Transmission of Plant 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

Description

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.