scholarly journals Genomic evidence for population-specific responses to coevolving parasites in a New Zealand freshwater snail

2016 ◽  
Author(s):  
Laura Bankers ◽  
Peter Fields ◽  
Kyle E. McElroy ◽  
Jeffrey L. Boore ◽  
John M. Logsdon ◽  
...  
Keyword(s):  
Natural Populations ◽  
Primary Source ◽  
Population Level ◽  
Freshwater Snail ◽  
Sequence Evolution ◽  
Specific Host ◽  
Host Parasite Interactions ◽  
Evolutionary Trajectories ◽  
Host Parasite ◽  
Genomic Basis

AbstractReciprocal coevolving interactions between hosts and parasites are a primary source of strong selection that can promote rapid and often population- or genotype-specific evolutionary change. These host-parasite interactions are also a major source of disease. Despite their importance, very little is known about the genomic basis of coevolving host-parasite interactions in natural populations, especially in animals. Here, we use gene expression and sequence evolution approaches to take critical steps towards characterizing the genomic basis of interactions between the freshwater snail Potamopyrgus antipodarum and its coevolving sterilizing trematode parasite, Microphallus sp., a textbook example of natural coevolution. We found that Microphallus-infected P. antipodarum exhibit systematic downregulation of genes relative to uninfected P. antipodarum. The specific genes involved in parasite response differ markedly across lakes, consistent with a scenario where population-level coevolution is leading to population-specific host-parasite interactions and evolutionary trajectories. We also used an FST-based approach to identify a set of loci that represent promising candidates for targets of parasite-mediated selection across lakes as well as within each lake population. These results constitute the first genomic evidence for population-specific responses to coevolving infection in the P. antipodarum-Microphallus interaction and provide new insights into the genomic basis of coevolutionary interactions in nature.

scholarly journals Differential Expression of Immune Defences Is Associated with Specific Host-Parasite Interactions in Insects

PLoS ONE ◽  
2009 ◽  
Vol 4 (10) ◽  
pp. e7621 ◽  
Author(s):  
Carolyn Riddell ◽  
Sally Adams ◽  
Paul Schmid-Hempel ◽  
Eamonn B. Mallon
Keyword(s):  
Differential Expression ◽  
Specific Host ◽  
Host Parasite Interactions ◽  
Host Parasite ◽  
Immune Defences

scholarly journals Host-pathogen coevolution increases genetic variation in susceptibility to infection

2018 ◽  
Author(s):  
Elizabeth ML Duxbury ◽  
Jonathan P Day ◽  
Davide Maria Vespasiani ◽  
Yannik Thüringer ◽  
Ignacio Tolosana ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Variants ◽  
Genetic Architecture ◽  
Natural Populations ◽  
Major Effect ◽  
Cross Infection ◽  
Host Susceptibility ◽  
Susceptibility To Infection ◽  
Host Parasite Interactions ◽  
Host Parasite

AbstractIt is common to find considerable genetic variation in susceptibility to infection in natural populations. We have investigated whether natural selection increases this variation by testing whether host populations show more genetic variation in susceptibility to pathogens that they naturally encounter than novel pathogens. In a large cross-infection experiment involving four species of Drosophila and four host-specific viruses, we always found greater genetic variation in susceptibility to viruses that had coevolved with their host. We went on to examine the genetic architecture of resistance in one host species, finding that there are more major-effect genetic variants in coevolved host-parasite interactions. We conclude that selection by pathogens increases genetic variation in host susceptibility, and much of this effect is caused by the occurrence of major-effect resistance polymorphisms within populations.

Do parasites matter? Assessing the fitness consequences of haemogregarine infection in snakes

2006 ◽  
Vol 84 (5) ◽  
pp. 668-676 ◽  
Author(s):  
G.P. Brown ◽  
C.M. Shilton ◽  
R. Shine
Keyword(s):  
Evolutionary Ecology ◽  
Natural Populations ◽  
Blood Parasites ◽  
Antipredator Behaviour ◽  
Host Fitness ◽  
Host Parasite Interactions ◽  
Fitness Consequences ◽  
Tropical Australia ◽  
Host Parasite ◽  
Striking Contrast

Although much research in evolutionary ecology is based upon the premise that high levels of parasitism impair the host's functioning, the assumed link between parasitism and fitness has been assessed for relatively few kinds of animals. At our study site in tropical Australia, keelback snakes ( Tropidonophis mairii (Gray, 1841), Colubridae) are heavily infected with haemogregarine blood parasites: 90% of snakes that we tested carried the parasite, with the proportion of erythrocytes containing haemogregarines averaging 15% and ranging up to a remarkable 64%. Prevalence increased with snake body size, but intensity decreased with age. Unlike lizards studied previously, the snakes did not respond to haemogregarine infection by releasing immature erythrocytes into the circulation. In striking contrast to results from a recent study on a sympatric snake species, we did not find any empirical links between parasite numbers and several measures of host fitness (body condition, growth rate, feeding rate, antipredator behaviour, locomotor performance, reproductive status, reproductive output, and recapture rate). The association between this parasite and its host thus appears to be surprisingly benign, suggesting that host–parasite interactions sometimes may have only trivial consequences for host fitness in natural populations. Plausibly, host–parasite coevolution weakens or eliminates fitness costs of parasitism.

Horizontal transmission of a parasite is influenced by infected host phenotype and density

Parasitology ◽  
2014 ◽  
Vol 142 (2) ◽  
pp. 395-405 ◽  
Author(s):  
K. E. ROBERTS ◽  
W. O. H. HUGHES
Keyword(s):  
Control Strategies ◽  
Horizontal Transmission ◽  
Population Level ◽  
Pathogen Transmission ◽  
Parasite Transmission ◽  
Microsporidian Parasite ◽  
Female Workers ◽  
Host Parasite Interactions ◽  
The Social ◽  
Host Parasite

SUMMARYTransmission is a key determinant of parasite fitness, and understanding the dynamics of transmission is fundamental to the ecology and evolution of host–parasite interactions. Successful transmission is often reliant on contact between infected individuals and susceptible hosts. The social insects consist of aggregated groups of genetically similar hosts, making them particularly vulnerable to parasite transmission. Here we investigate how the ratio of infected to susceptible individuals impacts parasite transmission, using the honey bee, Apis mellifera and its microsporidian parasite Nosema ceranae. We used 2 types of infected hosts found simultaneously in colonies; sterile female workers and sexual males. We found a higher ratio of infected to susceptible individuals in groups resulted in a greater proportion of susceptibles becoming infected, but this effect was non-linear and interestingly, the ratio also affected the spore production of infected individuals. The transmission level was much greater in an experiment where the infected individuals were drones than in an experiment where they were workers, suggesting drones may act as intracolonial ‘superspreaders’. Understanding the subtleties of transmission and how it is influenced by the phenotype of the infected/susceptible individuals is important for understanding pathogen transmission at population level, and for optimum targeting of parasite control strategies.

scholarly journals One day is enough: rapid and specific host–parasite interactions in a stickleback-trematode system

2006 ◽  
Vol 2 (3) ◽  
pp. 382-384 ◽  
Author(s):  
Gisep Rauch ◽  
Martin Kalbe ◽  
Thorsten B.H Reusch
Keyword(s):  
Immune System ◽  
Genotypic Variation ◽  
Adaptive Immune System ◽  
Host Defence ◽  
Defence Mechanism ◽  
Fish Family ◽  
Adaptive Immune ◽  
Specific Host ◽  
Host Parasite Interactions ◽  
Host Parasite

Red Queen models of host–parasite coevolution are based on genotype by genotype host–parasite interactions. Such interactions require a genotype specific host defence and, simultaneously, a genotype specific parasite infectivity. Specificity is defined here as defence or infection ability successful against only a subset of genotypes of the same species. A specific defence depends on detectable genotypic variation on the parasite side and on a host defence mechanism that differentiates between parasite genotypes. In vertebrates, the MHC-based adaptive immune system can provide such a defence mechanism, but it needs at least several days to get fully mounted. In contrast, the innate immune system is immediately ready. The trematode parasite species used here reaches the immunologically protected eye lens of its three-spined stickleback ( Gasterosteus aculeatus ) host within 24 h. Thus, it disappears too fast for the fully mounted MHC-based adaptive immune system. In a complete cross-infection experiment using five fish-families and five parasite-clones, we found for the first time fish-family by parasite-clone interactions in vertebrates, although the parasite was only exposed to the immune system for maximally one day. Such interactions require a fast genotype specific defence, suggesting the importance of other defence mechanisms than the too slow, fully mounted adaptive immune system in vertebrates.

Transcriptomics of host-specific interactions in natural populations of the parasitic plant purple witchweed (Striga hermonthica)

Weed Science ◽  
2019 ◽  
Vol 67 (4) ◽  
pp. 397-411 ◽  
Author(s):  
Lua Lopez ◽  
Emily S. Bellis ◽  
Eric Wafula ◽  
Sarah J. Hearne ◽  
Loren Honaas ◽  
...  
Keyword(s):  
Phenotypic Diversity ◽  
Natural Populations ◽  
Allelic Frequency ◽  
Genomic Diversity ◽  
Sub Saharan Africa ◽  
Striga Hermonthica ◽  
Specific Interactions ◽  
Host Parasite Interactions ◽  
Wide Range ◽  
Host Parasite

AbstractHost-specific interactions can maintain genetic and phenotypic diversity in parasites that attack multiple host species. Host diversity, in turn, may promote parasite diversity by selection for genetic divergence or plastic responses to host type. The parasitic weed purple witchweed [Striga hermonthica (Delile) Benth.] causes devastating crop losses in sub-Saharan Africa and is capable of infesting a wide range of grass hosts. Despite some evidence for host adaptation and host-by-Striga genotype interactions, little is known about intraspecific Striga genomic diversity. Here we present a study of transcriptomic diversity in populations of S. hermonthica growing on different hosts (maize [Zea mays L.] vs. grain sorghum [Sorghum bicolor (L.) Moench]). We examined gene expression variation and differences in allelic frequency in expressed genes of aboveground tissues from populations in western Nigeria parasitizing each host. Despite low levels of host-based genome-wide differentiation, we identified a set of parasite transcripts specifically associated with each host. Parasite genes in several different functional categories implicated as important in host–parasite interactions differed in expression level and allele on different hosts, including genes involved in nutrient transport, defense and pathogenesis, and plant hormone response. Overall, we provide a set of candidate transcripts that demonstrate host-specific interactions in vegetative tissues of the emerged parasite S. hermonthica. Our study shows how signals of host-specific processes can be detected aboveground, expanding the focus of host–parasite interactions beyond the haustorial connection.

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