Alkalinema aff. pantanalense Vaz et al. (2015: 305)

Cunha De Oliveira, Elane D., Da Cunha, Alan C., Da Silva, Natalina B., Castelo-Branco, Raquel, Morais, João, Schneider, Maria Paula C., Faustino, Silvia M. M., Ramos, Vitor & Vasconcelos, Vitor, 2019, Morphological and molecular characterization of cyanobacterial isolates from the mouth of the Amazon River, Phytotaxa 387 (4), pp. 269-288 : 276

Alkalinema aff. pantanalense Vaz et al. (2015: 305) ( Fig 2A )

Strains:— LEGE 15484 (MF629801)

Description:— The cultures are pale to bright blue-green, composed either of free-floating trichomes or of mats that float in the culture flask. Trichomes are short, straight, immotile, deeply constricted with a hyaline, thin, diffluent mucilage and without necridia. The cells are longer (1.2–4.0 μm) than wide (1.7–2.9 μm). Trichomes with round or narrow apical cells. The cell content is homogeneous and pale blue-green and lacks gas vesicles.

Phylogeny and polyphasic identification:— The 16S rRNA gene sequence of the isolate LEGE15484 shares more than 99% identity with sequences from four Alkalinema spp. Vaz et al. (2015: 302) strains, including A. pantanalense CENA 531 and CENA 529 ( Table 4 and Table S1). Indeed, as illustrated in Table 4, the sequence of A. pantanalense LEGE 15484 shares a very high similarity value with that of the type strain A. pantanalense CENA 528 (99.6%) and with Alkalinema sp. CMAA 1554 (99.8%). All those strains form a strong cluster ( Fig. 3 ), with node support values of 100% (ML and MP) or 1.00 (BI). Even though LEGE 15484 seems to be more closely related to two Alkalinema sp. CMAA strains, the phylogenetic distance between all the strains constituting the clade is minimal ( Fig. 3 ). The polyphasic evaluation of LEGE 15484 allowed the identification of this strain as Alkalinema aff. pantanalense ( Vaz et al. 2015) .

Figures

FIGURE 2 Microphotographs of the Amazonian cyanobacterial strains: A) Alkalinema aff. pantanalense LEGE 15484, B) Limnothrix cf. planctonica LEGE 15485, C) Leptolyngbya boryana LEGE 15486, D) Cephalothrix lacustris LEGE 15487, E) Phormidium sp. LEGE 15488, F) Pseudanabaena cf. galeata LEGE 15489, G) P. cf. galeata LEGE 15490, H) P. cf. galeata LEGE 15491, I) Cephalothrix lacustris LEGE 15492, J) C. lacustris LEGE 15493; K) unidentified Nostocales LEGE 15494, L) unidentified Nostocales LEGE 15495, M) unidentified Nostocales LEGE 15496, and N) Limnothrix cf. planctonica LEGE 15497.

FIGURE 3. ML phylogenetic tree based on 16S rRNA gene sequences showing the placement of the Amazonian cyanobacterial strains (in bold). Bootstrap values>70% or Posterior Probabilities>0.90 are indicated below the clade nodes (ML/BI/MP). Each strain sequence is identified by its accession number. The tree was rooted with the outgroup Chloroflexus aurantiacus J-10-fl (NR_074263), which was pruned from the tree for clarity. (T)refers to type strains according to CyanoType (Ramos et al. 2017).