ArticlePDF AvailableLiterature Review

Artificial cultivation of true morels: current state, issues and perspectives

Authors:

Abstract and Figures

Morels (Morchella, Ascomycota), which are some of the most highly prized edible and medicinal mushrooms, are of great economic and scientific value. Morel cultivation has been a research focus worldwide for more than 100 years, and the outdoor cultivation of morels has succeeded and expanded to a large scale in China in recent years. In this study, we review the progress in recent research regarding the life cycle and reproductive systems in the genus Morchella and the current state of outdoor cultivation. Sclerotia formation and conidia production are two important phases during the life cycle. The morel species cultivated commercially in America is M. rufobrunnea based on molecular phylogenetic analysis. The species currently cultivated in China are black morels, including M. importuna, M. sextalata and M. eximia. The field cultivation of morels expanded in the majority of the provinces in China with a yield of fresh morels of 0–7620 kg per ha. The key techniques include spawn production, land preparation and spawning, the addition of exogenous nutrition, fruiting management and harvesting. The application of exogenous nutrition is the most important breakthrough in the field of morel cultivation, but the mechanism remains unclear. It was estimated that the total amount of field cultivated fresh morels was ∼500 t in 2015–2016. We also discuss the potential issues remaining in the current literature and suggest directions for future studies.
Content may be subject to copyright.
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=ibty20
Download by: [Institute of Microbiology], [CH Dong] Date: 06 June 2017, At: 20:53
Critical Reviews in Biotechnology
ISSN: 0738-8551 (Print) 1549-7801 (Online) Journal homepage: http://www.tandfonline.com/loi/ibty20
Artificial cultivation of true morels: current state,
issues and perspectives
Qizheng Liu, Husheng Ma, Ya Zhang & Caihong Dong
To cite this article: Qizheng Liu, Husheng Ma, Ya Zhang & Caihong Dong (2017): Artificial
cultivation of true morels: current state, issues and perspectives, Critical Reviews in Biotechnology,
DOI: 10.1080/07388551.2017.1333082
To link to this article: http://dx.doi.org/10.1080/07388551.2017.1333082
Published online: 06 Jun 2017.
Submit your article to this journal
View related articles
View Crossmark data
REVIEW ARTICLE
Artificial cultivation of true morels: current state, issues and perspectives
Qizheng Liu
a
, Husheng Ma
b
, Ya Zhang
c
and Caihong Dong
a
a
State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China;
b
Guangxi Institute of
Botany, Guangxi Zhuangzu Autonomous Region and the Chinese Academy of Sciences, Guiling, China;
c
Sichuan Province Delilong
Agricultural Technology Co. Ltd., Chengdu, China
ABSTRACT
Morels (Morchella, Ascomycota), which are some of the most highly prized edible and medicinal
mushrooms, are of great economic and scientific value. Morel cultivation has been a research
focus worldwide for more than 100 years, and the outdoor cultivation of morels has succeeded
and expanded to a large scale in China in recent years. In this study, we review the progress in
recent research regarding the life cycle and reproductive systems in the genus Morchella and
the current state of outdoor cultivation. Sclerotia formation and conidia production are two
important phases during the life cycle. The morel species cultivated commercially in America is
M. rufobrunnea based on molecular phylogenetic analysis. The species currently cultivated in
China are black morels, including M. importuna,M. sextalata and M. eximia. The field cultivation
of morels expanded in the majority of the provinces in China with a yield of fresh morels of
07620 kg per ha. The key techniques include spawn production, land preparation and spawning,
the addition of exogenous nutrition, fruiting management and harvesting. The application of
exogenous nutrition is the most important breakthrough in the field of morel cultivation, but
the mechanism remains unclear. It was estimated that the total amount of field cultivated fresh
morels was 500 t in 20152016. We also discuss the potential issues remaining in the current
literature and suggest directions for future studies.
ARTICLE HISTORY
Received 3 February 2017
Revised 24 April 2017
Accepted 25 April 2017
KEYWORDS
Artificial cultivation; morel;
outdoor; exogenous
nutrition; Morchella
importuna; life cycle
Introduction
True morels (Morchella spp.) are commercially important
edible mushrooms with a delicate taste and a unique
appearance, belonging to Ascomycota, Pezizomycetes,
Pezizales, Morchellaceae, and Morchella Dill. ex Pers [1].
All species in this genus are edible [2]. Morels are
among the most sought after edible fungi in world mar-
kets with a premium demanded by suppliers, and paid
by consumers [3]. Morels are the most prized and popu-
lar mushrooms in most of Europe and North America.
Morel products were very early approved by the US
Food and Drug Administration (FDA) [4]. In China, mor-
els have been recorded in the prestigious pharmaceut-
ical text Compendium of Materia Medica,which was
written by Li Shizhen during the Ming Dynasty of China,
and used to treat a variety of stomach problems. Morels
are commonly referred to as Guchhiin the Indian mar-
ket and are some of the most important fungi from eco-
nomic, social and ethno-mycological perspectives in the
Northwest Himalayan range [5].
Recent studies have demonstrated that morels
can be used to treat a wide range of conditions based
on their antitumor and immunomodulatory activities
[6,7], anti-inflammatory effects [8], neuroprotective
effects [9], antioxidant activity [10], and hepatoprotec-
tive activity [11].
The economic value of morel mushrooms have been
notably realized worldwide. Large crops of wild morels
are harvested in China, India, Pakistan, Turkey, and
North America [12]. Morels are some of the more valu-
able special forest products in Western North America,
and the annual commerce related to morels likely
ranges from $5 million to $10 million in this region [12].
In China, the annual export of dried morels increased
five-fold from 181,000 kg to 900,000 kg during the past
5 years, averaging $160 US dollars per kg [13]. In India,
morels from the Himalayas are approximately Rs
14,00015,000 per kg [14].
Some morel species fruit in post-fire habitats. These
fire-adapted species, which are termed as burn morels
[15], proliferate mainly in coniferous forests following a
wildfire during spring or summer, typically for 1 or
2 years [13]. To date, there are four obligate fire-
adapted species, M. tomentosa,M. sextelata,M. eximia
CONTACT Caihong Dong dongch@im.ac.cn State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, NO.3 1st
Beichen West Road, Chaoyang District, Beijing 100101, China
ß2017 Informa UK Limited, trading as Taylor & Francis Group
CRITICAL REVIEWS IN BIOTECHNOLOGY, 2017
https://doi.org/10.1080/07388551.2017.1333082
(treated as M. septimelata in Kuo et al. [16]) and Mel-8,
collected on burned sites, and two facultative fire-
adapted species, M. exuberans (discussed as M. capitata
in Kuo et al. [16]) and M. importuna, collected on
burned and non-burned sites [13]. The majority of the
commercial harvest in western North America com-
prises burn morels collected in the first year following
forest fires [12]. In California, members of several Native
American tribes historically collected burn morels for
food, and some tribal members continue to collect
post-fire morels [17].
In nature, the fresh morel mushroom season is very
short, and they are typically found in the markets for
only a few weeks, mainly in the spring. In addition, the
accumulation of heavy metals in the ascocarps that are
picked from natural habitats has been reported [18,19].
The unique culinary flavor and rarity, profound bioactiv-
ities, short market fruiting season and heavy metal
accumulation of wild morels have resulted in the need
to develop a biotechnological process in order to culti-
vate morels under controlled conditions.
Because of their complex life cycle and the lack of
knowledge surrounding ascocarp formation, these deli-
cacies are not artificially cultivated, and the successful
cultivation of morels remains a rare and difficult task
despite more than 100 years of effort [20]. However, in
recent years, the outdoor artificial cultivation of morel
mushrooms has been rapidly developed in China. This
review will introduce the progress in research regarding
the life cycle and artificial cultivation of morels and crit-
ically discusses the issues in making these prized edible
fungi a benefit all humankind. This review provides a
summary of current knowledge and is a basis for future
research into morel cultivation.
Life cycle of morels and reproductive systems
The life cycle and reproductive systems of morels are
critical for their artificial cultivation. Morels are ascomy-
cetes, which have both asexual and sexual reproductive
phases. Each morel ascocarp consists of numerous asci,
and each ascus contains eight spores. Volk and Leonard
[21] produced their representation of the Morchella life
cycle based on cytological observations (Figure 1),
which has been recognized to date. Sclerotia formation
and conidia production are two important phases dur-
ing the life cycle (Figures 2 and 3). The primary myce-
lium germinated from the ejected ascospores can form
sclerotia to survive adverse conditions, such as winter
(Path 1). In the spring, sclerotia may germinate carpo-
genically to form a fruit body or myceliogenically to
develop a new primary mycelium. If a primary mycelium
meets another compatible primary mycelium, the two
hyphae fuze to form a heterokaryon with paired nuclei
(Path 2) [22]. This heterokaryotic mycelium may also
form sclerotia for overwintering. In the spring, these
sclerotia presumably also have the following two
options for germination: myceliogenic or carpogenic.
Two flaws are noted in this life cycle. The first is that
no evidence of sclerotia germinating to produce prim-
ordial is available to date. Fungal sclerotia are hard sub-
terranean structures that are believed to act as a resting
stage, which is resistant to unfavorable environmental
or physiological conditions [23]. Morel sclerotia are
actually pseudosclerotia, which form from the repeated
branching and enlargement of either terminal primary
(homokaryotic) or secondary (heterokaryotic) hyphae
(Figure 2)[22]. However, morel sclerotia are also
believed to enhance survival overwinter [21], but the
conditions that trigger ascocarp formation arising from
sclerotia are not clearly understood. The other flaw con-
cerns the conidia. During the outdoor cultivation of
morels, powdery mildew,which appear to be the con-
idia (Figure 3), is a necessary stage. However, the coni-
dia cannot germinate under experimental conditions,
and limited conidia production is noted in laboratory
cultures [24]. The function of conidia during the life
cycle remains puzzling.
Alvarado-Castillo et al. [25] provided another theoret-
ical life cycle of this genus that included the formation
of the conidia, chlamydospores, an imperfect phase and
sclerotia, which was complemented by genetic plasticity
and a possible capacity for haploid meiosis. However,
this life cycle is theoretical and has yet to be verified.
The reproduction mode of morels has been debated
by some researchers. Several studies have indicated
that species in the Elata and Esculenta clades of
Morchella might be heterothallic and could outcross in
nature [22,26,27]. However, Yoon et al. [28] reported
that the species in the M. esculenta complex (Esculenta
Clade) were haploid because no heterozygosity was
found, which is similar to the results observed in Mel-13
and M. eohespera [29]. It is hypothesized that selfing
might be very common in these morel species or that
they were homothallic, and their fruiting bodies were
developed from haploid mycelia. Dalgleish and
Jacobson [30] hypothesized the high inbreeding poten-
tial of M. esculenta. The recent study concluded that the
mating systems of morel species remains uncharacter-
ized [29].
Development of morel artificial cultivation
For centuries, various methods of morel cultivation
have been attempted. The first report of the outdoor
cultivation of morels occurred in France in 1882 in
2 Q. LIU ET AL.
association with Jerusalem artichokes and was reported
by Roze [31]. In 1904, Molliard claimed to have culti-
vated morels in an apple compost. However, there was
no evidence demonstrating that they were actually
responsible for the morels that grew, i.e. the morels
may have arisen naturally [3].
In 1982, Ower [32] reported the successful cultivation
of Morchella, and its life cycle was replicated in the
Figure 2. Morel sclerotia grown under artificial conditions (in this laboratory). (A) Sclerotia production in a PDA medium in a
plate (bar ¼1 cm). (B) Sclerotia morphology under an anatomical lens (bar ¼500 lm).
Figure 1. Morchella life cycle proposed by Volk and Leonard [21].
CRITICAL REVIEWS IN BIOTECHNOLOGY 3
mycology laboratories of San Francisco State University,
which produced a typical ascocarp in a walk-in growth
chamber. Then, three patents (US Patents 4594809,
4757640, and 4866878) were issued from 1986 to 1989
for morel cultivation to Ower et al. [3335]. Their work
revealed the optimal temperature, humidity and ventila-
tion for morel cultivation. The key process described in
their patents is an inoculation with the morels sclerotia.
Their work was a tremendous breakthrough in the
dreamof morel cultivation. After several more trans-
fers of cultivation rights and associated corporate merg-
ers, morel cultivation has resurfaced at Diversified
Natural Products(DNP, currently named Gourmet
Mushrooms Inc.) Mason County, MI, USA [12]. This com-
pany started selling fresh morels in 2005 [12]. In 2008,
the indoor cultivation of morels in America was aban-
doned thoroughly due to the reduction of output and
the bacterial contamination [36].
Later, Stewart C. Miller obtained a patent in 2005 (US
Patent 6907691B2) by constructing ectomycorrhizal
symbiosis between Morchella mycelium and tree seed-
lings [37]. Masaphy [20] reported the successful initi-
ation and development of the M. rufobrunnea fruit body
via a soilless-controlled process in laboratory-scale
experiments. This technique made indoor-cultivation of
morels possible but has not been transferred to scaled-
up industrial morel farming.
These experiences promoted research on techniques
for the artificial cultivation of morels. Since the 1980s,
numerous scientists in China started to focus their
research studies on morel cultivation. The first patent
was applied in 1993 based on the successful fruiting of
artificially cultivated M. esculenta [38]. However, this
technique is limited given its poor stability and repro-
ducibility, requiring further work for realizing techni-
ques for practical morel production. The bionic
cultivation of morels based on the Populus bonatii and
crop straw succeeded in 2002 and was commercialized
in Yunnan Province in 2004 [39,40]. The largest scale is
33 ha per year with a morel yield of 4503000 kg per ha
[40]. However, this technique is limited due to wood
consumption.
The most important progress in morel cultivation in
China is the invention and application of an exogen-
ous nutrition bag, which made an important break-
through in the field cultivation of morels. In fact, the
idea of exogenous nutrition initially originated from
Owers patent. R. D. Ower was honored as the Father
of Morelsby some Chinese scholars. In 2000, scien-
tists from the Sichuan Academy of Forestry obtained
the fruit body of a morel in a flowerpot grown outside
their door when exogenous nutrition was supplied
[36]. The followed studies demonstrated that the
exogenous nutrition supply is important for the out-
door cultivation of morels. In 2011, the scale cultiva-
tion of morels in the field began with 200 ha and
expanded quickly to 1600 ha in 2016 according to a
recent Chinese survey [41].
Figure 3. Powdery mildew and conidia in the outdoor cultivation of M. importuna (in this laboratory). (A) Powdery mildew in the
soil. (B) Conidia (bar ¼10 lm).
4 Q. LIU ET AL.
Current states of morel cultivation
Morel species currently under cultivation
According to the latest information contained in the
Index Fungorum [42], 323 terms related to Morchella
have been reported (including species, subspecies,
and varieties). Phylogenetic analyzes identified 65
species within Morchella, including the following
three lineages: a basal monotypic lineage represented
by M. rufobrunnea (Rufobrunnea Clade, two species)
and two sister clades comprising black (Elata Clade,
36 species) and yellow morels (Esculenta Clade, 27
species) [43].
Although the cultivation reported in 1982 was
based on one species (M. esculenta Fr. sensu Groves
& Hoare [32]), the patents claim that the methods
apply to all Morchella species [3335]. Kuo [44] sug-
gested that the species cultivated by Ower (and sub-
sequently by others) was M. rufobrunnea according to
the photographs, and the morels cultivated by
Diversified Natural Products also match M. rufobrun-
nea after examination.
The species currently cultivated in China include M.
importuna [29,4548], M. sextelata [4648], and M. exi-
mia [46,47](Figure 4). Identification of the cultivated
morels was based on morphological characters and
molecular evidence [46,47]. These species all belong to
black morels. M. importuna accounted for 8090% of
the cultivated area [47]. Sichuan Morel No.1(M. impor-
tuna, strain SCYDJ1-A1) was the first variety approved in
China. Morchella conica can also be cultivated [39].
Whether other species of Morchella can be cultivated is
currently unknown and deserves further research.
Morchella rufobrunnea Guzm
an & F. Tapia
Morchella rufobrunnea and M. anatolica comprise a sep-
arate evolutionary lineage, Rufobrunnea Clade, from the
Esculenta and Elata clades [49]. Morchella rufobrunnea is
easily distinguished on the basis of its abruptly conical
Figure 4. Morel species cultivated in China: M. importuna (A), M. sextalata (B) and M. eximia (C).
CRITICAL REVIEWS IN BIOTECHNOLOGY 5
young cap with pale ridges and nearly black pits, and
its rufescence[44]. Morchella. rufobrunnea appears in
woodchips and landscaping settings on the West Coast
from California to Seattle in USA [16].
Molecular phylogenetic analysis confirms that
M. rufobrunnea is the morel cultivated commercially in
USA [16,44]. This finding suggests a saprotrophic role
for this species. In 2010, Masaphy in Israel reported a
successful M. rufobrunnea fruiting body initiation and
development in laboratory-scale experiments [20]. This
laboratory-scale technique makes indoor cultivation of
morel possible but has not been transferred to scale-up
industrial morel farming.
Morchella importuna M. Kuo, ODonnell & T.J.
Volk
Morchella importuna,M. sextelata and M. septimelata
(termed as M. eximia in 2015 [50]) are three black mor-
els from North America described in 2012 [16].
Morchella importuna corresponds to the phylogenetic
species Mel-10 in ODonnell et al. [51]. The species is
distinguished from other morels on the basis of its
regular laddered, vertically oriented pits and ridges [16].
This species occurs in gardens, woodchip beds, and
other urban settings of northern California and the
Pacific Northwest region of USA and Canada [16]. The
fungus has also been reported in Turkey, Spain, France,
Switzerland, and China [5053].
The first morel variety approved in China, M.
importuna strain SCYDJ1-A1, was derived from a wild-
collected mushroom in eastern Tibetan Plateau and was
domesticated by a research group in the Soil and
Fertilizer Institute, Sichuan Academy of Agricultural
Sciences, China [54]. Morchella importuna appears to be
a facultative post-fire species given that it has been col-
lected from non-burned sites in Yunnan, China,
Germany, and Turkey [5054]. Its saprophytic life style
contrasts the ectomycorrhizal life style of numerous
other species of Morchella, for which associations and
interactions with plants are often essential at certain
stages.
Morchella sextelata M. Kuo
Morchella sextelata corresponds to the phylogenetic
species Mel-6 in ODonnell et al. [51]. This species has
been collected in Western North America, Mexico and
Yunnan, China [16,53] and is found at 10001500 m in
lightly to moderately burned conifer forests. Morchella
sextelata is often found primarily in years immediately
following forest fires [16]. From a strictly morphological
perspective, the species is virtually identical to several
members of the Elata Clade (M. eximia,M. brunnea,
M. angusticeps, and M. septentrionalis). However,
because it is apparently limited to conifer burn sites,
it can be easily separated from all species but M.
eximia [16].
Morchella sextelata has also been domesticated,
bred and commercially developed in China. The original
strain was isolated from the Aba area in northern
Sichuan, China [47], and the cultivation area for this
morel variety reached 67 ha in 2015 [48].
Morchella eximia boud.
Morchella septimelata is a species of fungus in the
Morchellaceae family described as new to science in
2012 by Kuo et al. [16]. In 2015, Richard et al. [50] clari-
fied the taxonomic status of this species, retaining the
name M. eximia rather than M. septimelata.M. eximia
corresponds to phylogenetic species Mel-7 in ODonnell
et al. [51]. Based on present data, the species can
only be reliably distinguished from M. sextelata via DNA
analysis [16]. Morchella eximia has been found in North
America [50], Europe, Turkey [52], China [53], and
Australia [50], appearing at 10002000 m in lightly to
moderately burned conifer forests often near creek
beds, springs and seeps [16]. This widespread post-fire
morel occasionally fruits extensively in burnt forests and
on rubble [50].
Similar to M. sextelata,M. eximia has also been
domesticated and bred in China. However, the cultiva-
tion of this species is under development, and its
market share is currently much lower than the other
two black morels [47]. The original strains were isolated
in Yunnan and Sichuan provinces [53].
Scale of morel cultivation in china
The area in China under morel cultivation has expanded
rapidly from 200 ha in 2011 to more than 1200 ha in
2015 [55]. The area is estimated to reach 1600 ha in
2016 [41]. Morel cultivation has expanded in the major-
ity of provinces in China, particularly in Sichuan,
Chongqing, Yunnan, Hubei, Shanxi, Henan, and
Guizhou. The field cultivation yield of fresh morels is
07620 kg per ha [40], with common yields of
03000 kg per ha and significant differences are noted
[56]. The total amount of field cultivated fresh morels
was estimated to be 500 t in 20152016.
After the successful outdoor cultivation of morels,
many growers began to attempt indoor cultivation and
industrialized production. However, to date, indoor cul-
tivation has not been successful.
6 Q. LIU ET AL.
Key techniques in the field cultivation of morels
The artificial cultivation of morels has attracted an
increasing number of farmers and is receiving the
enthusiastic support of governmental organizations and
policies in China. To date, the cultivation in farmlands
and forest farming are the main morel cultivation pat-
terns in China (Figure 5). Cultivation can be performed
in various terrains, including plain-hills zones, plateau
zones, and mountain zones. Given that dim light is
needed and direct sunlight is harmful to the growth of
morels, a canopy is necessary. The cultivation process
includes spawn production, land preparation and
spawning, an exogenous nutrition supply, fruiting man-
agement and harvesting.
Spawn production
The quality of the spawn is the most important factor
for the cultivation of any mushroom. Similar to the culti-
vation of numerous other mushrooms [57], the starter
culture (or mother culture), mother spawn and final
spawn are used for morel cultivation (Figure 6). The
starter culture can be made from fresh and healthy fruit
bodies of morels or obtained from a spawn producer or
a laboratory. More agar cultures are then made from
this starter culture. These cultures serve to inoculate
larger containers (bottles or bags), which can be used
to inoculate the final spawn substrate.
The medium used for the morel starter culture is typ-
ically potato dextrose agar (PDA) or PDA with humus.
The same or a similar substrate can be used for the
mother spawn and the final spawn. The most-widely
used raw substrate materials include: sawdust, wheat,
wheat bran, quicklime and humus. The following recipe
can be used: wheat 46%, husk 20%, wheat bran 18%,
sawdust 10%, gypsum 1%, precipitated calcium carbon-
ate (PCC) 1%, and humus 4% [55].
Glass or heat-resistant plastic bottles are often used
for the mother spawn, and heat-resistant bags are used
for the final spawn for convenient transportation.
Approximately 4500 bags (14 28 cm) of the final
spawn (30003375 kg) are used per ha. Numerous
spawn producers have recently emerged in China,
and the majority of morel growers directly purchased
the final spawns. The cost of the spawn is
52,50075,000 RMB per ha (US$7620-10880).
Spawning
Morels are aerobic, and loose soil is good for their
growth. Soil plowing and removing sundries, such as
rocks, are necessary before spawning (Figure 7(A)).
Occasionally, quicklime can be used in soil to kill some
pests and adjust the pH [58]. The mushroom bed
should be 80150 cm wide and 15 cm deep. The dis-
tance between the neighboring beds is 30 cm.
The spawning for morel cultivation is different from
that for most mushrooms given that the morel spawn is
sown directly into the cropland or forest, which is simi-
lar to the seeding of wheat crops (Figure 7(B)). The sea-
son for morel spawning changes based on the different
elevations and is mainly from October to the middle of
December. Spawning typically begins when the highest
local temperature is <20 C. The soil humidity is main-
tained at 5070%. Both sowing in trenches and strew-
ing are used.
Nonnutritive casing soil is spread over the spawn
evenly after spawning at a depth of 35 cm. Film
mulching and a canopy can help maintain the tempera-
ture, humidity, and dim sunlight.
Exogenous nutrition aiding
The morel mycelia are colonized in the soil after the
spawning under suitable temperature and humidity, i.e.
<20 C and 5070% soil humidity. After 1015 d, a vast
expanse of whiteness appears on the surface of the
mushroom bed, which is called a powdery mildew
(Figure 3(A)). In actuality, this white area is the morel
mycelia and conidia that are produced on the soil
(Figure 3(B)).
Figure 5. Morels cultivated in farmland (A) and forest farming (B).
CRITICAL REVIEWS IN BIOTECHNOLOGY 7
Then, an exogenous nutrition bag can be placed in
the mushroom bed. The substrates used for the
exogenous nutrition bag include wheat, chaff, saw-
dust, and cottonseed hull. The same recipe can be
used as the final spawn, and some recipes are pro-
vided in many Chinese patents [59,60], e.g. wheat
67%, sawdust 28%, and lime 5% [59]. The compos-
ition of exogenous nutrition does not appear to be
very strict. The exogenous nutrition bag is filled with
a heat-resistant plastic bag and is subsequently steri-
lized. Holes or a large cut on one side of the bag
should be made, and the bag is placed tightly in the
mushroom bed (Figure 7(C)).
An 50-cm interval is maintained between each
bag, and 22,50030,000 bags per ha were placed.
Under suitable temperature and humidity, morel
mycelia will grow using the added nutrition and
become full of the nutrition bag after 1520 d.
The bags can be removed when the nutrition bag is
depleted, which occurs after 4045 d. Exogenous
nutrition aiding is necessary for the ascomata
development of morels under the current technique.
However, the mechanism remains unknown.
Fruiting management
The most important environmental factor during morel
cultivation is soil moisture and air humidity. Micro-spray
irrigation is necessary for morel cultivation. Timely
draining of rain water and supplementing water during
drought should be performed. The humidity of the soil
surface should be maintained at >50%.
Before fruiting, the soil and air humidity should
be increased. When the temperature increases to
68C in the spring, the trench between the beds
should be slowly flooded to maintain the air
humidity at 8590% and the soil moisture at 6575%.
These conditions will stimulate the differentiation of
the primordium of the morels. Cotter [61] also found that
flooding is necessary for the outdoor cultivation of mor-
els, and flooding stimulates the morels to feed on benefi-
cial bacteria that are essential for fruiting. However, the
flooding mechanism remains to be studied.
Figure 6. Spawn used for morel cultivation (in this laboratory). (A) Starter culture (or mother culture). (B) Mother spawn. (C) Final
spawn.
8 Q. LIU ET AL.
Temperature is also important for morel cultivation.
The optimal temperature for primordium differentiation
is 610 C. Diurnal temperature variations >10 C stimu-
late primordium differentiation. Morel fruit bodies can-
not grow well at temperatures >20 C. However, the
temperature can only be adjusted by film mulching, a
canopy, and spraying and ventilating in outdoor
cultivation.
Another important management technique during
morel cultivation is pest control. Competitive contami-
nants include: Trichoderma,Aspergillus,Rhizopus,Mucor,
Neurospora,Coprinus and bacteria [62]. Common insects
include: Limax, mites, spring tail and maggot. All chem-
ical pesticides are absolutely prohibited, but physical
and biological control techniques can be used.
Harvesting
When the ascocarp grows to 1015 cm with an obvious
ridge and sinus, the fruit body can be harvested. Fruit
bodies can be dried at a low temperature.
Issues and perspectives
True morels are highly prized for their medicinal and
nutritional values and are intensively collected around
the world by mycophiles. Although outdoor artificial
cultivation has been successful in China, knowledge
regarding the factors controlling fruit body initiation
and development remains far from sufficient. Along
with the rapid expansion of morel artificial cultivation in
China, several notable problems, including spawn aging
and mechanisms of exogenous nutrition, are frustrating
to morel farmers. The enhancement of biological
research will be helpful for solving those problems and
promoting technology for the development of artificial
cultivation.
Life cycle and reproductive systems
Determining the life cycle and reproductive systems of
Morchella will contribute to the understanding of scler-
otia formation and ascocarp production. As Volk [63]
Figure 7. The process of morel cultivation in the field. (A) Soil plowing. (B) Spawning and casing. (C) Exogenous nutrition aiding.
(D) Primordium. (E) Nascent fruit body. (F) Mature fruit body.
CRITICAL REVIEWS IN BIOTECHNOLOGY 9
clearly indicated, morels have a complex life cycle that
complicates the process of scaling up cultivation meth-
ods to efficient commercial procedures. Although
numerous studies have been performed on the life
cycle, the information to date is limited and
inconclusive.
Conidia production seems to be necessary during
outdoor cultivation (Figure 3). However, in pure culture
under various conditions, no conidia production is
observed [24]. The conidia produced during outdoor
cultivation basically cannot germinate [64]. The mech-
anism by which morels produce the conidia and its
function are puzzling.
Morels appear to require the intermediate stage of
sclerotia formation [3335,63] before they produce fruit.
Stott and Mohammed [3] and Winder [65] asserted that
growth substrates and their nutritional composition
affected mycelial characteristics and sclerotia formation.
The presence of a sclerotial stage in morels may be a
precursor for ascocarp formation but could also simply
be a nutrient storage organ awaiting favorable condi-
tions for ascocarp production. During outdoor cultiva-
tion in China, it is not clear whether sclerotia formation
is necessary for fruit body development.
Sequencing morel genomes will provide unprece-
dented insights into fruiting-related genes, the mating
system and genes essential for the sexual reproduc-
tion of morels. To date, the genome of only two spe-
cies in the Elata Clade (M. importuna and M. conica)
has been completed and reported in the 1000 Fungal
Genomes project supported by the DOE Joint
Genome Institute [54].
Trophic mode of morels
The trophic mode of morels has been a source of scien-
tific interest and debate for a long time. It is suggested
that morels form an association with tree roots in stable
ecosystems [66]. A study on the muffs formed by M.
rotunda strongly indicates that M. rotunda can form a
symbiotic relationship with plant roots, but the role of
this symbiosis in the morel life cycle is unknown [67]. In
laboratory isolates, M. elata form ectomycorrhizal struc-
tures (mantle and Hartig net) with Larix occidentalis
(larch), Pinus contorta (lodgepole pine), Pinus ponderosa
(ponderosa pine), and Pseudotsuga menziesii (Douglas-
fir) but not with Arbutus menziesii (madrone) [68]. Stark
et al. [69] hypothesized that morels were associated
with orchids based on evidence obtained through a dir-
ect PCR amplification of root-extracted DNA and the
cloning of the PCR products.
By examining the relative abundance of the stable
isotopes, Hobbie et al. [70] suggested that morels were
largely saprophytic, whereas Li et al. [71] suggested that
morels with black pilei were saprophytic and that those
with yellow pilei were mycorrhizal. Baynes et al. [72]
studied Morchella, an endophyte in the aboveground
stem tissue of cheat grass, and reported that M.
sextelata could infect cheat grass roots. Although M.
sextelata and M. eximia were reported as obligate fire-
adapted species [53], they occasionally fruit extensively
in burnt forests and on rubble [16]. Successful cultiva-
tion in the field suggested that at least M. importuna,M.
sextelata, and M. eximia were saprophytic species, but
how ascomata development was triggered remains
unclear. A recent study also concluded that morels fruit-
ing in post-fire environments were saprotrophic using
isotopic analysis [73]. To date, the trophic strategies of
Morchella have not been consistent, but the available
data seem to indicate that Morchella likely includes not
only saprophytic species and mycorrhizal species but
also facultative mycorrhizal species. This relationship
does not imply that an ectomycorrhizal relationship is
essential for either the morel life cycle or ascocarp pro-
duction. More research in this area is needed to confirm
such a relationship.
Spawn quality
Spawn quality is a key for almost all mushroom culti-
vation. The cultural morphology of Morchella isolation
in different growing media is random and unstable
[74,75], which highlights the difficulty in spawn
quality evaluation. Currently, no quality standard is
available for morel spawns in China, and growers
empirically judge the quality exclusively based on the
quantity of sclerotia. In fact, the relationship between
sclerotia and ascocarp production has not been
determined. The insufficient knowledge regarding
morel biology, including genetics and life cycle, has
resulted in many unsolved problems regarding its
spawn.
On the other hand, morel strains senesce quickly,
losing their vigor and viability; thus, strains must be
repeatedly reselected from spore cultures [76]. The
application of the senesced spawns characterized by
slim mycelia, reduced growth rate and untidy growth
during the cultivation may result in a remarkable
reduction in production. Unfortunately, aging in
Morchella mushrooms has not been systematically
studied.
Producers must take effective measures to store the
spawn, which can preserve the spawns vigor and viabil-
ity, and an inappropriate storing method may acceler-
ate the spawns senescence or even contaminate it.
Research regarding how to effectively preserve morel
10 Q. LIU ET AL.
spawns in China is lacking, and more attention should
be given to this topic.
Mechanism of exogenous nutrition
Exogenous nutrition supply is a critical technique for
the successful outdoor cultivation of morels, but the
mechanism underlying the exogenous nutrition remains
unclear. The words exogenous nutritioninitially
appeared in Owers patent [35]. This researcher sug-
gested that alterations from a nutrient-rich to a nutri-
ent-poor environment will induce the fungus to enter
the sexual growth cycle in which ascocarps are pro-
duced. The majority of morel growers in China believe
that the exogenous nutrition bag supplies the nutrition
for mycelia growth [40]. Radiolabeling could be useful
for answering this question.
Morel cultivation using the current technique is
extremely labor intensive. Exogenous nutrition supply
increases the labor and cost given that making the
exogenous nutrition, sterilizing it and placing it in the
mushroom bed require a significant amount of labor.
Therefore, the mechanization of the exogenous nutri-
tion supply or another cultivation mode will serve as
other targets based on the mechanism of the exogen-
ous nutrition.
Indoor and industrial cultivation
Mushroom farming is and will continue to move
towards large-scale industrialization. Morel cultivation
in the field and forest has expanded rapidly in China.
However, there is a great risk given that outdoor culti-
vation is strongly affected by the climate and soil, e.g.
the intensive low temperature and cold wave in 2016
caused great losses for morel growers [36]. The indoor
cultivation of morels in America was completely aban-
doned in 2008, and indoor cultivation on a large scale is
not currently being performed. Techniques for the
indoor cultivation of morels will be the research focus
for the coming years, and we believe that it will succeed
within a couple years based on the detailed biological
research on morels.
Disclosure statement
No potential conflict of interest was reported by the
authors.
Funding
This study was funded by the National Basic Research
Program of China (2014CB138302), the Coal-Based Key
Scientific and Technological Project in Shanxi Province
(FT2014-03-01) and the Key Research and Development
Program from Government of Guangxi Zhuangzu
Autonomous Region (2016AB05317).
ORCID
Caihong Dong http://orcid.org/0000-0002-2558-3404
References
[1] Hibbett DS, Binder M, Bischoff JF, et al. A higher-level
phylogenetic classification of the fungi. Mycol Res.
2007;111:509547.
[2] Dai YC, Yang ZL. [A revised checklist of medicinal
fungi in China]. Mycosystema. 2008;27:801824.
Chinese.
[3] Stott K, Mohammed C. Specialty mushroom produc-
tion systems: maitake and morels. Australian: Rural
Industries Research and Development Corporation;
2004.
[4] Gilbert FA. The submerged culture of Morchella.
Mycologia. 1960;52:201209.
[5] Lakhanpal TN, Shad O, Rana M. Biology of Indian mor-
els. New Delhi: I.K. International Publishing House Pvt.
Ltd; 2010.
[6] Li S, Gao A, Dong S, et al. Purification, antitumor and
immunomodulatory activity of polysaccharides from
soybean residue fermented with Morchella esculenta.
Int J Biol Macromol. 2016;96:2634.
[7] Liu C, Sun Y, Mao Q, et al. Characteristics and antitu-
mor activity of Morchella esculenta polysaccharide
extracted by pulsed electric field. IJMS. 2016;17:986.
[8] Nitha B, Meera CR, Janardhanan KK. Anti-inflammatory
and antitumour activities of cultured mycelium of
morel mushroom, Morchella esculenta. Curr Sci.
2007;92:235239.
[9] Xiong C, Li Q, Chen C, et al. Neuroprotective effect of
crude polysaccharide isolated from the fruiting bodies
of Morchella importuna against H
2
O
2
-induced PC
12
cell
cytotoxicity by reducing oxidative stress. Biomed
Pharmacother. 2016;83:569576.
[10] Fu L, Wang Y, Wang J, et al. Evaluation of the antioxi-
dant activity of extracellular polysaccharides from
Morchella esculenta. Food Funct. 2013;4:871879.
[11] Nitha B, Fijesh PV, Janardhanan KK. Hepatoprotective
activity of cultured mycelium of morel mushroom,
Morchella esculenta. Exp Toxicol Pathol. 2013;65:
105112.
[12] Pilz D, Rebecca ML, Susan A, et al. Ecology and man-
agement of morels harvested from the forests of west-
ern North America. Portland (OR): US Department of
Agriculture, Forest Service, Pacific Northwest Research
Station; 2007.
[13] Du XH, Zhao Q, Yang ZL. A review on research advan-
ces, issues, and perspectives of morels. Mycology.
2015;6:18.
[14] Doctor V. Gucchi: wild mushrooms from Himalayas
worth their weight in gold. The Economic Times
[Internet] 2013 Mar 17 [cited 2017 Jan 08]; ET
CRITICAL REVIEWS IN BIOTECHNOLOGY 11
Magzine: [about 3 screens]. Available from: http://
economictimes.indiatimes.com/magazines/et-maga-
zine/gucchi-wild-mushrooms-from-himalayas-worth-
their-weight-in-gold/articleshow/19007096.cms
[15] Larson AJ, Cansler CA, Cowdery SG, et al. Post-fire
morel (Morchella) mushroom abundance, spatial struc-
ture, and harvest sustainability. For Ecol Manage.
2016;377:1625.
[16] Kuo M, Dewsbury DR, ODonnell K, et al. Taxonomic
revision of true morels (Morchella) in Canada and the
United States. Mycologia. 2012;104:11591177.
[17] Anderson MK, Lake FK. California Indian ethnomycol-
ogy and associated forest management. J Ethnobiol.
2013;33:3385.
[18] Isildak
O, Turkekul I, Elmastas M, et al. Analysis of
heavy metals in some wild-grown edible mushrooms
from the middle black sea region, Turkey. Food Chem.
2004;86:547552.
[19] Shavit E. Arsenic in morels: morels collected in New
Jersey apple orchards blamed for arsenic poisoning.
Fungi. 2008;1:816.
[20] Masaphy S. Biotechnology of morel mushrooms: suc-
cessful fruiting body formation and development in a
soilless system. Biotechnol Lett. 2010;32:15231527.
[21] Volk TJ, Leonard TJ. Cytology of the life-cycle of
Morchella. Mycol Res. 1990;94:399406.
[22] Volk TJ, Leonard TJ. Experimental studies on the
morel. I. Heterokaryon formation between monoas-
cosporous strains of Morchella. Mycologia.
1989;81:523531.
[23] Alexopoulos CJ, Mims CW, Blackwell M.
Introductory mycology. 4th ed. New York (NY): Wiley
& Sons; 1996.
[24] Liu W, Cai YL, He PX, et al. [Morphological and struc-
tural analysis of mitospore of Morchella importuna]. J
Fungal Res. 2016;14:157161. Chinese.
[25] Alvarado-Castillo G, Mata G, Sangabriel-Conde W.
Understanding the life cycle of morels (Morchella
spp.). Rev Mex Micol. 2014;40:4750.
[26] Hervey A, Bistis G, Leong I. Cultural studies of single
ascospore isolates of Morchella esculenta. Mycologia.
1978;70:12691274.
[27] Pagliaccia D, Douhan GW, Douhan L, et al.
Development of molecular markers and preliminary
investigation of the population structure and mating
system in one lineage of black morel (Morchella elata)
in the Pacific Northwestern USA. Mycologia.
2011;103:969982.
[28] Yoon CS, Gessner RV, Romano MA. Population genet-
ics and systematics of the Morchella esculenta com-
plex. Mycologia. 1990;82:227235.
[29] Du XH, Zhao Q, Xu J, et al. High inbreeding, limited
recombination and divergent evolutionary patterns
between two sympatric morel species in China. Sci
Rep. 2016;6:224234.
[30] Dalgleish HJ, Jacobson KM. A first assessment of gen-
etic variation among Morchella esculenta (morel) popu-
lations. J Hered. 2005;96:396403.
[31] Roze ME. Adherence de la base dappareils ascospores
de Morchella sur Helianthus tuberosus. Bull Soc Bot Fr.
1882;19:166167.
[32] Ower RD. Notes on the development of the morel
ascocarp. Mycologia. 1982;74:142144.
[33] Ower RD, Mills GL, Malachowski JA, et al., inventors;
Neogen Corporation, assignee. Cultivation of Morchella.
United States patent US 4,594,809. 1986 Jun 17.
[34] Ower RD, deceased, Mills GL, Malachowski JA, et al.,
inventors; Neogen Corporation, assignee. For culturing
ascocarps of species of the genus Morchella. United
States patent US 4,757,640. 1988 Jul 19.
[36] Ower RD, deceased, Mills GL, Malachowski JA, inven-
tors; Neogen Corporation, assignee. Cultivation of
morchella. United States patent US 4,866,878. 1989
Sep 19.
[36] Tan FH. [History, current station and prospect of Morel
cultivation]. Edible Med Mushrooms. 2016;24:140144.
Chinese.
[37] Miller SC, inventor; Miller SC, assignee. Cultivation of
Morchella. United States patent US 6,907,691 B2. 2005
Jun 21.
[38] Zhu DX, inventor; Yang YM, assignee. The
cultivation of Morels. Chinese patent CN 93,115,364.6.
1993 Oct 30.
[39] Zhao Q, Xu ZZ, Cheng YH, et al. [Bionic cultivation of
Morchella conica]. Southwest China J Agr Sci.
2009;22:16901693. Chinese.
[40] Zhao YC, Cai HM, Zhang XL. [Difficulties and prospect
of Morel commercialization in China]. Edible Med
Mushrooms. 2016;24:133139. Chinese.
[41] Weixin.qq.com [internet]. Wuhai: Emushroom net;
2017 [cited 2017 Mar 20]. Available from: http://mp.
weixin.qq.com/s/y4N_AdTXFFIeFOgUpbZAQQ
[42] Indexfungorum.org [Internet]. London: Royal Botanic
Gardens Kew; 2017 [cited 2017 Jan 10]. Available
from: http://www.indexfungorum.org/Index.htm
[43] Du XH, Zhao Q, Yang ZL, et al. How well do ITS rDNA
sequences differentiate species of true morels
(Morchella)? Mycologia. 2012;104:13511368.
[44] Kuo M. Morchella tomentosa, a new species from west-
ern North America, and notes on M. rufobrunnea.
Mycotaxon. 2008;105:441446.
[45] Wang B, Xian L. [Identification of cultivated Morchella].
Southwest China J Agr Sci. 2013;26:19881991.
Chinese.
[46] He PX, Liu W, Cai YL, et al. [Strain identification and
phylogenetic analysis of cultivated and wild strains of
Morchella belonging to Elata Clade in China].
J Zhengzhou Univ Light Indust (Nat Sci).
2015;30:2629. Chinese.
[47] Liu W, Zhang Y, He PX. Morel biology and cultivation.
Changchun: Jilin Science and Technology Press; 2017.
[48] Wsmbmp.org [Internet]. WSMBMP; 2010 [updated
2015 Jul 31; cited 2017 Jan 10]. Available from: http://
wsmbmp.org/Bol13/5.html
[49] Tas¸kin H, B
uy
ukalaca S, Hansen K, et al. Multilocus
phylogenetic analysis of true morels (Morchella)
reveals high levels of endemics in Turkey relative to
other regions of Europe. Mycologia. 2012;104:446461.
[50] Richard F, Bellanger JM, Clowez P, et al. True morels
(Morchella, Pezizales) of Europe and North America:
evolutionary relationships inferred from multilocus
data and a unified taxonomy. Mycologia. 2015;107:
359382.
12 Q. LIU ET AL.
[51] ODonnell K, Rooney AP, Mills GL, et al. Phylogeny and
historical biogeography of true morels (Morchella)
reveals an early Cretaceous origin and high continen-
tal endemism and provincialism in the holarctic.
Fungal Genet Biol. 2011;48:252265.
[52] Tas¸kin H, B
uy
ukalaca S, Do
gan HH, et al. A multigene
molecular phylogenetic assessment of true morels
(Morchella) in Turkey. Fungal Genet Biol. 2010;47:
672682.
[53] Du XH, Zhao Q, ODonnell K, et al. Multigene molecu-
lar phylogenetics reveals true morels (Morchella) are
especially species-rich in China. Fungal Genet Biol.
2012;49:455469.
[54] Genome.jgi.doe.gov [Internet]. California (CA): the
University of California; 1997 [cited 2017 Jan 10].
Available from: http://genome.jgi.doe.gov/Morimp1/
Morimp1.home.html
[55] Liu SL, Li KB, Zhu H, et al. [The current situation of
Morchella artificial cultivation technology and problem
analsis]. Edible Med Mushrooms. 2016;24:290293.
Chinese.
[56] Peng WH, Tang J, He XL, et al. [Analysis of the Morel
cultivation in Sichuan province]. Edible Med
Mushrooms. 2016;24:145150. Chinese.
[57] Oei P. Small scale mushroom cultivation. Netherlands:
Agromisa Foundation and CTA; 2005.
[58] Luo XC, Qin DH, Yang ST, etet al. [Cultivation tech-
nique of Morels and its cooking]. Beijing: China
Agriculture Press; 2016. p. 31. Chinese.
[59] Shi DY, inventor; Chendu Tianlv Fungi Co Ltd,
assignee. Preparation method of culture material for-
mula and nutrition pack formula for morel. Chinese
patent CN 103,819,281 A. 2014 May 28.
[60] Qin XB, Zhang GZ, Shi XD, et al., inventors; Wang ZX,
assignee. Morchella nutrition formula, nutrition bag,
preparation method of nutrition bag and morchella
culture method. Chinese patent CN 105,191,667 A.
2015 Dec 30.
[61] Cotter T. Organic mushroom farming and mycoreme-
diation: simple to advanced and experimental techni-
ques for indoor and outdoor cultivation. Vermont:
Chelsea Green Publishing; 2014. p. 212227.
[62] Liu W, Cai YL, He PX, et al. [Artifical cultivation of
Morchella]. Compilation of information from scene
view of morel cultivation and 2016 annual meeting of
edible fungi association of Hubei Province; 2016.
p. 2736. Chinese.
[63] Volk TJ. Understanding the morel life cycle: key to cul-
tivation. McIlvainea. 1991;10:7681.
[64] Carris LM, Peever TL, Mccotter SW. Mitospore stages
of Disciotis,Gyromitra and Morchella in the inland
Pacific Northwest USA. Mycologia. 2015;107:729744.
[65] Winder RS. Cultural studies of Morchella elata. Mycol
Res. 2006;110:612623.
[66] Buscot F, Munch JC, Charcosset JY, et al. Recent
advances in exploring physiology and biodiversity of
ectomycorrhizas highlight the functioning of these
symbioses in ecosystems. FEMS Microbiol Rev.
2000;24:601614.
[67] Buscot F, Roux J. Association between living roots and
ascocarps of Morchella rotunda. Trans Br Mycol Soc.
1987;89:249252.
[68] Dahlstrom JL, Smith JE, Weber NS. Mycorrhiza-like
interaction by Morchella with species of the Pinaceae
in pure culture synthesis. Mycorrhiza. 2000;9:279285.
[69] Stark C, Babik W, Durka W. Fungi from the roots of
the common terrestrial orchid Gymnadenia conopsea.
Mycol Res. 2009;113:952959.
[70] Hobbie EA, Weber NS, Trappe JM. Mycorrhizal vs
saprotrophic status of fungi: the isotopic evidence.
New Phytol. 2001;150:601610.
[71] Li QL, Ding C, Fan L. [Trophic manner of morels ana-
lyzed by using stable carbon isotopes]. Mycosystema.
2013;32:213223. Chinese.
[72] Baynes M, Newcombe G, Dixon L, et al. A novel plant-
fungal mutualism associated with fire. Fungal Biol.
2012;116:133144.
[73] Hobbie EA, Rice SF, Weber NS, et al. Isotopic evidence
indicates saprotrophy in post-fire Morchella in Oregon
and Alaska. Mycologia. 2016;108:638645.
[74] Chen LJ, Chai HM, Huang XQ, et al. Study on cultural
characteristics of single spore isolation population
from Morchella conica. Biotechnology. 2011;21:6370.
[75] Guler P, Ozkaya EG. Morphological development of
Morchella conica mycelium on different agar media.
J Environ Biol. 2009;30:601604.
[76] Stamets P. Growing gourmet and medicinal mush-
rooms. Berkeley (CA): Ten Speed Press; 2000. p. 574.
CRITICAL REVIEWS IN BIOTECHNOLOGY 13
... Since 2010, the morel cultivation industry has developed rapidly due to the breeding of several black morel varieties with improved fruiting yield and stability, and the development and wide application of exogenous nutrient bags . With the development of these technologies, successful morel cultivation not only alleviated the shortage of wild morels in the market, but also greatly promoted the local economic development (Liu et al. , 2018Tan et al. 2019). At present, morel cultivation covers almost all areas in China. ...
... At present, farmland and forest farming are the main morel cultivation methods. The cultivation protocol consists of spawn production, land preparation and spawning, an exogenous nutrition supply, fruiting management and harvesting (Liu et al. , 2018Zhao et al. 2021). ...
Article
Full-text available
Fungi are an understudied resource possessing huge potential for developing products that can greatly improve human well-being. In the current paper, we highlight some important discoveries and developments in applied mycology and interdisciplinary Life Science research. These examples concern recently introduced drugs for the treatment of infections and neurological diseases; application of –OMICS techniques and genetic tools in medical mycology and the regulation of mycotoxin production; as well as some highlights of mushroom cultivaton in Asia. Examples for new diagnostic tools in medical mycology and the exploitation of new candidates for therapeutic drugs, are also given. In addition, two entries illustrating the latest developments in the use of fungi for biodegradation and fungal biomaterial production are provided. Some other areas where there have been and/or will be significant developments are also included. It is our hope that this paper will help realise the importance of fungi as a potential industrial resource and see the next two decades bring forward many new fungal and fungus-derived products.
... In recent years, outdoor cultivation has succeeded and expanded on a large scale in China. However, there are many unsolved basic biological problems, resulting in unstable yields and a high risk in production [3]. ...
... The strains with the MAT1-1 type, MAT1-2 type, and a mixture of MAT1-1 and MAT1-2 type were cultivated in the Changping District, Beijing, China (N: 40 • 08 35.61 E: 116 • 20 45.62 ). Sowing and post-sowing were carried out according to the previous report [3]. Common vegetable garden soil was used for cultivation, and the soil humidity was maintained at 50-70%. ...
Article
Full-text available
True morels (Morchella spp.) are edible mushrooms that are commercially important worldwide due to their rich nutrition and unique appearance. In recent years, outdoor cultivation has been achieved and expanded on a large scale in China. However, the mechanisms of fruiting body development in morels are poorly understood. In this study, the role of mating-type genes in fruiting body development was researched. Fruiting bodies cultivated with different mating-type strains showed no difference in appearance, but the ascus and ascospores were slightly malformed in fruiting bodies obtained from the MAT1-1 strains. The transcript levels of mating-type genes and their target genes revealed that the regulatory mechanisms were conserved in ascomycetes fungi. The silencing of mat1-2-1 by RNA interference verified the direct regulatory effect of mat1-2-1 on its target genes at the asexual stage. When cultivated with the spawn of single mating-type strains of MAT1-1 or MAT1-2, only one corresponding mating-type gene was detected in the mycelial and conidial samples, but both mat1-1-1 and mat1-2-1 were detected in the samples of primordium, pileus, and stipe. An understanding of the mating-type genes' role in fruiting body development in M. sextelata may help to understand the life cycle and facilitate artificial cultivation.
... The majority of severe cases present a similar symptomatology: profuse diarrhea and vomiting, sometimes associated with gastrointestinal injury, followed by hypovolemic shock that may lead to death. Conclusion: These severe morel intoxications appeared in parallel with the arrival of imported morels from Asia into French territories [5]. Moreover, for 3/10 severe cases, a certainty on the Asian origin of the morels was confirmed. ...
... The aims of this pilot study were to determine the functionality of VSH and investigate usage characteristics. Methods: The prototype VSH kitchen was built in Unity [3] and delivered (as a website) using 3DVista [4] and Wix [5]. Twentyone childhood kitchen hazards were embedded in the game. ...
Poster
Objective: In June 2019, a paralytic shellfish poisoning (PSP) case related to the consumption of mussels contaminated by saxitoxins at a concentration below the regulatory threshold came to the attention of the French Agency for Food, Environmental and Occupational Health and Safety (ANSES) [1]. This pointed to probable undetected human cases of poisoning by neurotoxic phycotoxins. We conducted a review of shellfish poisonings recorded by the French Poison Control Centres (PCCs), looking for a link with phycotoxin concentrations in production areas when possible, in order to identify those cases presenting neurological signs compatible with neurotoxic phycotoxins. Methods: Retrospective study of poisoning cases by bivalve shellfish recorded by the PCCs from 2012 to 2019. All medical records were reviewed by a toxicologist. Cases that could be related to neurotoxic phycotoxins were selected and described. Diagnosis was based on symptoms compatible with ingestion of contaminated shellfish and on environmental data of shellfish production areas (analysed by the French National Institute for Ocean Science, Ifremer), or notifications to the European Rapid Alert System for Food and Feed for imported shellfish. Results: Among the 619 shellfish poisoning cases recorded by the PCCs from 2012 to 2019, 22% (n¼134) had at least one neurological symptom (headache, dizziness or paraesthesia). Review of the medical records for the 134 patients led to the suspicion of 14 cases of PSP and one case of amnesic shellfish poisoning (ASP). Five patients experienced persistent neurological symptoms. High concentrations of saxitoxins were found in shellfish production area for six cases whereas the harvested origin remains unknown for six others; two more cases were linked to the June 2019 alert. Concentration of domoic acid were above the regulatory threshold for the ASP case. Saxitoxins or domoic acid were not tested in the blood or urine of these patients. Conclusion: ANSES, PCCs and Ifremer developed a specific questionnaire and recommend actions to take (to keep any meal leftovers and go to the emergency department of a hospital to collect biological samples), when neurological symptoms related to shellfish consumption are reported to a PCC. Daily prospective monitoring of shellfish poisoning cases registered in the national PCCs database was also implemented. To date, no other cases of neurotoxic phycotoxins poisoning were suspected among new shellfish poisonings registered by the PCCs.
... The majority of severe cases present a similar symptomatology: profuse diarrhea and vomiting, sometimes associated with gastrointestinal injury, followed by hypovolemic shock that may lead to death. Conclusion: These severe morel intoxications appeared in parallel with the arrival of imported morels from Asia into French territories [5]. Moreover, for 3/10 severe cases, a certainty on the Asian origin of the morels was confirmed. ...
... The aims of this pilot study were to determine the functionality of VSH and investigate usage characteristics. Methods: The prototype VSH kitchen was built in Unity [3] and delivered (as a website) using 3DVista [4] and Wix [5]. Twentyone childhood kitchen hazards were embedded in the game. ...
Poster
Full-text available
Objective: Diphoterine is a decontamination solution commercialized for cutaneous and ocular chemical exposure in humans. Previous reviews reported conflicting results, and new studies are now available. We aimed to update the assessment of the evidence level of Diphoterine for the decontamination of cutaneous and ocular chemical burns in humans. Methods: We performed a systematic review, searching PubMed (27 January 2021) and Embase (19 March 2021) without time restriction, as well as Google and the manufacturer’s website in February 2021. We included all English and French-language studies comparing Diphoterine to water or physiological solution for cutaneous and ocular chemical burns decontamination in humans, assessing any criteria clinically evaluating burn severity (burn depth, duration of disability, etc). Qualitative analysis of internal validity of the studies was performed by assessing the statistical validity and the risk of bias for each study. Results: We identified 1020 records, from which seven studies were included, involving approximately 1200 patients in total. There were 2 studies related to ocular burns, 3 to cutaneous burns, and 2 related to both. The main findings claimed for the use of Diphoterine were reductions in the risk of serious burn, healing delay, the length of hospital stay and of time off work. Regarding statistical validity: studies showed multiple comparisons, without adjustment for multiple testing reported. Regarding selection bias: none of the studies were randomized. In two studies, type of decontamination was allocated differently depending on the time to presentation, in favor of Diphoterine. Three studies used a before/after design. Regarding measurement bias: all studies were open-label design, without blinded adjudication of efficacy outcomes reported. Regarding confounding factors: decontamination characteristics and chemical agents were rarely reported between groups. In three studies, time to decontamination was shorter in the Diphoterine group. Regarding conflicts of interest, they were reported in two studies. Conclusion: Available studies showed a high risk of false positive results, and a high risk of bias. Our review displayed several limits: only one reviewer analyzed the studies, we did not use a validated tool for risk of bias assessment. The superiority of Diphoterine over water or physiological solution has yet to be demonstrated, with more methodologically robust studies required.
... These mushrooms are widely found in temperate regions of the northern hemisphere, where they fruit for only a few weeks in the spring [1]. In Chinese culture, morels have a long history of human consumption as medicine to treat a variety of stomach problems, which was recorded in the ancient Chinese book Compendium of Materia Medica written by the Ming Dynasty physician Li Shi-Zhen in 1596 [2]. In Japan, Malaysia, India, and Pakistan, morels function as natural aphrodisiacs based on ethnomycological studies [3]. ...
... However, because morels have a complex life cycle, the cultivation of morel fruiting bodies remains unsuccessful, despite more than 100 years of effort [7]. It was only until recently that the first indoor cultivation of M. rufobrunnea in the United States, and M. importuna, M. sextalata, and M. eximia in China was reported [2]. Nevertheless, as morels have not yet been farmed successfully on a large scale, the industry still has to harvest wild mushrooms to meet the global demand. ...
Article
Full-text available
Morchella esculenta (ME), or “true” morel mushrooms, are one of the most expensive mushrooms. M. esculenta contain all the important nutrients including carbohydrates, proteins, polyunsaturated fatty acids, and several bioactive compounds such as polysaccharides, organic acids, polyphenolic compounds, and tocopherols, which are promising for antioxidant, immunomodulation, anti-cancer, and anti-inflammatory applications. However, the M. esculenta fruiting body is difficult to collect in nature and the quality is not always reliable. For this reason, the cultivation of its mycelia represents a useful alternative for large-scale production. However, for M. esculenta mycelia to be used as an innovative food ingredient, it is very important to prove it is safe for human consumption while providing high-quality nutrients. Hence, for the first time in this study, the nutritional composition, as well as 90 days of oral toxicity of fermented ME mycelia in Sprague Dawley rats, is examined. Results showed that the ME mycelia contained 4.20 ± 0.49% moisture, 0.32 ± 0.07% total ash, 17.17 ± 0.07% crude lipid, 39.35 ± 0.35% crude protein, 38.96 ± 4.60% carbohydrates, and 467.77 ± 0.21 kcal/100 g energy, which provides similar proportions of macronutrients as the U.S. Dietary Reference Intakes recommend. Moreover, forty male and female Sprague Dawley rats administrating ME mycelia at oral doses of 0, 1000, 2000, and 3000 mg/kg for 90 days showed no significant changes in mortality, clinical signs, body weight, ophthalmology, and urinalysis. Although there were alterations in hematological and biochemical parameters, organ weights, necropsy findings, and histological markers, they were not considered to be toxicologically significant. Hence, the results suggest that the no-observed-adverse-effects level (NOAEL) of ME mycelia was greater than 3000 mg/kg/day and can therefore be used safely as a novel food at the NOAEL.
... In 2010, a successful indoor cultivation of Morchella rufobrunnea in a soilless system was achieved at our research facilities in Israel [5]. At the same time, reports of outdoor cultivation systems began to emerge, mainly in China, as summarized by Liu et al. [6] and Sambyal and Singh [7], showing controlled fruitification of Morchella importuna, Morchella sextelata, Morchella eximia and Morchella conica. ...
Article
Full-text available
The cultivation of morel mushrooms (Morchella spp.) outdoors or in controlled indoor systems is a relatively new practice, and infections are beginning to be observed. Infection of indoor-cultivated Morchella rufobrunnea initials (primordia) occurred at our research facilities in Israel. The mushroom initials turned brown, were covered with a dense white mycelium of a foreign fungus and were disintegrated soon after. The isolation of a fungal contaminant from the infected mushroom revealed small colonies with a pinkish spore zone on potato dextrose agar medium. Molecular identification using partial large subunit 28S ribosomal DNA and rRNA internal transcribed spacer sequences identified the fungus as Purpureocillium lilacinum. Inoculation of Morchella colony on agar plat with the isolated fungus caused browning and inhibition of mycelial growth. Inoculation of a healthy primordium with P. lilacinum spores resulted in its browning and deterioration. This is the first report of an infection of indoor-cultivated mushroom and the first showing P. lilacinum as a pathogen of morels.
Article
Full-text available
Morels are highly prized edible fungi where sexual reproduction is essential for fruiting-body production. As a result, a comprehensive understanding of their sexual reproduction is of great interest. Central to this is the identification of the reproductive strategies used by morels. Sexual reproduction in fungi is controlled by mating-type ( MAT ) genes and morels are thought to be mainly heterothallic with two idiomorphs, MAT1-1 and MAT1-2. Genomic sequencing of black (Elata clade) and yellow (Esculenta clade) morel species has led to the development of PCR primers designed to amplify genes from the two idiomorphs for rapid genotyping of isolates from these two clades. To evaluate the design and theoretical performance of these primers we performed a thorough bioinformatic investigation, including the detection of the MAT region in publicly available Morchella genomes and in-silico PCR analyses. All examined genomes, including those used for primer design, appeared to be heterothallic. This indicates an inherent fault in the original primer design which utilized a single Morchella genome, as the use of two genomes with complementary mating types would be required to design accurate primers for both idiomorphs. Furthermore, potential off-targets were identified for some of the previously published primer sets, but verification was challenging due to lack of adequate genomic information and detailed methodologies for primer design. Examinations of the black morel specific primer pairs (MAT11L/R and MAT22L/R) indicated the MAT22 primers would correctly target and amplify the MAT1-2 idiomorph, but the MAT11 primers appear to be capable of amplifying incorrect off-targets within the genome. The yellow morel primer pairs (EMAT1-1 L/R and EMAT1-2 L/R) appear to have reporting errors, as the published primer sequences are dissimilar with reported amplicon sequences and the EMAT1-2 primers appear to amplify the RNA polymerase II subunit ( RPB2 ) gene. The lack of the reference genome used in primer design and descriptive methodology made it challenging to fully assess the apparent issues with the primers for this clade. In conclusion, additional work is still required for the generation of reliable primers to investigate mating types in morels and to assess their performance on different clades and across multiple geographical regions.
Article
Full-text available
Morels (Morchella spp.) are of great economic and scientific value. Paecilomyces penicillatus can cause white mold disease (WMD) widely emerging on morel ascocarps and is also a potential factor causing morel fructification failure. 1-octen-3-ol is a mushroom volatile compound with broad-spectrum antimicrobial activities. This study aimed to control the morel disease caused by P. penicillatus through suppressing P. penicillatus in the soil cultivated with Morchella sextelata using 1-octen-3-ol. Safe concentration of 1-octen-3-ol was estimated by comparing its inhibitory effect against P. penicillatus and M. sextelata, respectively, with mycelium-growth experiments on agar plates. The results showed that M. sextelata possesses a higher tolerance to 1-octen-3-ol than P. penicillatus with a 1-octen-3-ol concentration between 0 and 200 µL/L. Based on that, a sandy soil was supplemented with low (50 µL/L) or high concentration (200 µL/L) of 1-octen-3-ol. The effects of 1-octen-3-ol on soil microbial communities, WMD incidence, and morel yield were investigated. Compared to the non-supplemented control group, the incidence of WMD and the proportion of Paecilomyces in the soils of low- and high-concentration treatment groups were significantly decreased, corresponding to a significant increase in morel ascocarp yield. It suggests that 1-octen-3-ol effectively suppressed P. penicillatus in the soil, thereby reducing the severity of WMD and improving the morel yield. The diversity of soil bacterial communities was also altered by 1-octen-3-ol supplement. The proportion of Rhodococcus spp. in the soil was positively correlated with the 1-octen-3-ol concentration and ascocarp yield, suggesting its potential role in improving morel yield. Key points • A novel method for morel disease suppression was proposed. • Paecilomyces in soil affects white mold disease and fructification yield of morel. • 1-Octen-3-ol suppresses Paecilomyces and alters bacterial community in soil.
Article
Full-text available
Since morels were first successfully cultivated commercially in Sichuan in 2012, morel cultivation has expanded to more than 20 provinces in China. The highest yield currently reaches 15,000 kg/ha. Morel cultivation is characterized by its environmental friendliness, short cycle length, and high profit. However, the yield obtained is unstable which makes morel cultivation a high-risk industry. Although 10 production cycles have passed, there is still a gap between morel cultivation practice and our basic knowledge of morel biology. This mini-review concentrates on the development needs of morel cultivation. We illustrate the key techniques used in the large-scale commercial cultivation of morels and their relevant studies, including nutritional requirements, mechanisms of nutrient bag, soil type, vegetative and reproductive growth conditions, and disease control. This review will be a useful practical reference for the commercial artificial cultivation of morels and promoting the vital technologies required. Key points •Unstable yield still exists after commercial cultivation of morels realized. •There is a gap between cultivation practice and our knowledge of morel biology. •Key techniques are illustrated for morel cultivation practice.
Article
Full-text available
This study was conducted in order to test some agricultural wastes from fruits and sterilization method in the production of oyster mushroom Pleurotus sapidus. This study included two factors, the first is the type of substrate which consisting of seven combinations: A0 (wheat straw 80% + flour bran 20%), A1 (pomegranate peel 25% + wheat straw 75%), A2 (pomegranate peel 50% + wheat straw 50%), A3 (pomegranate peel 75% + wheat straw 25%), A4 (date fruit residues 25% + wheat straw 75%), A5 (date fruit residues 50% + wheat straw 50%), A6 (date fruit residues 75% + straw wheat 25%). The second factor is the sterilization method, represented by two methods of sterilization, the first is sterilization by Autoclave (P0) and the second is sterilization using hydrogen peroxide H2O2 at two concentrations of 3% (P1) and 5% (P2). A2 achieved the shortest period of growth and spread of mycelium which was 51.67 days and the highest amount of total wet yield was 199.2 g.kg-1. A0 and A6 had the shortest period for primordia formation which was 61.0 and 62.8 days, respectively. The mixture of A6 substrate gave the longest production cycle duration of 40.8 days and the highest biological efficiency rate was 44.78%. A1 and A2 gave the shortest fruiting period of 6.22 days. The P0 sterilization method recorded the shortest period for the growth and spread of mycelium, shortest period for the formation of primordia and the longest production cycle resulting in 48.88, 47.4 and 43.6 days, respectively, while the P1 sterilization method recorded highest wet yield of 175.6 g.kg-1 and the highest biological efficiency rate of 39.85%. Keywords. Pleurotus sapidus, hydrogen peroxide, sterilization, substrate
Article
Full-text available
Applying regular morphology combined with the technology of ITS sequence analysis the identification and phylogenetic analysis of the 4 cultivated strains and 5 wild morel isolates mainly collected from Sichuan province and Chongqing municipality were carried out. The study followed the sequence identification program required by data bank of multilocus sequence typing MLST . The phylogenetic tree was constructed with reliable sequences obtained from BLAST one-by-one comparison. The results suggested that the cultivated morel varieties were identified as Morchella importuna M. sextelata and M. septimelata. In addition 5 wild isolates were identified as M. elata and M. importuna respectively. Key words Morchella ITS sequence analysis technique strain identification phylogenetic germplasm resource
Article
Full-text available
A theoretical life cycle of Morchella was generated, analyzing two existing models and complementing these with information relating to their cultivation, experimental observations and other research. Consideration was given to different stages, cellular states and environmental conditions in order to better understand its biological cycle.
Article
Nine species of Morchella, and a number of strains of several of these species, have been grown in submerged culture. Morchella in submerged culture is quite omnivorous so far as its carbohydrate and nitrogen requirements are concerned. The mycelium develops the piquant flavor of the sporocarp. In submerged culture, using a standard nutrient formula, the following species and strain differences are distinguishable: rate of growth, habit of growth, development of discrete mycelial spheres, color of spheres, flavor of mycelium, intensity of flavor, color of the supernatant liquor, and odor of the effluent air. The mycelium will grow at temperatures as low as 36° F, but growth is much slower than at 55 to 70° F, a range which appears to be optimum. A production of 10–25 g (dry wt.), of mycelium per liter of nutrient medium may be expected. The mycelium may be utilized fresh, fresh-frozen, dry, powdered, or as a flavor concentrate. At least one strain has been shown to be adaptable to commercial production.
Article
Three lines of evidence are reported for heterokaryon formation in Morchella esculenta and related species. Cultural studies demonstrated a genetic basis for different types of interactions between mycelia from sister and non-sister spores. Cytological studies of the mycelial interaction between non-sister monoascosporous isolates demonstrated nuclear pairing in presumptive heterokaryons. Two different mutations isolated in this study were used to show genetic complementation in these heterokaryons.
Article
Allelic frequencies for strains of an early occurring gray form of Morchella and the tan M. esculenta were determined for collections from west central Illinois and southwestern Wisconsin. Horizontal starch gel electrophoresis was used to determine electromorph (allele) frequencies from fourteen enzyme systems encoded by twenty presumptive structural loci. A total of 122 monoascosporous isolates from 72 ascocarps were studied. Electrophoretic polymorphisms were found in strains of both forms demonstrating that they exist as Mendelian populations. In general, the gray form and M. esculenta had a high genetic similarity when they occurred at the same locality, indicating that they were likely derived from a common ancestral population. The Plymouth strains were genetically more similar to the Eagle Township strains than the strains from the Richland Center area, which had a larger separation than the other collections. Geographic distance between Illinois and Wisconsin strains resulted in substantial genetic differentiation attributable to genetic drift (Fst = 0.165). Strains of the two different forms, however, do not cluster separately in a phenetic analysis indicating that the two phenotypes are not different taxa.
Article
Crude polysaccharides (MPS) from soybean residue fermented with Morchella esculenta were extracted and purified by DEAE Sephadex A-50 chromatography and Sephadex G-100 size-exclusion chromatography in sequence. Three main fractions MP-1, MP-3 and MP-4 were obtained during the purification steps. The recovery rates based on MPS used were 26.2%, 29.1% and 18.7% for MP-1, MP-3 and MP-4 respectively. The monosaccharide composition, ultraviolet spectrum, infrared spectrum and NMR of the three fractions were analyzed. Furthermore, the influence of polysaccharides fractions upon activation of macrophage cells (RAW 264.7), antitumor activities of the human hepatocellular cell line (HepG-2) and human cervical carcinoma cells (Hela) in vitro were evaluated. The results indicated that the proliferation of MP-3 on RAW 264.7 was 313.57% at 25 μg/mL, which is high while MP-1 had a higher growth inhibition effect on HepG-2 cells of 68.01% at concentration of 50 μg/mL. The fractions of MP-1, MP-3 and MP-4 induced apoptosis in HepG-2 cells and Hela cells by arresting cell cycle progression at the G0/G1 phase. These findings suggest that the purified polysaccharides fractions may be a potent candidate for human hepatocellular and cervical carcinoma treatment and prevention in functional foods and pharmacological fields.