Cyanobacteria represent a prolific source of bioactive
compounds, some of which (cyanotoxins) elicit toxic effects
in vertebrates and therefore represent a health risk to
humans and animals. Cyanotoxin production has been
described in at least 20 cyanobacterial genera (Metcalf and
Codd, 2012) mostly within the orders Chroococcales, Nostocales
and Oscillatoriales and, much more rarely, in Stigonematales.
The order Stigonematales is comprised of
filamentous nitrogen-fixing cyanobacteria which exhibit
true-branching. They occur in freshwaters and soils
worldwide, but the majority of species are restricted to
tropical/subtropical and thermophilic habitats (Finsinger
et al., 2008). Recent whole-genome studies estimate that