Description of two new species of nostoc from China based on the polyphasic approach

Abstract

The present study described two new Nostoc species, Nostoc favosum (CHAB5709, CHAB5713, and CHAB5714) and Nostoc mirabile (CHAB5756 and CHAB5784) based on the polyphasic approach combining morphological, genetic and ecological characteristics. Five investigated strains were found to possess morphological features of the Nostoc genus. Results showed that the 16S rRNA gene sequences of these five strains displayed ≥ 95%, and ≤ 98% similarity to the genus Nostoc. The 16S rRNA gene phylogenetic analysis inferred using bayesian inference, maximum–likelihood and neighbour–joining methods placed these five strains on two separate nodes away from other Nostoc species. The 16S–23S rRNA internal transcribed spacer (ITS) secondary structure of two new species showed a unique pattern of D1–D1′, Box–B and V3 helix, which distinguished them from other Nostoc species. And the two species were further established by percent dissimilarity of ITS between another Nostoc species.