This ppt describe the definition, structure, characteristics, living and non- living properties and transmission of plant viruses.

1. PLANT VIRUS
DR. RAJBIR SINGH
Assistant Professor
Department of Plant Pathology
Gochar Mahavidyalaya (Post Graduate College)
Rampur Maiharan, Saharanpur (UP), India
Affiliated to: CCS University, Meerut (UP), India
Email: rajbirsingh2810@gmail.com

2. Virus
Definition: Viruses are nucleo-protein having
DNA or RNA.

3. Properties of Viruses
• Viruses are ultra microscopic.
• Can be filter through bacteria proof filter.
• Attack and survive in living organisms only.
• Virus are transmitted by several means.
• Replicate only in living cells
• Viruses are made of covering of protein coat
(Capsid) and Nucleic Acids (DNA or RNA)
• Nucleic Acids are single or double stranded.
• Crystallization of viruses can be done.
• Viruses have adaptation and variation capacity.
• Resistant to acids, base and salts.
• Infection of viruses depend upon dilution end point.

4. Non Living Nature of Virus
• Lack of cell
• No Protoplasm
• Can be crystallized
• Absence of respiration and several other
metabolite activities
• More specific gravity
• Lacking of water and enzymes
• Inactive out of host like chemicals
• They are autocatalytic

5. Living Nature of Virus
• Have Nucleic Acids (DNA or RNA)
• Replication capacity
• Can replicable only in living cells
• Growth may be only in living cells
• Have parental characters through gens
• Mutation
• Obligate parasite
• Sensitive to temperature

6. Transmission of Plant Viruses
Transmission of plant viruses take place by following methods:
• Vegetative reproduction -
• Contaminated tools -
• Seeds -
• Soils -
• Contact -
• Grafting -
• Pollen grains -
• Roots -
• Nematodes -
• Fungi -
• Mites -
• Parasitic plants -
• Insects - Mostly transmission take place by insect
vectors.

7. Thanks