scholarly journals Pawnobiome: manipulation of the hologenome within one host generation and beyond

2015 ◽  
Vol 6 ◽  
Author(s):  
Jameson D. Voss ◽  
Juan C. Leon ◽  
Nikhil V. Dhurandhar ◽  
Frank T. Robb
Keyword(s):  
Host Generation

scholarly journals The role of multilevel selection in host microbiome evolution

2019 ◽  
Vol 116 (41) ◽  
pp. 20591-20597 ◽  
Author(s):  
Simon van Vliet ◽  
Michael Doebeli
Keyword(s):  
Generation Time ◽  
Evolutionary Dynamics ◽  
Horizontal Transmission ◽  
Multilevel Selection ◽  
Microbiome Composition ◽  
Active Debate ◽  
Multilevel Selection Theory ◽  
Verbal Arguments ◽  
Host Generation

Animals are associated with a microbiome that can affect their reproductive success. It is, therefore, important to understand how a host and its microbiome coevolve. According to the hologenome concept, hosts and their microbiome form an integrated evolutionary entity, a holobiont, on which selection can potentially act directly. However, this view is controversial, and there is an active debate on whether the association between hosts and their microbiomes is strong enough to allow for selection at the holobiont level. Much of this debate is based on verbal arguments, but a quantitative framework is needed to investigate the conditions under which selection can act at the holobiont level. Here, we use multilevel selection theory to develop such a framework. We found that selection at the holobiont level can in principle favor a trait that is costly to the microbes but that provides a benefit to the host. However, such scenarios require rather stringent conditions. The degree to which microbiome composition is heritable decays with time, and selection can only act at the holobiont level when this decay is slow enough, which occurs when vertical transmission is stronger than horizontal transmission. Moreover, the host generation time has to be short enough compared with the timescale of the evolutionary dynamics at the microbe level. Our framework thus allows us to quantitatively predict for what kind of systems selection could act at the holobiont level.

The Phenologies of Cotesia-Urabae, Dolichogenidea-Eucalypti (Hymenoptera, Braconidae) and Their Host Uraba-Lugens (Lepidoptera, Noctuidae) in the Adelaide Region

1990 ◽  
Vol 38 (4) ◽  
pp. 347 ◽  
Author(s):  
GR Allen
Keyword(s):  
Field Study ◽  
Larval Stage ◽  
First Generation ◽  
Dry Weight ◽  
Head Capsule ◽  
Head Capsule Width ◽  
Two Generations ◽  
High Level ◽  
Lepidoptera Noctuidae ◽  
Host Generation

A field study was undertaken to determine the phenologies of the solitary larval endoparasitoids Cotesia urabae and Dolichogenidea eucalypti in relation to that of their bivoltine host Uraba lugens. C. urabae had two generations within both the summer and the winter generation of U. lugens, and D. eucalypti had two generations in the summer but only one generation in the winter. D. eucalypti parasitised a narrower range of host sizes in the field. Both parasitoids attacked recently hatched (typically 1st instar) or 'small hosts' at the beginning at each host generation. In summer D. eucalypti was the first to emerge from hosts, but both D. eucalypti and C. urabae, emerged from hosts which had modes of 0.85-1.05 mm in head capsule width and 0.9-1.5 mg in dry weight (mid hosts). In winter, C. urabae emerged from hosts which had modes of 1.15 mm in head capsule width and 2.7 mg in dry weight (large hosts). Both species in summer, and C. urabae in winter, then proceeded to parasitise hosts of around these sizes to commence second parasitoid generations. In its second generation in summer and its first generation in winter, D. eucalypti typically emerged after most unparasitised hosts had pupated. Both species of parasitoid overwintered within the larval stage of their host. Levels of parasitisation appeared to be low, and dropped between first and second generations within each host generation. It was concluded that C. urabae and D. eucalypti displayed continuity of generations and a high level of synchronisation with U. lugens in the Adelaide region.

The Interaction of the Spruce Budworm, Choristoneura fumiferana (Clem.), and the Parasite Glypta fumiferanae (Vier.)

1960 ◽  
Vol 92 (11) ◽  
pp. 839-850 ◽  
Author(s):  
C. A. Miller
Keyword(s):  
New Brunswick ◽  
Choristoneura Fumiferana ◽  
Adult Emergence ◽  
Spruce Budworm ◽  
Actual Number ◽  
Emergence Period ◽  
Realistic Estimate ◽  
Host Generation

This is the second of a series of papers (Miller, 1959) describing the interaction of primary parasites and the spruce budworm, Choristoneura fumiferana (Clem.), based on data collected during an outbreak of the budworm in northern New Brunswick during the period 1947–1958. The first paper showed that the interaction between the spruce budworm and Apanteles fumiferanae Vier. is adequately described by the general mathematicai model developed by Watt (1959). The data on the parasite Glypta fumiferanae (Vier.) to be presented in this paper are also analysed by means of Watt's model and consequently the method is essentially the same. There is, however, one important difference. In the case of A. fumiferanae, the estimated number of adult parasites was only an index based on the potential number emerging from the previous host generation. The observed density of G. fumiferanae is a more realistic estimate. It is based on the actual number of cocoons found on the foliage during the adult emergence period.

scholarly journals Secondary host generation of the gall aphid Cerataphis jamuritsu (Homoptera)

2004 ◽  
Vol 7 (4) ◽  
pp. 377-380
Author(s):  
Utako KUROSU ◽  
Shigeyuki AOKI ◽  
Chuan-Chan WANG ◽  
How-Jing LEE
Keyword(s):  
Host Generation

EFFECTS OF THE LARVAL PARASITES DIADEGMA INSULARIS AND MICROPLITIS PLUTELLAE ON THE ABUNDANCE OF THE DIAMONDBACK MOTH IN SASKATCHEWAN RAPE AND MUSTARD CROPS

1973 ◽  
Vol 53 (4) ◽  
pp. 911-914 ◽  
Author(s):  
L. G. PUTNAM
Keyword(s):  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Larval Population ◽  
Moth Population ◽  
The Third ◽  
Brassica Spp ◽  
Host Generation ◽  
Larval Parasites

The larvae of the diamondback moth (Plutella xylostella) in the rape and mustard (Brassica spp.) crops of Saskatchewan are parasitized in varying degrees by the ichneumonid Diadegma insularis and the braconid Microplitis plutellae. During a 10-yr period, reduction of the first host generation by the two parasites together varied from 35 to 81%, averaging 68%. M. plutellae was usually predominant in this generation. In a given larval population, the lesser percentage would permit a following moth population about three times that of the greater. The overall average parasitism declined to 41% in the second host generation, where it is of less importance because of the reduced importance of the third host generation.

scholarly journals Characterization of Phytophthora nicotianae Resistance Conferred by the Introgressed Nicotiana rustica Region, Wz, in Flue-Cured Tobacco

Plant Disease ◽  
2018 ◽  
Vol 102 (2) ◽  
pp. 309-317 ◽  
Author(s):  
Kestrel L. McCorkle ◽  
Katherine Drake-Stowe ◽  
Ramsey S. Lewis ◽  
David Shew
Keyword(s):  
Lesion Size ◽  
Resistance Mechanisms ◽  
Phytophthora Nicotianae ◽  
Slight Reduction ◽  
Additional Source ◽  
Black Shank ◽  
Initial Inoculum ◽  
Complete Resistance ◽  
Host Generation

Black shank, caused by Phytophthora nicotianae, is one of the most important diseases affecting tobacco worldwide and is primarily managed through use of host resistance. An additional source of resistance to P. nicotianae, designated as Wz, has been introgressed into Nicotiana tabacum from N. rustica. The Wz gene region confers high levels of resistance to all races, but has not been characterized. Our study found Wz-mediated resistance is most highly expressed in the roots, with only a slight reduction in stem-lesion size in Wz genotypes compared with susceptible controls. No substantial relationships were observed between initial inoculum levels and disease development on Wz genotypes, which is generally consistent with qualitative or complete resistance. Isolates of P. nicotianae adapted for five host generations on plants with the Wz gene caused higher disease severity than isolates adapted on Wz plants for only one host generation. Wz-adapted isolates did not exhibit increased aggressiveness on genotypes with other sources of partial resistance, suggesting pathogen adaptation was specific to the Wz gene. To reduce potential for pathogen population shifts with virulence on Wz genotypes, Wz should be combined with other resistance sources and rotation of varying black shank resistance mechanisms is also recommended.

scholarly journals Evolution and maintenance of microbe-mediated protection under occasional pathogen infection

2020 ◽  
Author(s):  
A. Kloock ◽  
M.B. Bonsall ◽  
K.C. King
Keyword(s):  
Staphylococcus Aureus ◽  
Caenorhabditis Elegans ◽  
Enterococcus Faecalis ◽  
Infection Frequency ◽  
Pathogen Infection ◽  
Defensive Symbiosis ◽  
Seasonal Epidemics ◽  
Host Generation ◽  
Over Time

AbstractEvery host is colonized by a variety of microbes, some of which can protect their hosts from pathogen infection. However, pathogen presence naturally varies over time in nature, such as in the case of seasonal epidemics. We experimentally coevolved populations of Caenorhabditis elegans worm hosts with bacteria possessing protective traits (Enterococcus faecalis), in treatments varying the infection frequency with pathogenic Staphylococcus aureus every host generation, alternating host generations, every fifth host generation or never. We additionally investigated the effect of initial pathogen presence at the formation of the defensive symbiosis. Our results show that enhanced microbe-mediated protection evolved during host-protective microbe coevolution when faced with rare infections by a pathogen. Initial pathogen presence had no effect on the evolutionary outcome of microbe-mediated protection. We also found that protection was only effective at preventing mortality during the time of pathogen infection. Overall, our results suggest that resident microbes can be a form of transgenerational immunity against rare pathogen infection.

Effect of Host Generation on the Luminescent and Charge Transporting Properties of Solution Processed OLEDs

2021 ◽  
pp. 2100820
Author(s):  
Mile Gao ◽  
Junhyuk Jang ◽  
Tanja Leitner ◽  
Van T. N. Mai ◽  
Chandana S. K. Ranasinghe ◽  
...  
Keyword(s):  
Solution Processed ◽  
Host Generation

scholarly journals The role of multilevel selection in host microbiome evolution

2019 ◽  
Author(s):  
Simon van Vliet ◽  
Michael Doebeli
Keyword(s):  
Generation Time ◽  
Evolutionary Dynamics ◽  
Horizontal Transmission ◽  
Multilevel Selection ◽  
Microbiome Composition ◽  
Active Debate ◽  
Multilevel Selection Theory ◽  
Verbal Arguments ◽  
Host Generation

Animals are associated with a microbiome that can affect their reproductive success. It is therefore important to understand how a host and its microbiome coevolve. According to the hologenome concept, hosts and their microbiome form an integrated evolutionary entity, a holobiont, on which selection can potentially act directly. However, this view is controversial and there is an active debate on whether the association between hosts and their microbiomes is strong enough to allow for selection at the holobiont level. Much of this debate is based on verbal arguments, but a quantitative framework is needed to investigate the conditions under which selection can act at the holobiont level. Here we use multilevel selection theory to develop such a framework. We found that selection at the holobiont level can in principle favor a trait that is costly to the microbes but that provides a benefit to the host. However, such scenarios require rather stringent conditions. The degree to which microbiome composition is heritable decays with time, and selection can only act at the holobiont level when this decay is slow enough, which occurs when vertical transmission is stronger than horizontal transmission. Moreover, the host generation time has to be short enough compared to the timescale of the evolutionary dynamics at the microbe level. Our framework thus allows us to quantitatively predict for what kind of systems selection could act at the holobiont level.

scholarly journals Defying Muller’s Ratchet: Ancient Heritable Endobacteria Escape Extinction through Retention of Recombination and Genome Plasticity

mBio ◽  
2016 ◽  
Vol 7 (3) ◽  
Author(s):  
Mizue Naito ◽  
Teresa E. Pawlowska
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Genome Plasticity ◽  
Escape Extinction ◽  
Muller's Ratchet ◽  
Evolutionary Forces ◽  
Slightly Deleterious Mutations ◽  
Muller’S Ratchet ◽  
Asexual Populations ◽  
Host Generation

ABSTRACT   Heritable endobacteria, which are transmitted from one host generation to the next, are subjected to evolutionary forces that are different from those experienced by free-living bacteria. In particular, they suffer consequences of Muller’s ratchet, a mechanism that leads to extinction of small asexual populations due to fixation of slightly deleterious mutations combined with the random loss of the most-fit genotypes, which cannot be recreated without recombination. Mycoplasma-related endobacteria (MRE) are heritable symbionts of fungi from two ancient lineages, Glomeromycota (arbuscular mycorrhizal fungi) and Mucoromycotina . Previous studies revealed that MRE maintain unusually diverse populations inside their hosts and may have been associated with fungi already in the early Paleozoic. Here we show that MRE are vulnerable to genomic degeneration and propose that they defy Muller’s ratchet thanks to retention of recombination and genome plasticity. We suggest that other endobacteria may be capable of raising similar defenses against Muller’s ratchet.

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