This document discusses various examples of symbiotrophic relationships between organisms, specifically fungi. It begins by defining symbiosis and noting that fungi are commonly involved in mutualistic relationships. It then examines specific examples in detail, including lichens, mycorrhizal associations, interactions between termites and fungi, ambrosia beetles and fungi, scale insects and fungi, and gut fungi in ruminant animals. Throughout, it describes the nutritional exchanges that make these relationships mutualistically beneficial. In conclusion, it emphasizes that these symbioses closely integrate the organisms and provide access to nutrients and dispersal mechanisms for both partners.

1. Manjunatha S
I M.Sc. (Botany)
University of Mysore
SYMBIOTROPHES

2. CONTENTS
1.Introduction
2.Symbiosis
3.Lichens: Mode of Nutrition
4.Mycorrhizae: Mode of Nutrition
5.Other examples of Symbiotrophes
6.Conclusion
7.References

3. INTRODUCTION
Symbiosis can be defined as the
association between dissimilar organisms
in which benefit may accrue to both at
least for a period during the association.
Associations need not be static. In a few
cases, the symbiotic phase may continue
to a parasitic or commensal phase.

4. FUNGI IS SEEN IN MAJORITY
OF SYMBIOTIC
RELATIONSHIPS…….!!!!!!
Many fungal mutualisms are driven
by the ability of the fungus to
decompose organic substrates that
are inaccessible to its host

5. EXAMPLES OF SYMBIOTIC
RELATIONSHIPS
1. Lichens
2. Mycorrhizae
3. Termites and Termitomyces (basidiomycete)
4. Ambrosia symbiosis
5. Gut symbionts
6. Scale Insects and Fungi

6. LICHE
NS
Lichen is defined as a ‘self supporting association of a fungus
(Mycobiont) and a Green algae or Cyanobacterium (Photobiont),
resulting in stable thallus of specific structure’
• Some 13500 species of Lichenized Fungi
have been described to date & only 100
species of photobiont is known.
• Most of the lichens do not have the
mechanism to absorb nutrients from the
soil and they depend on atmospheric
sources for nutrients.

7. Three main types of lichens:
1. Crustose lichens form flat crusty plates.
2. Foliose lichens are leafy in appearance,
although lobed or branched structures
are not true leaves.
3. Fruticose lichens are even more finely
branched and may hang down like beards
from branches or grow up from the ground
like tiny shrubs

9. NUTRITION IN
LICHENS
Hill and Smith(1972) devised simple and elegant method termed
the “Inhibition technique” to show the transport of glucose from
Photoibiont to Mycobiont
1. Cyanobacterial Photobionts export Glucose to Mycobiont,
whereas Green algae export polyols such as Erythritol
(Trentepohlia), Sorbitol(Hyalococcus, Stichoccus),
Ribitol(Trebouxia, Coccomyxa, Myrmecia) to Mycobiont.
2. Nitrogen fixed by the Cyanobacterium is released to the
Mycobiont as ammonium and is incorporated into amino acid pool
as Glutamate.

10. 1. In simple, non-stratified crustose lichens, haustoria formed
within the photobiont cells.
2. In more highly differentiated lichens, haustoria are often
reduced to a pad-like infection peg appressed to but not breaking
the algal wall Such structures have been called Intraparietal
haustoria

11. 1.The benefits to the photo-biont may include the
buffering against adverse environmental conditions
such as high solar irradiation. The upper cortex of
many lichens is brightly coloured due to the presence
of pigments which screen out UV light
2. The fungus provides water and minerals to it.
3. Creates a firm substratum within which the phycobiont
can grow & protected from environmental stress.

12. MYCHORRHIZAE
 More than 70% of vascular plants are Mycorrhizal, as are
many Pteridophytes(ferns & their allies) & some
bryophytes especially Liverworts.
 Mycorrhizae refers to an intimate association between a
root and other underground organ and Fungus.
 Major types of Mycorrhiza are
1. Arbuscular mycorrhiza
2. Ectotrophic mycorrhiza
3. Ericoid mycorrhiza
4. Orchid mycorrhiza
5. Ectendotrophic mycorrhiza

14. NUTRITION IN
MYCORRHIZA
It is a Mutualistic association where both get
benefitted
Fungus gains most or all of its organic carbon from Plant,
while the Plant obtain mineral nutrition's from soil via
Fungal hyphae.
• In Natural and cropping environment, its major role is to
supply Minerals mainly the Phosphate, because Phosphate
is extremely immobile element in soils.
• But in acidic soils of moorlands and woodlands where the
rates of decay of leaf litter are relatively slow, mycorrhizal
fungi helps in obtaining Nitrogen by means of their
protease enzyme.

15. TERMITES AND TERMITOMYCES
(BASIDIOMYCETE)
In Africa, termites in the
subfamily Macrotermitinae
cultivate basidiomycetes,
much like attine ants. The
termites consume plant
material and deposit it as fecal
material in the nest. Fungi in
the nest digest the plant tissue
and the termites consume the
fungi.Fungal cellulases remain active in the termite’s gut.
As in attine ants, females that disperse to found new
colonies bring fungal inoculum with them.

16. AMBROSIA SYMBIOSIS
• Its evolutionary mode referred to as Fungal farming.
• More than 3200 known ambrosia beetle species gain nutrition
from fungi
• All ambrosia beetles studied to date cultivate Ascomycotan
fungi.
• Recently Scientists discovered Ambrosia- Basidiomycotan
Fungi association i.e., between Ambrosiodmus-Flavodon
• Ambrosiodmus possessed preoral mycangia containing hyphae.
• Capable of turning rotten wood into complete animal nutrition

17. AMBROSIA BEETLES, BARK
BEETLES AND THE SIREX WOOD
WASP
A range of insects that are
found in living trees utilize fungi
they carry with them to partially
digest the timber thus nourishing
the larvae. The associations are
symbiotic, in that the insect carries
the fungus from tree to tree in
specific pouches called mycangia,
and the fungus digests the food for
the insect.

18. SCALE INSECTS AND
FUNGI
It involves Septobasidial fungi (Basidiomycota) and
scale insects.
1.They form an association in which the insect relies
on the fungus to provide protection from predators,
parasites and pathogens.
2.The fungus gains nutrients and a means of dispersal,
and appears to rely on the insect absolutely.

19. GUT SYMBIONTS
Neocallimastix spp. – CHYTRIDIOMYCETES
Found in the stomachs of cows and other
ruminant herbivores. Along with bacteria and other
microorganisms, these anaerobic fungi help cows
digest plant matter.

20. CONCLUSION
1. Lichens are fungi that have discovered
agriculture" — Trevor Goward
2. A few fungi have evolved close functional and
structural associations with insects and other
organisms. The associations are closely integrated
and mutually beneficial. In each case, the fungus
appears to be gaining access to organic energy,
and in a few systems, the animal ensures close
association by dispersing with the symbiont
attached.

21. REFERENCES
1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4569427/
2. http://bugs.bio.usyd.edu.au/
3. Alexopoulos and Mims, Introductory Mycology 4th edition
4. John webster and Roland weber, Introduction to fungi,
3rd Edition, Cambridge University press
5. Presscot, Harley, Klein, Microbiology, 5th Edition 2002, Tata McGraw Hill
Company
6. https://en.m.wikipedia.org
7. www.researchgate.net

22. THANK YOU