Ectomycorrhizal fungi form mutualistic associations with plant roots. They produce a soil mycelium network linking roots and fruiting bodies. Ectomycorrhizal roots are characterized by a fungal mantle and Hartig net. Structural diversity includes mushrooms, truffles, and crust fungi. Ectomycorrhizal associations benefit plants through improved nutrient acquisition and stress resistance. Common anatomical terms are mantle, Hartig net, and short and long roots.

2. Definition
• These are the fungi which form ectomycorrhizal
association with plants and Ectomycorrhizal
associations (abbreviated as ECM, or EM) are
mutualistic associations between higher fungi
and Gymnosperms or Angiosperms. ECM
associations consist of a soil mycelium system,
linking mycorrhizal roots and storage or
reproductive structures. Ectomycorrhizal roots
(formerly known as ectotrophic or sheathing
mycorrhizas) are characterized by the presence of
a mantle and Hartig net.

4. Structural Diversity

5. Structural Diversity
• Many ECM fungi have mushroom-like fruit
bodies with gills, tubes, teeth, etc. arising
from soil, but there are also many saprophytes
in most of these categories.
• The majority of subterranean fungi (called
truffles or truffle-like) are considered to be
ECM associates, but some probably are not.

6. Structural Diversity
• Fungi fruiting on wood are usually not
mycorrhizal, with the exception of some crust
fungi.

7. • Root system
• Soil hyphae
• Root contact & hyphal proliferation
• Mycorrhizal roots
• Harting net
• Reproduction

9. • Most ECM roots have a modified lateral root
branching pattern. This pattern, which is
called heterorhizy, consists of short
mycorrhizal lateral roots (called short roots)
supported by a network of long roots.

11. • Mycorrhizal fungi produce a hyphal network in
soil consisting of individual strands of hyphae
and/or relatively undifferentiated bundles of
hyphae called mycelial strands, or
rhizomorphs with specialized conducting
hyphae.
• Sclerotia, which are larger, resistant storage
structures, may also be produced.

12. • Soil hyphae function by acquiring nutrients re-
allocating resources for fungus reproduction
or mycorrhizal exchange and by functioning as
propagules for survival and spread of the
fungus.

14. Root Contact and Hyphal Proliferation
• Hyphae contact, recognise and adhere to root
epidermal cells near the apex of young,
actively growing, high-order, lateral root.
These laterals are called short roots because
they normally have restricted growth

15. Mycorrhizal roots
• After ECM associations are established,
mycorrhizal short roots often continue to
grow by elongation and branching.
• Conifer roots with ECM have dichotomous
branching patterns, while angiosperms have
sympodial branching.

16. Mycorrhizal roots

17. The Hartig Net
• Hyphae penetrate between host cells and
branch to form a labyrinthine structure called
the Hartig net.
• Host responses may include polyphenol
production in cells and the deposition of
secondary metabolites in walls .

18. The Hartig Net
• Angiosperms with ECM, such as Eucalyptus,
Betula, Populus, Fagus, Shorea, etc., usually
have a one cell layer Hartig net confined to
the epidermis. This is the epidermal category
of ECM
• In gymnosperms such as Pinus, where Hartig
net hyphae extend deep into the cortex. This
is the cortical category of ECM.

20. Reproduction
• The hyphal network that interconnects ECM
fungi in soils is also responsible for
reproduction. Fruit bodies grow from
primordia at times of the year when
environmental conditions are favorable. Some
fungi will fruit under mycorrhizal plants
growing in pots, as shown below.

21. Fruit bodies of an ECM fungus (Laccaria sp.) under a Eucalyptus
globulus seedling inoculated with fungal mycelia

22. Anatomical terms of ECM fungi
• Mantle
• Hartig net
• Heterorhizy
• Short roots
• Long roots
• Dichotomous branching
• Pinnate branching
• Soil hyphae

23. Anatomical terms of ECM fungi
• Mycelial strands
• Rhizomorphs
• Fruit bodies
• Sclerotia

24. Host plants
• Dominant in coniferous forests
• Cold boreal or alpine regions,
• Broad-leaved forests in temperate or
Mediterranean regions,
• Some in tropical or subtropical savanna or
rain forests habitats

25. • Ectomycorrhizal associations can improve the
phosphate status of plants in soils that are
phosphate deficient.
• Enhance nitrogen nutrition of plants where
nitrogen is deficient.
• Ectomycorrhizal fungi helps plants avoid
disease and survive periods of drought.

26. • The size, color, texture and branching patterns
of ECM roots vary with different host-fungus
combinations, which are called morphotypes.

27. Ectomycorrhizal morphotype

28. ECM fungi of Pakistan
• Cantharellus cibarius is associated with Pinus
wallichiana.

29. • Tricholoma aurantium is associated with Abies
pindrow.

30. • Suillus brevipes is associated with Querus
incana.

31. • Suillus sibiricus is associated with pinus
wallichiana.

32. • Russula livescens, Peziza and 3 species of
Tomentella are associated with Cedrus
deodara.

33. • Lactarius sanguifluus is associated with
Quercus incana, and Populus