Shahulinema minutum gen. & sp. nov. (Oculatellaceae) and Euryhalinema shahuense sp. nov. (Nodosilineaceae), two new Cyanobacteria isolated from Shahu Lake in China

Two novel cyanobacteria (strains SH01 and SH02) with thin filaments and simple morphology were isolated from Shahu Lake in China. The two strains were morphologically similar to the thin, simple filamentous cyanobacteria. The 16S rRNA gene data phylogeny revealed the distinct lineage of SH01, which was nearest to the clade incorporating the genera Kaiparowitsia, Thermoleptolyngbya and Aerofilum. The strain SH02, together with other Euryhalinema species, grouped in a unique cluster, in which the type species Euryhalinema mangrovii was included. The 16S rRNA gene sequences of SH01 and SH02 showed maximum similarities as 94.2% and 98.5%, respectively, compared to those of established genera and other Euryhalinema species to which they were phylogenetically related. Furthermore, the ITS secondary structures for both strains SH01 and SH02 revealed significant distinction and uniqueness when compared with their respective reference strains (the genera of Oculatellaceae for SH01 and Euryhalinema species for SH02). To sum up, these results verified the establishment of strain SH01 as a novel genus named Shahulinema gen. nov., and strain SH02 as the fourth novel species under the genus Euryhalinema, as E. shahuense sp. nov.