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Questions and Answers
Which virus family is associated with persistent transmission in plant viruses?
Which virus family is associated with persistent transmission in plant viruses?
What type of viral transmission does Rhabdoviridae exhibit?
What type of viral transmission does Rhabdoviridae exhibit?
Which of the following is NOT involved in receptor-mediated endocytosis for luteovirus acquisition?
Which of the following is NOT involved in receptor-mediated endocytosis for luteovirus acquisition?
In the context of viral transmission, which term best describes the mechanism of regulating vector-specific luteovirus acquisition?
In the context of viral transmission, which term best describes the mechanism of regulating vector-specific luteovirus acquisition?
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What characterizes non-propagative viruses among the listed options?
What characterizes non-propagative viruses among the listed options?
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What is a primary characteristic of non-persistent virus transmission in plants?
What is a primary characteristic of non-persistent virus transmission in plants?
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In the context of plant-virus-vector interactions, what distinguishes persistent transmission from the others?
In the context of plant-virus-vector interactions, what distinguishes persistent transmission from the others?
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Which molecular mechanism is primarily involved in the persistent transmission of viruses?
Which molecular mechanism is primarily involved in the persistent transmission of viruses?
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Which of the following is NOT a mode of plant-virus-vector interaction?
Which of the following is NOT a mode of plant-virus-vector interaction?
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What is the primary purpose of PCR in molecular biology?
What is the primary purpose of PCR in molecular biology?
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Which component was replaced by thermostable DNA polymerase in the advancements of PCR?
Which component was replaced by thermostable DNA polymerase in the advancements of PCR?
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What is a common consequence of semi-persistent virus transmission in plants?
What is a common consequence of semi-persistent virus transmission in plants?
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Which phase of PCR is characterized by a limited number of target sites and a large number of primer copies?
Which phase of PCR is characterized by a limited number of target sites and a large number of primer copies?
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During which step of PCR does the double-stranded DNA separate into single strands?
During which step of PCR does the double-stranded DNA separate into single strands?
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At what temperature does the annealing phase typically occur in the standard PCR protocol?
At what temperature does the annealing phase typically occur in the standard PCR protocol?
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Where does the virus primarily replicate in the body?
Where does the virus primarily replicate in the body?
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What two pathways can the virus use to invade other tissues?
What two pathways can the virus use to invade other tissues?
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Which of the following correctly describes the route of the virus from its replication site?
Which of the following correctly describes the route of the virus from its replication site?
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What is the significance of the principal salivary glands in the viral life cycle?
What is the significance of the principal salivary glands in the viral life cycle?
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Which cell type is primarily affected by the initial viral replication?
Which cell type is primarily affected by the initial viral replication?
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What role do the 5' and 3' noncoding sequences play in ssRNA viruses?
What role do the 5' and 3' noncoding sequences play in ssRNA viruses?
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Which of the following best describes the function of noncoding sequences in ssRNA viruses?
Which of the following best describes the function of noncoding sequences in ssRNA viruses?
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How do noncoding sequences in ssRNA viruses influence viral functions?
How do noncoding sequences in ssRNA viruses influence viral functions?
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Which statement accurately reflects the role of the 5' and 3' noncoding regions in TMV?
Which statement accurately reflects the role of the 5' and 3' noncoding regions in TMV?
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What is a key feature of the noncoding sequences in ssRNA viruses like TMV?
What is a key feature of the noncoding sequences in ssRNA viruses like TMV?
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What is the primary function of the HC-Pro protein in Potyvirus?
What is the primary function of the HC-Pro protein in Potyvirus?
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Which protein is involved in the RNA replication process in Potyvirus?
Which protein is involved in the RNA replication process in Potyvirus?
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How many open reading frames (ORFs) are present in the genome of Potato virus X?
How many open reading frames (ORFs) are present in the genome of Potato virus X?
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What is the molecular weight of the viral coat protein (CP) in Potyvirus?
What is the molecular weight of the viral coat protein (CP) in Potyvirus?
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What type of RNA virus is the Potato yellow dwarf virus classified as?
What type of RNA virus is the Potato yellow dwarf virus classified as?
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Which protein is suggested to have an unknown function in the Potyvirus genome?
Which protein is suggested to have an unknown function in the Potyvirus genome?
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What is the role of the P3-PIPO protein in Potyvirus?
What is the role of the P3-PIPO protein in Potyvirus?
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What type of virus is a member of the Potexvirus family?
What type of virus is a member of the Potexvirus family?
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Study Notes
Plant Virus Transmission Mechanisms
- Plant viruses can be transmitted through various methods, including mechanical, seed, pollen, vegetative propagation, grafting, and dodder.
Mechanical Transmission
- This method involves physical contact between infected and healthy plants.
- Viruses can spread through contaminated tools, vectors, or plant fluids.
- This is a common way for many viruses to spread, but it's not the most efficient.
Seed Transmission
- Some viruses can infect developing embryos by direct invasion after fertilization or indirect invasion by infecting the gametes before fertilization.
- The percentage of seed transmission depends on the virus, the host plant, the time of infection of the mother plant, and the seed's age.
- The distribution of virus-infected seeds in infected mother plants is random.
Pollen Transmission
- Viruses can be transmitted through pollen from infected plants to healthy ones; in this manner, viruses can spread quickly and widely.
Vegetative Propagation
- Transmission occurs through growing processes such as stem cuttings, root grafts, or other plant propagation methods.
- This is a common method for certain virus types to spread and infect numerous plants.
Grafting
- Viruses can be transmitted when propagating by grafting plants.
- The virus spreads rapidly and widely through the grafting process.
Dodder
- A parasitic plant (dodder) can transmit viruses through its parasitic relationships.
Transmission by Invertebrates
- Arthropoda (Insects):
- Insecta (e.g., aphids, leafhoppers, planthoppers, cicadas) are the most common insect vectors.
- Arachnida (e.g., spider mites, and eriophyid mites) are also commonly involved.
- Nematodes:
- Nematodes can also transmit some plant viruses.
Viral Genome Organization and Strategies
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A. General Properties of Plant Viral Genomes: Plant viruses may have single or multiple genomic RNA/DNA pieces.
- Kind of NA: The type of nucleic acid (RNA or DNA) in the virus.
- Number of genome pieces (components): The number of distinct RNA/DNA segments in the virus.
- Terminal structures: Often have specific sequences at the ends of their RNA or DNA.
- nt sequence: Specific order of nucleotides.
- Regulatory signals: Sequences that regulate viral gene expression.
- mRNAs: The messenger RNA molecules produced during viral transcription.
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B. Coding regions: Areas of the genome containing genes for viral proteins.
- initiation codon: (AUG, AUU, CUG) Start codon for protein synthesis.
- stop codon: (UAA, UAG, UGA) Stop codon for protein synthesis.
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C. Non-coding regions: Areas in the genome that do not encode proteins; these regions may have important roles, such as regulatory sequences.
- End-group structures: Structures at the ends of the RNA/DNA molecule.
- 3′ and 5′ non-coding regions (NCR): Non-coding regions located on the 3' and 5' ends of the genome.
- Intergenic regions: Non-coding regions between genes.
- 1. Subgenomic RNAs: Some viruses generate smaller RNA molecules from one larger genome RNA molecule. These are used to make sub-genomic mRNAs.
- 2. Polyprotein strategy: Some viruses make long proteins (polyproteins) that are then cut into smaller, functional proteins.
- 3. Multi-partite genomes: Some viruses have multiple RNA or DNA molecules (segments). All these segments are packaged in the same virion.
- 4. Internal initiation: Some viruses can initiate translation at internal ribosome entry sites (IRES) instead of the normal 5' cap-dependent method.
- 5. Leaky scanning: This approach allows the ribosome to continue translating into a new open reading frame (ORF) upon encountering a stop codon in one ORF.
- 6. Read-through: Ribosomes sometimes ignore a stop codon and continue translating into another ORF.
- 7. Frame-shift: A change in the reading frame during translation.
- 8. Splicing: A process where non-coding regions are removed from a viral mRNA molecule before it's translated into protein.
Viral Protein Functions
- Viral proteins can be structural (forming parts of the virus particle) or functional (enzymes involved in various viral processes, such as replication or movement). They can also play other specific tasks such as interacting with host cells and/or the host's immune systems.
Virus Replication
- Replicative intermediate (RF): Intermediate stage in replication.
- Semiconservative replication: Each new DNA molecule contains one original strand and one new strand.
- Conservative replication: Each new DNA molecule consists of two new strands formed from an original.
Transmission characteristics
- Site of transmission: The place where transmission happens (e.g., foregut, midgut, etc.).
- Type of transmission: How the virus is transmitted between plants or vectors.
- Virus product interacting with vector: This refers to specific factors.
- Acquisition time: Estimated time the vector takes to acquire the virus.
- Retention time: How long the vector retains the virus.
- Viruses in vector hemolymph: The presence of virus in the insect's hemolymph.
- Latent period: Time between acquisition and symptom expression.
- Transovarial transmission: Transmission of the virus from an infected mother to her offspring .
- Transmission characteristics: The way in which the virus spreads.
Additional Notes
- Plant viruses use various mechanisms to move systemically and infect the plant’s cells.
- Many plant viruses rely on invertebrate vectors that carry viruses between infected plants and healthy ones.
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Description
Explore the various methods of plant virus transmission, including mechanical, seed, pollen, and other propagation techniques. Understand the efficiency and processes involved in each transmission mechanism in this informative quiz. Test your knowledge on how plant viruses spread and affect agriculture.
