30 Questions
What is the main challenge in conferring virus resistance by manipulating host factors?
Understanding the viral infection cycle in detail
What was the recent development that enables the specific editing of various host factors?
Genome editing technologies
What is the role of SA in plant defense pathways against pathogens?
Activating systemic acquired resistance (SAR) in distal tissues
What was the unexpected observation regarding eIF4E null mutant of A. thaliana?
It showed resistance to ClYVV but susceptibility to TuMV
What is the main function of AGO1 as described in the former section?
A core component of RNA silencing as a slicer of its target RNA
What is the role of RDR1 and DCL4 in antiviral RNA silencing?
They are involved in small RNA biogenesis in antiviral RNA silencing
What is the main reason why pesticides are ineffective in controlling viral diseases in plants?
Viruses use the cellular functions of their host for infection
What is the conventional method of controlling viral diseases in plants?
Using the inherent resistance of plants through breeding
What has genome editing technology enabled in terms of viral resistance in plants?
Artificially inducing new resistance types by manipulating host factors necessary for viral infection
What is an example of a new type of virus resistance facilitated by genome editing technology?
(1) an in-frame mutation of host factors necessary to confer viral resistance, sometimes resulting in resistance to different viruses and that (2) certain host factors exhibit antiviral resistance and viral-supporting (proviral) properties.
What do mutations of host factors, such as the eIF4E genes, demonstrate in terms of viral resistance?
Mutations can function as recessive resistance genes
Why are there often limited genetic sources of viral resistance in plants?
Viral infections often overcome existing resistances, leading to limited genetic sources.
Which eIF4E family gene mutations lead to virus resistance?
eIF4E and eIF(iso)4E
Which eIF4E family member was initially not a susceptible factor for viral infection?
nCBP
Which genome editing technique was not available in plants until the development of CRISPR/Cas9?
Site-directed mutagenesis
Which eIF4E family member exhibits a wider resistance spectrum against certain viruses in tomato plants?
pot1 allele of eIF4E1
What kind of genome editing technique was used to edit eIF4E1 in tomato plants?
(CRISPR/Cas9)
Which technique mostly results in (partial) loss of function of a particular gene?
All of the above
What triggers R gene-mediated resistance against viruses?
Recognition of viral avirulence (Avr) proteins by R genes
What is the proposed model for the plant immune system consisting of two defense response layers?
The zig-zag model
What is the major antiviral mechanism for PTI?
RNA silencing
Which resistance model does not fit viral resistance?
Any common resistance model for fungi and bacteria
What triggers effector-triggered immunity (ETI)?
Detection of specific effectors by R genes
What is the nature of viruses in relation to the host cell?
Intracellular parasites requiring a live host cell machinery
What is the major antiviral mechanism in plants against viruses with RNA or DNA genomes?
RNA silencing
What is the role of Dicer-like enzymes in antiviral RNA silencing?
Cleavage of viral dsRNAs into vsRNAs
What is the function of RNA-dependent RNA polymerase (RDR) 6 in antiviral defense?
Amplification of vsRNA as an antiviral RNA silencing signal
What is the efficient defense approach that exhibits recessive inheritance?
Modification of a host factor necessary for viral infection cycle
"Coat protein (CP)-mediated transgenic papaya resistance against papaya ringspot virus" is an example of:
"A successful application of RNA silencing for commercial use"
"Spray-induced gene silencing" in tobacco with exogenous TSWV-derived dsRNA shows a promising prospect for:
"Plant-virus interactions"
Study Notes
- Eukaryotic translation initiation factor (eIF) genes, specifically eIF4E, eIF4G, and their isoforms, are commonly used as recessive resistance genes against a subset of viral species in various plant species.
- Several recessive resistance genes have been identified in different plant-virus interactions.
- RNA silencing is a major antiviral mechanism in plants against viruses with RNA or DNA genomes.
- Successful antiviral RNA silencing results in the degradation of viral genome at the infection site and triggers a defense response.
- Antiviral RNA silencing is triggered by viral double-stranded (ds) RNA generated during replication or secondary intramolecular folding.
- Viral dsRNAs are cleaved by Dicer-like enzymes into virus-induced small RNAs (vsRNAs) which guide Argonaute proteins for viral RNA degradation or translational arrest.
- vsRNA, as an antiviral RNA silencing signal, is amplified by RNA-dependent RNA polymerase (RDR) 6 and transferred through the plasmodesmata and phloem for systemic viral defense.
- Viruses depend on host cellular mechanisms for survival and require numerous host factors for a successful infection cycle.
- The absence or modification of a host factor necessary for viral infection cycle is an efficient defense approach, considered as passive resistance, and exhibits recessive inheritance.
- Viruses might have acquired counter-defense mechanisms by suppressing host antiviral RNA silencing.
- Exogenous applications of viral dsRNA and siRNA for disease protection are based on the understanding of RNA silencing mechanisms.
- The coat protein (CP)-mediated transgenic papaya resistance against papaya ringspot virus through RNA silencing is a successful application of RNA silencing for commercial use.
- Spray-induced gene silencing in tobacco with exogenous tomato spotted wilt virus (TSWV)-derived dsRNA shows a promising prospect for plant-virus interactions.
Test your knowledge about the use of deficient genes in eukaryotic translation initiation factors for developing resistance against viral infections in plants. Explore how high throughput sequence and genome editing technologies have enhanced plant genetic resources for breeding. This quiz covers multiple recessive resistance genes identified in various plant–virus interactions.
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