scholarly journals Horizontal transfer of microbial toxin genes to gall midge genomes

2021 ◽  
Author(s):  
Kirsten I. Verster ◽  
Rebecca L. Tarnopol ◽  
Saron M. Akalu ◽  
Noah K. Whiteman
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Horizontal Transfer ◽  
Acyrthosiphon Pisum ◽  
Phylogenetic Signal ◽  
Eukaryotic Cells ◽  
Toxin Gene ◽  
Toxin Genes ◽  
Nuclear Genomes ◽  
Secondary Endosymbiont

AbstractA growing body of evidence points to a role for horizontal gene transfer (HGT) in the evolution of animal novelties. Previously, we discovered the horizontal transfer of the gene encoding the eukaryotic genotoxin cytolethal distending toxin B (CdtB) from the Acyrthosiphon pisum Secondary Endosymbiont (APSE) bacteriophage to drosophilid and aphid genomes. Here, we report that cdtB is also found in the nuclear genome of the gall-forming ‘swede midge’ Contarinia nasturtii (Diptera: Cecidomyiidae). We subsequently searched genome sequences of all available cecidomyiid species for evidence of microbe-to-insect HGT events. We found evidence of pervasive transfer of APSE-like toxin genes to cecidomyiid nuclear genomes. Many of the toxins encoded by these horizontally transferred genes target eukaryotic cells, rather than prokaryotes. In insects, catalytic residues important for toxin function are conserved. Phylogenetic analyses of HGT candidates indicated APSE phages were often not the ancestral donor of the toxin gene to cecidomyiid genomes, suggesting a broader pool of microbial donor lineages. We used a phylogenetic signal statistic to test a transfer-by-proximity hypothesis for HGT, which showed, that prokaryotic-to-insect HGT was more likely to occur between taxa in common environments. Our study highlights the horizontal transfer of genes encoding a new functional class of proteins in insects, toxins that target eukaryotic cells, which is potentially important in mediating interactions with eukaryotic pathogens and parasites.Significance StatementThe diversity of genes encoded by phages infecting bacterial symbionts of eukaryotes represents an enormous, relatively unexplored pool of new eukaryotic genes through horizontal gene transfer (HGT). In this study, we discovered pervasive HGT of toxin genes encoded by Acyrthosiphon pisum secondary endosymbiont (APSE) bacteriophages and other microbes to the nuclear genomes of gall midges (Diptera: Cecidomyiidae). We found five toxin genes were transferred horizontally from phage, bacteria, or fungi into genomes of several cecidomyiid species. These genes were aip56, cdtB, lysozyme, rhs, and sltxB. Most of the toxins encoded by these genes antagonize eukaryotic cells, and we posit that they may play a protective role in the insect immune system.

scholarly journals Horizontal transfer of microbial toxin genes to gall midge genomes

2021 ◽  
Author(s):  
Verster Kirsten I ◽  
Rebecca L Tarnopol ◽  
Saron M Akalu ◽  
Noah K Whiteman
Keyword(s):  
Horizontal Transfer ◽  
Acyrthosiphon Pisum ◽  
Phylogenetic Signal ◽  
Phylogenetic Analyses ◽  
Gall Midge ◽  
Nuclear Genome ◽  
Toxin Gene ◽  
Animal Evolution ◽  
Toxin Genes ◽  
Nuclear Genomes

Abstract A growing body of evidence has underscored the role of horizontal gene transfer (HGT) in animal evolution. Previously, we discovered the horizontal transfer of the gene encoding the eukaryotic genotoxin cytolethal distending toxin B (cdtB) from the pea aphid Acyrthosiphon pisum secondary endosymbiont (APSE) phages to drosophilid and aphid nuclear genomes. Here, we report cdtB in the nuclear genome of the gall-forming ‘swede midge’ Contarinia nasturtii (Diptera: Cecidomyiidae) via HGT. We searched all available gall midge genome sequences for evidence of APSE-to-insect HGT events and found five toxin genes (aip56, cdtB, lysozyme, rhs, and sltxB) transferred horizontally to cecidomyiid nuclear genomes. Surprisingly, phylogenetic analyses of HGT candidates indicated APSE phages were often not the ancestral donor lineage of the toxin gene to cecidomyiids. We used a phylogenetic signal statistic to test a transfer-by-proximity hypothesis for animal HGT, which suggested that microbe-to-insect HGT was more likely between taxa that share environments than those from different environments. Many of the toxins we found in midge genomes target eukaryotic cells, and catalytic residues important for toxin function are conserved in insect copies. This class of horizontally transferred, eukaryotic cell-targeting genes is potentially important in insect adaptation.

scholarly journals Involvement of plastid, mitochondrial and nuclear genomes in plant-to-plant horizontal gene transfer

2014 ◽  
Vol 83 (4) ◽  
pp. 317-323 ◽  
Author(s):  
Maria Virginia Sanchez-Puerta
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Plant Mitochondria ◽  
Genetic Material ◽  
Single Copy ◽  
Convincing Evidence ◽  
Cell Contact ◽  
Plant Mtdna ◽  
Nuclear Genomes ◽  
Foreign Genes

This review focuses on plant-to-plant horizontal gene transfer (HGT) involving the three DNA-containing cellular compartments. It highlights the great incidence of HGT in the mitochondrial genome (mtDNA) of angiosperms, the increasing number of examples in plant nuclear genomes, and the lack of any convincing evidence for HGT in the well-studied plastid genome of land plants. Most of the foreign mitochondrial genes are non-functional, generally found as pseudogenes in the recipient plant mtDNA that maintains its functional native genes. The few exceptions involve chimeric HGT, in which foreign and native copies recombine leading to a functional and single copy of the gene. Maintenance of foreign genes in plant mitochondria is probably the result of genetic drift, but a possible evolutionary advantage may be conferred through the generation of genetic diversity by gene conversion between native and foreign copies. Conversely, a few cases of nuclear HGT in plants involve functional transfers of novel genes that resulted in adaptive evolution. Direct cell-to-cell contact between plants (e.g. host-parasite relationships or natural grafting) facilitate the exchange of genetic material, in which HGT has been reported for both nuclear and mitochondrial genomes, and in the form of genomic DNA, instead of RNA. A thorough review of the literature indicates that HGT in mitochondrial and nuclear genomes of angiosperms is much more frequent than previously expected and that the evolutionary impact and mechanisms underlying plant-to-plant HGT remain to be uncovered.

Type III Secretion: More Systems Than You Think

Physiology ◽  
2005 ◽  
Vol 20 (5) ◽  
pp. 326-339 ◽  
Author(s):  
Paul Troisfontaines ◽  
Guy R. Cornelis
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Type Iii Secretion ◽  
Plant Cells ◽  
Effector Proteins ◽  
Eukaryotic Cells ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Type Iii ◽  
Target Animal

The type III secretion (T3S) pathway allows bacteria to inject effector proteins into the cytosol of target animal or plant cells. T3S systems evolved into seven families that were distributed among Gram-negative bacteria by horizontal gene transfer. There are probably a few hundred effectors interfering with control and signaling in eukaryotic cells and offering a wealth of new tools to cell biologists.

scholarly journals Horizontal gene transfer of a bacterial insect toxin gene into the Epichloë fungal symbionts of grasses

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Karen V. Ambrose ◽  
Albrecht M. Koppenhöfer ◽  
Faith C. Belanger
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Toxin Gene ◽  
Insect Toxin

scholarly journals Extensive Phenotypic Changes Associated with Large-scale Horizontal Gene Transfer

2013 ◽  
Author(s):  
Kevin Dougherty ◽  
Brian A Smith ◽  
Autum F Moore ◽  
Shannon Maitland ◽  
Chris Fanger ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Horizontal Transfer ◽  
Large Scale ◽  
Pseudomonas Stutzeri ◽  
Transfer Event ◽  
Small Plasmid ◽  
Phenotypic Changes ◽  
Evolutionary Trajectories ◽  
Evolutionary Consequences

Horizontal gene transfer often leads to phenotypic changes within recipient organisms independent of any immediate evolutionary benefits. While secondary phenotypic effects of horizontal transfer (i.e. changes in growth rates) have been demonstrated and studied across a variety of systems using relatively small plasmid and phage, little is known about how size of the acquired region affects the magnitude or number of such costs. Here we describe an amazing breadth of phenotypic changes which occur after a large-scale horizontal transfer event (~1Mb megaplasmid) within Pseudomonas stutzeri including sensitization to various stresses as well as changes in bacterial behavior. These results highlight the power of horizontal transfer to shift pleiotropic relationships and cellular networks within bacterial genomes. They also provide an important context for how secondary effects of transfer can bias evolutionary trajectories and interactions between species. Lastly, these results and system provide a foundation to investigate evolutionary consequences in real time as newly acquired regions are ameliorated and integrated into new genomic contexts.

scholarly journals Repression of YdaS Toxin is Mediated by Transcriptional Repressor RacR in the cryptic rac prophage of Escherichia coli-K12

2017 ◽  
Author(s):  
Revathy Krishnamurthi ◽  
Swagatha Ghosh ◽  
Supriya Khedkar ◽  
Aswin Sai Narain Seshasayee
Keyword(s):  
Escherichia Coli ◽  
Transcription Factor ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Driving Force ◽  
Transcriptional Repressor ◽  
Genomic Diversity ◽  
Toxin Gene ◽  
Escherichia Coli K12 ◽  
Putative Transcription Factor

AbstractHorizontal gene transfer is a major driving force behind the genomic diversity seen in prokaryotes. Theracprophage inE.coliK12 encodes a putative transcription factor RacR, whose deletion is lethal. We have shown that the essentiality ofracRinE.coliK12 is attributed to its role in transcriptionally repressing a toxin gene calledydaS, which is coded adjacent and divergently toracR.

scholarly journals Mitochondrial genomes of two parasitic Cuscuta species show little evidence of horizontal gene transfer and retain unusually fragmented ccmFC genes

2021 ◽  
Author(s):  
Benjamin M. Anderson ◽  
Kirsten Krause ◽  
Gitte Petersen
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Genetic Material ◽  
Mitochondrial Genes ◽  
Mitochondrial Genomes ◽  
Sexual Exchange ◽  
Intimate Association ◽  
Nuclear Genomes ◽  
Candidate Regions ◽  
Complete Mitochondrial Genomes

Background: The intimate association between parasitic plants and their hosts favours the exchange of genetic material, potentially leading to horizontal gene transfer (HGT) between plants. With the recent publication of several parasitic plant nuclear genomes, there has been considerable focus on such non-sexual exchange of genes. To enhance the picture on HGT events in a widely distributed parasitic genus, Cuscuta (dodders), we assembled and analyzed the organellar genomes of two recently sequenced species, C. australis and C. campestris, making this the first account of complete mitochondrial genomes (mitogenomes) for this genus. Results: The mitogenomes are 265,696 and 275,898 bp in length and contain a typical set of mitochondrial genes, with ten missing or pseudogenized genes often lost from angiosperm mitogenomes. Each mitogenome also possesses a structurally unusual ccmFC gene, which exhibits splitting of one exon and a shift to trans-splicing of its intron. Based on phylogenetic analysis of mitochondrial genes from across angiosperms and similarity-based searches, there is little to no indication of HGT into the Cuscuta mitogenomes. A few candidate regions for plastome-to-mitogenome transfer were identified, with one suggestive of possible HGT. Conclusions: The lack of HGT is surprising given examples from the nuclear genomes, and may be due in part to the relatively small size of our Cuscuta mitogenomes, limiting the capacity to integrate foreign sequences.

scholarly journals Horizontal Gene Transfer of Functional Type VI Killing Genes by Natural Transformation

2017 ◽  
Author(s):  
Jacob Thomas ◽  
Samit S. Watve ◽  
William C. Ratcliff ◽  
Brian K. Hammer
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Horizontal Transfer ◽  
Direct Injection ◽  
Spatially Explicit ◽  
Type Vi Secretion System ◽  
Effector Genes ◽  
Type Vi Secretion ◽  
A Cell ◽  
Explicit Simulation

AbstractHorizontal gene transfer can have profound effects on bacterial evolution by allowing individuals to rapidly acquire adaptive traits that shape their strategies for competition. One strategy for intermicrobial antagonism often used by Proteobacteria is the genetically-encoded contact-dependent Type VI secretion system (T6SS); a weapon used to kill heteroclonal neighbors by direct injection of toxic effectors. Here, we experimentally demonstrate thatVibrio choleraecan acquire new T6SS effector genes via horizontal transfer and utilize them to kill neighboring cells. Replacement of one or more parental alleles with novel effectors allows the recombinant strain to dramatically outcompete its parent. Through spatially-explicit simulation modeling, we show that the HGT is risky: transformation brings a cell into conflict with its former clonemates, but can be adaptive when superior T6SS alleles are acquired. More generally, we find that these costs and benefits are not symmetric, and that high rates of HGT can act as hedge against competitors with unpredictable T6SS efficacy. We conclude that antagonism and horizontal transfer drive successive rounds of weapons-optimization and selective sweeps, dynamically shaping the composition of microbial communities.

scholarly journals Horizontal Gene Transfer and the Evolution of Microvirid Coliphage Genomes

2006 ◽  
Vol 188 (3) ◽  
pp. 1134-1142 ◽  
Author(s):  
D. R. Rokyta ◽  
C. L. Burch ◽  
S. B. Caudle ◽  
H. A. Wichman
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Horizontal Transfer ◽  
Sparse Sampling ◽  
Apparent Difference ◽  
Genomic Evolution ◽  
Single Family ◽  
Bacterial Host ◽  
Double Stranded Dna ◽  
The Family

ABSTRACT Bacteriophage genomic evolution has been largely characterized by rampant, promiscuous horizontal gene transfer involving both homologous and nonhomologous source DNA. This pattern has emerged through study of the tailed double-stranded DNA (dsDNA) phages and is based upon a sparse sampling of the enormous diversity of these phages. The single-stranded DNA phages of the family Microviridae, including φX174, appear to evolve through qualitatively different mechanisms, possibly as result of their strictly lytic lifestyle and small genome size. However, this apparent difference could reflect merely a dearth of relevant data. We sought to characterize the forces that contributed to the molecular evolution of the Microviridae and to examine the genetic structure of this single family of bacteriophage by sequencing the genomes of microvirid phage isolated on a single bacterial host. Microvirids comprised 3.5% of the detectable phage in our environmental samples, and sequencing yielded 42 new microvirid genomes. Phylogenetic analysis of the genes contained in these and five previously described microvirid phages identified three distinct clades and revealed at least two horizontal transfer events between clades. All members of one clade have a block of five putative genes that are not present in any member of the other two clades. Our data indicate that horizontal transfer does contribute to the evolution of the microvirids but is both quantitatively and qualitatively different from what has been observed for the dsDNA phages.

scholarly journals Involvement of β-Carbonic Anhydrase Genes in Bacterial Genomic Islands and Their Horizontal Transfer to Protists

2018 ◽  
Vol 84 (15) ◽  
Author(s):  
Reza Zolfaghari Emameh ◽  
Harlan R. Barker ◽  
Vesa P. Hytönen ◽  
Seppo Parkkila
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Carbonic Anhydrase ◽  
Horizontal Transfer ◽  
Bacterial Species ◽  
Critical Role ◽  
Genomic Islands ◽  
Ph Homeostasis ◽  
Gene Sequences ◽  
Biochemical Pathways

ABSTRACT Genomic islands (GIs) are a type of mobile genetic element (MGE) that are present in bacterial chromosomes. They consist of a cluster of genes that produce proteins that contribute to a variety of functions, including, but not limited to, the regulation of cell metabolism, antimicrobial resistance, pathogenicity, virulence, and resistance to heavy metals. The genes carried in MGEs can be used as a trait reservoir in times of adversity. Transfer of genes using MGEs, occurring outside reproduction, is called horizontal gene transfer (HGT). Previous data have shown that numerous HGT events have occurred through endosymbiosis between prokaryotes and eukaryotes. β-Carbonic anhydrase (β-CA) enzymes play a critical role in the biochemical pathways of many prokaryotes and eukaryotes. We previously suggested the horizontal transfer of β-CA genes from plasmids of some prokaryotic endosymbionts to their protozoan hosts. In this study, we set out to identify β-CA genes that might have been transferred between prokaryotic and protist species through HGT in GIs. Therefore, we investigated prokaryotic chromosomes containing β-CA-encoding GIs and utilized multiple bioinformatics tools to reveal the distinct movements of β-CA genes among a wide variety of organisms. Our results identify the presence of β-CA genes in GIs of several medically and industrially relevant bacterial species, and phylogenetic analyses reveal multiple cases of likely horizontal transfer of β-CA genes from GIs of ancestral prokaryotes to protists. IMPORTANCE The evolutionary process is mediated by mobile genetic elements (MGEs), such as genomic islands (GIs). A gene or set of genes in the GIs is exchanged between and within various species through horizontal gene transfer (HGT). Based on the crucial role that GIs can play in bacterial survival and proliferation, they were introduced as environment- and pathogen-associated factors. Carbonic anhydrases (CAs) are involved in many critical biochemical pathways, such as the regulation of pH homeostasis and electrolyte transfer. Among the six evolutionary families of CAs, β-CA gene sequences are present in many bacterial species, which can be horizontally transferred to protists during evolution. This study shows the involvement of bacterial β-CA gene sequences in the GIs and suggests their horizontal transfer to protists during evolution.

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