Neptunomonas phycophila sp. nov. isolated from a culture of Symbiodinium sp., a dinoflagellate symbiont of the sea anemone Aiptasia tagetes

Abstract

A Gram-stain-negative, facultatively anaerobic, oxidase-and catalase-positive, rod-shaped bacterium, strain SYM1 T , was isolated from a culture of Symbiodinium sp., an algal symbiont of the sea anemone Aiptasia tagetes collected in Puerto Rico. Growth was observed at 4-40 6C (optimum 30 6C), at pH 5.0-11.0 (optimum pH 8.0) and with 0.5-8 % (optimum 2 %) (w/v) NaCl. Phylogenetic analyses of 16S rRNA gene sequences showed that strain SYM1 T was a member of the genus Neptunomonas with the type strain of Neptunomonas naphthovorans as the closest phylogenetic relative with a pairwise sequence similarity of 98.15 %. However, DNA-DNA relatedness between strain SYM1 T and N. naphthovorans CIP 106451 T was 24 %. Moreover, strain SYM1 T could be distinguished from its closest relative by several phenotypic characteristics such as NaCl, pH and temperature tolerance, nitrate reduction and utilization of carbon substrates. The major cellular fatty acids were C 16 : 0 , C 18 : 1 v7c and summed feature 3 (comprising C 16 : 1 v7c and/or iso-C 15 : 0 2-OH). The genomic DNA G+C content of strain SYM1 T was 45 mol%. Ubiquinone-8 (Q-8) was the only respiratory quinone detected. Based on a polyphasic taxonomic characterization, strain SYM1 T represents a novel species of the genus Neptunomonas, for which the name Neptunomonas phycophila sp. nov. is proposed. The type strain is SYM1 T (5LMG 28329 T 5CECT 8716 T ).

Complete characterization of new isolates of Neptunomonas phycophila leads to emend its description and opens possibilities of biotechnological applications

“…These results were slightly different to those given in N. phycophila description even though the conditions and growth medium were the same used by Frommlet et al. () (Table ). Summed Feature 3 is composed by C 16:1 ω7c/C 16:1 ω6c in our study, whereas in the description of N. phycophila contains C 16:1 ω7c/iso‐C 15:0 2‐OH.…”

“…The description of the N. phycophila is based on that given previously by Frommlet et al. () but with the following changes. Bacteria form punctiform and adherent colonies with 0.5–1.5 mm in diameter on MA after 2 days of cultivation.…”

“…Neptunomonas phycophila was recently described on the basis of a unique bacterial strain isolated during a study of the microbiota associated with in vitro cultures of the dinoflagellate Symbiodinium sp. (Frommlet et al., ). To our knowledge, no further reference exists in the literature on this bacterial species.…”

“…Species of this group are Gram‐negative, facultatively aerobic, oxidase and catalase positive, and they can use several carbohydrates, sugar alcohols, organic acids, and some PAH as sole carbon and energy sources. In the last decade, six additional species have been described within this genus: Neptunomonas japonica (Miyazaki et al., ), Neptunomonas antarctica (Zhang et al., ), Neptunomonas concharum (Lee et al., ), Neptunomonas qingdaonensis (Liu et al., ), Neptunomonas acidivorans (Yang, Seo, Lee, Kim, & Kwon, ), and recently, Neptunomonas phycophila (Frommlet, Guimarães, Sousa, Serodio, & Alves, ), all of them isolated from marine environments. The latter species was described on the basis of a unique bacterial isolate associated to the dinoflagellate Symbiodinium species, a symbiont of the anemone Aiptasia tagetes in Puerto Rico.…”

Coral symbiotic algae calcify ex hospite in partnership with bacteria

“…To examine the role of bacteria further, we isolated and identified 12 bacterial strains from symbiolite-forming Symbiodinium cultures (Table S3). Two isolates, a previously undescribed species of Neptunomonas (Neptunomonas phycophila) (27) and a strain of Pseudoalteromonas atlantica, a bacterium first isolated from marine algae and known for its production of large amounts of EPS (28), were tested in bacteria-addition experiments. Culturing of antibiotics-treated Symbiodinium strains in antibiotics-free medium reinitiated calcification in 18.75% of cultures, suggesting that the previous antibiotics treatment had not produced fully axenic cultures but instead had inhibited bacterial growth sufficiently to suppress calcification.…”