Classification, Characteristics and Reproduction
The Genus Trichoderma is one of the most
abundant fungi that have been shown to be present in all climatic zones. As
such, it can be found in virtually all soils or rotting wood given that they
are found in the roots of plants. However, this fungi can also be found
on various parts of plants including the leaves, seeds and grains.
the most unique traits of this genus, compared to other fungi, is that they
tend to attack other types of fungi. This has resulted in Trichoderma fungi
being labeled as antagonists to other types of fungi. While it
can be found living in symbiosis with plants (in the roots of plants) they have
also been shown to exist as parasites in plants and a variety of other
- T. effusum
- T. atroviride
- T. hamatum
Classification of Trichoderma Fungi
- Kingdom: Fungi kingdom composed of
multicellular and unicellular organisms that obtain their nutrients from
- Phylum: Ascomycota - Fungi that
are characterized by their ascus, a sac-like structure for reproduction
- Class: Euascomycetes - Fungi
that tend to form lichen with other organisms
- Order: Hypocreales - fungi with
brightly colored sphaeriaceous (structures that produce spores are brightly
- Family: Hypocreaceae - contains
species with perithecial ascomata that are brightly colored (red, yellow etc)
As already mentioned, Trichoderma fungi can be
found in many more habitats compared to other types of fungi. They are also
more prevalent because they have developed the capacity to attack other fungi.
Apart from simply attacking other fungi, this species have also been
shown to live as parasites in other types of fungi. This allows them to survive
at the expense of other organisms given that they obtain nutrients from other
fungi without profiting them in return. This is a beneficial characteristic in that it allows them to colonize many more habitats in
The following are some of the other
characteristic of Trichoderma genus:
- They have branched
conidiophores that cluster into fascicles
- Broad and straight/flexuous
- They may have conidial
pigments that are either white or bright green in color
To compete with other fungi better, this
fungi uses the following means of interaction with other organisms:
Hyperparasitism is the process through which Trichoderma
come into contact with other fungi, penetrates the fungi and ultimately
According to research, this type of fungi has developed
mechanisms that has made it possible to identify other pathogenic
fungi, which it then attacks and eliminate. As soon as it penetrates the
pathogenic fungi, they start to release enzymes (lytic enzyme)
that degrade the cell structures of the pathogen.
Some of the enzymes here
include; Lipase, cellulase and amylase among others.
Antibiosis involves the release of secondary
metabolites that have an inhibitory effect on other parasitic fungi. This
prevents them from becoming active parasites or even kills them.
In addition to
acting against other forms of fungi, these metabolites are also active against
various bacteria and virus that may pose a threat to the fungi. Some of the
secondary metabolites released by the fungi include trichorovins and
Trichoderma may also compete with other fungi in
order dominate a given habitat. This is achieved differently for different
species in this genus.
For instance, species like T. longibrachiatum will
compete by producing iron chelating compounds referred to as siderophores that
stunt the growth of its competitors in its environment. By trapping iron in the
habitat, organisms like B. cinerea are greatly affected given that they require
iron for their growth. With their growth affected, the Trichoderma fungi are
able to dominate.
Some of the other means of competition used include:
- Acidification - Some of the
fungi in this genus compete by causing the environment to become more acidic.
This creates an acidic environment that makes it difficult for other fungi to
- Surviving tough conditions
(they can grow at 45 degree Celsius) and high growing in high numbers - this type of fungi can survive tough environmental conditions, which allow them
to continue surviving when others fail to do so. They also
grow in high numbers making it possible for the fungi to dominate a given
environment while making it difficult for the other fungi to grow successfully.
For a majority of the fungi in this genus,
asexual spores are the means of reproduction. When viewed under the microscope, the hyphae, conidiosporeas and conidia can be observed.
Here, the conidiophores
located at the tip of the hyaline hyphae are responsible for the production of
conidia (green spores) that then germinate and grow to form new fungi as the
Some of the species have been shown to be capable of
Benefits of Trichoderma Fungi
- A majority of this
species are free-living organisms. As such, they play two
important roles as decomposers and in their symbiotic relationship with plants.
In a plant's roots (rhizosphere) the fungi helps increase biomass, by decomposing
various organic material using their enzymes, and supporting the development of
root hairs. Research has shown this to greatly benefit plants given that more
root hairs allow plants to penetrate deeper into the soil where they can take
up more water and nutrients to support the development of the plant. For this
reason, the fungi are being used more and more to increase yields.
- As decomposers, the Trichoderma
fungi not only make nutrients readily available for plants (biomass) but also
play an important role in nitrogen and carbon cycle (important for plant development).
- Because of their capacity
to attack and destroy other types of fungi as well as various other organisms
such as bacteria, Trichoderma are also used for the production of pesticides
and other biological agents used to control the spread of other fungi and
pathogenic organisms in agriculture.
While Trichoderma species have been shown to
present many advantages in agriculture and other industries, they also present
health problems for those with compromised immunity. Among such individuals,
opportunistic fungal infection may occur. This has also been shown to be the
case during organ transplants.
Also take a look at Mold under the Microscope
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Cornejo, H. A. C. et al. Trichoderma virens, a
Plant Beneficial Fungus, Enhances Biomass Production and Promotes Lateral Root
Growth through an Auxin-Dependent Mechanism in Arabidopsis. Plant Physiol. 2009
Mar; 149(3): 1579–1592..
Joseph Guaro et al. Fatal Case of Trichoderma
harzianum Infection in a Renal Transplant Recipient. J Clin Microbiol. 1999
Nov; 37(11): 3751–3755.
Lidia Błaszczyk et al. Trichoderma spp. –
application and prospects for use in organic farming and industry. Journal of
Plant Protection Research Vol. 54, No. 4 (2014).