Abstract
Trichoderma spp. are free-living fungi common in soils from different
ecosystems, but can also establish endophytic associations with plants, roots,
and seeds. Trichoderma are economically important due to their production of
secondary metabolites of great interest in medicine, biotechnology, and agriculture. Fungal metabolites comprise nonvolatile and volatile compounds that
include alcohols, aldehydes, organic acids, esters, hydrocarbonated compounds,
ketones, and nitrogen- and sulfur-containing metabolites as the cyclic molecules
indole-3-acetic acid and gliovirin, respectively. Fungal metabolites have been
identified as natural products, and consequently, some compounds of interest
have been obtained by chemical syntheses. In a natural scenario, a number of
Trichoderma secondary metabolites have key roles regulating plant growth and
development or affecting the proliferation of plant pathogenic microorganisms in
the soil due to their production of antibiotics or siderophores. In this work, we
consider the chemical basis for how Trichoderma spp. exert directly or indirectly
beneficial effects on plants and control plant pathogenic microorganisms.
Keywords
Trichoderma · Secondary metabolites · Plant-microbe interactions · Biocontrol
1
Introduction
Trichoderma fungi occur as free-living organisms on the soil surface, in the soil core,
or in association with belowground parts of living plants or organic material derived
from dead plants and animals [1]. Since at least the 1920s, the fungi became famous
for their ability to act as biocontrol agents against plant pathogens, protecting several
major crops [2, 3]. Today it is well known that Trichoderma also has the ability to
directly promote plant growth and development by the production of secondary
metabolites, which play a central role in their interactions with other biota. Species
like T. atroviride, T. asperellum, T. citrinoviride, T. gamssi, T. harzianum,
T. longibrachiatum, T. parareesei, T. reesei, T. viride, and T. virens are the species
most frequently studied due to their effect on plants and their natural products with
potential application in medicine and agriculture [4–7].
The interaction strategies of Trichoderma with plants have been studied at various
levels: (1) when the inoculum is near the root, so the fungal diffusible compounds
play an important role during plant growth; (2) when the mycelium reached the plant
root and both organisms physically interact, (3) when Trichoderma interact with
plants only through the emission of volatiles, and (4) in multitrophic interaction
systems, in which the beneficial effects of the fungal inoculation or its individual
compounds have been tested for biocontrol purposes against plant pathogens or
herbivores.
To understand the effect of the fungus on plants, it is first necessary to know the
response of the fungus at different stimuli. In natural conditions, Trichoderma
264
H. A. Contreras-Cornejo et al.
Trichoderma spp. are free-living fungi common in soils from different
ecosystems, but can also establish endophytic associations with plants, roots,
and seeds. Trichoderma are economically important due to their production of
secondary metabolites of great interest in medicine, biotechnology, and agriculture. Fungal metabolites comprise nonvolatile and volatile compounds that
include alcohols, aldehydes, organic acids, esters, hydrocarbonated compounds,
ketones, and nitrogen- and sulfur-containing metabolites as the cyclic molecules
indole-3-acetic acid and gliovirin, respectively. Fungal metabolites have been
identified as natural products, and consequently, some compounds of interest
have been obtained by chemical syntheses. In a natural scenario, a number of
Trichoderma secondary metabolites have key roles regulating plant growth and
development or affecting the proliferation of plant pathogenic microorganisms in
the soil due to their production of antibiotics or siderophores. In this work, we
consider the chemical basis for how Trichoderma spp. exert directly or indirectly
beneficial effects on plants and control plant pathogenic microorganisms.
Keywords
Trichoderma · Secondary metabolites · Plant-microbe interactions · Biocontrol
1
Introduction
Trichoderma fungi occur as free-living organisms on the soil surface, in the soil core,
or in association with belowground parts of living plants or organic material derived
from dead plants and animals [1]. Since at least the 1920s, the fungi became famous
for their ability to act as biocontrol agents against plant pathogens, protecting several
major crops [2, 3]. Today it is well known that Trichoderma also has the ability to
directly promote plant growth and development by the production of secondary
metabolites, which play a central role in their interactions with other biota. Species
like T. atroviride, T. asperellum, T. citrinoviride, T. gamssi, T. harzianum,
T. longibrachiatum, T. parareesei, T. reesei, T. viride, and T. virens are the species
most frequently studied due to their effect on plants and their natural products with
potential application in medicine and agriculture [4–7].
The interaction strategies of Trichoderma with plants have been studied at various
levels: (1) when the inoculum is near the root, so the fungal diffusible compounds
play an important role during plant growth; (2) when the mycelium reached the plant
root and both organisms physically interact, (3) when Trichoderma interact with
plants only through the emission of volatiles, and (4) in multitrophic interaction
systems, in which the beneficial effects of the fungal inoculation or its individual
compounds have been tested for biocontrol purposes against plant pathogens or
herbivores.
To understand the effect of the fungus on plants, it is first necessary to know the
response of the fungus at different stimuli. In natural conditions, Trichoderma
264
H. A. Contreras-Cornejo et al.