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 ◽  
...  

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.

2021 ◽  
Author(s):  
Sarina Tsui ◽  
Welington Luiz Araújo

Abstract This study describes the n-TASE cluster in Burkholderia seminalis TC3.4.2R3, which was present in B. contaminans (CP046609.1), but absent in other related Burkholderia species. Phylogeny, comparative genomics and molecular analysis indicated it is not common to B. seminalis species, presenting similarity with homologous genes presents Aquamicrobium sp. SK-2 and B. contaminans LMG23361, probably acquired by an HGT (Horizontal Gene Transfer) event. It was not possible to determine which was the most likely donor strain of the n-TASE cluster. The HGT event did not occur in all strains of the Bcc group, nor in the B. seminalis, but it did occur punctually in the strain B. seminalis TC34.2R3. It has a correlation in biotechnological applications related processes. Aiming at understanding the involvement of the n-TASE cluster in the interaction of this bacterium in the environment, genes in this cluster will be inactivated, next.


2019 ◽  
Author(s):  
David A. Baltrus ◽  
Caitlin Smith ◽  
MacKenzie Derrick ◽  
Courtney Leligdon ◽  
Zoe Rosenthal ◽  
...  

AbstractHorizontal gene transfer is a significant driver of evolutionary dynamics across microbial populations. Although the benefits of the acquisition of new genetic material are often quite clear, experiments across systems have demonstrated that gene transfer events can cause significant phenotypic changes and entail fitness costs in a way that is dependent on the genomic and environmental context. Here we test for the generality of one previously identified cost, sensitization of cells to the antibiotic nalidixic acid after acquisition of a ∼1Mb megaplasmid, across Pseudomonas strains and species. Overall, we find that the presence of this megaplasmid sensitizes many different Pseudomonas strains to nalidixic acid, but that this same horizontal gene transfer event increases resistance of Pseudomonas putida KT2440 to nalidixic acid across assays as well as to ciprofloxacin under competitive conditions. These phenotypic results are not easily explained away as secondary consequences of overall fitness effects and appear to occur independently of another cost associated with this megaplasmid, sensitization to higher temperatures. Lastly, we draw parallels between these reported results and the phenomenon of sign epistasis for de novo mutations and explore how context dependence of effects of plasmid acquisition could impact overall evolutionary dynamics and the evolution of antimicrobial resistance.ImportanceNumerous studies have demonstrated that gene transfer events (e.g. plasmid acquisition) can entail a variety of costs that arise as byproducts of the incorporation of foreign DNA into established physiological and genetic systems. These costs can be ameliorated through evolutionary time by the occurrence of compensatory mutations, which stabilize presence of a horizontally transferred region within the genome but which also may skew future adaptive possibilities for these lineages. Here we demonstrate another possible outcome, that phenotypic changes arising as a consequence of the same horizontal gene transfer event are costly to some strains but may actually be beneficial in other genomic backgrounds under the right conditions. These results provide new a new viewpoint for considering conditions that promote plasmid maintenance and highlight the influence of genomic and environmental contexts when considering amelioration of fitness costs after HGT events.


PLoS ONE ◽  
2014 ◽  
Vol 9 (7) ◽  
pp. e102170 ◽  
Author(s):  
Kevin Dougherty ◽  
Brian A. Smith ◽  
Autumn F. Moore ◽  
Shannon Maitland ◽  
Chris Fanger ◽  
...  

mSphere ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
David A. Baltrus ◽  
Caitlin Smith ◽  
MacKenzie Derrick ◽  
Courtney Leligdon ◽  
Zoe Rosenthal ◽  
...  

ABSTRACT Horizontal gene transfer is a significant driver of evolutionary dynamics across microbial populations. Although the benefits of the acquisition of new genetic material are often quite clear, experiments across systems have demonstrated that gene transfer events can cause significant phenotypic changes and entail fitness costs in a way that is dependent on the genomic and environmental context. Here, we test for the generality of one previously identified cost, sensitization of cells to the antibiotic nalidixic acid after acquisition of an ∼1-Mb megaplasmid, across Pseudomonas strains and species. Overall, we find that the presence of this megaplasmid sensitizes many different Pseudomonas strains to nalidixic acid but that this same horizontal gene transfer event increases resistance of Pseudomonas putida KT2440 to nalidixic acid across assays as well as to ciprofloxacin under competitive conditions. These phenotypic results are not easily explained away as secondary consequences of overall fitness effects and appear to occur independently of another cost associated with this megaplasmid, sensitization to higher temperatures. Lastly, we draw parallels between these reported results and the phenomenon of sign epistasis for de novo mutations and explore how context dependence of effects of plasmid acquisition could impact overall evolutionary dynamics and the evolution of antimicrobial resistance. IMPORTANCE Numerous studies have demonstrated that gene transfer events (e.g., plasmid acquisition) can entail a variety of costs that arise as by-products of the incorporation of foreign DNA into established physiological and genetic systems. These costs can be ameliorated through evolutionary time by the occurrence of compensatory mutations, which stabilize the presence of a horizontally transferred region within the genome but which also may skew future adaptive possibilities for these lineages. Here, we demonstrate another possible outcome, that phenotypic changes arising as a consequence of the same horizontal gene transfer (HGT) event are costly to some strains but may actually be beneficial in other genomic backgrounds under the right conditions. These results provide a new viewpoint for considering conditions that promote plasmid maintenance and highlight the influence of genomic and environmental contexts when considering amelioration of fitness costs after HGT events.


Genes ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1308
Author(s):  
Mercedes Sánchez-Costa ◽  
Alba Blesa ◽  
José Berenguer

Genes coding for enzymes of the denitrification pathway appear randomly distributed among isolates of the ancestral genus Thermus, but only in few strains of the species Thermus thermophilus has the pathway been studied to a certain detail. Here, we review the enzymes involved in this pathway present in T. thermophilus NAR1, a strain extensively employed as a model for nitrate respiration, in the light of its full sequence recently assembled through a combination of PacBio and Illumina technologies in order to counteract the systematic errors introduced by the former technique. The genome of this strain is divided in four replicons, a chromosome of 2,021,843 bp, two megaplasmids of 370,865 and 77,135 bp and a small plasmid of 9799 pb. Nitrate respiration is encoded in the largest megaplasmid, pTTHNP4, within a region that includes operons for O2 and nitrate sensory systems, a nitrate reductase, nitrate and nitrite transporters and a nitrate specific NADH dehydrogenase, in addition to multiple insertion sequences (IS), suggesting its mobility-prone nature. Despite nitrite is the final product of nitrate respiration in this strain, the megaplasmid encodes two putative nitrite reductases of the cd1 and Cu-containing types, apparently inactivated by IS. No nitric oxide reductase genes have been found within this region, although the NorR sensory gene, needed for its expression, is found near the inactive nitrite respiration system. These data clearly support that partial denitrification in this strain is the consequence of recent deletions and IS insertions in genes involved in nitrite respiration. Based on these data, the capability of this strain to transfer or acquire denitrification clusters by horizontal gene transfer is discussed.


2012 ◽  
Vol 194 (23) ◽  
pp. 6642-6643 ◽  
Author(s):  
Isabel Brunet-Galmés ◽  
Antonio Busquets ◽  
Arantxa Peña ◽  
Margarita Gomila ◽  
Balbina Nogales ◽  
...  

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.


2008 ◽  
Vol 9 (2) ◽  
pp. 115-126 ◽  
Author(s):  
Patrick Boerlin ◽  
Richard J. Reid-Smith

AbstractNew concepts have emerged in the past few years that help us to better understand the emergence and spread of antimicrobial resistance (AMR). These include, among others, the discovery of the mutator state and the concept of mutant selection window for resistances emerging primarily through mutations in existing genes. Our understanding of horizontal gene transfer has also evolved significantly in the past few years, and important new mechanisms of AMR transfer have been discovered, including, among others, integrative conjugative elements and ISCR(insertionsequences withcommonregions) elements. Simultaneously, large-scale studies have helped us to start comprehending the immense and yet untapped reservoir of both AMR genes and mobile genetic elements present in the environment. Finally, new PCR- and DNA sequencing-based techniques are being developed that will allow us to better understand the epidemiology of classical vectors of AMR genes, such as plasmids, and to monitor them in a more global and systematic way.


2017 ◽  
Author(s):  
Jacob Thomas ◽  
Samit S. Watve ◽  
William C. Ratcliff ◽  
Brian K. Hammer

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.


2021 ◽  
Author(s):  
Apurva Narechania ◽  
Rob DeSalle ◽  
Barun Mathema ◽  
Barry N Kreiswirth ◽  
Paul J Planet

Most microbes have the capacity to acquire genetic material from their environment. Recombination of foreign DNA yields genomes that are, at least in part, incongruent with the vertical history of their species. Dominant approaches for detecting such horizontal gene transfer (HGT) and recombination are phylogenetic, requiring a painstaking series of analyses including sequence-based clustering, alignment, and phylogenetic tree reconstruction. Given the breakneck pace of genome sequencing, these traditional pan-genomic methods do not scale. Here we propose an alignment-free and tree-free technique based on the sequential information bottleneck (SIB), an optimization procedure designed to extract some portion of relevant information from one random variable conditioned on another. In our case, this joint probability distribution tabulates occurrence counts of k-mers with respect to their genomes of origin (the relevance information) with the expectation that HGT and recombination will create a strong signal that distinguishes certain sets of co-occuring k-mers. The technique is conceptualized as a rate-distortion problem. We measure distortion in the relevance information as k-mers are compressed into clusters based on their co-occurrence in the source genomes. This approach is similar to topic mining in the Natural Language Processing (NLP) literature. The result is model-free, unsupervised compression of k-mers into genomic topics that trace tracts of shared genome sequence whether vertically or horizontally acquired. We examine the performance of SIB on simulated data and on the known large-scale recombination event that formed the Staphylococcus aureus ST239 clade. We use this technique to detect recombined regions and recover the vertically inherited core genome with a fraction of the computing power required of current phylogenetic methods.


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