20 Questions
Explain the concept of host range in the context of plant virus emergence and evolution.
The host range refers to the number of host species used by a pathogen. It is a key factor in understanding pathogen epidemiology and pathogenicity. However, it is not an immutable trait and is influenced by ecological factors such as species distribution and interaction.
Why is estimating a virus host range difficult, especially for plant viruses?
Estimating a virus host range is difficult because identifying all 'non-hosts' is practically impossible. This task is particularly challenging for plant viruses, and knowledge on host ranges may be limited, especially in wild ecosystems.
How does host range evolution contribute to plant virus emergence?
Host range evolution may result in a shift or change between hosts, or in the acquisition of new hosts or loss of existing ones. This contributes to the ability of the virus to encounter new hosts and adapt to ensure effective between-host transmission.
What ecological factors influence the host range of a virus?
Ecological factors such as species distribution, abundance, and interaction determine the range of potential hosts a virus comes into contact with. These factors play a central role in shaping the host range of a virus.
Why have studies on host ranges of plant viruses strongly favored those causing diseases in crops, and what remains relatively unexplored?
Studies have favored viruses causing diseases in crops, leading to limited knowledge on host ranges in wild ecosystems. Interactions in wild ecosystems remain relatively unexplored compared to those in agricultural settings.
What are some of the traits quantified in ecological and evolutionary studies related to disease risk?
Host resistance, tolerance, susceptibility, and pathogen virulence
How does connectivity affect virus expansion or host range alteration?
Connectivity covaries with biodiversity and affects contact rates, influencing virus expansion or host range alteration
What are some of the factors hypothesized to play a role in infection distribution?
Host resistance, tolerance, susceptibility, and pathogen virulence are hypothesized to play a role in infection distribution
What does the conceptual framework highlight in terms of disease spread?
The conceptual framework highlights the indirect effects of evolutionary and ecological factors in causing disease spread
How are prevalence-diversity relationships affected in a given habitat?
Prevalence-diversity relationships are affected by host diversity of a given habitat and habitat-related host ranges of plant viruses
How does co-infection affect the pleiotropic effects of resistance-breaking mutations on plant virus multiplication?
Co-infection affects the pleiotropic effects of resistance-breaking mutations on plant virus multiplication, depending on the type and combination of mutants.
What environmental factors may modulate across-host fitness trade-offs in the evolution of host range for plant viruses?
Environmental factors such as multiple or single infection may modulate across-host fitness trade-offs in the evolution of host range for plant viruses.
What are some conflicting trade-offs that may constrain the evolution of organisms, including plant viruses?
Conflicting trade-offs between different fitness components, such as reproduction and survival, may constrain the evolution of organisms, including plant viruses.
How is selection for a broader host range in plant viruses manifested in terms of traits unrelated to the plant-virus interaction?
Selection for a broader host range in plant viruses involves altered particle stability and survival, indicating selection for traits not directly related to the plant-virus interaction.
What influences the evolution of a species' resource breadth, including plant viruses?
Virus fitness trade-offs, community connectivity, and environmental heterogeneity influence the evolution of a species' resource breadth, including plant viruses.
What are the major intrinsic and extrinsic factors influencing host range evolution in viruses?
The major intrinsic factor is genetic specificity, while extrinsic factors include ecology and epidemiology.
Explain the gene-for-gene (GFG) and matching-alleles (MA) co-evolutionary models and their application in analyzing plant virus host range evolution.
The GFG and MA co-evolutionary models are used to analyze the interactions between host resistance genes and pathogen avirulence genes. These models have been applied to analyze plant virus host range evolution.
Describe the structure of virus-host interaction networks and how it can vary depending on geographical and taxonomical scales.
Virus-host interaction networks can be modular or nested, with the structure depending on geographical and taxonomical scales.
What role does specificity of infection play in the evolution of virus host range?
Specificity of infection leads to adaptive trade-offs among hosts, hindering host range expansion and favoring the evolution of specialism rather than generalism.
How do resistance-breaking mutations in viruses affect virus multiplication and host range?
Resistance-breaking mutations in viruses can have pleiotropic effects on virus multiplication, depending on the specific mutation and the susceptible host genotype.
Study Notes
Host Range Evolution in Viruses
- Host range evolution is influenced by both intrinsic factors (genetic traits) and extrinsic factors (ecology and epidemiology).
- Genetic specificity is a major intrinsic determinant of host range, with some viruses and genotypes only able to infect specific hosts.
- The gene-for-gene (GFG) and matching-alleles (MA) co-evolutionary models have been applied to analyze plant virus host range evolution.
- The structure of virus-host interaction networks can be modular or nested, depending on geographical and taxonomical scales.
- A study of a virus-plant species infection matrix revealed a nested network with significant modules corresponding to viruses infecting particular plant families.
- Specificity of infection leads to adaptive trade-offs among hosts, hindering host range expansion and favoring the evolution of specialism rather than generalism.
- Across-host fitness trade-offs affect transmission across host species and can result from antagonistic pleiotropy of host-range mutations and epistatic interactions among them.
- Evidence of across-host fitness trade-offs mostly comes from experiments, which may complicate predictions on host range evolution when a higher number of interactions are examined.
- Adaptation to a new host may result in adaptation to closely related hosts, favoring virus jumps to related species.
- Resistance-breaking mutations in viruses can have pleiotropic effects on virus multiplication, depending on the specific mutation and the susceptible host genotype.
- The distribution of effects of host range mutations may depend on demographic factors of the virus population associated with the host genotype.
- Predicting host range evolution in genetically heterogeneous, susceptible host populations is difficult due to the complex effects of host-range mutations modulated by extrinsic environmental factors.
Explore the factors influencing the evolution of host range in viruses, from genetic specificity to virus-host interaction networks and adaptation to new hosts. Understand the impact of across-host fitness trade-offs and resistance-breaking mutations on virus multiplication and transmission.
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