Tetraflagellochloris mauritanica gen. et sp. nov. (Chlorophyceae), a New Flagellated Alga from the Mauritanian Desert: Morphology, Ultrastructure, and Phylogenetic Framing

Abstract

Morphological, ultrastructural, and molecular-sequence data were used to assess the phylogenetic position of a tetraflagellate green alga isolated from soil samples of a saline dry basin near F'derick, Mauritania. This alga can grow as individual cells or form non-coenobial colonies of up to 12 individuals. It has a parietal chloroplast with an embedded pyrenoid covered by a starch sheath and traversed by single parallel thylakoids, and an eyespot located in a parietal position opposite to the flagellar insertion. Lipid vacuoles are present in the cytoplasm. Microspectroscopy indicated the presence of chlorophylls a and b, with lutein as the major carotenoid in the chloroplast, while the eyespot spectrum has a shape typical of green-algal eyespots. The cell has four flagella, two of them long and two considerably shorter. Sequence data from the 18S rRNA gene and ITS2 were obtained and compared with published sequences for green algae. Results from morphological and ultrastructural examinations and sequence analysis support the placement of this alga in the Chlorophyceae, as Tetraflagellochloris mauritanica L. Barsanti et A. Barsanti, gen. et sp. nov.

Chloroplast phylogenomic analysis of chlorophyte green algae identifies a novel lineage sister to the Sphaeropleales (Chlorophyceae)

“…The flagellar basal bodies of most chlorophycean green algae are displaced in a clockwise (CW, 1–7 o’clock) direction or are directly opposed (DO, 12–6 o’clock). In the Chlamydomonadales (often designated as the CW clade), biflagellates display a CW orientation of basal bodies, whereas quadriflagellates harbor distinct and more complex flagellar apparatus ultrastructures [ 7 , 8 ]. The vegetatively nonmotile unicellular or colonial taxa found in the Sphaeropleales (DO clade) produce zoospores with two flagella arranged in a DO configuration [ 9 ].…”

Morphology and phylogeny of a new wall‐less freshwater volvocalean flagellate, Hapalochloris nozakii gen. et sp. nov. (Volvocales, Chlorophyceae)

“…The more recently described Tetraflagellochloris is quadriflagellate (Barsanti et al. ), distinguishing it from Dunaliella and H. nozakii . However, many species, including type species of Dunaliella , inhabit saline or marine environments, and all non‐saline species of Dunaliella have two or no contractile vacuoles in each cell, distinguishing them from H. nozakii , which has four contractile vacuoles.…”

“…More recently, a sixth wall‐less genus, Tetraflagellochloris L.Barsanti & A.Barsanti, was described by Barsanti et al. (). Although the basal phylogenetic relationships of the Volvocales have yet to be completely resolved, Hafniomonas , Spermatozopsis , and Tetraflagellochloris are likely ancestral wall‐less lineages (Nozaki et al.…”

Swimming patterns of the quadriflagellate Tetraflagellochloris mauritanica (Chlamydomonadales, Chlorophyceae)

“…Cells were grown as nonclonal cultures in modified Johnson's medium at 24°C (dynamic viscosity 0.96 × 10 −3 · m −2 · s −1 ), and a 12:12 h L:D cycle (150 μmol photons · m −2 · s −1 ; Barsanti et al. ).…”

“…A nonstereotypical synchronization mode between flagella is present, with a pattern that does not fit any of the modes present in other Chlamydomonadales. MATERIAL (dynamic viscosity 0.96 9 10 À3 Á m À2 Á s À1 ), and a 12:12 h L:D cycle (150 lmol photons Á m À2 Á s À1 ; Barsanti et al 2013).…”