Papaya Mosaic Virus (PapMV) Introduction Life cycle Symptoms Management and Controls

1. Plant pathogenic virus
Genus: Potex virus
Family: Alphaflexiviridae
Papaya Mosaic Virus (PapMV)
BY: SURAJ SHRESTHA

2.  It is a filamentous, flexuous rod,
530nm in length.
 Virus is monopartite strand of
positive sense, single stranded RNA
surrounded by a capsid made for
single viral encoded protein.
 Genome is completely sequenced
and 6656 nucleotides long.

3. Mode of transmission:
• By Mechanical Inoculation.
• No insect vector is involved and not transmitted in
seeds.
• But Vimala et al.,2017 reported Aphid (Aphis
craccivora) as vector.(sap transmissible).

4. Host restricted to: Cucurbits and Papaya.

5. Viral replication is cytoplasmic.
Replication follows the positive stranded RNA virus replication
model. Positive stranded RNA virus transcription is the method
of transcription. Translation takes place by leaky scanning.
The virus exits the host cell by tripartite non-tubule guided viral
movement. Transmission routes are mechanical.
Life Cycle of Virus

6. SYMPTOM
S

7.  Seriously affected
when about a year old.
 First infection in top
leaves.
 Mild mosaic symptoms
on papaya leaves and
stunting of plants.
 No symptoms in stem
and flowers.

8. INFECTED HEALTHY

9. Approximately 5 days after inoculation, green house young seedlings
show vein pairing and downward cupping of leaves while
adopting upright position.

10.  Destruction of affected plants.
 Use virus free seedlings.
 Disinfect working tools or heat them in an oven at 150o
C for 1 hour to kill the virus.
 Working tools or gloves can be dipped in 0.525%
sodium hypochlorite & then rinsed in water.
 Do NOT save seed from infected crops.
 Crop rotation with non host crop.
 Soil sterilization.
Management and Controls
There are no cures for viral
diseases such as mosaic once
a plant is infected.

11. Thermotherapy
+
Cryotherapy

12. Chavez-Calvillo, Gabriela & Contreras-Paredes, Carlos & Mora,
Javier & Noa-Carrazana, Juan Carlos & Serrano-Rubio, A. Alejandra
& Dinkova, Tzvetanka & Carrillo-Tripp, Mauricio & Silva-Rosales,
Laura. (2016). Antagonism or synergism between papaya ringspot
virus and papaya mosaic virus in Carica papaya is determined by
their order of infection. Virology. 489. 179-191.
10.1016/j.virol.2015.11.026.

13. PapMV
PRSV
(Chávez-Calvillo et al. 2016)

15. Their studies showed that:
 Two unrelated viruses, papaya ringspot virus (PRSV) and
papaya mosaic virus (PapMV) produce different
symptomatic outcomes during mixed infection depending
on the inoculation order.
 Synergism occurs in plants infected first with PRSV or in
plants infected simultaneously with PRSV and PapMV.
 And antagonism occurs in plants infected first with
PapMV and later inoculated with PRSV.