RELATED TO 1 ST SEMINAR ON PLANT VIRUSES IN ICMR , LIKE INSTITUTE ,NIV

1. OVERVIEW OF PLANT
VIROLOGY
Satish Gunjal
Msc 1
Roll no 11

2. Need for the study
India Agricultural country
Economy of India depends on agriculture
Important to study plant diseases

3. INTRODUCTION
TULIPOMANIA
Virus - filterable infectious
agent
“in this village ,
It looks as if frosting continuously ,
For the plant I saw
In the field of summer
The colour of the leaves were yellowing”

4. HISTORY
• Prehistory
752 AD plant virus in Japanese poem ,
tulipomania by Carolus clusius
• Recognition
1886 Meyer & iwanowski experiment
on TMV
1898 bejernick viruses as an entity
• Biological age
1900- 1935 descriptions of many viruses

5. • Biophysical / biochemical age
1935 purification of TMV
1956 virus particle made up of identical
protein subunit
1962 structure of isometric particle
1983 structure of TBSV to 2.9 A ̊
• . Molecular age
1980 Sequence of CaMV DNA genome
1984 Infectious transcipts of multicomponent BMV
1986 Transgenic Protection of plants Against TMV

6. Classification of plant viruses
Plant
viruses
dna
Ss ds
rna
Ss+ Ss-
ds

7. • dS DNA : Caulimoviridae , Badnavirus,
Tungrovirus
• SS DNA :Geminiviridae
• SS RNA (+) : Bromoviridae , Commaviridae
• SS RNA (- ) : Rhabdoviridae , Bunyaviridae
• ds RNA : Reovaridae

8. Plant virus groups and families

9. Virus transmission
• Through insects
• Mechanical
• Seed
• Grafting
scion
stock
Aphids White flies

10. TRANSMISSION OF PLANT VIRUSES
MECHANICAL TRANSMISSION
The procedure and equipments required for experimental
transmission by sap inoculation

11. Symptoms
• MACROSCOPIC :
Leaf rolling ,
mosaic pattern
yellow disease
ring spot
• CYTOLOGICAL :
changes in nuclei , cytoplasm & chloroplast

12. •
•Leaf rolling induced by
BLRV in broad bean (Vicia
faba)
•Distortion of the leaf, funnel
shaped outgrowth and
complete reduction of leaf
blade at vein on top.
(Nicotinia glutinosa)
Leaf rolling

13. Mosaic
Vein clearing in Physalis
floridana by PVY
Chlorotic streaks of MSV in maize.
Streaks parallel to venation

14. Ringspotting:
Systemic ringspotting caused by
TMV in Nicotiana clevelandii
ringspots- spreading and fusing
with one another
Symptoms of PRSV on the
fruits of papaya.
Some of the dark green
ringspots are turning necrotic

15. Viral entry
& uncoating
Virus initial entry (wound)
Uncoating
Transcription
Translation of mRNA
Replication of genome
in cytoplasm ,(NEPO, BROMO)
in nucleus :(potex ,caulimo,gem)
chloroplast: (tymo)
Assembly
Release & (transfer
trough plasmodesmata)

16. Control
• Remove source of infection
• Vector control
 Insecticide
• Virus free seeds
• Agronomic technique, (insect trapping)
• Conventional control:
(Alteration of crops , burning neem leaves )

17. Uses of plant viruses
• Genetic enginering
• viral genome use as Vector
• Vaccine production