Cartusia fontana (Hansgirg) Mai, Johansen et Pietrasiak, 2018

Mai, Truc, Johansen, Jeffrey R., Pietrasiak, Nicole, Bohunická, Markéta & Martin, Michael P., 2018, Revision of the Synechococcales (Cyanobacteria) through recognition of four families including Oculatellaceae fam. nov. and Trichocoleaceae fam. nov. and six new genera containing 14 species, Phytotaxa 365 (1), pp. 1-59 : 38-40

Cartusia fontana (Hansgirg) Mai, Johansen et Pietrasiak comb. nov.

Basionym:— Lyngbya fontana Hansgirg 1892 , Archiv für die naturwissenschaftliche Landesdurchforschung von Böhmen 8: 85.

Later Synonym:— Leptolyngbya fontana (Hansgirg) Komárek in Anagnostidis 2001, Preslia , Praha 73: 374.

Description of epitype:— Colony bright blue-green, becoming olive-green with age, fasciculated. Filaments straight or flexuous, sometimes with more than one trichome in a common sheath ( Fig. 19a ), sometimes forming fascicles of trichomes, without false branching, with variations in width between young and mature filaments ( Figs. 19a, c ), up to 5.4 μm wide in filaments with sheath. Sheath colorless, firm, usually thin, but occasionally widened ( Fig. 19b–d ), up to 1.6 μm wide. Trichomes not or slightly constricted at crosswalls, with necredia ( Fig. 19b, d ), with meristematic zones often occurring in wider trichomes ( Figs. 19b–c ), young trichomes narrower, 1.8–2.7 μm wide, mature trichomes larger, 2.7–3.5 μm wide. End cells rounded. Cells in young trichomes isodiametric or slightly shorter than wide, 1.3–2.0 μm long, in mature trichomes shorter than wide, 1.0–1.3 μm long, with one large single central granule commonly visible in cells.

D1-D1’ helix 107 nucleotides long, with a basal 3’ unilateral bulge of 8 nucleotides (5’-CAUCCCAA-3’), and multiple side branches from two large internal loops ( Fig. 6m ), a length and structure unique within the Oculatellaceae ( Fig. 6m ). Box B helix 60 nucleotides long, with two internal loops at positions 5/55–56 and 15–19/42–46, and one unpaired adenine residue at position 9 on the 5’ strand ( Fig. 7l ). V2 helix nonexistent. V3 helix not identified due to short end sequence.

Collection locality: ― Slovakia: National Park Slovak Paradise, ruins of the Cartusian Monaster, collected in 1999 by Łubomir Kovácík. Found in pale green biofilm on wall at interior of church.

Epitype:— BRY37780!, Monte L. Bean Museum, Provo, Utah.

Reference strain: ―Kovacik 1999/1, Algal Culture Collection at John Carroll University, Cleveland, USA.

Taxonomic notes:— The strictly subaerophytic condition where the species was found limited our comparison to only subaerophytic species. Three morphospecies of Leptolyngbya were similar to our strain: L. fontana (Hansgirg 1892: 85) Komárek in Anagnostidis (2001: 374), Leptolyngbya cataractarum (Rabenhorst 1853 ex Hansgirg 1885: 292) Komárek (2001: 374) , and L. fallax (Hansgirg ex Forti 1907: 185) Komárek (2001: 374) . L. fontana was a perfect match to our strain, matching in every regard to the morphological and ecological characteristics. Furthermore, L. fontana was described from mountainous regions of the Czech Republic, a close geographical match to National Park Slovak Paradise. L. fontana was incompletely described (no illustration, few details on morphology), but given the absence of any variance in characters, we feel that it is good to use this species epithet for our strain. The other two species are also not illustrated, but differ morphologically in terms of sheath characteristics and cell morphology.

Compared to other species belonging to Oculatellaceae , morphology of C. fontana is similar to Drouetiella fasciculata and several species of Pegethrix ( P. bostrychoides , P. convolute and P. indistincta ). C. fontana was observed to have meristematic zones of cell division, which were absent in D. fasciculata , as well as cells shorter than wide. In comparison to Pegethrix species, C. fontana does not form pseudobranches or nodules. Furthermore, the two genera are separated by their position in the 16S rRNA phylogeny ( Fig. 2 ), and the distinctive sequences and shape of the secondary structures of ITS regions. The D1-D1’ helix in C. fontana is distinct from the typical structure found in the vast majority of Synechococcales , with several small helices branching off from large internal loop structures ( Fig. 6 m ). This structure was probably formed after a large insertion and several mutations starting from position 14–41/54–86, as the basal structure and sequence at position 1–13/87–107, as well as of the terminal loop and helix (42–45/50–53) in C. fontana was observed to be typical for the Synechococcales D1-D1’ helix. Box B helix structure of the species is also unique in length, much longer compared to other species described in this family ( Table 6).

Cartusia is in a clade with two other taxa ( Fig. 2 ). “ Marsacia ferruginose ” JSC-1 is an undescribed genus and species ( Brown et al. 2010) based on a strain from thermal springs in Yellowstone National Park and is 97.2% similar in 16S rRNA sequence. It is possible that this undescribed taxon could be described as another species of Cartusia . It currently is a nomen nuda , without description or a type specimen designated. Elainella saxicola Jahodářová et al. (2017: 4) was very recently published and is 97.0% similar in 16S rRNA sequence. Elainella differs morphologically in the repeated false branching and the restriction of only a single trichome per sheath. An uncultured cyanobacterium, NCBI accession JX127186 is 99.4% similar in 16S rRNA sequence. This is almost surely a Cartusia species, possibly C. fontana , sequenced in an environmental sample from building stone in Germany. Unfortunately, we do not have a strain of this material. Of these sequences, only “Marsacia ferruginose” JSC-1 has ITS sequence available, and the region is different in structure and lengths of domains.

Figures

FIGURE 2. 16S rRNA Bayesian Inference analysis of the filamentous group of Synechococcales cyanobacteria, showing Oculatellaceae. Black polygons represent genera that have been validly described or are named in provision (e.g., “Trichotorquatus”), with length corresponding to the distance from the most basal OTU to the most diverged OTU of the genus. Posterior probabilities for the BI analysis are given above the nodes. Taxa which we consider to be incorrectly named in NCBI or requiring revisionary work are in quotation marks.

FIGURE 6. D1-D1’ stems of species described in Oculatellaceae.The stem structures of genera described previously in other publications (Oculatella, Thermoleptolyngbya, Timaviella) or in publications under provision (Trichotorquatus) are not shown here.

FIGURE 7. Box B helices of species described in Oculatellaceae. The structures of genera described previously in other publications (Oculatella, Thermoleptolyngbya, Timaviella) or in publications under provision (Trichotorquatus) are not shown here.

FIGURE 19. Cartusia fontana. A. Fasicle of trichomes within one common sheath. B. Expanded and lamellate sheath. C. Variation in width between young and mature trichome, with cell division in meristematic zones. D. Meristematic zone of cell division in mature trichomes, with necridia; necridia in both young and senescing trichomes, filaments in mature trichomes occasionally with thick, slightly layered sheath. Scale bar 10μm in 1000X magnification.