Compactonostoc shennongjiaensis gen . & sp. nov . (Nostocales, Cyanobacteria) from a wet rocky wall in China

<italic>Violetonostoc minutum</italic> gen. et sp. nov. (Nostocales, Cyanobacteria) from a rocky substrate in China

“…Cyanobacterial communities in the Small Sevenhole Scenic Area of China remain largely understudied, thus it is necessary to increase sampling in this region, as well as using the polyphasic approach to elucidate cyanobacterial diversity in the future studies. that genera in Nostocaceae shared higher similarities in the 16S rRNA gene sequence, as frequently more similar than 96% (Flechtner et al 2002, Řeháková et al 2007, Berrendero et al 2011, Kaštovský et al 2014, Hentschke et al 2017, Cai et al 2019b. The phylogenetic analysis revealed that the two strains (CHAB 5840, CHAB 5841) in this study formed a single and unique clade, thus the proposal for the new genus will contribute to solve taxonomic confusion and achieve monophyly within the genus Nostoc.…”

“…The traditional definition of Nostoc includes several distinct but not closely related phylogenetic clusters, some of which have been already formally separated from Nostoc, such as Mojavia (Řeháková et al 2007) and Desmonostoc (Hrouzek et al 2013). In recent years, many studies using the polyphasic approach led to the establishment of more novel genera by splitting from Nostoc (Genuário et al 2015, Bagchi et al 2017, Hentschke et al 2017, Cai et al 2019a, 2019b. In China, the investigation on cyanobacteria from all kinds of environmental conditions and researches on cyanobacterial taxonomy ments aggregated and entangled irregularly in gelatinous colonies, and usually shown as macroscopic with peripheral periderm enveloping the whole spherical colonies.…”

“…In spite of its well-established morphological features, Nostoc has been proven to be genetically heterogeneous, and several genotypic groups were shown to fall outside of the 'Nostoc sensu stricto' clade based on 16S rRNA gene phylogeny (Hrouzek et al 2005, Rajaniemi et al 2005a, Papaefthimiou et al 2008, Lukešová et al 2009, Silva et al 2014. Therefore, the genus Nostoc has been proposed to be amended in consideration of phylogenetic data, and some Nostoc-related morphotypes have been established as new genera including Mojavia, Desmonostoc, Halotia, Komarekiella, Aliinostoc, Compactonostoc, and Minunostoc (Řeháková et al 2007, Hrouzek et al 2013, Genuário et al 2015, Bagchi et al 2017, Hentschke et al 2017, Cai et al 2019a, 2019b.…”

“…5K). The base stem of Compactonostoc have been largely performed (Song et al 2015a, 2015b, Li and Li 2016, Li et al 2017, Cai et al 2018, 2019a, 2019b, Wang et al 2019). The present study described Violetonostoc as a new cyanobacterial genus isolated from the Small Seven-hole Scenic Area in Guizhou province, and this is the second new Nostoc-like genus from the same site, following the first new one as Minunostoc (Cai et al 2019a).…”

Phylogenetically distant clade of Nostoc-like taxa with the description of Minunostoc gen. nov. and Minunostoc cylindricum sp. nov

“…Phylogenetic results have shown that Nostoc is polyphyletic (Rajaniemi et al 2005a, b). Recently, several novel genera, Mojavia (Řeháková et al 2007), Desmonostoc (Hrouzek et al 2013), Halotia (Genuário et al 2015), Komarekiella (Hentschke et al 2017), Aliinostoc (Bagchi et al 2017) and Compactonostoc (Cai et al 2018), which morphologically appears to be Nostoc-like, have been proposed and separated from the 'Nostoc sensu stricto' clade based on the phylogenetic analysis of the 16S rRNA gene sequences. Over 300 species of the genus Nostoc have been described and many of which are not identifiable according to modern taxonomic system and need further investigation and revision.…”