scholarly journals Did a plant-herbivore arms race drive chemical diversity in Euphorbia?

2018 ◽  
Author(s):  
M. Ernst ◽  
L.-F. Nothias ◽  
J. J. J. van der Hooft ◽  
R. R. Silva ◽  
C. H. Saslis-Lagoudakis ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Arms Race ◽  
Chemical Diversity ◽  
Evolutionary Adaptation ◽  
Evolutionary Time ◽  
Cosmopolitan Distribution ◽  
Ecological Relevance ◽  
Evolutionary Origins ◽  
Geographic Separation ◽  
Plant Herbivore

AbstractThe genus Euphorbia is among the most diverse and species-rich plant genera on Earth, exhibiting a near-cosmopolitan distribution and extraordinary chemical diversity, especially across highly toxic macro-and polycyclic diterpenoids. However, very little is known about drivers and evolutionary origins of chemical diversity within Euphorbia. Here, we investigate 43 Euphorbia species to understand how geographic separation over evolutionary time has impacted chemical differentiation. We show that the structurally highly diverse Euphorbia diterpenoids are significantly reduced in species native to the Americas, compared to the Eurasian and African continents, where the genus originated. The localization of these compounds to young stems and roots suggest ecological relevance in herbivory defense and immunomodulatory defense mechanisms match diterpenoid levels, indicating chemoevolutionary adaptation to reduced herbivory pressure.One Sentence SummaryGlobal chemo-evolutionary adaptation of Euphorbia affected immunomodulatory defense mechanisms.

scholarly journals Evolutionarily recent dual obligatory symbiosis among adelgids indicates a transition between fungus- and insect-associated lifestyles

2021 ◽  
Author(s):  
Gitta Szabó ◽  
Frederik Schulz ◽  
Alejandro Manzano-Marín ◽  
Elena Rebecca Toenshoff ◽  
Matthias Horn
Keyword(s):  
Defense Mechanisms ◽  
Amino Acid Production ◽  
Evolutionary Transition ◽  
Evolutionary Time ◽  
Evolutionary Trajectories ◽  
Host Infection ◽  
Phylogenomic Analyses ◽  
Time Specific ◽  
High Level ◽  
Metagenomic Approach

AbstractAdelgids (Insecta: Hemiptera: Adelgidae) form a small group of insects but harbor a surprisingly diverse set of bacteriocyte-associated endosymbionts, which suggest multiple replacement and acquisition of symbionts over evolutionary time. Specific pairs of symbionts have been associated with adelgid lineages specialized on different secondary host conifers. Using a metagenomic approach, we investigated the symbiosis of the Adelges laricis/Adelgestardus species complex containing betaproteobacterial (“Candidatus Vallotia tarda”) and gammaproteobacterial (“Candidatus Profftia tarda”) symbionts. Genomic characteristics and metabolic pathway reconstructions revealed that Vallotia and Profftia are evolutionary young endosymbionts, which complement each other’s role in essential amino acid production. Phylogenomic analyses and a high level of genomic synteny indicate an origin of the betaproteobacterial symbiont from endosymbionts of Rhizopus fungi. This evolutionary transition was accompanied with substantial loss of functions related to transcription regulation, secondary metabolite production, bacterial defense mechanisms, host infection, and manipulation. The transition from fungus to insect endosymbionts extends our current framework about evolutionary trajectories of host-associated microbes.

scholarly journals Diversity of molecular mechanisms used by anti-CRISPR proteins: the tip of an iceberg?

2020 ◽  
Vol 48 (2) ◽  
pp. 507-516 ◽  
Author(s):  
Pierre Hardouin ◽  
Adeline Goulet
Keyword(s):  
Immune System ◽  
Structure Function ◽  
Defense Mechanisms ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Arms Race ◽  
Allosteric Inhibitors ◽  
Fundamental Knowledge ◽  
Attack And Defense ◽  
Fine Tune

Bacteriophages (phages) and their preys are engaged in an evolutionary arms race driving the co-adaptation of their attack and defense mechanisms. In this context, phages have evolved diverse anti-CRISPR proteins to evade the bacterial CRISPR–Cas immune system, and propagate. Anti-CRISPR proteins do not share much resemblance with each other and with proteins of known function, which raises intriguing questions particularly relating to their modes of action. In recent years, there have been many structure–function studies shedding light on different CRISPR–Cas inhibition strategies. As the anti-CRISPR field of research is rapidly growing, it is opportune to review the current knowledge on these proteins, with particular emphasis on the molecular strategies deployed to inactivate distinct steps of CRISPR–Cas immunity. Anti-CRISPR proteins can be orthosteric or allosteric inhibitors of CRISPR–Cas machineries, as well as enzymes that irreversibly modify CRISPR–Cas components. This repertoire of CRISPR–Cas inhibition mechanisms will likely expand in the future, providing fundamental knowledge on phage–bacteria interactions and offering great perspectives for the development of biotechnological tools to fine-tune CRISPR–Cas-based gene edition.

scholarly journals Comment on “Information arms race explains plant-herbivore chemical communication in ecological communities”

2021 ◽  
Author(s):  
Ethan Bass ◽  
André Kessler
Keyword(s):  
Chemical Communication ◽  
Evolutionary Theory ◽  
Null Model ◽  
Arms Race ◽  
Community Level ◽  
Ecological Communities ◽  
Proposed Model ◽  
Plant Herbivore

Zu et al (Science, 19 Jun 2020, p. 1377) propose that an ‘information arms-race’ between plants and herbivores explains plant-herbivore communication at the community level. However, our analysis shows that key assumptions of the proposed model either a) conflict with standard evolutionary theory or b) are not supported by the available evidence. We also show that the presented statistical patterns can be explained more parsimoniously (e.g. through a null model) without invoking an unlikely process of community selection.

scholarly journals Evolutionary recent dual obligatory symbiosis among adelgids indicates a transition between fungus and insect associated lifestyles

2020 ◽  
Author(s):  
Gitta Szabó ◽  
Frederik Schulz ◽  
Alejandro Manzano-Marín ◽  
Elena Rebecca Toenshoff ◽  
Matthias Horn
Keyword(s):  
Defense Mechanisms ◽  
Amino Acid Production ◽  
Evolutionary Transition ◽  
Evolutionary Time ◽  
Evolutionary Trajectories ◽  
Host Infection ◽  
Phylogenomic Analyses ◽  
Time Specific ◽  
High Level ◽  
Metagenomic Approach

ABSTRACTAdelgids (Insecta: Hemiptera: Adelgidae) form a small group of insects but harbor a surprisingly diverse set of bacteriocyte-associated endosymbionts, which suggest multiple replacement and acquisition of symbionts over evolutionary time. Specific pairs of symbionts have been associated with adelgid lineages specialized on different secondary host conifers. Using a metagenomic approach, we investigated the symbiosis of the Adelges laricis/tardus species complex containing betaproteobacterial (‘ Candidatus Vallotia tarda’) and gammaproteobacterial (‘Candidatus Profftia tarda’) symbionts. Genomic characteristics and metabolic pathway reconstructions revealed that Vallotia and Profftia are evolutionary young endosymbionts, which complement each other’s role in essential amino acid production. Phylogenomic analyses and a high level of genomic synteny indicate an origin of the betaproteobacterial symbiont from endosymbionts of Rhizopus fungi. This evolutionary transition was accompanied with substantial loss of functions related to transcription regulation, secondary metabolite production, bacterial defense mechanisms, host infection and manipulation. The transition from fungus to insect endosymbionts extends our current framework about evolutionary trajectories of host-associated microbes.

scholarly journals Response to Comment on “Information arms race explains plant-herbivore chemical communication in ecological communities"

2021 ◽  
Author(s):  
Pengjuan Zu ◽  
Karina Boege ◽  
Ek del Val ◽  
Meredith Christine Schuman ◽  
Phil Stevenson ◽  
...  
Keyword(s):  
Arms Race ◽  
Ecological Communities ◽  
Neutral Model ◽  
Race Theory ◽  
Circular Reasoning ◽  
Plant Volatile ◽  
Herbivore Interactions ◽  
Plant Herbivore ◽  
Herbivore Communities ◽  
Simple Parameter

Zu et al. 2020 (1) proposed a simple, parameter-free, information-arms-race theory to explain the distributions of plant-herbivore interactions and plant-volatile associations observed in plant-herbivore communities. We received a comment by Bass and Kessler (Oct. 2020) questioning this theory and suggesting that a simpler neutral model can explain the observed distributions. This, with our response, went to peer review and was not published (Oct. 29, 2020). The authors have decided to publish their comment on EcoEvoRxiv (2) and so here, we are posting our reply. In sum, we present arguments to show that the comment from Bass and Kessler is based on an incorrect understanding of our study and furthermore suffers from circular reasoning, and that therefore their conclusions are not supported.

Using Molecular Data to Detect Selection: Signatures from Multiple Historical Events

2018 ◽  
Author(s):  
Bruce Walsh ◽  
Michael Lynch
Keyword(s):  
Empirical Data ◽  
Time Scale ◽  
Molecular Data ◽  
Rate Of Change ◽  
Arms Race ◽  
Specific Site ◽  
Selection Signatures ◽  
Historical Events ◽  
Evolutionary Time

This chapter examines the search for a pattern of repetitive adaptive substitutions over evolutionary time. In contrast with the previous chapter, only a modest number of tests toward this aim have been proposed. The HKA and McDonald-Kreitman tests contrast the polymorphism to divergence ratio between different genomic classes (such as different genes or silent versus replacement sites within the same gene). These approaches can detect an excess of substitutions, which allows one to estimate the fraction of adaptive sites. This chapter reviews the empirical data on estimates of this fraction and discusses some of the sources of bias it its estimation. Over an even longer time scale, one can contrast the rate of change of sites in a sequence over a phylogeny. These tests require a rather special type of selection, wherein the same specific site (usually a codon) experiences multiple adaptive substitutions over a phylogeny, such as might occur in arms-race genes.

scholarly journals Evolutionary origins of metabolic compartmentalization in eukaryotes

2010 ◽  
Vol 365 (1541) ◽  
pp. 847-855 ◽  
Author(s):  
William Martin
Keyword(s):  
Protein Targeting ◽  
Protein Product ◽  
Eukaryotic Cells ◽  
Evolutionary Time ◽  
Free Living ◽  
Evolutionary Origins ◽  
Dual Targeting ◽  
Targeting Signals ◽  
A Minor ◽  
Host Genes

Many genes in eukaryotes are acquisitions from the free-living antecedents of chloroplasts and mitochondria. But there is no evolutionary ‘homing device’ that automatically directs the protein product of a transferred gene back to the organelle of its provenance. Instead, the products of genes acquired from endosymbionts can explore all targeting possibilities within the cell. They often replace pre-existing host genes, or even whole pathways. But the transfer of an enzymatic pathway from one compartment to another poses severe problems: over evolutionary time, the enzymes of the pathway acquire their targeting signals for the new compartment individually, not in unison. Until the whole pathway is established in the new compartment, newly routed individual enzymes are useless, and their genes will be lost through mutation. Here it is suggested that pathways attain novel compartmentation variants via a ‘minor mistargeting’ mechanism. If protein targeting in eukaryotic cells possesses enough imperfection such that small amounts of entire pathways continuously enter novel compartments, selectable units of biochemical function would exist in new compartments, and the genes could become selected. Dual-targeting of proteins is indeed very common within eukaryotic cells, suggesting that targeting variation required for this minor mistargeting mechanism to operate exists in nature.

scholarly journals Epidemic spreading under pathogen evolution

2021 ◽  
Author(s):  
Xiyun Zhang ◽  
Ruan Zhongyuan ◽  
Muhua Zheng ◽  
Jie Zhou ◽  
Boccaletti Stefano ◽  
...  
Keyword(s):  
Selection Pressure ◽  
General Framework ◽  
Resistant Mutant ◽  
Arms Race ◽  
Epidemic Spreading ◽  
Evolutionary Time ◽  
Novel Mutations ◽  
Pathogen Evolution ◽  
Pathogen Prevalence ◽  
Vaccination Campaigns

Abstract Battling a widespread pandemic is an arms race between our mitigation efforts, e.g., social distancing or vaccination, and the pathogen's evolving persistence. This is being observed firsthand during the current COVID-19 crisis, as novel mutations are constantly challenging our global vaccination race. To address this, we introduce here a general framework for epidemic spreading under pathogen evolution, which shows that mutations can fundamentally alter the projection of the spread. Specifically, we detect a new pandemic phase - the mutated phase - in which, despite the fact that the pathogen is initially non-pandemic (R0 < 1), it may still spread due to the emergence of a critical mutation. The boundaries of this phase portray a balance between the epidemic and the evolutionary time-scales. If the mutation rate is too low, the pathogen prevalence decays prior to the appearance of a critical mutation. On the other hand, if mutations are too rapid, the pathogen evolution becomes volatile and, once again, it fails to spread. Between these two extremes, however, a broad range of conditions exists in which an initially sub-pandemic pathogen will eventually gain prevalence. This is especially relevant during vaccination, which creates, as it progresses, increasing selection pressure towards vaccine-resistance. To overcome this, we show that vaccination campaigns must be accompanied by fierce mitigation efforts, to suppress the potential rise of a resistant mutant strain.

Ritualization and social communication in Rhesus monkeys

1966 ◽  
Vol 251 (772) ◽  
pp. 285-294 ◽  
Keyword(s):  
Related Species ◽  
Rhesus Monkeys ◽  
Penile Erection ◽  
Developmental Stages ◽  
Evolutionary Time ◽  
Closely Related Species ◽  
Evolutionary Origins ◽  
Evolutionary Changes ◽  
Lower Vertebrates ◽  
The Comparative Study

The concept of ritualization, as used in the study of the signal movements of lower vertebrates, refers primarily to the evolutionary changes which such movements have undergone in adaptation to their function in communication. In this context, the term is thus used in reference only to movements which have such a function, and only when there is evidence that the resultant signal has undergone changes which make it more effective in that role. Many movements which influence the behaviour of others (e.g. penile erection, eating and drinking in rhesus monkeys, according to Altman 1962) have apparently not been ritualized, though homologous movements in other species may have been (e.g. penile erection in squirrel monkeys (Ploog & Maclean 1963)). The changes involved have almost invariably been evolutionary ones, and thus reference to ritualization implies evidence that the properties of the signal have changed on an evolutionary time scale. This usually comes from the comparative study of contemporary closely related species. Just as the comparison, between related species, of morphological structures may suggest not only homologies but also views as to the evolutionary origins of the homologous structures, so also does comparison of patterns of behaviour. In addition, just as comparison within a species of related structures, such as the segmental limbs of a crustacean, or of different developmental stages of the same structure, can provide evidence of the course of evolution, so also can comparison of related movement patterns (e.g. Lorenz 1935, 1941; Tinbergen 1952, 1959, 1962).

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