Mycorrhiza | Difference between endo- and ectomycorrhiza | Benefits to plants | Symbiosis

Summary

The lecture discusses mycorrhizae, a symbiotic association between fungi and plant roots, introduced by A.B. Frank in 1885. It highlights the different types of mycorrhizae, primarily endomycorrhizae (arbuscular) and ectomycorrhizae, explaining their structures and functions. Endomycorrhizae penetrate plant root cells, aiding nutrient absorption, while ectomycorrhizae form external fungal layers that protect against pathogens. Mycorrhizal associations benefit plants by improving water, nutrient uptake, and resistance to environmental stress. Over 95% of plant species rely on these associations for growth and survival.

Takeaways

• 🌿 Mycorrhizae is a symbiotic relationship between fungi and the roots of higher plants, first identified by A.B. Frank in 1885.
• 🍄 The term 'mycorrhizae' combines Greek words: 'mykes' (fungus) and 'rhiza' (root), indicating a fungal-root association.
• 🤝 Mycorrhizae is mutualistic, benefiting both the plant and fungi. Over 95% of plant species have mycorrhizal associations.
• 🔍 Soil contains a vast, unseen network of fungal mycelia that interact with plant roots, playing a vital role in agriculture.
• 🌱 Two primary types of mycorrhizae exist: Endomycorrhiza (arbuscular mycorrhiza) and Ectomycorrhiza, each with unique characteristics.
• 🌾 Endomycorrhizae, also known as AM (arbuscular mycorrhizae), form intracellular vesicles and arbuscules in the root cells to exchange nutrients.
• 🌐 Ectomycorrhizae remain extracellular, forming a protective fungal sheath (mantle) around the root and creating a Hartig net inside the root cortex.
• 🔬 Endomycorrhizae are found in most vascular plants, while Ectomycorrhizae are primarily associated with woody plants like oak and pine.
• 💧 Mycorrhizae enhance water and nutrient uptake, especially phosphorus, and increase plant resistance to drought, frost, and soil-borne pathogens.
• 🛡 The fungal mantle in ectomycorrhizae acts as a barrier, protecting plants from nematodes and other root pathogens, offering significant agricultural benefits.

Q & A

Who coined the term 'mycorrhizae' and when?

The term 'mycorrhizae' was coined by a German forest pathologist, A.B. Frank, in 1885.

What is mycorrhizae and what is the origin of the term?

Mycorrhizae is a symbiotic association between fungus and the roots of higher plants. The term originates from the Greek words 'mykes' (fungus) and 'rhizo' (root).

What percentage of plant species have mycorrhizal associations?

More than 95% of plant species have mycorrhizal associations.

What is the difference between endomycorrhizae and ectomycorrhizae?

Endomycorrhizae involve fungi that penetrate the root cells, forming vesicles and arbuscules. In contrast, ectomycorrhizae form a mantle around the root surface and remain in the intercellular space without entering the root cells.

What are vesicles and arbuscules, and what are their functions in endomycorrhizae?

In endomycorrhizae, vesicles are storage organs for the fungi, while arbuscules act as absorptive organs, helping the fungi to extract nutrients from the plant roots.

Which fungi form endomycorrhizae, and what are some examples?

Endomycorrhizae are formed by fungi from the Glomeromycota group. Examples include Glomus, Gigaspora, and Acaulospora.

What is the role of the fungal mantle in ectomycorrhizae?

In ectomycorrhizae, the fungal mantle forms a thick layer around the root surface, preventing direct contact with the rhizosphere. It acts as a barrier against pathogens, such as nematodes.

What is a 'Hartig net' in ectomycorrhizae?

A Hartig net is a network of fungal mycelia that occupies the intercellular space in the root cortex in ectomycorrhizal associations.

What are the main benefits of mycorrhizae to plants?

Mycorrhizae help plants by enhancing nutrient uptake (e.g., phosphorus, nitrogen, calcium), increasing drought and frost resistance, providing protection against pathogens, and producing growth hormones and antibiotics.

How do mycorrhizal associations help protect plants from nematodes?

In ectomycorrhizae, the fungal mantle acts as a mechanical barrier that prevents nematodes from reaching the root surface, thereby protecting the plant from nematode attacks.

Outlines

00:00

🌱 Introduction to Mycorrhizae

The term 'mycorrhizae' was coined by German forest pathologist A. B. Frank in 1885. It refers to a symbiotic relationship between fungi and the roots of higher plants. The word originates from Greek, where 'mykes' means fungus and 'rhiza' means root. This relationship is mutualistic, benefiting both the fungi and the plants, and is present in over 95% of plant species. The soil is home to various microorganisms, including fungi that form a vast network of thread-like structures called mycelia, and finer threads called hyphae. Mycorrhizae help create this dense network that plays a crucial role in plant health.

05:01

🍄 Types of Mycorrhizae: Endomycorrhiza

There are two main types of mycorrhizae: endomycorrhizae and ectomycorrhizae. Endomycorrhizae, previously known as vesicular-arbuscular mycorrhiza (VAM), are found in over 90% of vascular plants. These fungi form structures inside root cells called vesicles (storage organs) and arbuscules (absorptive organs similar to haustoria). Some fungi that form endomycorrhizae include Glomus, Gigaspora, and Acaulospora. These fungi enter the roots through the epidermis and spread to the cortex, where they interact with plant cells, both inter- and intracellularly, facilitating nutrient exchange.

10:02

🌿 Ectomycorrhizae: Structure and Function

Ectomycorrhizae occur in only 5% of plant species, typically in trees like pine, oak, and beech. In this type, fungal mycelia form a thick, multi-layered covering called the mantle, preventing direct contact between the roots and the rhizosphere. The mycelia penetrate the root cortex, forming an intercellular network known as the Hartig net, but never enter the root cells. Common ectomycorrhizal fungi include species like Boletus, Russula, and Pisolithus. This external fungal structure protects roots from pathogens and environmental stressors like nematodes by acting as a barrier.

15:03

🌍 Comparing Ectomycorrhizae and Endomycorrhizae

Ectomycorrhizae form a thick fungal mat outside the roots, while endomycorrhizae penetrate inside the root cells. In ectomycorrhizae, a dense fungal mantle and the Hartig net protect the plant by staying in the intercellular space, preventing pathogen attacks. In contrast, endomycorrhizae form vesicles and arbuscules inside root cells for nutrient absorption. These differences influence their occurrence, with endomycorrhizae being more widespread, while ectomycorrhizae are more common in woody plants. Ectomycorrhizae can also be cultured in the lab, unlike endomycorrhizae.

Keywords

💡Mycorrhizae

Mycorrhizae refers to the symbiotic association between fungi and the roots of higher plants. It plays a crucial role in nutrient exchange, benefiting both the plant and the fungus. This association allows plants to absorb water and nutrients more efficiently, as discussed in the lecture, where it is explained that over 95% of plant species have this relationship.

💡Symbiotic association

A symbiotic association refers to a mutually beneficial relationship between two different organisms. In the case of mycorrhizae, the fungus and plant roots work together: the fungus helps the plant absorb nutrients like phosphorus, while the plant provides carbohydrates to the fungus. The lecture emphasizes how this mutualism supports plant health and growth.

💡Endomycorrhizae

Endomycorrhizae, also known as arbuscular mycorrhizae (AM), is a type of mycorrhiza where the fungal hyphae penetrate the root cells of the plant. This type forms structures called arbuscules inside the root cells, which aid in nutrient exchange. The lecture highlights that over 90% of vascular plants form endomycorrhizal associations.

💡Ectomycorrhizae

Ectomycorrhizae is a form of mycorrhiza where the fungal hyphae form a dense sheath (mantle) around the outside of plant roots and enter the spaces between root cells (intercellular), but do not penetrate the cells themselves. These associations are common in trees like pine and oak, as described in the lecture, and provide protection against root pathogens.

💡Arbuscules

Arbuscules are specialized structures formed by endomycorrhizal fungi inside plant root cells. They function as absorptive organs, helping the fungi extract nutrients from the plant in exchange for aiding in the plant's nutrient uptake. The lecture explains that arbuscule formation is essential for all endomycorrhizal fungi.

💡Mantle

The mantle is a thick layer of fungal hyphae that forms around the roots of plants in ectomycorrhizal associations. This structure protects the roots by preventing direct contact with the soil, thus shielding them from pathogens and helping the plant absorb nutrients. The lecture describes how the mantle acts as a physical barrier, particularly against nematodes.

💡Hartig net

The Hartig net is a network of fungal hyphae that occupies the intercellular spaces of plant root cells in ectomycorrhizal associations. This network facilitates the exchange of nutrients between the plant and fungus without the hyphae penetrating the root cells. The lecture explains its role in the mutualistic relationship, especially in woody plants.

💡Vesicles

Vesicles are storage structures formed by endomycorrhizal fungi within plant roots. They store nutrients for the fungus and are not always present in all types of endomycorrhizae. The lecture mentions that while arbuscules are essential, vesicles are formed by some endomycorrhizal fungi as storage organs.

💡Fungal mycelium

Fungal mycelium refers to the mass of thread-like hyphae that make up the body of a fungus. In the context of mycorrhizae, mycelium forms extensive networks that interact with plant roots to enhance nutrient and water absorption. The lecture describes how mycelium creates a vast underground network, especially in agricultural soils.

💡Nutrient uptake

Nutrient uptake is the process through which plants absorb essential minerals and nutrients from the soil. Mycorrhizal fungi enhance this process by extending the reach of plant roots through their hyphal networks. The lecture emphasizes how mycorrhizal associations help plants absorb nutrients like phosphorus, nitrogen, and calcium from the soil.

Highlights

The term mycorrhizae was coined by German forest pathologist A.B. Frank in 1885.

Mycorrhizae is a symbiotic association between fungi and the roots of higher plants, benefiting both partners.

More than 95% of plant species have mycorrhizal associations, showing its vast prevalence in nature.

Fungi in soil have thread-like bodies called mycelia, and part of mycelia are hyphae, which form an extensive network.

There are two primary types of mycorrhizae: endomycorrhizae (arbuscular mycorrhiza) and ectomycorrhizae.

Endomycorrhizae form structures inside root cells called vesicles and arbuscules, where the latter function as absorptive organs for the fungus.

Ectomycorrhizae form a multi-layered covering on the root surface, called a mantle, which protects roots from direct contact with harmful pathogens.

Ectomycorrhizae benefit plants by preventing nematode attacks, as their thick mantle layer blocks nematodes from accessing root cells.

Endomycorrhizae occur in more than 90% of vascular plants, while ectomycorrhizae occur in less than 5%.

Endomycorrhizae fungi cannot be cultured on artificial media, whereas ectomycorrhizae can be grown in lab environments.

Orchids can only germinate in nature when associated with endomycorrhizal fungi like Ceratobasidium and Sebacina.

Mycorrhizae enhance plant nutrient uptake, water absorption, and translocation of phosphorus, nitrogen, calcium, and other minerals.

Fungal mycelia can reach far beyond the rhizosphere, extending the absorptive area of plant roots.

Mycorrhizae improve plant tolerance to stress, such as drought, frost, high soil acidity, and heavy metal toxicity.

More than 95% of plants benefit from mycorrhizal associations, making it a critical ecological and agricultural component.

Transcripts

hello everyone today our topic is

mycorrhizae

the term mycorrhizae was coined by

a german forest pathologist a b frank

in the year 1885

you all know that mycorrhizae is a

symbiotic association between

fungus and roots of higher plants

the word

fungus comes from a greek word my case

and

rhizo meaning root

so when a fungus

associates with the roots

then it becomes mycorrhizae

and in common parlance

we

see mycorrhizae as a symbiotic

association between

fungus and roots of

higher plants only

now this is a mutualistic relationship

where

both the partners benefit each other

more than 95 percent of plant species

have

mycorrhizal associations

there are different types of mycorrhizae

we will see them here in this lecture

so

what is there in the soil we can't see

with our naked eye

we only see the plant

above ground parts

so

for a plant it is the root system

but

in addition to the root system

we know that soil is the habitat of

diverse group of microflora or

microfauna

and here

among the microorganisms bacteria are

the dominating ones

then comes actinomyces

then comes fungi

and fungi have

thread like bodies

these thread like structures are called

as mycelia

and part of mycelia

is called as

hypha

in plural hyphae

so

we can imagine that in the soil there is

a

huge

network a vast network of fungal

mycelium

so in any agricultural land

we can imagine that

below the ground there is a vast

spread of

fungal mycelium

and it will obviously look like this or

even more dense than what it is shown

here

okay

now what are the types of mycorrhizae

there are many

basically we have endomycorrhizae and

ectomycorrhiza

and others are all derivatives of

ecto or

endomycorrhiza

so first is endomycorrhiza then

ectomycorrhizal

ecto endomycorrhiza

required mycorrhizae arbutoid

mycorrhizae

monotropoid mycorrhizae or kid

mycorrhizae

first let us talk about

endomycorrhizae

endomycorrhiza

was earlier called as vam

vesicular are vascular mycorrhizae

now they are called as

arbuscular mycorrhizae or

am

more than 90 percent of vascular plants

of the world

flora form endomycorrhiza

this microwave was earlier named as

vam

because

vesicles and arbor skulls

these two modified structures

are produced by the fungi

in association with the

roots of higher plants

and these modified structures

vesicles and harvest skulls are produced

inside the root cells

inside the

root cells

of the

plant

where they are forming association

so they were called as vam

now these vesicles

these vesicles are basically the storage

organs

for the fungi

and arbor skulls function as

absorptive organs

it functions similar to

hostilia

through our vascules

that the fungi derive nutrients from the

root cells

now all the

endomycorrhizal fungi do not form

vesicles but they form hostilia or

arva skulls because our vascules are the

essential parts

of a fungus

through which it derives nutrients from

the host so formation of arbitral is a

must for endomycorrhiza

so since

all the

endometriosis fungi form our vascules

now endomic result fungi are also known

as are vascular mycorrhizae

here we have some examples of fungi that

form endomycorrhiza like glomas

gigaspora

and akolospora

now what happens inside the root cells

see here

we have epidermal cell layer

epidermis of the root

ok

then this is the entry point of the

fungus fungus which is present in the

soil from the rhizosphere it comes to

the root surface and then it enters

it enters

and then it penetrates further

to hypodermis then to cortex region

and the fungal mycelium spreads all over

in all directions and this fungal

hypha penetrates the cortex and

hypha enters

the root cell

hypha

goes inside the root cell

ok hypha goes inside the root cell

hypha can also

remain intercellular here between

two cells

the space between two cells

hypha can also enter the root cells

now it spreads

enter cellularly and also

intracellularly

and it forms vesicles which are the

storage organs

and

are vasculars which are the absorptive

organs or hostilia through which the

fungi derive nutrients from the root

cells through

hostilia or arbescules

now here the hindu mycorrhizal fungi

i enter the

root

and

spray it in the root cortex

both intercellularly and intracellularly

produce vesicle

and arbor skulls physical formation is

not must for all

but arvascal formation is must for all

mycorrhizal fungi

all right

now

ectomycorrhizal

only five percent of vascular plants

develop ectomycorrhizal in the plants

belonging to the family's pioneer

phagasi and

betulasi

in this type of mycorrhizal association

fungi remain outside the root surface

mostly

fungal mycelia

form a compact and multi-layered

covering

on the root surface and it is called as

mantle

that prevents direct contact of root

tissue with

rhizosphere and the fungi which form

ectomycorrhizal

also enter the root cortex

and form a network of mycelia in the

root cortex

but

do not enter the cells

mycelia

do not become

intracellular

mycelia

are only intercellular

okay now this network of mycelia in the

root cortex

is known as hartig net

these fungi remain in the intercellular

space and never enter the root cells

and this ectomycorrhizal fungi also do

not form vesicle or arabascals

so the fungi which

are responsible for formation of

ectomycorrhizal are

boletas edulis rusula species

rhizopogan species

piso lithar species etc

now in this

picture you can see

formation of ectomycorrhizal

association

in angiosperm

and here in gymnosperm

in angiosperm

we can see here

external hypha okay this is the root

here also

root we have external hifi here

external hypha

and we have

this is epidermis

epidermal layer

epidermal cell epidermal cell

and

just outside the epidermal layer we have

a thick mat of fungal hyphae

thick matter fungal hyphae

and this

mat of fungal hyphae a thick layer of

fungal hyphae is known as mantle

then

we have inter cellular

presence of fungal hyphae we have

epidermal cell here epidermal cell here

and then we have space between two cells

and this is filled by

fungal hyphae

and

in angiosperm this is your

heart ignite

heart ignite in case of pine

ah this is your

mantle

very thin layer of mantle

and fungal hyphae

enter

intercellularly and occupy the

intercellular space

forming a network of haifa

and this is your

hartig net

okay

network of haifa but never enters the

root cell

never enters the root cell remain in the

intercellular space

so this is hypodermis cortex

so fungal hyphae enter the cortex

forming the heart ignite

and outside the root surface

makes

mantle or

a thick layer of fungal hyphae now this

thick layer of fungal hyphae

prevents the root surface to be

to remain in direct contact with the

rhizosphere so rhizosphere soil

and the root surface

they are not in direct contact there is

an interface here and it is fungal

mental ectomycorrhizal

mantle so

any harmful pathogen occurring in the

rhizosphere will find it difficult to

access

the root surface

and will find it difficult to penetrate

the thick layer of mantle and then

access to

root surface to cause any disease

especially it is true for pneumatotes

pneumatotes which have a sucking type of

behavior

it penetrates the stylet in the root

cell and then

it sucks nutrients from the root

but because of presence of mental

thick layer of fungal hyphae that the

nematodes cannot access

the root cells so nematode

attack can be prevented

by

formation of ac2 mycorrhiza in the root

system

so this is one benefit of having

ectomycorrhizal

mental

now we can compare ectomycorrhizal

endomycorrhizae in this diagram

so in the left hand side we have

ectomycorrhizal on the right hand side

am or are vascular mycorrhizae or

endomycorrhiza so in ectomycorrhizal as

we have said just now

so we have fungal mycelium

this is the rhizosphere lysosphere

region

and it forms

the fungal mycelium forms a thick layer

of

fungal

mat this is your mantle

and the fungal hypha also enter the root

intercellularly

and occupies the intercellular space and

it is your heart ignite

all right so mental and heart ignite no

vesicle no harvard skull

whereas in case of am or endo

mycorrhizae we have presence of mycelium

in the rightosphere

it enters the

root then it penetrates the root cortex

remain in the root

intercellularly as well as

intracellularly

produces

vesicle and armaskill

so here only arbor scale has been shown

harvard skulls are the

sucking organs or absorption organs

so these are like hostilia

so this is mainly the difference between

ectomycorrhizal and

endo mycorrhizae in brief

so to

elaborate the differences between ac2

and endomycorrhiza

we have

some points here

occurrence

endo microalgae occurs in more than 90

percent of the cases and ectomycorrhizal

occurs in less than

um

about four percent or so

cases

penetration

fungal hyphae penetrate cortical cells

of root inter and intracellular presence

can be seen

ectomycorrhizal they don't penetrate the

root cells

they are only intercellular or

extracellular

fungal structures formed for

endomycorrhiza vesicle and nervous scale

for ectomycorrhizal

hyphal sheath or mental mental is also

known as hyphal sheath

and

net

okay

now sheath is formed in the

root surface

and hardignate is formed in the root

cortex

now which fungi form the endomycorrhiza

the fungi which belong to

glomerulomycota group

they form endomecology and the fungi

which belong to

basidiomycota acid ascomycota and

zygomicota some of them are

ectomycorrhizal

plants involved

endometriosis are found in

most vascular plants including orchids

ra foliage plants trees

but ectomycorrhizal are found mostly in

woody plants okay beach eucalyptus

oak pine etc

culturability

endo mycorrhizae cannot be cultured on

artificial media so this fungi cannot be

cultured on artificial media whereas

ectomycorrhizal can be cultured on

artificial media so you can isolate them

in the lab

and grow them and multiply them

morphological changes in the root

endo mycorrhizae does not cause

morphological changes in the root

but ectomycology cause morphological

changes in the root

because they form high false sheath or

mantle

which increases the

thickness of the

root

root here

there are other types of mycorrhizae

like ecto-endomicrosia

here we have qualities of both ecto and

endometriosis but

we have less developed

mantle

okay otherwise the fungi will be

forming mantle

but also

they will enter the root and form

vesicle or our muscle a required

microlight these are found in the plants

of tribe ericoidy

or family irrigacy

for example

uh

fungi

pesi zella

claveria so these are the fungi which

form

mycorrhizal association with planes of

aricoidy tribe

arbutoid mycorrhizae these are found in

the plants of tribe arbutoid of family

ericacy

monotropoid mycorrhiza these are found

in the plants of

the family monotropic orchid mycorrhiza

in the nature orchids germinate only

with endomycorrhizal fungi

for example

serato basidium sebasina tulos nella

these are the fungi which help orchid to

germinate

now what are the benefits

of mycorrhizae give to plant

nutrient uptake and translocation

fungal mycelia are

thin thread like and

can be very long

and so can be spread to places away from

risosphere much away from rhizosphere so

since the fungal mycelium is

very thin they have high

surface to volume ratio so they have

high

absorptive surface

okay so they increase the absorptive

surface of the root

they increase the uptake of water and

nutrient

when there is no enough moisture

in the soil the fungal mycelia can bring

water and minerals

from far off places because the mycelia

are

distributed to far off places

ectomycorrhizal fungi translocate

phosphorus nitrogen calcium and amino

acids

okay so phosphorous nutrition is very

important as far as mycorrhizal benefits

to plant is concerned

increase translocation of zinc sodium

and other minerals

then transfer of metabolites from host

to fungal symbiont and other plants

production of growth hormone and

antibiotics

protection of plants

mycorrhizae make

plant drought and frost resistant

the increase

tolerance to stress against soil

temperature toxins

high acidity heavy metal toxicity

then fungal mantle acts as passive

mechanical barrier for root pathogens

like nematodes

so these are the benefits that a host

plant gets from mycorrhizae that may be

the reason why

most of the plants more than 95 percent

of the

plants have mycorrhizal association

so with this the present lecture ends

here

if you have any query please write to me

in the comment box thank you very much