This document discusses different types of parasitism relationships. It defines a parasite as an organism that lives on or in another organism, known as the host, and obtains nutrients from the host. Parasites are classified as either ectoparasites, which live on the external surface of the host, or endoparasites, which live inside the host. Endoparasites can be either intercellular, living between host cells, or intracellular, living inside host cells. Parasites are also classified based on their relationship with the host, including destructive parasites, balanced parasites, facultative parasites, and facultative saprophytes. Examples of different parasite types are provided.

1. Parasitism

2. Parasitism - The relationship between a parasite and its
host

3. Parasite is an organism that lives in or on the body of another
organism (the lost).
Parasite fungi obtain food from living tissues of plants or animals,
which they parasitize.

4. • Saprophyte or saprobe is an organism, which obtains food from
dead organic materials.
• Eg. Saprolegnia, Achlya , Aspergillus, Penicillium, Mucor,
Rhizopus, Peziza, Pilobolus, Polyporus etc.
Parasite & Saprophyte

5. Types of Parasite based on mode of
Parasitism
• Ectoparasite - Live on external surface
• Endoparasite - Grow inside the host cell
1. Intercellular
2. Intracellular
• Destructive parasite – Destroy the host
• Balanced parasite – Draw nutrition without
killing the host
• Facultative parasite - Pythium spp.,Rhizopus sp.
• Facultative saprophyte – Phytophthora sp.

6. Ectoparasite – Erysiphe polygoni
Endoparasite – Helminthosporium oryzae

7. Facultative parasite - Pythium spp.,Rhizopus sp.

8. Facultative saprophytes generally grow parasitically on
the hosts but continue to live, grow and multiply on the
dead tissues of the host and may further move out of
the host debris into the soil or other decaying plant
material to grow and multiply strictly as saprophytes,
e.g., Phytophthora infestans.

9. Intercellular
•Obligate
parasites and
facultative
saprophytes
are intercellular
•Haustorial formation has
been observed in facultative
saprophytes like
Phytophthora infestans,
Cercospora personata, C.
arachidicola

10. Intracellular
Saprophytes and
facultative parasites
usually intracellular

11. Types of Parasitism
Luttrell (1974)

12. Biotroph or obligate parasite
• Biotroph or obligate parasite is an organism, which entirely
depend upon living organism for supply of food nutrients
• Organism that occurs in an intimate association with and
which is wholly dependant for its nutrition on another living
organism
• Downy mildew fungi (Peronospora, Sclerospora, Plasmopara )
• Powdery mildew fungi (Erysiphe, Uncinula, Leveillula,
Phyllactinia, Podosphaera, Sphaerotheca, Albugo,
Synchytrium etc.
• Virus, Viroid and Phytoplasma

14. •Obligate inappropriate – Biotroph which can be cultured in
artificial media
•E.g. Rust fungi, (Puccinia, Uromyces Phakopsora)

15. Hemibiotroph
• Pathogens attack living tissues and grow in or on plants in the
same way as that of biotrophs but continue to grow and
reproduce after the tissue is dead.
• The plant cells remain alive initially but killed later
• E.g. leaf spotting fungi

16. • The organisms which kill the tissue in advance of penetration
and then live saprophytically.
• Kill the plant tissues by secreting enzymes and toxins
• E.g. Sclerotium rolfsii
Perthotroph / Necrotroph

17. Difference between Facultative and Obligate Parasite
S.
No.
Facultative Parasite Obligate Parasite
1. Grows inter and
intracellularly
Grows intercellularly
2. Usually kill the host and
are more destructive
Less destructive and
nourished cells are not killed
3. Have broad host range Narrow host range
4. Cause localized infection Local and systemic infection
5. Grow on artificial media Grow only on living tissues

18. Symbiotic relationship
Symbiosis – the living together of unlike organisms
1. Parasitism – non mutual symbiotic relationship
One of the participants either harms its host lives
at the expense of the host
2. Mutualism – mutual symbiotic relationship
Two dissimilar organisms living together in close
association for mutual benefits
Lichens – Fungus
and Algae
Mycorrhizae –
Fungus and Plant
roots

19. MYCORRHIZA
• It is one kind of mutualism between the fungi and roots of
higher plants.
• The name 'mycorrhiza' literally means "fungus root" and it was
coined by Frank in 1885.
• i.e. fungal hyphae like in association with the roots either on
the periphery or in the cells of certain layers of the cortex.
• Ectomycorrhiza – e.g. Amanita spp.
• Endomycorrhiza / Arbuscular mycorrhizae– e.g. Glomus spp.
• Ectendomycorrhizae -0 e.g. Endogone sp.

20. MYCORRHIZA

21. Synergism - It means the ability of two kinds of
organisms to grow better or produce greater effect
conjointly than either one could alone
E.g. Diplodia natalensis and Colletotrichum
gloeosporioides together produce much greater
effect on citrus bark than either one of the pair
alone can produce.
Metabiosis – one organism creates or prepares a
suitable environment for the other
E.g. Apple tissues infected by Glomerella
cingulata supported the growth of bacterial food
borne pathogens

22. Thank you…