scholarly journals How do invasion syndromes evolve? An experimental evolution approach using the ladybird Harmonia axyridis

2021 ◽  
Vol 1 ◽  
pp. 1-None
Author(s):  
Julien Foucaud ◽  
Ruth A. Hufbauer ◽  
Virginie Ravigné ◽  
Laure Olazcuaga ◽  
Anne Loiseau ◽  
...  
mBio ◽  
2015 ◽  
Vol 6 (4) ◽  
Author(s):  
Diego Gonzalez ◽  
Justine Collier

ABSTRACTCcrM is an orphan DNA methyltransferase nearly universally conserved in a vast group ofAlphaproteobacteria.InCaulobacter crescentus, it controls the expression of key genes involved in the regulation of the cell cycle and cell division. Here, we demonstrate, using an experimental evolution approach, thatC. crescentuscan significantly compensate, through easily accessible genetic changes like point mutations, the severe loss in fitness due to the absence of CcrM, quickly improving its growth rate and cell morphology in rich medium. By analyzing the compensatory mutations genome-wide in 12 clones sampled from independent ΔccrMpopulations evolved for ~300 generations, we demonstrated that each of the twelve clones carried at least one mutation that potentially stimulatedftsZexpression, suggesting that the low intracellular levels of FtsZ are the major burden of ΔccrMmutants. In addition, we demonstrate that the phosphoenolpyruvate-carbohydrate phosphotransfer system (PTS) actually modulatesftsZandmipZtranscription, uncovering a previously unsuspected link between metabolic regulation and cell division inAlphaproteobacteria. We present evidence that point mutations found in genes encoding proteins of the PTS provide the strongest fitness advantage to ΔccrMcells cultivated in rich medium despite being disadvantageous in minimal medium. This environmental sign epistasis might prevent such mutations from getting fixed under changing natural conditions, adding a plausible explanation for the broad conservation of CcrM.IMPORTANCEIn bacteria, DNA methylation has a variety of functions, including the control of DNA replication and/or gene expression. The cell cycle-regulated DNA methyltransferase CcrM modulates the transcription of many genes and is critical for fitness inCaulobacter crescentus. Here, we used an original experimental evolution approach to determine which of its many targets make CcrM so important physiologically. We show that populations lacking CcrM evolve quickly, accumulating an excess of mutations affecting, directly or indirectly, the expression of theftsZcell division gene. This finding suggests that the most critical function of CcrM inC. crescentusis to promote cell division by enhancing FtsZ intracellular levels. During this work, we also discovered an unexpected link between metabolic regulation and cell division that might extend to otherAlphaproteobacteria.


Author(s):  
Thomas. P. Peacock ◽  
Carol M. Sheppard ◽  
Ecco Staller ◽  
Rebecca Frise ◽  
Olivia C. Swann ◽  
...  

AbstractANP32 proteins, which act as influenza polymerase co-factors, vary between birds and mammals. The well-known mammalian adaptation, PB2-E627K, enables influenza polymerase to use mammalian ANP32 proteins. However, some mammalian-adapted influenza viruses do not harbour this adaptation. Here, we show that alternative PB2 adaptations, Q591R and D701N also allow influenza polymerase to use mammalian ANP32 proteins. PB2-E627K strongly favours use of mammalian ANP32B proteins, whereas D701N shows no such bias. Accordingly, PB2-E627K adaptation emerges in species with strong pro-viral ANP32B proteins, such as humans and mice, while D701N is more commonly seen in isolates from swine, dogs and horses where ANP32A proteins are more strongly pro-viral. In an experimental evolution approach, passage of avian viruses in human cells drives acquisition of PB2-E627K, but not when ANP32B is ablated. The strong pro-viral support of ANP32B for PB2-E627K maps to the LCAR region of ANP32B.


2007 ◽  
Vol 274 (1619) ◽  
pp. 1779-1788 ◽  
Author(s):  
Adam Bjork ◽  
William T Starmer ◽  
Dawn M Higginson ◽  
Christopher J Rhodes ◽  
Scott Pitnick

Postcopulatory sexual selection favours males which are strong offensive and defensive sperm competitors. As a means of identifying component traits comprising each strategy, we used an experimental evolution approach. Separate populations of Drosophila melanogaster were selected for enhanced sperm offence and defence. Despite using a large outbred population and evidence of substantive genetic variation for each strategy, neither trait responded to selection in the two replicates of this experiment. Recent work with fixed chromosome lines of D. melanogaster suggests that complex genotypic interactions between females and competing males contribute to the maintenance of this variation. To determine whether such interactions could explain our lack of response to selection on sperm offence and defence, we quantified sperm precedence across multiple sperm competition bouts using an outbred D. melanogaster population exhibiting continuous genetic variation. Both offensive and defensive sperm competitive abilities were found to be significantly repeatable only across matings involving ejaculates of the same pair of males competing within the same female. These repeatabilities decreased when the rival male stayed the same but the female changed, and they disappeared when both the rival male and the female changed. Our results are discussed with a focus on the complex nature of sperm precedence and the maintenance of genetic variation in ejaculate characteristics.


2021 ◽  
Author(s):  
Agathe Ballu ◽  
Philomene Despreaux ◽  
Clementine Duplaix ◽  
Anne Deredec ◽  
Florence Carpentier ◽  
...  

The evolution of resistance to pesticides is a major burden in agriculture. Resistance management involves maximizing selection pressure heterogeneity, particularly by combining active ingredients with different modes of action. We tested the hypothesis that alternation may delay the build-up of resistance not only by spreading selection pressure over longer periods, but also by decreasing the rate of evolution of resistance to alternated fungicides, by applying an experimental evolution approach to the economically important crop pathogen Zymoseptoria tritici. Our results show that alternation is either neutral or slows the evolution of resistance, relative to continuous fungicide use, but results in higher levels of generalism in evolved lines. We demonstrate that the relative risk of resistance intrinsic to fungicide alternation probably underlies a trade-off between the number of fungicides and the frequency of alternation. This trade-off is also dynamic over the course of resistance evolution. These findings open up new possibilities for tailoring resistance management effectively while optimizing interplay between alternation components.


2018 ◽  
Author(s):  
Hagay Enav ◽  
Shay Kirzner ◽  
Debbie Lindell ◽  
Yael Mandel-Gutfreund ◽  
Oded Béjà

Marine cyanophages are viruses that infect oceanic cyanobacteria, thus affecting global ecological processes. Cyanophages of theMyoviridaefamily are of great interest since they include generalist viruses capable of infection of a wide range of hosts including those from different cyanobacterial genera. While the influence of phages on host evolution has been studied previously, it is not known how the infection of distinct hosts influences the evolution of cyanophage populations. In marine systems this question is of special interest as the abundance of differentSynechococcusandProchlorococcushosts constantly changes, temporally and spatially. Here, using an experimental evolution approach, we investigated the adaptation of multiple cyanophage populations to three distinct cyanobacterial hosts. We show that when infecting an “optimal” host, whose infection is the most efficient, phage populations accumulated only a few mutations. However, when infecting “sub-optimal” hosts, different, largely host-specific sets of mutations, spread in the phage populations, leading to rapid diversification into distinct subpopulations. The mutations included insertions, deletions, SNPs and codon adaptations. Most of the mutations were found in genes encoding for proteins responsible for host recognition, attachment and infection, regardless of their evolutionary conservation. Based on our results, we propose a model demonstrating how shifts in bacterial abundance, which lead to infection of “sub-optimal” hosts, act as a driver for rapid diversification of phage populations.


Evolution ◽  
2009 ◽  
Vol 63 (10) ◽  
pp. 2491-2503 ◽  
Author(s):  
Alexei A. Maklakov ◽  
Russell Bonduriansky ◽  
Robert C. Brooks

2019 ◽  
Author(s):  
Eva J. P. Lievens ◽  
Yannis Michalakis ◽  
Thomas Lenormand

AbstractThe evolution of host specialization has been studied intensively, yet it is still often difficult to determine why parasites do not evolve broader niches – in particular when the available hosts are closely related and ecologically similar. Here, we used an experimental evolution approach to study the evolution of host specialization, and its underlying traits, in two sympatric parasites: Anostracospora rigaudi and Enterocytospora artemiae, microsporidians infecting the brine shrimp Artemia franciscana and Artemia parthenogenetica. In the field, both parasites regularly infect both hosts, yet experimental work has revealed that they are each partially specialized. We serially passaged the parasites on one, the other, or an alternation of the two hosts; after ten passages, we assayed the infectivity, virulence, and spore production rate of the evolved lines. In accordance with previous studies, A. rigaudi maintained a higher fitness on A. parthenogenetica, and E. artemiae on A. franciscana, in all treatments. The origin of this specialization was not infectivity, which readily evolved and traded off weakly between the host species for both parasites. Instead, the overall specialization was caused by spore production, which did not evolve in any treatment. This suggests the existence of a strong trade-off between spore production in A. franciscana and spore production in A. parthenogenetica, making this trait a barrier to the evolution of generalism in this system. This study highlights that the shape of between-host trade-offs can be very heterogeneous across parasite traits, so that only some traits are pivotal to specialization.


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