mycoviruses have advantgeous to dletrious effect on host fungi

2. Mycoviruses and their pathogenesis
Submitted to :
Dr Yasir Iftikhar
Submitted by :
Roll no’s: 24 , 39 , 41, 53

3. Myco-viruses:
The virus that infect fungi and replicate inside
fungi are called Mycovirus.
 These are also called as fungal virus ,mycophage
and fungicidal virus.
 Mycovirus first time was recorded on cultivated
mushrooms (Agaricus bisporus) in the late 1940’s and
was called the La France disease or watery strip .

4. La France Disease
The La France Disease of mushroom is also
known as X disease or watery stripe.
Due to this Disease:
Reduced yield
Slow mycelial growth
Water logging of tissue
Malformation
Miss shaped mushroom

6. Mycovirology
Mycovirology is the study of viruses infecting
fungi.

7. General characteristics
They are isometric particles.
The majority of Mycoviruses have segmented
double-stranded RNA (dsRNA) genomes.
 Approximately 30% have positive sense, single-
stranded RNA (+ssRNA) genome.

8. Host range
Mycoviruses are found in all four phyla of the
true fungi.
Chytridiomycota
Zygomycota
Ascomycota
Basidiomycota

10. Symptoms associated with
Mycoviruses:
Infections with fungal viruses often remain
persistently unappear in their hosts.
 Micoviruses can alter phenotypes, such as
reduced growth, pigmentation, lack of
sporulation .

13.  Changes of colony and lesion in morphology of
fungus is very important .

14. Transmission
Natural vectors of Mycoviruses are unknown due
to lack of extracellular movement from cell to
cell.
 Intercellular transmissions only through hyphal
fusion and cell division and spread via sexually or
asexually spores have been observed .
Vegetative incompatibility reactions inhibit
hyphal fusion and reduce viral transmission.

17. Movement of mycoviruses within
fungi:
Virus dissemination in mycelial networks
via dolipores and septa , as organelles easily
migrate in between adjacent cells.
Virus can move with the cytoplasm and
extends into new hyphae.

18. Pathogenesis
The majority of Mycovirus families do not
exclusively infect fungi.
The families which exclusively infect fungi are
 Reoviridae
 Hypoviridae
 totiviridae.
 Narnaviridae etc.

20. Hypovirulence:
 It is advantageous infection of viruses which
decrease the pathogenicity of plant pathogenic
fungi .
It is most common in Mycoviruses and use for
biological control.
Its most common example are cryphonecteria
parasitica on chestnut blight.

22. Importance :

24.  Killer isolates secrete proteins that are toxic to
sensitive cells of the same or closely related
species . There are potentially interesting
application of killer yeast in medicine, food
industry, and in agriculture.
 harmful pests such as Botrytis cinerae
,cryphonecteria parasitica , provide significant
information that Mycoviruses can decrease
Fungal pathogencity.
 So these can be used as biological control against
harmful Fungus.

26. Are Mycovirus a
fungicidal??