Mycorrhizae

Agricultural Microbiology

1. Mycorrhiza –Importance of ectoandendo-
mycorrhizalfungi –solubilisationand mobilization of
phosphorus –mechanism involved
Dr. S. PARTHASARATHY,
Assistant Professor (Plant Pathology)

4. Mycorrhiza
•Theterm'mycorrhiza'wasfirstusedbyProfessorA.B.Frankinthe
1880's
•ThewordcomesfromtheGreekmykesandrhiza,thecombination
meaningfungus-root(Gr.myces=fungus,rhizo=roots)
•Fungibelongingtobasidiomycetes,ascomycetesorzygomycetes
areinvolveddependingonthetypeofendomycorrhizalassociation.

5. Mycorrhizaswere traditionally classified into the two types:
Ectotrophicand
Endotrophic.
Types (Seven)
Endomycorrhizae
1.Arbuscular(AM) endomycorrhiza
2.Ericoid endomycorrhiza
3. Arbutoid
4. Monotropoid
5. Orchid mycorrhiza
6. Ectomycorrhizae
7. Ectoendomycorrhiza

11. Ectomycorrhizae
Endomycorrhizae

14. ECTOMYCORRHIZAS
*Ectomycorrhizaearethemostadvancedsymbiotic
associationbetweenhigherplantsandfungi,involving
about3%ofseedplantsincludingthemajorityofforest
trees
*Thehyphaepenetratebetweentheoutermostcell
layersformingwhatiscalledtheHartignet.
*Fromthisanetworkofhyphalelements(hyphae,
strandsandrhizomorphs)extendsouttoexplorethe
soildomainandinterfacewiththefungaltissueofthe
root.

16. EctomycorrhizalfungiaremainlyBasidiomycotaandincludecommon
woodlandmushrooms,suchasAmanitaspp.,Boletusspp.andTricholomaspp.
MycorrhizalHyphaeabsorbPintheformoforthophosphateandtransported
activelyaspolyphosphates.
Ectomycorrhizaincludehighlyspecific(forexampleBoletuseleganswithlarch)
andnon-specific(forexampleAmanitamuscariawith20ormoretreespecies)

17. The phosphorus uptake pathways of mycorrhizal root
1. Direct pathway
2. Mycorrhizal pathway

18. ENDOMYCORRHIZAS
In this association the fungi form external
hyphal networks in the soil and grow
extensively within the cells of the root cortex.
It is formed by 120 species of zygomycetes, all
belonging to the order Glomales (Glomus,
Acaulospora, Gigaspora, Sclerocystis,
Entrophospora andScutellospora).
None of these fungi has yet been successfully
cultured axenically.
Endomycorrhizae are formed by nearly 90% of the land plants.

20. Arbuscles Vesicles Fungal spore

21. VAM
•Kingdom -Mycota
•Subkingdon -Eumycota
•Subdivision-Zycomyctina
•Class -Zygomycetes
•Order -Glomales
•Family -Endogonaceae
•Genus -Gigaspora, Scutellospora,
Acaulospora
(Gerdemann and Trappe, 1974)

22. Spore identification

23. Different types-mycorrhizas
1-Glomus, 2-Scutellosporaand Gigaspora,3-Acaulospora,4 .G. tenue

24. Different spores AM fungi
Glomus sp
Glomus clarum
Glomus invermaium
Glomus invermaium

25. Different spores AM fungi
Scutellospora reticulata.
Scutellospora
Acaulospora
Acaulospora

26. 1-Gigaspora marginata, 2-Glomus musiferae, 3-Glomus mosseae, 4-G.
mosseae

27. Glomus mosseaeScutellospora
Spore hyphae

28. -contd
Gigaspora

29. Vesicles
Glomus
Hydrophyllum
Acaulospora

30. L.S-Vesicles

32. Ectendomycorrhizas
Intermediate mycorrhizaltype
Form ‘HartigNet’ and haustoria.
Hyphalcoil in epidermal and cortical cells.
Initially designated as ‘E-strain’.
Later shown to be ascomycetes.

33. Beneficial effects of ECM fungi

38. Functions
1. Nutrient acquisition
•Mycorrhizaalso produce ectoenzymeswhich provide host plant with the potential to
access organic N and P forms that are normally unavailable to AM fungi or to non
mycorrhizalroots.
•Increase ion uptake
•Uptake and transport P nutrient and other elements like N, K, Ca, Mg, Zn, Cu, S, B,
Mo, Fe, Mn, Fl.
•Mycorrhizalfungi improve the soil phosphorus availability by solubilizing inorganic
forms of phosphorus or by mineralization of organic phosphorus.
2. Water use
•Increase water uptake
3. Root protection
•Cover the entire root system
•Increase root architecture.
4. Interaction with other microorganisms
•Stimulate the growth of beneficial microorganism.
•Provide space and nutrients for associated microorganism.
5. Impact on carbon cycle