Interactions of fungi

1. Fungal Interactions
Dr. Harinatha Reddy M.sc, Ph.D.
biohari14@gmail.com
Department of Microbiology
Sri Krishnadevaraya University
Anantapur, A.p. India

2. Symbiotic association:
Example: Mycorrhiza
 Mycorrhiza is a symbiotic association between a fungus and the
roots of a vascular host plant.
 The association is generally mutualistic, some times it is
pathogenic in the host plants.
 Many Ascomycetes, Basidiomycetes and Zoomycetes form
symbiotic relationships with other organisms, it includes
algae, plants and animals.

3. Lichens:
 Lichens is a symbiotic association between fungi and various
groups of algae or Cyanobacteria.
 The most characteristic feature of lichens is that the
combination of algae (called the phytobiont) and fungus
(called the mycobiont),

4. Fungi & insect Mutualism:
 Fungi have symbiotic relation with numerous insects.
 Arthropods depend on the fungus for protection from
predators and pathogens, while the fungus obtains nutrients
from insect.
 The association between species of Basidiomycota and scale
insects is one example.

5. Second example:
 The association between leaf-cutting ants of Central and South
America and Saprophytic fungi.
 Ants cut disks of leaves from plants and pile them up in gardens.
 Fungi are cultivated in these disk gardens, digesting the cellulose
in the leaves and release proteins and sugar for leaf cutting ants.
Some times trees in tropical forest
contain toxic compounds.
These toxic compounds Break down by
fungi and release proteins
And sugars for the leaf cutting ants.

7. Gut mutualisms:
 Ruminants digestive systems contain several large chambers like
that of big fermentation tank. It contains, semi-fluid suspension of
chewed plant material.
 A mixture of fungi (Spizellomyces sp., Synchytrium sp. and
Yeast) that are able to convert the indigestible cellulose of the plant
in to simple organic molecules.

8. Parasitism:
FUNGAL PARASITES OF PLANTS:
 In parasitism the fungus benefits from the association and
damages the host organism (animals and plants).
 A great diversity of fungi cause plant disease.
 Two types of fungal parasites: Nectrotrophs and Biotrophs.

9.  Citrus canker caused by Xanthomonas citri.
 Red rot of sugarcane is caused by Colletotrichum falcatum.
 Wheat leaf rust caused by pathogen is Puccinia (rust fungus).
 Tikka Disease of Groundnut caused by Cercospora personata.


10. FUNGAL PARASITES OF ANIMALS:
Some of the fungi are pathogenic to animals, causing
infections that are called mycoses.
Fungi cause two types of infections:
Superficial infections, are caused by fungi that attack the skin
and nails and hair.
These fungi are known as dermatophytes.
Systemic infections: are caused by fungi that attack the
tissues, vital organs and the nervous system.

11.  Aspergillus fumigatus cause serious lung infection called
Aspergillosis.
 Candida albicans, causes white patches on the mouth
mucosa called Candidiasis.

12.  A large part of mycoses is transmitted through inhalation,
ingestion or the infection of skin wounds and attack the skin,
hairs, nails and mucosa.
 When inhaled, the spores of the genus Aspergillus fumigatus cause
serious lung infection called Aspergillosis.
 The mouth, the digestive and the reproductive systems can be
infected by the Candida albicans, causes white patches on the
mouth mucosa called Candidiasis.
 Dermatophytosis, also known as ringworm, is a fungal infection
of the skin.
 About 40 types of fungi can cause ringworm. They are typically of
the Trichophyton and Microsporum.

13. Predation:
 Predaceous fungi or Carnivorous fungi are fungi that derive
some of their nutrients from trapping and eating microscopic or
other minute animals.
 More than 200 species have been described, belonging to the
division Ascomycota and Basidiomycota.
 They usually live in soil and many species trap nematodes
(nematophagous fungus), while others attack amoebae.

14. Trapping the Nematodes:
Fungi use many methods in order to trap their prey.
Hyphal Rings:
 One method used by fungi to trap nematodes is the fungal ring.
 The fungus produces hyphae that end in an open constricting loop.
 When a nematode swims through this loop, the loop suddenly fills
with water.

15. Adhesive Hyphae:
 Another method commonly used by nematophagous fungi is
the use of adhesive hyphae.
 The fungi who utilize this method create adhesive knobs or
nets of adhesive hyphae.
 The fungus creates such structures in order to trap the
nematode within the structure.

17. THANK YOU