A non‐toxigenic but morphologically and phylogenetically distinct new species of Pseudo‐nitzschia, P. sabit sp. nov. (Bacillariophyceae)

Abstract

A new species of Pseudo-nitzschia (Bacillariophyceae) is described from plankton samples collected from Port Dickson (Malacca Strait, Malaysia) and Manzanillo Bay (Colima, Mexico). The species possesses a distinctive falcate cell valve, from which they form sickle-like colonies in both environmental samples and cultured strains. Detailed observation of frustules under TEM revealed ultrastructure that closely resembles P. decipiens, yet the new species differs by the valve shape and greater ranges of striae and poroid densities. The species is readily distinguished from the curve-shaped P. subcurvata by the presence of a central interspace. The morphological distinction is further supported by phylogenetic discrimination. We sequenced and analyzed the nuclear ribosomal RNA genes in the LSU and the second internal transcribed spacer, including its secondary structure, to infer the phylogenetic relationship of the new species with its closest relatives. The results revealed a distinct lineage of the new species, forming a sister cluster with its related species, P. decipiens and P. galaxiae, but not with P. subcurvata. We examined the domoic acid (DA) production of five cultured strains from Malaysia by Liquid chromatography-mass spectrometry (LC-MS), but they showed no detectable DA. Here, we present the taxonomic description of the vegetative cells, document the sexual reproduction, and detail the molecular phylogenetics of Pseudo-nitzschia sabit sp. nov.

Pseudo‐nitzschia arctica sp. nov., a new cold‐water cryptic Pseudo‐nitzschia species within the P. pseudodelicatissima complex

“…, Teng et al. ). The analysis of the secondary structure of the ITS2 of all our strains of P. arctica shows 2 HCBCs and 2 nucleotide deletions compared to P. granii and P. subcurvata .…”

Species occurrence of the potentially toxigenic diatom genus Pseudo-nitzschia and the associated neurotoxin domoic acid in the Argentine Sea

“…The genus now comprises 48 recognized species (Teng et al, 2014(Teng et al, , 2015Percopo et al, 2016), most of them described within the last two decades. Among these species, at least 23 have been mentioned as potential producers of domoic acid (DA) (Teng et al, 2015, a secondary amine neurotoxin.…”

“…The genus now comprises 48 recognized species (Teng et al, 2014(Teng et al, , 2015Percopo et al, 2016), most of them described within the last two decades. Among these species, at least 23 have been mentioned as potential producers of domoic acid (DA) (Teng et al, 2015, a secondary amine neurotoxin. This neurotoxin can be accumulated throughout the marine food web, causing amnesic shellfish poisoning (ASP), a neurological syndrome with even lethal effects on sea birds, marine mammals and humans in extreme cases (Fire and Van Dolah, 2012).…”

Pseudo-nitzschia species (Bacillariophyceae) identification and delineation using mitochondrial cox1 gene sequences as compared to LSU rDNA

“…High species diversity of Pseudo-nitzschia species in Malaysian coastal waters was reported by Teng et al [5], with more than 23 species documented. Among the 23 species, six species have been identified from the waters as new morphotypes, and described as P. batesiana H.C. Lim kodamae was found to be highly toxic, while others are non-toxic [7][8][9][10].…”

“…Molecular species characterization using nucleotide sequences of the nuclearencoded large-subunit (LSU) ribosomal DNA (rDNA) and the internal transcribed spacer region (ITS1-5.8S-ITS2) have become essential supporting criteria in species delineation [9][10][11][12][13][14][15][16]. Other molecular techniques used in Pseudonitzschia studies included automated ribosomal intergenic spacer analysis (ARISA) [17][18][19]; rapid whole-cell detection using fluorescence in situ hybridization (FISH) [12,[20][21][22][23]; and the development of species-specific microsatellite markers for population genetics [24,25].…”