Evolutionary genomics of APSE: a tailed phage that lysogenically converts the bacterium Hamiltonella defensa into a heritable protective symbiont of aphids

Abstract Background Most phages infect free-living bacteria but a few have been identified that infect heritable symbionts of insects or other eukaryotes. Heritable symbionts are usually specialized and isolated from other bacteria with little known about the origins of associated phages. Hamiltonella defensa is a heritable bacterial symbiont of aphids that is usually infected by a tailed, double-stranded DNA phage named APSE. Methods We conducted comparative genomic and phylogenetic studies to determine how APSE is related to other phages and prophages. Results Each APSE genome was organized into four modules and two predicted functional units. Gene content and order were near-fully conserved in modules 1 and 2, which encode predicted DNA metabolism genes, and module 4, which encodes predicted virion assembly genes. Gene content of module 3, which contains predicted toxin, holin and lysozyme genes differed among haplotypes. Comparisons to other sequenced phages suggested APSE genomes are mosaics with modules 1 and 2 sharing similarities with Bordetella-Bcep-Xylostella fastidiosa-like podoviruses, module 4 sharing similarities with P22-like podoviruses, and module 3 sharing no similarities with known phages. Comparisons to other sequenced bacterial genomes identified APSE-like elements in other heritable insect symbionts (Arsenophonus spp.) and enteric bacteria in the family Morganellaceae. Conclusions APSEs are most closely related to phage elements in the genus Arsenophonus and other bacteria in the Morganellaceae.

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Genome Sequences of Three Agrobacterium Biovars Help Elucidate the Evolution of Multichromosome Genomes in Bacteria

Journal of Bacteriology ◽

10.1128/jb.01779-08 ◽

2009 ◽

Vol 191 (8) ◽

pp. 2501-2511 ◽

Cited By ~ 159

Author(s):

Steven C. Slater ◽

Barry S. Goldman ◽

Brad Goodner ◽

João C. Setubal ◽

Stephen K. Farrand ◽

...

Keyword(s):

Plant Pathogens ◽

Biochemical Properties ◽

Gene Content ◽

Bacterial Genomes ◽

Associated Bacteria ◽

Narrow Host Range ◽

Chromosome Architecture ◽

The Family ◽

Chromosome Formation ◽

Conserved Gene

ABSTRACT The family Rhizobiaceae contains plant-associated bacteria with critical roles in ecology and agriculture. Within this family, many Rhizobium and Sinorhizobium strains are nitrogen-fixing plant mutualists, while many strains designated as Agrobacterium are plant pathogens. These contrasting lifestyles are primarily dependent on the transmissible plasmids each strain harbors. Members of the Rhizobiaceae also have diverse genome architectures that include single chromosomes, multiple chromosomes, and plasmids of various sizes. Agrobacterium strains have been divided into three biovars, based on physiological and biochemical properties. The genome of a biovar I strain, A. tumefaciens C58, has been previously sequenced. In this study, the genomes of the biovar II strain A. radiobacter K84, a commercially available biological control strain that inhibits certain pathogenic agrobacteria, and the biovar III strain A. vitis S4, a narrow-host-range strain that infects grapes and invokes a hypersensitive response on nonhost plants, were fully sequenced and annotated. Comparison with other sequenced members of the Alphaproteobacteria provides new data on the evolution of multipartite bacterial genomes. Primary chromosomes show extensive conservation of both gene content and order. In contrast, secondary chromosomes share smaller percentages of genes, and conserved gene order is restricted to short blocks. We propose that secondary chromosomes originated from an ancestral plasmid to which genes have been transferred from a progenitor primary chromosome. Similar patterns are observed in select Beta- and Gammaproteobacteria species. Together, these results define the evolution of chromosome architecture and gene content among the Rhizobiaceae and support a generalized mechanism for second-chromosome formation among bacteria.

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Defensive hypervariable regions confer superinfection exclusion in microviruses

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2102786118 ◽

2021 ◽

Vol 118 (28) ◽

pp. e2102786118

Author(s):

Paul C. Kirchberger ◽

Zachary A. Martinez ◽

Landry J. Luker ◽

Howard Ochman

Keyword(s):

Hypervariable Region ◽

Bacterial Genomes ◽

Human Gut ◽

Dominant Position ◽

Evolutionary Origins ◽

Dna Injection ◽

Hypervariable Regions ◽

Double Stranded Dna ◽

The Family ◽

Additional Role

Single-stranded DNA phages of the family Microviridae have fundamentally different evolutionary origins and dynamics than the more frequently studied double-stranded DNA phages. Despite their small size (around 5 kb), which imposes extreme constraints on genomic innovation, they have adapted to become prominent members of viromes in numerous ecosystems and hold a dominant position among viruses in the human gut. We show that multiple, divergent lineages in the family Microviridae have independently become capable of lysogenizing hosts and have convergently developed hypervariable regions in their DNA pilot protein, which is responsible for injecting the phage genome into the host. By creating microviruses with combinations of genomic segments from different phages and infecting Escherichia coli as a model system, we demonstrate that this hypervariable region confers the ability of temperate Microviridae to prevent DNA injection and infection by other microviruses. The DNA pilot protein is present in most microviruses, but has been recruited repeatedly into this additional role as microviruses altered their lifestyle by evolving the ability to integrate in bacterial genomes, which linked their survival to that of their hosts. Our results emphasize that competition between viruses is a considerable and often overlooked source of selective pressure, and by producing similar evolutionary outcomes in distinct lineages, it underlies the prevalence of hypervariable regions in the genomes of microviruses and perhaps beyond.

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DNA Packaging and Genomics of the Salmonella 9NA-Like Phages

Journal of Virology ◽

10.1128/jvi.00848-19 ◽

2019 ◽

Vol 93 (22) ◽

Author(s):

Chi Zeng ◽

Eddie B. Gilcrease ◽

Roger W. Hendrix ◽

Yicheng Xie ◽

Michael J. Jalfon ◽

...

Keyword(s):

Bacterial Communities ◽

Core Genome ◽

Phage Type ◽

Dna Packaging ◽

Measuring Device ◽

Content Type ◽

Virion Assembly ◽

Double Stranded Dna ◽

The Family ◽

Potential Use

ABSTRACT We present the genome sequences of Salmonella enterica tailed phages Sasha, Sergei, and Solent. These phages, along with Salmonella phages 9NA, FSL_SP-062, and FSL_SP-069 and the more distantly related Proteus phage PmiS-Isfahan, have similarly sized genomes of between 52 and 57 kbp in length that are largely syntenic. Their genomes also show substantial genome mosaicism relative to one another, which is common within tailed phage clusters. Their gene content ranges from 80 to 99 predicted genes, of which 40 are common to all seven and form the core genome, which includes all identifiable virion assembly and DNA replication genes. The total number of gene types (pangenome) in the seven phages is 176, and 59 of these are unique to individual phages. Their core genomes are much more closely related to one another than to the genome of any other known phage, and they comprise a well-defined cluster within the family Siphoviridae. To begin to characterize this group of phages in more experimental detail, we identified the genes that encode the major virion proteins and examined the DNA packaging of the prototypic member, phage 9NA. We show that it uses a pac site-directed headful packaging mechanism that results in virion chromosomes that are circularly permuted and about 13% terminally redundant. We also show that its packaging series initiates with double-stranded DNA cleavages that are scattered across a 170-bp region and that its headful measuring device has a precision of ±1.8%. IMPORTANCE The 9NA-like phages are clearly highly related to each other but are not closely related to any other known phage type. This work describes the genomes of three new 9NA-like phages and the results of experimental analysis of the proteome of the 9NA virion and DNA packaging into the 9NA phage head. There is increasing interest in the biology of phages because of their potential for use as antibacterial agents and for their ecological roles in bacterial communities. 9NA-like phages that infect two bacterial genera have been identified to date, and related phages infecting additional Gram-negative bacterial hosts are likely to be found in the future. This work provides a foundation for the study of these phages, which will facilitate their study and potential use.

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The chloroplast genome evolution of Venus slipper (Paphiopedilum): IR expansion, SSC contraction, and highly rearranged SSC regions

BMC Plant Biology ◽

10.1186/s12870-021-03053-y ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Yan-Yan Guo ◽

Jia-Xing Yang ◽

Ming-Zhu Bai ◽

Guo-Qiang Zhang ◽

Zhong-Jian Liu

Keyword(s):

Gene Order ◽

Inverted Repeat ◽

Single Copy ◽

Gene Content ◽

Comparative Genomic ◽

Substitution Rates ◽

Plastome Evolution ◽

Chloroplast Genomes ◽

Ideal System ◽

Small Single Copy

Abstract Background Paphiopedilum is the largest genus of slipper orchids. Previous studies showed that the phylogenetic relationships of this genus are not well resolved, and sparse taxon sampling documented inverted repeat (IR) expansion and small single copy (SSC) contraction of the chloroplast genomes of Paphiopedilum. Results Here, we sequenced, assembled, and annotated 77 plastomes of Paphiopedilum species (size range of 152,130 – 164,092 bp). The phylogeny based on the plastome resolved the relationships of the genus except for the phylogenetic position of two unstable species. We used phylogenetic and comparative genomic approaches to elucidate the plastome evolution of Paphiopedilum. The plastomes of Paphiopedilum have a conserved genome structure and gene content except in the SSC region. The large single copy/inverted repeat (LSC/IR) boundaries are relatively stable, while the boundaries of the inverted repeat and small single copy region (IR/SSC) varied among species. Corresponding to the IR/SSC boundary shifts, the chloroplast genomes of the genus experienced IR expansion and SSC contraction. The IR region incorporated one to six genes of the SSC region. Unexpectedly, great variation in the size, gene order, and gene content of the SSC regions was found, especially in the subg. Parvisepalum. Furthermore, Paphiopedilum provides evidence for the ongoing degradation of the ndh genes in the photoautotrophic plants. The estimated substitution rates of the protein coding genes show accelerated rates of evolution in clpP, psbH, and psbZ. Genes transferred to the IR region due to the boundary shift also have higher substitution rates. Conclusions We found IR expansion and SSC contraction in the chloroplast genomes of Paphiopedilum with dense sampling, and the genus shows variation in the size, gene order, and gene content of the SSC region. This genus provides an ideal system to investigate the dynamics of plastome evolution.

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The Mycobacteriophage Ms6 LysB N-Terminus Displays Peptidoglycan Binding Affinity

Viruses ◽

10.3390/v13071377 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1377

Author(s):

Adriano M. Gigante ◽

Francisco Olivença ◽

Maria João Catalão ◽

Paula Leandro ◽

José Moniz-Pereira ◽

...

Keyword(s):

Mycobacterium Smegmatis ◽

Fluorescent Protein ◽

Cell Envelope ◽

Structural Similarity ◽

Lytic Cycle ◽

Specific Lysis ◽

Double Stranded Dna ◽

The Family ◽

N Terminus ◽

Green Fluorescent

Double-stranded DNA bacteriophages end their lytic cycle by disrupting the host cell envelope, which allows the release of the virion progeny. Each phage must synthesize lysis proteins that target each cell barrier to phage release. In addition to holins, which permeabilize the cytoplasmic membrane, and endolysins, which disrupt the peptidoglycan (PG), mycobacteriophages synthesize a specific lysis protein, LysB, capable of detaching the outer membrane from the complex cell wall of mycobacteria. The family of LysB proteins is highly diverse, with many members presenting an extended N-terminus. The N-terminal region of mycobacteriophage Ms6 LysB shows structural similarity to the PG-binding domain (PGBD) of the φKZ endolysin. A fusion of this region with enhanced green fluorescent protein (Ms6LysBPGBD-EGFP) was shown to bind to Mycobacterium smegmatis, Mycobacterium vaccae, Mycobacterium bovis BGC and Mycobacterium tuberculosis H37Ra cells pretreated with SDS or Ms6 LysB. In pulldown assays, we demonstrate that Ms6 LysB and Ms6LysBPGBD-EGFP bind to purified peptidoglycan of M. smegmatis, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis, demonstrating affinity to PG of the A1γ chemotype. An infection assay with an Ms6 mutant producing a truncated version of LysB lacking the first 90 amino acids resulted in an abrupt lysis. These results clearly demonstrate that the N-terminus of Ms6 LysB binds to the PG.

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Phylogenetic relationships of Mediterranean black corals (Cnidaria : Anthozoa : Hexacorallia) and implications for classification within the order Antipatharia

Invertebrate Systematics ◽

10.1071/is17043 ◽

2018 ◽

Vol 32 (5) ◽

pp. 1102 ◽

Cited By ~ 10

Author(s):

M. Bo ◽

M. Barucca ◽

M. A. Biscotti ◽

M. R. Brugler ◽

A. Canapa ◽

...

Keyword(s):

Type Species ◽

Sequence Data ◽

Coral Fauna ◽

Black Coral ◽

Phylogenetic Studies ◽

Black Corals ◽

The Family ◽

The Mediterranean ◽

Its1 And Its2 Rdna ◽

Its1 And Its2

The Mediterranean black coral fauna includes type species of four antipatharian genera belonging to four different families, therefore phylogenetic studies hold great potential for enhancing systematics within the order. The analysis of six Mediterranean antipatharian species by means of nuclear sequence data of internal transcribed spacer (ITS1 and ITS2) rDNA confirms the separation into different families, as was previously noted on a morphological basis, with a clear distinction of the family Leiopathidae, whose position is supported by a unique number of mesenteries and lack of spines on thicker ramifications. The position of a newly recorded black coral species for the Mediterranean basin belonging to the genus Phanopathes is discussed. Antipathes dichotoma, the type species of the genus Antipathes, on which the order Antipatharia was based, does not group with other members of the family Antipathidae. Supporting a recent finding based on mitochondrial markers, this suggests a critical need for revision of the families that will be impacted by reassignment of this nomenclaturally important taxon.

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Rhopalocnemis phalloides has one of the most reduced and mutated plastid genomes known

PeerJ ◽

10.7717/peerj.7500 ◽

2019 ◽

Vol 7 ◽

pp. e7500 ◽

Cited By ~ 4

Author(s):

Mikhail I. Schelkunov ◽

Maxim S. Nuraliev ◽

Maria D. Logacheva

Keyword(s):

Plant Species ◽

Mutation Rate ◽

Plastid Genome ◽

Gene Content ◽

High Mutation Rate ◽

Base Pairs ◽

Plastid Genomes ◽

The Family

Although most plant species are photosynthetic, several hundred species have lost the ability to photosynthesize and instead obtain nutrients via various types of heterotrophic feeding. Their plastid genomes markedly differ from the plastid genomes of photosynthetic plants. In this work, we describe the sequenced plastid genome of the heterotrophic plant Rhopalocnemis phalloides, which belongs to the family Balanophoraceae and feeds by parasitizing other plants. The genome is highly reduced (18,622 base pairs vs. approximately 150 kbp in autotrophic plants) and possesses an extraordinarily high AT content, 86.8%, which is inferior only to AT contents of plastid genomes of Balanophora, a genus from the same family. The gene content of this genome is quite typical of heterotrophic plants, with all of the genes related to photosynthesis having been lost. The remaining genes are notably distorted by a high mutation rate and the aforementioned AT content. The high AT content has led to sequence convergence between some of the remaining genes and their homologs from AT-rich plastid genomes of protists. Overall, the plastid genome of R. phalloides is one of the most unusual plastid genomes known.

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The Fourth International Symposium on Ranaviruses: Summary of North American Herpetological Content and Points of Interest

Journal of North American Herpetology ◽

10.17161/jnah.vi.13539 ◽

2020 ◽

pp. 29

Author(s):

Lauren Ash ◽

Rachel Marschang ◽

Jolianne Rijks ◽

Amanda Duffus

Keyword(s):

North America ◽

International Symposium ◽

North American ◽

Fourth International Symposium ◽

Dna Viruses ◽

The North ◽

Double Stranded Dna ◽

Points Of Interest ◽

The Family ◽

Globally Distributed

Ranaviruses are large double stranded DNA viruses from the family Iridoviridae. They are globally distributed and are currently known to affect fish, reptiles and amphibians. In North America, ranaviruses are also widely distributed, and cause frequent morbidity and mortality events in both wild and cultured populations. This is a synopsys of the North American content of the 4th International Symposium on Ranaviruses held in May 2017 in Budapest, Hungary.

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Digging deeper: new gene order rearrangements and distinct patterns of codons usage in mitochondrial genomes among shrimps from the Axiidea, Gebiidea and Caridea (Crustacea: Decapoda)

PeerJ ◽

10.7717/peerj.2982 ◽

2017 ◽

Vol 5 ◽

pp. e2982 ◽

Cited By ~ 20

Author(s):

Mun Hua Tan ◽

Han Ming Gan ◽

Yin Peng Lee ◽

Gary C.B. Poore ◽

Christopher M. Austin

Keyword(s):

Codon Usage ◽

Gene Order ◽

Phylogenetic Relationships ◽

Decapod Crustacean ◽

Illumina Miseq ◽

Comparative Genomic ◽

Decapod Crustaceans ◽

Phylogenetic Studies ◽

Significant Gene ◽

Taxonomic Groups

BackgroundWhole mitochondrial DNA is being increasingly utilized for comparative genomic and phylogenetic studies at deep and shallow evolutionary levels for a range of taxonomic groups. Although mitogenome sequences are deposited at an increasing rate into public databases, their taxonomic representation is unequal across major taxonomic groups. In the case of decapod crustaceans, several infraorders, including Axiidea (ghost shrimps, sponge shrimps, and mud lobsters) and Caridea (true shrimps) are still under-represented, limiting comprehensive phylogenetic studies that utilize mitogenomic information.MethodsSequence reads from partial genome scans were generated using the Illumina MiSeq platform and mitogenome sequences were assembled from these low coverage reads. In addition to examining phylogenetic relationships within the three infraorders, Axiidea, Gebiidea, and Caridea, we also investigated the diversity and frequency of codon usage bias and mitogenome gene order rearrangements.ResultsWe present new mitogenome sequences for five shrimp species from Australia that includes two ghost shrimps,Callianassa ceramicaandTrypaea australiensis, along with three caridean shrimps,Macrobrachium bullatum,Alpheus lobidens, andCaridinacf.nilotica. Strong differences in codon usage were discovered among the three infraorders and significant gene order rearrangements were observed. While the gene order rearrangements are congruent with the inferred phylogenetic relationships and consistent with taxonomic classification, they are unevenly distributed within and among the three infraorders.DiscussionOur findings suggest potential for mitogenome rearrangements to be useful phylogenetic markers for decapod crustaceans and at the same time raise important questions concerning the drivers of mitogenome evolution in different decapod crustacean lineages.

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The genus Microniphargus (Crustacea, Amphipoda): evidence for three lineages distributed across northwestern Europe and transfer from Niphargidae to Pseudoniphargidae

Belgian Journal of Zoology ◽

10.26496/bjz.2021.92 ◽

2021 ◽

Vol 151 ◽

Author(s):

Dieter Weber ◽

Fabio Stoch ◽

Lee R.F.D. Knight ◽

Claire Chauveau ◽

Jean-François Flot

Keyword(s):

Cytochrome C ◽

Cytochrome C Oxidase ◽

Phylogenetic Analyses ◽

Ribosomal Gene ◽

Phylogenetic Position ◽

Mitochondrial Cytochrome ◽

Monotypic Genus ◽

Centre Of Origin ◽

Phylogenetic Studies ◽

The Family

Microniphargus leruthi Schellenberg, 1934 (Amphipoda: Niphargidae) was first described based on samples collected in Belgium and placed in a monotypic genus within the family Niphargidae. However, some details of its morphology as well as recent phylogenetic studies suggest that Microniphargus may be more closely related to Pseudoniphargus (Amphipoda: Pseudoniphargidae) than to Niphargus. Moreover, M. leruthi ranges over 1,469 km from Ireland to Germany, which is striking since only a few niphargids have confirmed ranges in excess of 200 km. To find out the phylogenetic position of M. leruthi and check whether it may be a complex of cryptic species, we collected material from Ireland, England and Belgium then sequenced fragments of the mitochondrial cytochrome c oxidase subunit 1 gene as well as of the nuclear 28S ribosomal gene. Phylogenetic analyses of both markers confirm that Microniphargus is closer to Pseudoniphargus than to Niphargus, leading us to reallocate Microniphargus to Pseudoniphargidae. We also identify three congruent mito-nuclear lineages present respectively in Ireland, in both Belgium and England, and in England only (with the latter found in sympatry at one location), suggesting that M. leruthi is a complex of at least three species with a putative centre of origin in England.

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