10 Questions
How do plant viruses typically enter a plant cell?
Through wounded living cells
Which of the following is a method of plant virus transmission?
Mechanical contact
What is the function of inhibitors in plant cells?
To reduce the susceptibility of the host plant
What is the effect of quinones on virus particles?
They permanently inactivate virus particles
Why do quinones render virus particles non-infectious?
Because they cause a single rupture in the virus nucleic acid
What is grafting considered to be a universal method for?
Transmitting viruses
Why may virus transmission by grafting not be 100%-effective?
The virus source plant was not totally invaded
Which type of virus can be transmitted only when vascular tissues are united?
Viruses restricted to the vascular system
What determines the success of virus transmission through grafting?
The characteristics of the virus and the union achieved
What is a benefit of using grafting for virus transmission?
It is useful for transmitting phloem-restricted viruses
Study Notes
Transmission of Plant Viruses
- Plant viruses do not penetrate the intact plant cuticle, hence they are not disseminated by wind or water.
- Viruses are transmitted from plant to plant through various means, including:
- Mechanical contact
- Grafting
- Vegetative propagation
- Botanical (sexual) seed
- Pollen
- Common dodder
- Vectors
Infection Inhibitors
- Inhibitors are found in many plants and decrease infection in inoculated plants.
- These substances act by:
- Reducing the susceptibility of the host plant
- Interfering with the infection process
Virus Particle Inactivators
- Quinones are formed by the oxidation of polyphenols as they come into contact with cytoplasmic enzymes during tissue maceration.
- Quinones are highly toxic compounds that:
- Can destroy some proteins
- Degrade virus protein subunits, exposing the nucleic acid to ribonucleases
- Abolish virus infectivity with a single rupture in the virus nucleic acid
Grafting
- Grafting is a technique that involves placing cut tissue surfaces of different plants in close contact.
- Grafting is a universal method for transmitting viruses, particularly useful for:
- Phloem-restricted viruses that cannot be transmitted mechanically
- Viruses whose vectors remain unknown
- Detecting viruses found in low concentrations
- Virus transmission by grafting may not be 100%-effective if:
- The virus is unable to cross the graft union
- The virus source plant was not totally invaded and the portion used was virus-free due to irregular virus distribution
- Successful virus transmission depends on:
- Characteristics of the virus
- Union achieved through grafting
- Types of grafts:
- Side grafts
- Wedge grafts
- Approach grafts
- Bud grafts
Learn about the different ways plant viruses are transmitted from one plant to another, including mechanical contact, grafting, and more. Understand how viruses infect plants and how they are not spread through wind or water.
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