Prochlorococcus exudate stimulates heterotrophic bacterial competition with rival phytoplankton for available nitrogen

The marine cyanobacterium Prochlorococcus numerically dominates the phytoplankton community of the nutrient-limited open ocean, establishing itself as the most abundant photosynthetic organism on Earth. This ecological success has been attributed to lower cell quotas for limiting nutrients, superior resource acquisition, and other advantages associated with cell size reduction and genome streamlining. In this study we tested the prediction that Prochlorococcus outcompetes its rivals for scarce nutrients, and that this advantage leads to its numerical success in nutrient-limited waters. Strains of Prochlorococcus and its sister genus Synechococcus grew well in both mono- and co-culture when nutrients were replete. However, in nitrogen-limited medium Prochlorococcus outgrew Synechococcus, but only when heterotrophic bacteria were also present. In the nitrogen-limited medium, the heterotroph Alteromonas macleodii outcompeted Synechococcus for nitrogen, but only if stimulated by exudate released by Prochlorococcus, or if a proxy organic carbon source was provided. Analysis of a nitrate reductase mutant Alteromonas suggested that Alteromonas outcompetes Synechococcus for nitrate, during which co-cultured Prochlorococcus grows on ammonia or other available nitrogen species. We propose that Prochlorococcus can stimulate antagonism between heterotrophic bacteria and potential phytoplankton competitors through a metabolic cross-feeding interaction, and this stimulation could contribute to the numerical success of Prochlorococcus in the nutrient-limited regions of the ocean.

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Prochlorococcus Exudate Stimulates Heterotrophic Bacterial Competition with Rival Phytoplankton for Available Nitrogen

mBio ◽

10.1128/mbio.02571-21 ◽

2022 ◽

Author(s):

Benjamin C. Calfee ◽

Liz D. Glasgo ◽

Erik R. Zinser

Keyword(s):

Open Ocean ◽

Limited Resources ◽

Available Nitrogen ◽

Bacterial Competition ◽

Photosynthetic Organism

In nutrient-poor habitats, competition for limited resources is thought to select for organisms with an enhanced ability to scavenge nutrients and utilize them efficiently. Such adaptations characterize the cyanobacterium Prochlorococcus , the most abundant photosynthetic organism in the nutrient-limited open ocean.

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Are Bacterio- and Phytoplankton Community Compositions Related in Lakes Differing in Their Cyanobacteria Contribution and Physico-Chemical Properties?

Genes ◽

10.3390/genes12060855 ◽

2021 ◽

Vol 12 (6) ◽

pp. 855

Author(s):

Mikołaj Kokociński ◽

Dariusz Dziga ◽

Adam Antosiak ◽

Janne Soininen

Keyword(s):

Environmental Factors ◽

Community Composition ◽

Phytoplankton Community ◽

Heterotrophic Bacteria ◽

Bacterial Community Composition ◽

Physical Factors ◽

Research Attention ◽

Phytoplankton Community Composition ◽

The Impact ◽

Bacteria Communities

Bacterioplankton community composition has become the center of research attention in recent years. Bacteria associated with toxic cyanobacteria blooms have attracted considerable interest. However, little is known about the environmental factors driving the bacteria community, including the impact of invasive cyanobacteria. Therefore, our aim has been to determine the relationships between heterotrophic bacteria and phytoplankton community composition across 24 Polish lakes with different contributions of cyanobacteria including the invasive species Raphidiopsis raciborskii. This analysis revealed that cyanobacteria were present in 16 lakes, while R. raciborskii occurred in 14 lakes. Our results show that bacteria communities differed between lakes dominated by cyanobacteria and lakes with minor contributions of cyanobacteria but did not differ between lakes with R. raciborskii and other lakes. Physical factors, including water and Secchi depth, were the major drivers of bacteria and phytoplankton community composition. However, in lakes dominated by cyanobacteria, bacterial community composition was also influenced by biotic factors such as the amount of R. raciborskii, chlorophyll-a and total phytoplankton biomass. Thus, our study provides novel evidence on the influence of environmental factors and R. raciborskii on lake bacteria communities.

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Release of available nitrogen from river-discharged dissolved organic matter by heterotrophic bacteria associated with the cyanobacteriumMicrocystis aeruginosa

Estonian Journal of Ecology ◽

10.3176/eco.2010.3.02 ◽

2010 ◽

Vol 59 (3) ◽

pp. 184 ◽

Cited By ~ 5

Author(s):

S Purvina ◽

C Béchemin ◽

M Balode ◽

C Verite ◽

C Arnaud ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Heterotrophic Bacteria ◽

Available Nitrogen

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Phytoplankton Community Ecology: The Role of Limiting Nutrients

Annual Review of Ecology and Systematics ◽

10.1146/annurev.es.13.110182.002025 ◽

1982 ◽

Vol 13 (1) ◽

pp. 349-372 ◽

Cited By ~ 603

Author(s):

D Tilman ◽

S S Kilham ◽

P Kilham

Keyword(s):

Community Ecology ◽

Phytoplankton Community ◽

Limiting Nutrients

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Transcriptomic Study of Substrate-Specific Transport Mechanisms for Iron and Carbon in the Marine Copiotroph Alteromonas macleodii

mSystems ◽

10.1128/msystems.00070-20 ◽

2020 ◽

Vol 5 (2) ◽

Cited By ~ 2

Author(s):

Lauren E. Manck ◽

Josh L. Espinoza ◽

Christopher L. Dupont ◽

Katherine A. Barbeau

Keyword(s):

Organic Matter ◽

Marine Environment ◽

Heterotrophic Bacteria ◽

Microbial Loop ◽

Cellular Transport ◽

High Molecular Weight Fraction ◽

Transport Mechanisms ◽

Transport Capacity ◽

Content Type ◽

Alteromonas Macleodii

ABSTRACT Iron is an essential micronutrient for all microbial growth in the marine environment, and in heterotrophic bacteria, iron is tightly linked to carbon metabolism due to its central role as a cofactor in enzymes of the respiratory chain. Here, we present the iron- and carbon-regulated transcriptomes of a representative marine copiotroph, Alteromonas macleodii ATCC 27126, and characterize its cellular transport mechanisms. ATCC 27126 has distinct metabolic responses to iron and carbon limitation and, accordingly, uses distinct sets of TonB-dependent transporters for the acquisition of iron and carbon. These distinct sets of TonB-dependent transporters were of a similar number, indicating that the diversity of carbon and iron substrates available to ATCC 27126 is of a similar scale. For the first time in a marine bacterium, we have also identified six characteristic inner membrane permeases for the transport of siderophores via an ATPase-independent mechanism. An examination of the distribution of specific TonB-dependent transporters in 31 genomes across the genus Alteromonas points to niche specialization in transport capacity, particularly for iron. We conclude that the substrate-specific bioavailability of both iron and carbon in the marine environment will likely be a key control on the processing of organic matter through the microbial loop. IMPORTANCE As the major facilitators of the turnover of organic matter in the marine environment, the ability of heterotrophic bacteria to acquire specific compounds within the diverse range of dissolved organic matter will affect the regeneration of essential nutrients such as iron and carbon. TonB-dependent transporters are a prevalent cellular tool in Gram-negative bacteria that allow a relatively high-molecular-weight fraction of organic matter to be directly accessed. However, these transporters are not well characterized in marine bacteria, limiting our understanding of the flow of specific substrates through the marine microbial loop. Here, we characterize the TonB-dependent transporters responsible for iron and carbon acquisition in a representative marine copiotroph and examine their distribution across the genus Alteromonas. We provide evidence that substrate-specific bioavailability is niche specific, particularly for iron complexes, indicating that transport capacity may serve as a significant control on microbial community dynamics and the resultant cycling of organic matter.

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Down to the bone: the role of overlooked endolithic microbiomes in reef coral health

The ISME Journal ◽

10.1038/s41396-019-0548-z ◽

2019 ◽

Vol 14 (2) ◽

pp. 325-334 ◽

Cited By ~ 9

Author(s):

Mathieu Pernice ◽

Jean-Baptiste Raina ◽

Nils Rädecker ◽

Anny Cárdenas ◽

Claudia Pogoreutz ◽

...

Keyword(s):

Calcium Carbonate ◽

Heterotrophic Bacteria ◽

Reef Coral ◽

Coral Skeleton ◽

Coral Reef Ecosystems ◽

Metabolic Interactions ◽

Ecological Success ◽

Coral Health ◽

Internal Volume

Abstract Reef-building corals harbour an astonishing diversity of microorganisms, including endosymbiotic microalgae, bacteria, archaea, and fungi. The metabolic interactions within this symbiotic consortium are fundamental to the ecological success of corals and the unique productivity of coral reef ecosystems. Over the last two decades, scientific efforts have been primarily channelled into dissecting the symbioses occurring in coral tissues. Although easily accessible, this compartment is only 2–3 mm thick, whereas the underlying calcium carbonate skeleton occupies the vast internal volume of corals. Far from being devoid of life, the skeleton harbours a wide array of algae, endolithic fungi, heterotrophic bacteria, and other boring eukaryotes, often forming distinct bands visible to the bare eye. Some of the critical functions of these endolithic microorganisms in coral health, such as nutrient cycling and metabolite transfer, which could enable the survival of corals during thermal stress, have long been demonstrated. In addition, some of these microorganisms can dissolve calcium carbonate, weakening the coral skeleton and therefore may play a major role in reef erosion. Yet, experimental data are wanting due to methodological limitations. Recent technological and conceptual advances now allow us to tease apart the complex physical, ecological, and chemical interactions at the heart of coral endolithic microbial communities. These new capabilities have resulted in an excellent body of research and provide an exciting outlook to further address the functional microbial ecology of the “overlooked” coral skeleton.

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Limiting nutrients of phytoplankton community in Hiroshima Bay, Japan

Water Research ◽

10.1016/0043-1354(95)00307-x ◽

1996 ◽

Vol 30 (6) ◽

pp. 1490-1494 ◽

Cited By ~ 18

Author(s):

Young Sik Lee ◽

Tohru Seiki ◽

Tetsuo Mukai ◽

Kazuto Takimoto ◽

Mitsumasa Okada

Keyword(s):

Phytoplankton Community ◽

Limiting Nutrients

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Degradation and utilization of Alginate by marine Pseudoalteromonas : a review

Applied and Environmental Microbiology ◽

10.1128/aem.00368-21 ◽

2021 ◽

Author(s):

Fei Xu ◽

Qian-Qian Cha ◽

Yu-Zhong Zhang ◽

Xiu-Lan Chen

Keyword(s):

Carbon Source ◽

Marine Algae ◽

Heterotrophic Bacteria ◽

Comprehensive Overview ◽

Important Group ◽

Catalytic Mechanisms ◽

Organic Carbon Source ◽

Alginate Lyases ◽

Alginate Degradation ◽

Marine Organic Carbon

Alginate, which is mainly produced by brown algae and decomposed by heterotrophic bacteria, is an important marine organic carbon source. The genus Pseudoalteromonas contains diverse forms of heterotrophic bacteria that are widely distributed in marine environments and are an important group in alginate degradation. In this review, the diversity of alginate-degrading Pseudoalteromonas is introduced and the character of Pseudoalteromonas alginate lyases, including their sequences, enzymatic properties, structures and catalytic mechanisms, and the synergistic effect of Pseudoalteromonas alginate lyases on alginate degradation are introduced. The acquisition of the alginate-degradation capacity and the alginate utilization pathways of Pseudoalteromonas are also introduced. This paper provides a comprehensive overview of alginate degradation by Pseudoalteromonas, which will contribute to the understanding of the degradation and recycling of marine algae polysaccharides driven by marine bacteria.

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