Unstable Relationship Between Braarudosphaera bigelowii (= Chrysochromulina parkeae) and Its Nitrogen-Fixing Endosymbiont

Marine phytoplankton are major primary producers, and their growth is primarily limited by nitrogen in the oligotrophic ocean environment. The haptophyte Braarudosphaera bigelowii possesses a cyanobacterial endosymbiont (UCYN-A), which plays a major role in nitrogen fixation in the ocean. However, host-symbiont interactions are poorly understood because B. bigelowii was unculturable. In this study, we sequenced the complete genome of the B. bigelowii endosymbiont and showed that it was highly reductive and closely related to UCYN-A2 (an ecotype of UCYN-A). We succeeded in establishing B. bigelowii strains and performed microscopic observations. The detailed observations showed that the cyanobacterial endosymbiont was surrounded by a single host derived membrane and divided synchronously with the host cell division. The transcriptome of B. bigelowii revealed that B. bigelowii lacked the expression of many essential genes associated with the uptake of most nitrogen compounds, except ammonia. During cultivation, some of the strains completely lost the endosymbiont. Moreover, we did not find any evidence of endosymbiotic gene transfer from the endosymbiont to the host. These findings illustrate an unstable morphological, metabolic, and genetic relationship between B. bigelowii and its endosymbiont.

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Faculty Opinions recommendation of Origins and evolution of the recA/RAD51 gene family: evidence for ancient gene duplication and endosymbiotic gene transfer.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1033431.386704 ◽

2006 ◽

Author(s):

Guenter Theissen

Keyword(s):

Gene Transfer ◽

Gene Duplication ◽

Gene Family ◽

Endosymbiotic Gene Transfer ◽

Rad51 Gene ◽

Ancient Gene ◽

Ancient Gene Duplication

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Plasmids Related to the Symbiotic Nitrogen Fixation Are Not Only Cooperated Functionally but Also May Have Evolved over a Time Span in Family Rhizobiaceae

Genome Biology and Evolution ◽

10.1093/gbe/evaa152 ◽

2020 ◽

Vol 12 (11) ◽

pp. 2002-2014

Author(s):

Ling-Ling Yang ◽

Zhao Jiang ◽

Yan Li ◽

En-Tao Wang ◽

Xiao-Yang Zhi

Keyword(s):

Nitrogen Fixation ◽

Gene Transfer ◽

Horizontal Gene Transfer ◽

Symbiotic Nitrogen Fixation ◽

Gene Families ◽

Time Span ◽

Soil Conditions ◽

Gene Gain ◽

Nitrogen Fixing ◽

Pan Genome

Abstract Rhizobia are soil bacteria capable of forming symbiotic nitrogen-fixing nodules associated with leguminous plants. In fast-growing legume-nodulating rhizobia, such as the species in the family Rhizobiaceae, the symbiotic plasmid is the main genetic basis for nitrogen-fixing symbiosis, and is susceptible to horizontal gene transfer. To further understand the symbioses evolution in Rhizobiaceae, we analyzed the pan-genome of this family based on 92 genomes of type/reference strains and reconstructed its phylogeny using a phylogenomics approach. Intriguingly, although the genetic expansion that occurred in chromosomal regions was the main reason for the high proportion of low-frequency flexible gene families in the pan-genome, gene gain events associated with accessory plasmids introduced more genes into the genomes of nitrogen-fixing species. For symbiotic plasmids, although horizontal gene transfer frequently occurred, transfer may be impeded by, such as, the host’s physical isolation and soil conditions, even among phylogenetically close species. During coevolution with leguminous hosts, the plasmid system, including accessory and symbiotic plasmids, may have evolved over a time span, and provided rhizobial species with the ability to adapt to various environmental conditions and helped them achieve nitrogen fixation. These findings provide new insights into the phylogeny of Rhizobiaceae and advance our understanding of the evolution of symbiotic nitrogen fixation.

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Complete Genome Sequence of the Naphthalene-Degrading Bacterium Pseudomonas stutzeri AN10 (CCUG 29243)

Journal of Bacteriology ◽

10.1128/jb.01753-12 ◽

2012 ◽

Vol 194 (23) ◽

pp. 6642-6643 ◽

Cited By ~ 26

Author(s):

Isabel Brunet-Galmés ◽

Antonio Busquets ◽

Arantxa Peña ◽

Margarita Gomila ◽

Balbina Nogales ◽

...

Keyword(s):

Gene Transfer ◽

Horizontal Gene Transfer ◽

Genome Sequence ◽

Complete Genome Sequence ◽

Complete Genome ◽

Pseudomonas Stutzeri ◽

Content Type ◽

Naphthalene Degradation ◽

Degrading Bacterium ◽

Model Strain

ABSTRACTPseudomonas stutzeriAN10 (CCUG 29243) can be considered a model strain for aerobic naphthalene degradation. We report the complete genome sequence of this bacterium. Its 4.71-Mb chromosome provides insights into other biodegradative capabilities of strain AN10 (i.e., benzoate catabolism) and suggests a high number of horizontal gene transfer events.

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Experimental design and statistical rigor in phylogenomics of horizontal and endosymbiotic gene transfer

BMC Evolutionary Biology ◽

10.1186/1471-2148-11-259 ◽

2011 ◽

Vol 11 (1) ◽

Cited By ~ 32

Author(s):

John W Stiller

Keyword(s):

Experimental Design ◽

Gene Transfer ◽

Endosymbiotic Gene Transfer

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Investigations on the root nodule bacteria of leguminous plants: XIX. Influence of various factors on the excretion of nitrogenous compounds from the nodules

The Journal of Agricultural Science ◽

10.1017/s0021859600051650 ◽

1937 ◽

Vol 27 (3) ◽

pp. 332-348 ◽

Cited By ~ 16

Author(s):

Artturi Ilmari Virtanen ◽

Synnöve von Hausen ◽

Tauno Laine

Keyword(s):

Amino Acids ◽

Nitrogen Fixation ◽

Root Nodule ◽

Nitrogen Nutrition ◽

Nitrogen Compounds ◽

Nodule Bacteria ◽

Fixed Nitrogen ◽

Nitrogenous Compounds ◽

Primary Products ◽

Equal Effectiveness

1. It has been shown experimentally that the excretion of nitrogen noted by us in cultures of inoculated legumes takes place from the nodule bacteria, probably from the intranodular ones, and not from the roots. No excretion of amino acids occurs in cultures of uninoculated legumes growing on nitrate nitrogen.2. Our earlier hypothesis that the legumes receive their nitrogen nutrition from the nodules in the form of organic nitrogen compounds, particularly amino acids, is in perfect accord with our new observations concerning the process of excretion. All facts indicate that the amino acids concerned are primary products of the nitrogen fixation, and not breakdown products of proteins. Bond's valuable work along quite different lines produced results which support this conclusion. He, however, did not study the chemical nature of the nitrogen compounds in question.3. The excretion of nitrogen occurs in media capable of absorbing the excreted nitrogen compounds (cellulose, kaolin, sand, soil). The demonstration of the excretion is not possible in water cultures except when very large quantities of water are used. On the basis of these facts a hypothesis is advanced to explain the nature of the excretion.4. The term total fixed nitrogen has been used as an expression for the extent of nitrogen fixation, while the term extent of excretion is employed to indicate that percentage of the total fixed nitrogen which is excreted from the nodules.5. The extent of excretion depends largely on the strain used for inoculation. With strains of apparently equal effectiveness in nitrogen fixation, the extent of excretion may vary considerably, so that actually such strains differ in their effectiveness.

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The effect of Inoculation and cobalt application on the growth of and nitrogen fixation by sweet lupins

Australian Journal of Agricultural Research ◽

10.1071/ar9781191 ◽

1978 ◽

Vol 29 (6) ◽

pp. 1191 ◽

Cited By ~ 19

Author(s):

DL Chatel ◽

AD Robson ◽

JW Gartrell ◽

MJ Dilworth

Keyword(s):

Nitrogen Fixation ◽

Cell Division ◽

Plant Growth ◽

Nitrogen Content ◽

Lupinus Angustifolius ◽

Fixed Nitrogen ◽

Soil Application ◽

Seed Inoculation

The response of sweet lupins, Lupinus angustifolius L., to a soil application of cobalt and to seed inoculation was examined in both field and glasshouse experiments. Plant growth was dependent on nodule-fixed nitrogen, and the addition of cobalt increased the nitrogen content and the growth of the lupins in the absence of inoculation. Bacteroids in the nodules of inoculated plants without cobalt were found to be fewer and longer than those with cobalt, which suggests that cobalt is involved in the mechanism of rhizobial cell division.

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Complete Genome Sequences of Six Legionella pneumophila Isolates from Two Collocated Outbreaks of Legionnaires’ Disease in 2005 and 2008 in Sarpsborg/Fredrikstad, Norway

Genome Announcements ◽

10.1128/genomea.01367-16 ◽

2016 ◽

Vol 4 (6) ◽

Author(s):

Marius Dybwad ◽

Tone Aarskaug ◽

Else-Marie Fykse ◽

Elisabeth Henie Madslien ◽

Janet Martha Blatny

Keyword(s):

Comparative Genomics ◽

Genetic Relationship ◽

Legionella Pneumophila ◽

Complete Genome ◽

Sequence Similarity ◽

Secretion Systems ◽

Environmental Isolates ◽

Genome Sequences ◽

High Sequence Similarity ◽

Legionnaires Disease

Here, we report the complete genome sequences of Legionella pneumophila isolates from two collocated outbreaks of Legionnaires’ disease in 2005 and 2008 in Sarpsborg/Fredrikstad, Norway. One clinical and two environmental isolates were sequenced from each outbreak. The genome of all six isolates consisted of a 3.36 Mb-chromosome, while the 2005 genomes featured an additional 68 kb-episome sharing high sequence similarity with the L. pneumophila Lens plasmid. All six genomes contained multiple mobile genetic elements including novel combinations of type-IVA secretion systems. A comparative genomics study will be launched to resolve the genetic relationship between the L. pneumophila isolates.

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Unique genome evolution in an intracellular N2-fixing symbiont of a rhopalodiacean diatom

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.2014.046 ◽

2014 ◽

Vol 83 (4) ◽

pp. 409-413 ◽

Cited By ~ 6

Author(s):

Takuro Nakayama ◽

Yuji Inagaki

Keyword(s):

Nitrogen Fixation ◽

Genome Evolution ◽

Nitrogen Compounds ◽

Diatom Species ◽

Comparative Genome Analysis ◽

Fixed Nitrogen ◽

Metabolic Capacity ◽

Symbiotic Relationships ◽

The Family ◽

Spheroid Body

Cyanobacteria, the major photosynthetic prokaryotic lineage, are also known as a major nitrogen fixer in nature. N2-fixing cyanobacteria are frequently found in symbioses with various types of eukaryotes and supply fixed nitrogen compounds to their eukaryotic hosts, which congenitally lack N2-fixing abilities. Diatom species belonging to the family Rhopalodiaceae also possess cyanobacterial symbionts called spheroid bodies. Unlike other cyanobacterial N2-fixing symbionts, the spheroid bodies reside in the cytoplasm of the diatoms and are inseparable from their hosts. Recently, the first spheroid body genome from a rhopalodiacean diatom has been completely sequenced. Overall features of the genome sequence showed significant reductive genome evolution resulting in a diminution of metabolic capacity. Notably, despite its cyanobacterial origin, the spheroid body was shown to be truly incapable of photosynthesis implying that the symbiont energetically depends on the host diatom. The comparative genome analysis between the spheroid body and another N2-fixing symbiotic cyanobacterial group corresponding to the UCYN-A phylotypes – both were derived from cyanobacteria closely related to genus Cyanothece – revealed that the two symbionts are on similar, but explicitly distinct tracks of reductive evolution. Intimate symbiotic relationships linked by nitrogen fixation as seen in rhopalodiacean diatoms may help us better understand the evolution and mechanisms of bacterium-eukaryote endosymbioses.

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Complete Genome Sequence of Neisseria gonorrhoeae NCCP11945

Journal of Bacteriology ◽

10.1128/jb.00566-08 ◽

2008 ◽

Vol 190 (17) ◽

pp. 6035-6036 ◽

Cited By ~ 44

Author(s):

Gyung Tae Chung ◽

Jeong Sik Yoo ◽

Hee Bok Oh ◽

Yeong Seon Lee ◽

Sun Ho Cha ◽

...

Keyword(s):

Antibiotic Resistance ◽

Gene Transfer ◽

Horizontal Gene Transfer ◽

Neisseria Gonorrhoeae ◽

Genome Sequence ◽

Complete Genome Sequence ◽

Complete Genome ◽

Multidrug Resistant ◽

Human Pathogen ◽

Korean Patient

ABSTRACT Neisseria gonorrhoeae is an obligate human pathogen that is the etiological agent of gonorrhea. We explored variations in the genes of a multidrug-resistant N. gonorrhoeae isolate from a Korean patient in an effort to understand the prevalence, antibiotic resistance, and importance of horizontal gene transfer within this important, naturally competent organism. Here, we report the complete annotated genome sequence of N. gonorrhoeae strain NCCP11945.

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