Cafeteria graefeae Schoenle and Arndt, 2020

Park, Dong Hyuk Jeong and Jong Soo, 2021, Characterizations of five heterotrophic nanoflagellates newly recorded in Korea, Journal of Species Research 10 (4), pp. 356-363 : 358-359

2. Cafeteria graefeae Schoenle and Arndt, 2020

( Fig. 1C, D )

Isolation. Dong Hyuk Jeong and Jong Soo Park performed specimen collection on 13 October 2020, from Ulleungdo (37°28′49.06″N, 130°54″31.00″E), Korea. Temperature: 20.2℃, Salinity: 32.4 PSU, pH: 8.3 .

Morphological description. The live strain UL001 was a biflagellate form and D- and glove-shaped ( Fig. 1C, D ). The average length and width of the cell body were 4.5±0.6 μm (mean±STD) and 3.7±0.5 μm, respectively (n = 20). A slightly curved channel was observed on the dorsal side of the cell ( Fig. 1C ). Sometimes, contractile and food vacuoles showed within the cell body ( Fig. 1C ). The average length of the anterior and posterior flagellum was 5.0±0.7 μm and 3.8±0.7 μm, respectively (n = 20). When cells swam, the anterior flagellum was directed forwards, and the posterior flagellum trailed posteriorly. Also, when the posterior flagellum was attached to a substrate, cells showed a jerking motion, whereas the anterior flagellum beat for feeding.

Molecular phylogeny. The partial 18S rDNA sequence of the strain UL001 was 823 bp in length (G + C content: 46%). The 18S rDNA sequence of strain UL001 was 99.64% (822/825 bp) identical to that of Cafeteria graefeae strain HFCC33 (accession number; MN315607, 1,629 bp long, G + C content: 49%), suggesting identical species. The ML tree revealed that strain UL001 and Cafeteria graefeae formed a highly supported value clade (ML: 98%) and a posterior probability of 1 ( Fig. 1E ).

Remarks. The cell shape of the strain UL001 is very similar to a typical genus Cafeteria . The strain UL001 had a slightly curved channel, which was very similar to C. biegae ( Schoenle et al., 2020) . However, the original C. biegae (2.6-4.4 μm long and 2.1-3.4 μm wide) was smaller than the strain UL001, while the two flagella lengths of C. biegae (5.0-9.7 μm) was longer than the strain UL001. Furthermore, it seems that the length of the posterior flagellum of the strain UL001 was the shortest in Cafeteria groups. This character is similar to the original C. graefeae . However, the length of the anterior flagellum of the strain UL001 was longer than that of the original C. graefeae (2.3-5.5 μm long). It seems that the strain UL001 was identical to C. graefeae strain HFCC33 and HFCC772 based on the molecular phylogenetic analyses. Thus, the strain UL001 is proposed to be a member of Cafeteria graefeae strains.

Habitat. Surface water of coastal areas.

Specimen deposition. National Institute of Biological Resources, Korea (KPZXPR0000000017-KPZXPR0000 000021).

Identifiers. Dong Hyuk Jeong and Jong Soo Park.

Figures

Fig. 1. (A, B) General light micrographs and sketch of Cafeteria burkhardae strain PH003. AF: anterior flagellum, PF: posterior flagellum, CV: contractile vacuole, FV: food vacuole, scale bar=5 μm. Arrowhead represents curved channel.All micrographs are differential interference contrast (DIC) images. (C, D) General light micrographs and sketch of Cafeteria graefeae strain UL001. (E) Maximum likelihood phylogenetic tree inferred from the 18S rDNA sequences of Cafeteria(genus) species including Cafeteria graefeae strain UL001 and Cafeteria burkhardae strain PH003 and outgroup (Paramonas globosa strain ATCC 50531 and Nerada mexicana strain ATCC 50535). Bootstrap support values (>70%) are shown at the nodes. Solid circles indicate a Bayesian posterior probability of 1 (posterior probability<0.95 not shown).