Fungi are also widely used in the industrial production of detergents, sweeteners,
or personal care products. In agriculture, a number of fungal species have been
used as biological agents to control weeds, pests, and pathogens. Fungi include
yeasts, molds, and mushrooms. Mushrooms are defined according to the Oxford
Dictionary (2013) as ‘‘… fruiting bodies that produce spores, growing from the
hyphae of fungi concealed in soil or wood…’’. In a more practical definition, Hall
et al. (2003 after Chang and Miles, 1992) defined a mushroom as ‘‘… any fungus
with a distinctive fruiting body that is large enough to be … picked by hand …’’.
Mushrooms constitute a component of paramount importance in the structure and
function of all the known ecosystems of the planet, mainly in nutrient recycling.
Mushrooms, as any fungi, are heterotrophic organisms, and therefore they have to
use extracellular sources of energy for their maintenance, growth, and reproduction. Therefore, they have at least three different pathways, not mutually exclusive,
to acquire their energy sources (from plants, animals, or other microorganisms),
as carbon compounds, being therefore (i) saprotrophic, (ii) parasitic, or
(iii) mutualistic.
One the most fascinating groups of mushrooms are those that are able to
establish symbiotic relationships with the roots of plants, called mycorrhizae. The
word mycorrhiza was coined at the end of the nineteenth century, by Anton Frank
(1894), to define the structures formed between the roots of trees that were
completely covered with hyphae of some edible underground fungi called truffles
(Tuber spp.). Since that time, but particularly in the last two decades, due to their
paramount ecophysiological and biotechnological importance, the study of
mycorrhizal symbiosis established between the plant roots and fungi has
blossomed in the scientific literature. Mushrooms and truffles establish mainly a
type of mycorrhiza called ectomycorrhiza with the roots of Gymnosperm and
Angiosperm trees, but also with some shrubs and herbs. It has been estimated that
the number of fungal species that establish ectomycorrhizal symbiosis ranges
between 20,000 and 25,000 species (Comandini et al. 2012; Rinaldi et al. 2008).
Despite the fact that some of the ectomycorrhizal mushrooms (EEMs) are able to
produce some intoxications to humans, called mycetisms, including mortal
poisoning in a limited number of species including the ‘‘angels of death’’ such as
Amanita phalloides, Amanita verna, Amanita bisporigera, and Amanita virosa
(Pérez-Moreno and Ferrera-Cerrato 1995; Pérez-Moreno et al. 1994), there is a
vast group of edible ectomycorrhizal mushroom (EEM) species (Fig. 6.1), and
belowground truffles that are included among the most expensive edible mushrooms in the world (Table 6.1). Due to these high prices, the worldwide market of
edible EEMs has been valued in billions of American dollars annually.
The cultivation of around 100 species of commercial mushrooms in large
factories include only saprotrophic species (Chang 2008). In contrast, the highly
priced edible EEMs can only be cultivated in tightly controlled plantations of trees
and shrubs, at a relatively limited scale, due to the fact that they are obligate
symbionts with living plants. Unlike the widely cultivated saprotrophic mushrooms, in the case of the ectomycorrhizal edible mushrooms, which are the subject
6 Edible Ectomycorrhizal Mushrooms
153
or personal care products. In agriculture, a number of fungal species have been
used as biological agents to control weeds, pests, and pathogens. Fungi include
yeasts, molds, and mushrooms. Mushrooms are defined according to the Oxford
Dictionary (2013) as ‘‘… fruiting bodies that produce spores, growing from the
hyphae of fungi concealed in soil or wood…’’. In a more practical definition, Hall
et al. (2003 after Chang and Miles, 1992) defined a mushroom as ‘‘… any fungus
with a distinctive fruiting body that is large enough to be … picked by hand …’’.
Mushrooms constitute a component of paramount importance in the structure and
function of all the known ecosystems of the planet, mainly in nutrient recycling.
Mushrooms, as any fungi, are heterotrophic organisms, and therefore they have to
use extracellular sources of energy for their maintenance, growth, and reproduction. Therefore, they have at least three different pathways, not mutually exclusive,
to acquire their energy sources (from plants, animals, or other microorganisms),
as carbon compounds, being therefore (i) saprotrophic, (ii) parasitic, or
(iii) mutualistic.
One the most fascinating groups of mushrooms are those that are able to
establish symbiotic relationships with the roots of plants, called mycorrhizae. The
word mycorrhiza was coined at the end of the nineteenth century, by Anton Frank
(1894), to define the structures formed between the roots of trees that were
completely covered with hyphae of some edible underground fungi called truffles
(Tuber spp.). Since that time, but particularly in the last two decades, due to their
paramount ecophysiological and biotechnological importance, the study of
mycorrhizal symbiosis established between the plant roots and fungi has
blossomed in the scientific literature. Mushrooms and truffles establish mainly a
type of mycorrhiza called ectomycorrhiza with the roots of Gymnosperm and
Angiosperm trees, but also with some shrubs and herbs. It has been estimated that
the number of fungal species that establish ectomycorrhizal symbiosis ranges
between 20,000 and 25,000 species (Comandini et al. 2012; Rinaldi et al. 2008).
Despite the fact that some of the ectomycorrhizal mushrooms (EEMs) are able to
produce some intoxications to humans, called mycetisms, including mortal
poisoning in a limited number of species including the ‘‘angels of death’’ such as
Amanita phalloides, Amanita verna, Amanita bisporigera, and Amanita virosa
(Pérez-Moreno and Ferrera-Cerrato 1995; Pérez-Moreno et al. 1994), there is a
vast group of edible ectomycorrhizal mushroom (EEM) species (Fig. 6.1), and
belowground truffles that are included among the most expensive edible mushrooms in the world (Table 6.1). Due to these high prices, the worldwide market of
edible EEMs has been valued in billions of American dollars annually.
The cultivation of around 100 species of commercial mushrooms in large
factories include only saprotrophic species (Chang 2008). In contrast, the highly
priced edible EEMs can only be cultivated in tightly controlled plantations of trees
and shrubs, at a relatively limited scale, due to the fact that they are obligate
symbionts with living plants. Unlike the widely cultivated saprotrophic mushrooms, in the case of the ectomycorrhizal edible mushrooms, which are the subject
6 Edible Ectomycorrhizal Mushrooms
153