A new diatom species P. hallegraeffii sp. nov. belonging to the toxic genus Pseudo-nitzschia (Bacillariophyceae) from the East Australian Current

Type Article
Date 2018-04
Language English
Author(s) Ajani Penelope A.1, Verma Arjun1, Lassudrie MalwennORCID1, Doblin Martina A.1, Murray Shauna A.1
Affiliation(s) 1 : Univ Technol Sydney, C3, Broadway, NSW, Australia.
Source Plos One (1932-6203) (Public Library Science), 2018-04 , Vol. 13 , N. 4 , P. e0195622 (20p.)
DOI 10.1371/journal.pone.0195622
WOS© Times Cited 20

A new species belonging to the toxin producing diatom genus Pseudo-nitzschia, P. hallegraeffii sp. nov., is delineated and described from the East Australian Current (EAC). Clonal cultures were established by single cell isolation from phytoplankton net hauls collected as part of a research expedition in the EAC region in 2016 on the RV Investigator. Cultures were assessed for their morphological and genetic characteristics, their sexual compatibility with other Pseudo-nitzschia species, and their ability to produce domoic acid. Light and transmission electron microscopy revealed cells which differed from their closest relatives by their cell width, rows of poroids, girdle band structure and density of band straie. Phylogenetic analyses based on sequencing of nuclear-encoded ribosomal deoxyribonucleic acid (rDNA) regions showed this novel genotype clustered within the P. delicatissima complex, but formed a discrete clade from its closest relatives P. dolorosa, P. simulans, P. micropora and P. delicatissima. Complementary base changes (CBCs) were observed in the secondary structure of the 3’ nuclear ribosomal transcribed spacer sequence region (ITS2) between P. hallegraeffii sp. nov. and its closest related taxa, P. simulans and P. dolorosa. Under laboratory conditions, and in the absence of any zooplankton cues, strains of P. hallegraeffii sp. nov. did not produce domoic acid (DA) and were not sexually compatible with any other Pseudo-nitzschia clones tested. A total of 18 Pseudo-nitzschia species, including three confirmed toxigenic species (P. cuspidata, P. multistriata and P. australis) have now been unequivocally confirmed from eastern Australia.

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Publisher's official version 20 11 MB Open access
S1 Fig. Predicted ITS2 structures of A. P. simulans MC984 (GenBank accession number: MF374772) and B. P. dolorosa 300 (GenBank accession number: DQ336153). 7 MB Open access
S1 Table. List of Pseudo-nitzschia clones used for phylogenetic reconstruction and for inferring p-distances (sequences obtained from Genbank, NCBI). 2 177 KB Open access
S2 Table. Genetic distance (pairwise uncorrected p-distance) based on ITS-5.8S sequences. 63 KB Open access
S3 Table. Genetic distance (pairwise uncorrected p-distance) based on D1-D3 LSU rDNA sequences. 69 KB Open access
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