are related to Dunaliellinia, but a freshwater species (D. lateralis) is related to Oogamochlamydinia (Nakada et al, 2008a;Assunção et al, 2012). A pyrenoid is absent or present.…”