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Smahajcsik D, Roager L, Strube ML, Zhang SD, Gram L. Stronger together: harnessing natural algal communities as potential probiotics for inhibition of aquaculture pathogens. Microbiol Spectr 2025:e0042125. [PMID: 40396728 DOI: 10.1128/spectrum.00421-25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2025] [Accepted: 03/22/2025] [Indexed: 05/22/2025] Open
Abstract
Intensive fish rearing in aquaculture is challenged by infectious diseases, and although vaccines have been successfully developed for mature fish, alternative disease control measures are needed for fish larvae and juveniles. Probiotics offer a promising alternative to antibiotics, with the potential to reduce the risk of antibiotic resistance. Probiotics are typically isolated and used as pure cultures; however, in natural environments, it is the concerted effort of the complex microbiome that keeps pathogens at bay. Here, we developed an in vitro assay to evaluate the anti-pathogen efficacy of mixed algal microbiomes from the live feed microalgae Tetraselmis suecica and Isochrysis galbana. The inhibition of a green fluorescent protein (GFP)-tagged Vibrio anguillarum, a key fish pathogen, by microbial communities was measured and quantified as reduction in fluorescence. The Isochrysis galbana microbiome was more inhibitory to V. anguillarum than the Tetraselmis suecica microbiome. During co-culture with the pathogen, the bacterial density of the Isochrysis microbiomes increased, while the diversity was reduced as determined by metataxonomic analyses. Bacteria isolated from the fully inhibitory microbiomes were members of Alteromonadaceae, Halomonadaceae, Rhodobacteraceae, Vibrionaceae, Flavobacteriaceae, and Erythrobacteraceae. Although some strains individually inhibited the pathogen, these were not the key members of the microbiome, and enhanced inhibition was observed when Sulfitobacter pontiacus D3 and Vreelandella alkaliphila D2 were co-cultured, even though neither was inhibitory as monocultures. Thus, this study demonstrates that microbial communities derived from natural algal microbiomes can have anti-pathogen effects, and that bacterial co-cultures may offer synergistic advantages over monocultures as probiotics, highlighting their promise for aquaculture health strategies.IMPORTANCEAquaculture is the fastest-growing food protein-producing sector, and sustainable disease control measures are required. Probiotics have gained interest as a promising solution for combating fish pathogens, and using mixtures of microorganisms rather than pure cultures may represent a more stable pathogen control. We developed an assay using green fluorescent protein (GFP) tagging of a fish pathogen, enabling the quantitative assessment of the anti-pathogen effects of complex microbiomes. We show that the efficiency of pathogen suppression can be increased with co-cultures compared to monocultures, thus emphasizing the potential in using mixtures of bacteria as probiotics.
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Affiliation(s)
- Dóra Smahajcsik
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Line Roager
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Mikael Lenz Strube
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Sheng-Da Zhang
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Lone Gram
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
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Nedashkovskaya O, Baldaev S, Ivaschenko A, Bystritskaya E, Zhukova N, Eremeev V, Kukhlevskiy A, Kurilenko V, Isaeva M. Description and Comparative Genomics of Algirhabdus cladophorae gen. nov., sp. nov., a Novel Aerobic Anoxygenic Phototrophic Bacterial Epibiont Associated with the Green Alga Cladophora stimpsonii. Life (Basel) 2025; 15:331. [PMID: 40141677 PMCID: PMC11943960 DOI: 10.3390/life15030331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2024] [Revised: 02/11/2025] [Accepted: 02/18/2025] [Indexed: 03/28/2025] Open
Abstract
A novel, strictly aerobic, non-motile, and pink-pigmented bacterium, designated 7Alg 153T, was isolated from the Pacific green alga Cladophora stimpsonii. Strain 7Alg 153T was able to grow at 4-32 °C in the presence of 1.5-4% NaCl and hydrolyze L-tyrosine, gelatin, aesculin, Tweens 20, 40, and 80 and urea, as well as produce catalase, oxidase, and nitrate reductase. The novel strain 7Alg 153T showed the highest similarity of 96.75% with Pseudaestuariivita rosea H15T, followed by Thalassobius litorarius MME-075T (96.60%), Thalassobius mangrovi GS-10T (96.53%), Tritonibacter litoralis SM1979T (96.45%), and Marivita cryptomonadis CL-SK44T (96.38%), indicating that it belongs to the family Roseobacteraceae, the order Rhodobacteales, the class Alphaproteobacteria, and the phylum Pseudomonadota. The respiratory ubiquinone was Q-10. The main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, two unidentified aminolipids, and one unidentified lipid. The predominant cellular fatty acids (>5%) were C18:1 ω7c, C16:0, C18:0, and 11-methyl C18:1 ω7c. The 7Alg 153T genome is composed of a single circular chromosome of 3,786,800 bp and two circular plasmids of 53,157 bp and 37,459 bp, respectively. Pan-genome analysis showed that the 7Alg 153T genome contains 33 genus-specific clusters spanning 92 genes. The COG20-annotated singletons were more often related to signal transduction mechanisms, cell membrane biogenesis, transcription, and transport, and the metabolism of amino acids. The complete photosynthetic gene cluster (PGC) for aerobic anoxygenic photosynthesis (AAP) was found on a 53 kb plasmid. Based on the phylogenetic evidence and phenotypic and chemotaxonomic characteristics, the novel isolate represents a novel genus and species within the family Roseobacteraceae, for which the name Algirhabdus cladophorae gen. nov., sp. nov. is proposed. The type strain is 7Alg 153T (=KCTC 72606T = KMM 6494T).
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Affiliation(s)
- Olga Nedashkovskaya
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Pr. 100 Let Vladivostoku 159, 690022 Vladivostok, Russia; (S.B.); (E.B.); (V.E.); (V.K.)
| | - Sergey Baldaev
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Pr. 100 Let Vladivostoku 159, 690022 Vladivostok, Russia; (S.B.); (E.B.); (V.E.); (V.K.)
| | - Alexander Ivaschenko
- Institute of High Technology and Advanced Materials, Far Eastern Federal University, Ajax Bay 10, Russky Island, 690922 Vladivostok, Russia;
| | - Evgenia Bystritskaya
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Pr. 100 Let Vladivostoku 159, 690022 Vladivostok, Russia; (S.B.); (E.B.); (V.E.); (V.K.)
| | - Natalia Zhukova
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Palchevskogo Street 17, 690041 Vladivostok, Russia; (N.Z.); (A.K.)
| | - Viacheslav Eremeev
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Pr. 100 Let Vladivostoku 159, 690022 Vladivostok, Russia; (S.B.); (E.B.); (V.E.); (V.K.)
| | - Andrey Kukhlevskiy
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Palchevskogo Street 17, 690041 Vladivostok, Russia; (N.Z.); (A.K.)
| | - Valeria Kurilenko
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Pr. 100 Let Vladivostoku 159, 690022 Vladivostok, Russia; (S.B.); (E.B.); (V.E.); (V.K.)
| | - Marina Isaeva
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Pr. 100 Let Vladivostoku 159, 690022 Vladivostok, Russia; (S.B.); (E.B.); (V.E.); (V.K.)
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Ahmed MA, Campbell BJ. Genome-resolved adaptation strategies of Rhodobacterales to changing conditions in the Chesapeake and Delaware Bays. Appl Environ Microbiol 2025; 91:e0235724. [PMID: 39772877 PMCID: PMC11837527 DOI: 10.1128/aem.02357-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2024] [Accepted: 11/27/2024] [Indexed: 01/11/2025] Open
Abstract
The abundant and metabolically versatile aquatic bacterial order, Rhodobacterales, influences marine biogeochemical cycles. We assessed Rhodobacterales metagenome-assembled genome (MAG) abundance, estimated growth rates, and potential and expressed functions in the Chesapeake and Delaware Bays, two important US estuaries. Phylogenomics of draft and draft/closed Rhodobacterales genomes from this study and others placed 46 nearly complete MAGs from these bays into 11 genera, many were not well characterized. Their abundances varied between the bays and were influenced by temperature, salinity, and silicate and phosphate concentrations. Rhodobacterales genera possessed unique and shared genes for transporters, photoheterotrophy, complex carbon degradation, nitrogen, and sulfur metabolism reflecting their seasonal differences in abundance and activity. Planktomarina genomospecies were more ubiquitous than the more niche specialists, HIMB11, CPC320, LFER01, and MED-G52. Their estimated growth rates were correlated to various factors including phosphate and silicate concentrations, cell density, and light. Metatranscriptomic analysis of four abundant genomospecies commonly revealed that aerobic anoxygenic photoheterotrophy-associated transcripts were highly abundant at night. These Rhodobacterales also differentially expressed genes for CO oxidation and nutrient transport and use between different environmental conditions. Phosphate concentrations and light penetration in the Chesapeake Bay likely contributed to higher estimated growth rates of HIMB11 and LFER01, respectively, in summer where they maintained higher ribosome concentrations and prevented physiological gene expression constraints by downregulating transporter genes compared to the Delaware Bay. Our study highlights the spatial and temporal shifts in estuarine Rhodobacterales within and between these bays reflected through their abundance, unique metabolisms, estimated growth rates, and activity changes. IMPORTANCE In the complex web of global biogeochemical nutrient cycling, the Rhodobacterales emerge as key players, exerting a profound influence through their abundance and dynamic activity. While previous studies have primarily investigated these organisms within marine ecosystems, this study delves into their roles within estuarine environments using a combination of metagenomic and metatranscriptomic analyses. We uncovered a range of Rhodobacterales genera, from generalists to specialists, each exhibiting distinct abundance patterns and gene expression profiles. This diversity equips them with the capacity to thrive amidst the varying environmental conditions encountered within dynamic estuarine habitats. Crucially, our findings illuminate the adaptable nature of estuarine Rhodobacterales, revealing their various energy production pathways and diverse resource management, especially during phytoplankton or algal blooms. Whether adopting a free-living or particle-attached existence, these organisms demonstrate remarkable flexibility in their metabolic strategies, underscoring their pivotal role in driving ecosystem dynamics within estuarine ecosystems.
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Affiliation(s)
- Mir Alvee Ahmed
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| | - Barbara J. Campbell
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
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Deng Y, Zhu Y, He J, Yin X, Li Q, Chen Z, Wang B, Zheng L. Complete genome analysis of deep-sea hydrothermal sulfur-oxidizing bacterium Sulfitobacter sp. TCYB15 associated with mussel Bathymodiolus marisindicus and insights into its habitat adaptation. Mar Genomics 2024; 78:101148. [PMID: 39388762 DOI: 10.1016/j.margen.2024.101148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2024] [Revised: 10/03/2024] [Accepted: 10/04/2024] [Indexed: 10/12/2024]
Affiliation(s)
- Yadan Deng
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362200, China
| | - Yunjin Zhu
- Qingdao Key Laboratory of Analytical Technology Development and Offshore Eco-Environment Conservation, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China
| | - Jiaxuan He
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362200, China
| | - Xin Yin
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362200, China
| | - Qian Li
- Qingdao Key Laboratory of Analytical Technology Development and Offshore Eco-Environment Conservation, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China
| | - Zhengxing Chen
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362200, China
| | - Bingshu Wang
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362200, China
| | - Li Zheng
- Qingdao Key Laboratory of Analytical Technology Development and Offshore Eco-Environment Conservation, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China; Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China.
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Xu X, He M, Xue Q, Li X, Liu A. Genome-based taxonomic classification of the genus Sulfitobacter along with the proposal of a new genus Parasulfitobacter gen. nov. and exploring the gene clusters associated with sulfur oxidation. BMC Genomics 2024; 25:389. [PMID: 38649849 PMCID: PMC11034169 DOI: 10.1186/s12864-024-10269-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 03/29/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND The genus Sulfitobacter, a member of the family Roseobacteraceae, is widely distributed in the ocean and is believed to play crucial roles in the global sulfur cycle. However, gene clusters associated with sulfur oxidation in genomes of the type strains of this genus have been poorly studied. Furthermore, taxonomic errors have been identified in this genus, potentially leading to significant confusion in ecological and evolutionary interpretations in subsequent studies of the genus Sulfitobacter. This study aims to investigate the taxonomic status of this genus and explore the metabolism associated with sulfur oxidation. RESULTS This study suggests that Sulfitobacter algicola does not belong to Sulfitobacter and should be reclassified into a novel genus, for which we propose the name Parasulfitobacter gen. nov., with Parasulfitobacter algicola comb. nov. as the type species. Additionally, enzymes involved in the sulfur oxidation process, such as the sulfur oxidization (Sox) system, the disulfide reductase protein family, and the sulfite dehydrogenase (SoeABC), were identified in almost all Sulfitobacter species. This finding implies that the majority of Sulfitobacter species can oxidize reduced sulfur compounds. Differences in the modular organization of sox gene clusters among Sulfitobacter species were identified, along with the presence of five genes with unknown function located in some of the sox gene clusters. Lastly, this study revealed the presence of the demethylation pathway and the cleavage pathway used by many Sulfitobacter species to degrade dimethylsulfoniopropionate (DMSP). These pathways enable these bacteria to utilize DMSP as important source of sulfur and carbon or as a defence strategy. CONCLUSIONS Our findings contribute to interpreting the mechanism by which Sulfitobacter species participate in the global sulfur cycle. The taxonomic rearrangement of S. algicola into the novel genus Parasulfitobacter will prevent confusion in ecological and evolutionary interpretations in future studies of the genus Sulfitobacter.
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Affiliation(s)
- Xiaokun Xu
- Department of Pathogenic Biology, College of Basic Medicine, Jining Medical University, 272067, Jining, Shandong, P. R. China
| | - Mengdan He
- School of Basic Medical Sciences, Shandong Second Medical University, 261042, Weifang, Shandong, P. R. China
| | - Qingjie Xue
- Department of Pathogenic Biology, College of Basic Medicine, Jining Medical University, 272067, Jining, Shandong, P. R. China
| | - Xiuzhen Li
- Department of Pathogenic Biology, College of Basic Medicine, Jining Medical University, 272067, Jining, Shandong, P. R. China
| | - Ang Liu
- Department of Pathogenic Biology, College of Basic Medicine, Jining Medical University, 272067, Jining, Shandong, P. R. China.
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Lin S, Guo Y, Huang Z, Tang K, Wang X. Comparative Genomic Analysis of Cold-Water Coral-Derived Sulfitobacter faviae: Insights into Their Habitat Adaptation and Metabolism. Mar Drugs 2023; 21:md21050309. [PMID: 37233503 DOI: 10.3390/md21050309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/15/2023] [Accepted: 05/17/2023] [Indexed: 05/27/2023] Open
Abstract
Sulfitobacter is one of the major sulfite-oxidizing alphaproteobacterial groups and is often associated with marine algae and corals. Their association with the eukaryotic host cell may have important ecological contexts due to their complex lifestyle and metabolism. However, the role of Sulfitobacter in cold-water corals remains largely unexplored. In this study, we explored the metabolism and mobile genetic elements (MGEs) in two closely related Sulfitobacter faviae strains isolated from cold-water black corals at a depth of ~1000 m by comparative genomic analysis. The two strains shared high sequence similarity in chromosomes, including two megaplasmids and two prophages, while both contained several distinct MGEs, including prophages and megaplasmids. Additionally, several toxin-antitoxin systems and other types of antiphage elements were also identified in both strains, potentially helping Sulfitobacter faviae overcome the threat of diverse lytic phages. Furthermore, the two strains shared similar secondary metabolite biosynthetic gene clusters and genes involved in dimethylsulfoniopropionate (DMSP) degradation pathways. Our results provide insight into the adaptive strategy of Sulfitobacter strains to thrive in ecological niches such as cold-water corals at the genomic level.
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Affiliation(s)
- Shituan Lin
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunxue Guo
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Zixian Huang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kaihao Tang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
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Kim M, Cha IT, Lee KE, Park SJ. Sulfitobacter albidus sp. nov., isolated from marine sediment of Jeju Island. Arch Microbiol 2022; 204:691. [DOI: 10.1007/s00203-022-03305-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/22/2022] [Accepted: 10/26/2022] [Indexed: 11/07/2022]
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Oren A, Garrity GM. Validation List no. 206. Valid publication of new names and new combinations effectively published outside the IJSEM. Int J Syst Evol Microbiol 2022; 72. [PMID: 35904866 DOI: 10.1099/ijsem.0.005422] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/09/2024] Open
Affiliation(s)
- Aharon Oren
- The Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus, 9190401 Jerusalem, Israel
| | - George M Garrity
- Department of Microbiology & Molecular Genetics, Biomedical Physical Sciences, Michigan State University, East Lansing, MI 48824-4320, USA
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Yang Q, Ge YM, Iqbal NM, Yang X, Zhang XL. Sulfitobacter alexandrii sp. nov., a new microalgae growth-promoting bacterium with exopolysaccharides bioflocculanting potential isolated from marine phycosphere. Antonie van Leeuwenhoek 2021; 114:1091-1106. [PMID: 33895907 DOI: 10.1007/s10482-021-01580-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/13/2021] [Indexed: 02/04/2023]
Abstract
Marine phycosphere harbors unique cross-kingdom associations with enormous ecological significance in aquatic ecosystems as well as relevance for algal biotechnology industry. During our investigating the microbial composition and bioactivity of marine phycosphere microbiota (PM), a novel lightly yellowish and versatile bacterium designated strain AM1-D1T was isolated from cultivable PM of marine dinoflagellate Alexandrium minutum amtk4 that produces high levels of paralytic shellfish poisoning toxins (PSTs). Strain AM1-D1T demonstrates notable bioflocculanting bioactivity with bacterial exopolysaccharides (EPS), and microalgae growth-promoting (MGP) potential toward its algal host. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain AM1-D1T was affiliated to the members of genus Sulfitobacter within the family Rhodobacteraceae, showing the highest sequence similarity of 97.9% with Sulfitobacter noctilucae NB-68T, and below 97.8% with other type strains. The complete genome of strain AM1-D1T consisted of a circular 3.84-Mb chromosome and five circular plasmids (185, 95, 15, 205 and 348 Kb, respectively) with the G+C content of 64.6%. Low values obtained by phylogenomic calculations on the average nucleotide identity (ANI, 77.2%), average amino acid identity (AAI, 74.7%) and digital DNA-DNA hybridization (dDDH, 18.6%) unequivocally separated strain AM1-D1T from its closest relative. The main polar lipids were identified as phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, diphosphatidylglycerol, one unidentified phospholipid and one unidentified lipid. The predominant fatty acids (> 10%) were C18:1 ω7c, C19:0 cyclo ω8c and C16:0. The respiratory quinone was Q-10. The genome of strain AM1-D1T was predicted to encode series of gene clusters responsible for sulfur oxidation (sox) and utilization of dissolved organic sulfur exometabolites from marine dinoflagellates, taurine (tau) and dimethylsulfoniopropionate (DMSP) (dmd), as well as supplementary vitamin B12 (cob), photosynthesis carotenoids (crt) which are pivotal components during algae-bacteria interactions. Based on the evidences by the polyphasic characterizations, strain AM1-D1T represents a novel species of the genus Sulfitobacter, for which the name Sulfitobacter alexandrii sp. nov. is proposed. The type strain is AM1-D1T (= CCTCC 2017277T = KCTC 62491T).
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Affiliation(s)
- Qiao Yang
- Department of Marine Chemistry, Zhejiang Ocean University, Zhoushan, China.,ABI Group of GPM Project, Zhejiang Ocean University, Zhoushan, China
| | - Ya-Ming Ge
- National Engineering Research Center for Marine Aquaculture, Zhoushan, China
| | - Nurhezreen Md Iqbal
- Malaysia Genome Institute, National Institute of Biotechnology Malaysia, Kajang, Malaysia
| | - Xi Yang
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Xiao-Ling Zhang
- Department of Marine Chemistry, Zhejiang Ocean University, Zhoushan, China.
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