THE CONTRIBUTION OF SUB‐SAHARAN AFRICAN STRAINS TO THE PHYLOGENY OF CYANOBACTERIA: FOCUSING ON THE NOSTOCACEAE (NOSTOCALES, CYANOBACTERIA)¹

Abstract

To date, phylogenies have been based on known gene sequences accessible at GenBank, and the absence of many cyanobacterial lineages from collections and sequence databases has hampered their classification. Investigating new biotopes to isolate more genera and species is one way to enrich strain collections and subsequently enhance gene sequence databases. A polyphasic approach is another way of improving our understanding of the details of cyanobacterial classification. In this work, we have studied phylogenetic relationships in strains isolated from freshwater bodies in Senegal and Burkina Faso to complement existing morphological and genetic databases. By comparing 16S rDNA sequences of African strains to those of other cyanobacteria lineages, we placed them in the cyanobacterial phylogeny and confirmed their genus membership. We then focused on the Nostocaceae family by concatenated analysis of four genes (16S rDNA, hetR, nifH, and rpoC1 genes) to characterize relationships among Anabaena morphospecies, in particular, Anabaena sphaerica var. tenuis G. S. West. Using a polyphasic approach to the Nostocaceae family, we demonstrate that A. sphaerica var. tenuis is more closely related to Cylindrospermospsis ⁄ Raphidiopsis than to other planktonic Anabaena ⁄ Aphanizomenon. On the basis of phylogeny and morphological data, we propose that these three significantly different clusters should be assigned to three genera.

Diversity of cyanobacteria and cyanotoxins in Hartbeespoort Dam, South Africa

“…Therefore, it cannot be excluded that C. curvispora is actually another morphotype of C. raciborskii. This is supported by a study from Thomazeau et al (2010), who concluded that C. curvispora cannot be distinguished genetically from C. raciborskii using 16S rRNA gene sequences. Cylindrospermopsis spp.…”

“…Sphaerospermopsis aphanizomenoides GU197720 Sphaerospermopsis aphanizomenoides GU197719 Thomazeau et al 2010). McGregor and Fabbro (2000) have described coiled morphotypes of Australian C. raciborskii with a similar morphology to C. curvispora strain AB2011/30.…”

Comparison of Quantitative PCR and Droplet Digital PCR Multiplex Assays for Two Genera of Bloom-Forming Cyanobacteria, Cylindrospermopsis and Microcystis

“…tenuis that match CYL rpoC1 primers and probes. In fact, a phylogenetic study of four genes (the 16S rRNA gene and hetR, nifH, and rpoC1 genes) of Anabaena morphospecies led to the conclusion that A. sphaerica is phylogenetically closer to Cylindrospermopsis and Raphidiopsis and, thus, should be considered a sister group with Cylindrospermopsis instead of Anabaena (35), thus supporting our assay design.…”

Evidence for saxitoxins production by the cyanobacterium Aphanizomenon gracile in a French recreational water body

“…The sxtA data set was incremented with four sxtA sequences from GenBank (Supplementary data S1). For both alignments, Lyngbya wollei sequence was chosen as outgroup (Thomazeau et al, 2010).…”