Search Results (3)

Cyanobacteria, known for their remarkable adaptability, are a diverse group of oxygenic photoautotrophic organisms found in various habitats worldwide. While their presence in aquatic ecosystems has been extensively studied, research on terrestrial and aerophytic cyanobacteria remains relatively limited, particularly concerning their taxonomic diversity and molecular characteristics. In this study, utilizing morphological and molecular data derived from the 16S rRNA gene, we unveiled and described two new species of filamentous cyanobacteria growing epiphytically on Laurus novocanariensis in the laurel forest (laurisilva) of the Canary Islands. The first species, Brasilonema novocanariensis sp. nov., belongs to a genus of aerophytic and subaerophytic nostocalean cyanobacteria. The second, Rhizonema melkonianarum sp. nov., belongs to the genus Rhizonema. The discovery of a new species of Brasilonema from the Canary Islands related to species initially found on the opposite side of the Atlantic Ocean, and recently in Asia, Europe, and Portugal, raises questions about their dispersal mechanisms, whether through natural means or human-mediated processes, prompting the need for future studies to investigate these propagation patterns. In the case of Rhizonema melkonianarum sp. nov., the transition from adapting to a basidiolichen host to inhabiting the phyllosphere of angiosperms raises ecological and evolutionary adaptation questions regarding cyanobacterial adaptability and their ecological roles in diverse habitats. This research expands our understanding of the diversity and geographic distribution of these terrestrial phyllosphere-associated cyanobacteria. Full article

Six strains of subaerial cyanobacteria were isolated from a Gomso saltern in the Republic of Korea, all of which were studied using morphological and molecular traits. Trichotorquatus salinus sp. nov. was studied using a light microscope (LM), transmission electron microscope (TEM), 16S rRNA, 16S–23S ITS region, and ecological data. T. salinus is a thin and simple filament with a false branch and a firm collar sheath. The phylogenetic analyses of 16S rRNA revealed that Trichotorquatus formed a monophyletic lineage and the strains of T. salinus formed a distinct clade among the species in the genus Trichotorquatus. In the statistical analysis, the inter-species genetic distance of the five species of Trichotorquatus, including T. salinus, is shown to be greater than the distance of the previously reported species of Trichotorquatus. Additionally, 16S–23S ITS gene sequences between T. salinus and four species of Trichotorquatus showed dissimilarities of 55.3–59.4%. In the secondary structure of 16S–23S ITS region (type 2 operon), D1–D1′, Box-B, and V3 helix of T. salinus were different from the other taxa in the genus Trichotorquatus. These results demonstrate that T. salinus sp. nov. has unique morphological, ecological, and molecular traits. Therefore, we propose that T. salinus sp. nov. is a novel species belonging to the genus Trichotorquatus. Full article

Thin filamentous cyanobacteria isolated from three collection sites in the Republic of Korea were suggested as three new species belonging to the genus Plectolyngbya, mainly according to their molecular characteristics. The species of Plectolyngbya, including the type species of P. hodgsonii, were cryptic species that were difficult to distinguish morphologically from each other, and had appeared in ecologically diverse habitats. P. terrestris and P. koreana were subaerophytes collected from certain black spots and soils between stone walls in Seoul, Republic of Korea. In addition, hypersaline species collected from a saltern, P. salina, shared the same halophytic feature as the P. hodgsonii from the littoral zone of a coastal lake in the Antarctic. The 16S rRNA gene phylogeny supported the monophyly of Plectolyngbya with solid support, 99% Maximum Likelihood, 98% Neighbor-Joining bootstrap support values, and 1.0 Bayesian posterior probability. The ITS sequences of P. terrestris, P. koreana, and P. salina were unique in length and nucleotide composition, with different secondary structures of D1–D1ʹ and Box-B helices, compared with those of P. hodgsonii. These results demonstrate that the proposed new Plectolyngbya species were unique in their molecular traits. Therefore, we suggest them as new species belonging to the genus Plectolyngbya with the names P. terrestris sp. nov., P. koreana sp. nov., and P. salina sp. nov. Full article