Nitratireductor alexandrii sp. nov., from phycosphere microbiota of toxic marine dinoflagellate Alexandrium tamarense

Abstract

<jats:p>A taxonomic study was carried out on a novel algae-associated bacterial strain Z3-1<jats:sup>T</jats:sup>, which was isolated from phycosphere microbiota of toxic marine dinoflagellate <jats:italic>Alexandrium tamarense</jats:italic> 880. Cells of strain Z3-1<jats:sup>T</jats:sup> were Gram-stain-negative, rod-shaped and strictly aerobic and were motile by means of flagella. Strain Z3-1<jats:sup>T</jats:sup> grew at 25–42 °C, pH 5.0–10.0 and 1.0–5.0 % (w/v) NaCl. Strain Z3-1<jats:sup>T</jats:sup> reduced nitrate to nitrite, but did not reduce nitrite to nitrogen gas. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain Z3-1<jats:sup>T</jats:sup> belongs to the genus <jats:italic> <jats:named-content content-type="genus"> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://doi.org/10.1601/nm.1423" xlink:type="simple">Nitratireductor</jats:ext-link> </jats:named-content> </jats:italic> showing the highest sequence similarity (97.0 %) to <jats:italic> <jats:named-content content-type="species"> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://doi.org/10.1601/nm.13472" xlink:type="simple">Nitratireductor basaltis</jats:ext-link> </jats:named-content> </jats:italic> JCM 14935<jats:sup>T</jats:sup>. The average nucleotide identity and digital DNA–DNA hybridization relatedness between strain Z3-1<jats:sup>T</jats:sup> and type strains of genus <jats:italic> <jats:named-content content-type="genus"> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://doi.org/10.1601/nm.1423" xlink:type="simple">Nitratireductor</jats:ext-link> </jats:named-content> </jats:italic> with available genome sequences were in the ranges of 72.4–74.4 % and 22.7–23.3 %, respectively. The major fatty acids were summed in feature 8 (C<jats:sub>18:1</jats:sub> <jats:italic>ω</jats:italic>7c and/or C<jats:sub>18:1</jats:sub> <jats:italic>ω</jats:italic>6c), C<jats:sub>19:0</jats:sub> <jats:italic>ω</jats:italic>8c cyclo, C<jats:sub>18:1</jats:sub> <jats:italic>ω</jats:italic>7c 11-metyl and iso-C<jats:sub>17:0</jats:sub>. The major polar lipids were determined as diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, two unidentified phospholipids and four unidentified polar lipids. The genomic DNA G+C content calculated from genome sequence was 65.6 mol%. Based on genotypic, chemotaxonomic and phenotypic data obtained, strain Z3-1<jats:sup>T</jats:sup> represents a novel species of the genus <jats:italic> <jats:named-content content-type="genus"> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://doi.org/10.1601/nm.1423" xlink:type="simple">Nitratireductor</jats:ext-link> </jats:named-content> </jats:italic>, for which the name <jats:italic>Nitratireductor alexandrii</jats:italic> sp. nov. is proposed with the type strain Z3-1<jats:sup>T</jats:sup> (=KCTC 62458<jats:sup>T</jats:sup>=CCTCC AB 2017227<jats:sup>T</jats:sup>).</jats:p>

Nitratireductor rhodophyticola sp. nov., isolated from marine red algae

“…Q-10 was the sole respiratory quinone detected in strains L1-7-SE T and R6, which was in line with those in all other members of the genus Nitratireductor [4,5,37]. Major cellular fatty acids (>10 % of the total fatty acids) of strains L1-7-SE T and R6 were C 19 : 0 cyclo ω8c and summed feature 8 (comprising C 18 : 1 ω7c and/or C 18 : 1 ω6c).…”

“…Growth of strains L1-7-SE T and R6 was assessed at 30 °C for 2 days on MA, Reasoner's 2A (R2A) agar (BD), Luria-Bertani (LB) agar, and tryptic soy agar (BD), which were supplemented additionally with NaCl to final concentrations of approximately 2 % (w/v). Growth of strains L1-7-SE T and R6 at different temperatures (5,10,15,20,25,30,35,40,45, 50 and 55 °C) was evaluated on MA for 2 days. Growth of strains L1-7-SE T and R6 at different pH values (4.0-12.0 at 1.0 pH unit intervals) was tested in MB at 30 °C for 2 days.…”

“…The CheckM-based genome completeness and contamination rates of strains L1-7-SE T , R6 and KACC 11904 T were 98.8% and 1.1, 98.8 and 1.1 and 99.1 % and 0.5 %, respectively. The DNA G+C contents of strains L1-7-SE T , R6 and KACC 11904 T calculated from their whole genomes were 61.62, 61.62 and 59.80 mol%, respectively, which were in the range of the DNA G+C contents of Nitratireductor species [4, 5]. The sequencing summaries and general genomic features of strains L1-7-SE T , R6 and KACC 11904 T are presented in , and it was shown that their general genomic features were similar to each other.…”

“…Members of the genus Nitratireductor have been isolated from mainly marine environments such as a marine denitrification system [1], black beach sand [2], dried seaweed [3], diatom and dinoflagellates [4,5], sea water [6,7] and a salt lake [7]. Cells of Nitratireductor members are generally strictly aerobic, Gramnegative, catalase-and oxidase-positive and motile or non-motile rods containing ubiquinone-10 (Q-10) as the major respiratory quinone and C 19 : 0 cyclo ω8c and summed feature 8 (comprising C 18 : 1 ω7c and/or C 18 : 1 ω6c) as the major fatty acids, and they have 56.7-65.6 mol% G+C contents [4,5]. During research regarding the interactions between marine red algae and bacteria, we have isolated many novel bacteria from marine red algae [8][9][10].…”

“…At the time of writing, the genus Nitratireductor includes 9 validly and five invalidly published species (https://lpsn.dsmz.de/genus/nitratireductor). Members of the genus Nitratireductor have been isolated from mainly marine environments such as a marine denitrification system [1], black beach sand [2], dried seaweed [3], diatom and dinoflagellates [4,5], sea water [6,7] and a salt lake [7]. Cells of Nitratireductor members are generally strictly aerobic, Gramnegative, catalase-and oxidase-positive and motile or non-motile rods containing ubiquinone-10 (Q-10) as the major respiratory quinone and C 19 : 0 cyclo ω8c and summed feature 8 (comprising C 18 : 1 ω7c and/or C 18 : 1 ω6c) as the major fatty acids, and they have 56.7-65.6 mol% G+C contents [4,5].…”