Publication Date:
2015-12-21
Description:
The marine dinophycean genus Azadinium has been identified as the primary source of azaspiracids
(AZA), a group of lipophilic phycotoxins known to accumulate in shellfish. Blooms of Azadinium in the
southern Atlantic off Argentina have been described from the 1990s, but due to a lack of cultures, the
diversity of South-Atlantic Azadinium has not yet been fully explored and their toxin production
potential is completely unknown. During a spring 2010 research cruise covering the El Rinco´n (ER)
estuarine system (North Patagonian coast, Argentina, Southwestern Atlantic) a search was conducted for
the presence of Azadinium. Although neither Azadinium cells nor AZA in field plankton samples were
detected, 10 clonal strains of Azadinium poporum were successfuly established by incubation of sediment
samples. Argentinean A. poporum were more variable in size and shape than the type description but
conformed to it by the presence of multiple pyrenoids with starch sheath, in plate pattern and
arrangement, and in the position of the ventral pore located on the left side of the pore plate. In contrast
to all previous description of A. poporum, isolates of the Argentinean A. poporum possessed a distinct field
of pores on the second antapical plate. Conspecificity of the Argentinean isolates with A. poporum was
confirmed by molecular phylogeny of concatenated ITS and LSU rDNA sequences, where all Argentinean
isolates together with some Chinese A. poporum strains formed a well-supported ribotype clade within A.
poporum. All isolates produced AZA with the same profile, consisting of AZA-2 as the major compound
and, to a lesser extent, its phosphated form. This is the first report of a phosphated marine algal toxin.
This first confirmation of the presence of AZA producing Azadinium in the Argentinean coastal area
underlines the risk of AZA shellfish contamination episodes in the Southwestern Atlantic region.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf