Morphology and Phylogenetics of Benthic Prorocentrum Species (Dinophyceae) from Tropical Northwestern Australia

Abstract

Approximately 70 species of Prorocentrum are known, of which around 30 species are associated with benthic habitats. Some produce okadaic acid (OA), dinophysistoxin (DTX) and their derivatives, which are involved in diarrhetic shellfish poisoning. In this study, we isolated and characterized Prorocentrum concavum and P. malayense from Broome in north Western Australia using light and scanning electron microscopy as well as molecular sequences of large subunit regions of ribosomal DNA, marking the first record of these species from Australian waters. The morphology of the motile cells of P. malayense was similar to P. concavum in the light microscopy, but differed by the smooth thecal surface, the pore pattern and the production of mucous stalk-like structures and a hyaline sheath around the non-motile cells. P. malayense could also be differentiated from other closely related species, P. leve and P. foraminosum, despite the similarity in thecal surface and pore pattern, by its platelet formula and morphologies. We tested the production of OA and DTXs from both species, but found that they did not produce detectable levels of these toxins in the given culturing conditions. This study aids in establishing more effective monitoring of potential harmful algal taxa in Australian waters for aquaculture and recreational purposes.

Cryptic speciation of benthic Prorocentrum (Dinophyceae) species and their potential as ecological indicators

“…LSU rDNA (D1-D3) sequence differences (above the diagonal line) and similarity (below the diagonal line) of Prorocentrum mexicanum. produce detectable toxins, consistent with previous findings on strains from Hainan, China, and Australia (Luo et al, 2017;Verma et al, 2019;Zou et al, 2021). Toxin production might serve to differentiate strains of different origins.…”

Spatial-Temporal Distribution of Prorocentrum concavum Population in Relation to Environmental Factors in Xincun Bay, a Tropical Coastal Lagoon in China

“…To date, many studies have demonstrated that P. concavum is a tychoplanktonic dinoflagellate. This species has been reported in the Arabian Sea (Morton et al, 2002), Knight Key, Gulf of Mexico, northwestern Australia (Verma et al, 2019), northern Hainan Island (Luo et al, 2017), and the Xincun Bay of China (present study). Moreover, Morton et al (2002) described a new species, P. arabianum [synonym of P. concavum; Mohammad-Noor et al ( 2007)], and reported a planktonic P. arabianum bloom in the Gulf of Oman, Arabian Sea in May 1995.…”

“…Among nine toxic epibenthic Prorocentrum, results on the production of OA by P. concavum are often contradictory. Some studies report that this dinoflagellate can produce OA (Dickey et al, 1990;Hu et al, 1992;Juranovic et al, 1997), while other recent studies demonstrated no detectable OA using liquid chromatography-tandem mass spectrometry (Luo et al, 2017;Verma et al, 2019). Despite the debate regarding whether P. concavum produces OA or not, this species is certainly a toxic dinoflagellate and can be lethal to marine invertebrates (Zou et al, 2020).…”

Ribosomal DNA Sequence-Based Taxonomy and Antimicrobial Activity of Prorocentrum spp. (Dinophyceae) from Mauritius Coastal Waters, South-West Indian Ocean

“…Ehrenberg (1834) contains potentially toxic dinoflagellate species [13,14] and has been reported to possess promising bioactive compounds [15][16][17][18]. So far, 81 Prorocentrum species are taxonomically accepted [19], and of these, 35 have been reported as benthic species [20][21][22][23][24]. The aim here is to characterize epiphytic Prorocentrum species from Mauritius coastal waters based on morphology and DNA sequence analyses and investigate their antimicrobial properties of crude extracts against selected human pathogenic bacteria.…”