Taxonomic and phylogenetic evaluation of Limnothrix strains (Oscillatoriales, Cyanobacteria) by adding Limnothrix planktonica strains isolated from central China

Abstract

Six Limnothrix strains, isolated for the first time from a shallow eutrophic lake in central China, were taxonomically and phylogenetically evaluated by investigating their polyphasic characteristics, including morphological features, cellular ultrastructures, and 16S rRNA gene sequences. All the six strains were morphologically similar, and their trichomes were in average 1.7 lm wide and cells 4.0 lm long, and having small gas vesicles within cells, and therefore identified as Limnothrix planctonica (Woloszynska) Meffert. Cellular ultrastructures of them showed that peripheral thylakoids with 3-5 parallel layers were parietally distributed in the cells. The phylogenetic results based on the 16S rRNA gene sequences showed that all the Limnothrix strains, including the six in this study and those from the Genbank, formed two distinct clusters. The similarity in 16S rDNA sequences between these two clusters was lower than 90%, indicating that these Limnothrix strains belong to different genera. This is the first report on the morphology and phylogeny of L. planctonica strains, providing the new information on taxonomy of the genus Limnothrix.

Polyphasic characterization of four species of Pseudanabaena (Oscillatoriales, Cyanobacteria) from China and insights into polyphyletic divergence within the Pseudanabaena genus

“…The average similarities of the 16S rRNa gene sequences between P. catenata (KM020004, KM020005, and ab039020) and P. tremula or P. persicina were 88.6% and 85.3%, respectively. Similar to the results of a previous study (Zhu et al 2012), the findings of the present study revealed that the three strains of Limnothrix redekei mixed with Pseudanabaena strains in cluster I.…”

“…Considering the complexity of Pseudanabaena, Komárek and anagnostidis (2005) pointed out that Pseudanabaena still needs further taxonomic studies. With the accumulation of DNa sequences in Genbank and the description of new species, the current taxonomic state of Pseudanabaena remains unsatisfactory (Komárek and anagnostidis 2005, Kling et al 2003, 2012. This lag may be attributed to the lack of knowledge about the type strain of the type species (P. catenata) of Pseudanabaena.…”

“…The polymerase chain reactions (PCR) were performed in 50 μl reactions according to Lin et al (2010). The examination and purification were according to Zhu et al (2012). Phylogenetic analysis:-DNa sequences, both examined in this study and obtained from Genbank, were aligned using CluSTalW integrated into the bioedit package (hall 1999).…”

“…anagnostidis and Komárek (1988) provided a modern taxonomic system of cyanobacteria and classified the genus Pseudanabaena under the subfamily Pseudanabaenoideae, family Pseudanabaenaceae, and order oscillatoriales (Komárek and anagnostidis 2005). as a result of continuous changes in the cyanobacterial taxonomic system and the discovery of new species, Pseudanabaena has currently become a large group with more than 33 species and described forms, of which many were incorporated from the genera Oscillatoria Vaucher ex Gomont (1892: 198), Phormidium Kützing ex Gomont (1892: 156), Lyngbya C. Agardh ex Gomont (1892: 118), and Spirulina Turpin ex Gomont (1892: 96, 249) (Komárek and anagnostidis 2005, Kling et al 2003, 2012. The rapid development of modern molecular biology in recent years has led to the common use of a polyphasic approach that combines phenotypic, chemotypic, and genotypic features in characterizing cyanobacterial taxa ideally at the species level.…”

Preface: phytoplankton responses to human impacts at different scales

“…Taxonomic papers review present state of the systematics of coccoid green algae (Krienitz & Bock, 2012), and provide an update to modern (2011) taxonomy of planktic heterocytous cyanobacteria (Komárek & Mareš, 2012). Zapomělová et al (2012) while discussing biogeographically interesting nostocalean species revised taxonomic positions of two formerly Anabaena species and Zhu et al (2012) provided a taxonomic and phylogenetic evaluation of Limnothrix strains.…”