''Rhizopogon roseolus'', shōro (

Japanese Japanese may refer to: * Something from or related to Japan, an island country in East Asia * Japanese language, spoken mainly in Japan * Japanese people, the ethnic group that identifies with Japan through ancestry or culture ** Japanese diaspor ...

: 松露/ショウロ), is a species of

ectomycorrhiza An ectomycorrhiza (from Greek ἐκτός ', "outside", μύκης ', "fungus", and ῥίζα ', "root"; ectomycorrhizas or ectomycorrhizae, abbreviated EcM) is a form of symbiotic relationship that occurs between a fungal symbiont, or mycobio ...

l fungus. It is considered a delicacy in Japan.

Description

The

fruiting bodies The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life cyc ...

are approximately spherical to elongated, often pear-shaped. Their diameter is up to in dry specimens. Their color is initially white, but soon turns pink to reddish-brownish, sometimes also delicately violet-pink. At their base are root-like strands of

mycelium Mycelium (: mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Its normal form is that of branched, slender, entangled, anastomosing, hyaline threads. Fungal colonies composed of mycelium are fo ...

. They give off a faint odor. There are numerous fine elastic fibrils or veins, which are not prominent and are colored the same as the

peridium The peridium is the protective layer that encloses a mass of spores in fungi. This outer covering is a distinctive feature of gasteroid fungi. Description Depending on the species, the peridium may vary from being paper-thin to thick and rubb ...

or darker. This is 240–400

μm The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

thick and single-layered. The

gleba Gleba (, from Latin ''glaeba, glēba'', "lump") is the fleshy spore-bearing inner mass of certain fungi such as the puffball or stinkhorn. The gleba is a solid mass of spores, generated within an enclosed area within the sporocarp. The conti ...

is initially white and becomes yellowish as it dries. The cavities within are labyrinthine, empty or filled with

spores In biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plant ...

where small. They are formed by hyaline (transparent), branched

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

e. The

basidia A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also ...

are club-shaped and hyaline, measuring 12–13 by 9–10 μm. The

sterigma In biology, a sterigma (: sterigmata) is a small supporting structure. It commonly refers to an extension of the basidium (the spore-bearing cells) consisting of a basal filamentous part and a slender projection which carries a spore at the tip ...

ta are as long as the spores, which are uniquely colored, some ocher-tawny, smooth, and ellipsoidal in shape; they measure 7–16 by 3–5 μm. Since the basidia have lost the function of actively ejecting spores, the spores are dispersed not only by rainwater washing away the matured and viscous fruiting body fragments but also by insects and other animals.

Distribution and ecology

''Rhizopogon roseolus'' is considered a cosmopolite species, distributed in Europe, North America and northeastern Asia. It has also been artificially introduced into

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

as an edible fungus. The fungus lives by forming

e with pine trees. It has characteristics similar to those of the pioneer plants, and often appears when the typical pioneer plants settle in areas that have been subjected to strong disturbance. In Europe it grows under ''

Pinus nigra ''Pinus nigra'', the Austrian pine or black pine, is a moderately variable species of pine, occurring across Southern Europe from the Iberian Peninsula and Lower Austria to the eastern Mediterranean, on the Anatolian peninsula of Turkey, Corsica ...

'' on

calcareous soil Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an adje ...

, and it forms fruiting bodies from August to November. In Japan, it is found under pine trees such as ''

Pinus densiflora ''Pinus densiflora'', also called the Japanese red pine, the Japanese pine, or Korean red pine, is a species of pine tree native to East Asia and Siberia. In China, the plant is known as 赤松 (pinyin: chì sōng, literally "red pine"). Distrib ...

'' and ''

Pinus thunbergii ''Pinus thunbergii'' (syn: ''Pinus thunbergiana''), the black pine, Japanese black pine, or Japanese pine, is a pine tree native to coastal areas of Japan (Kyūshū, Shikoku and Honshū) and South Korea. It is called () in Korean, () in Chin ...

'' and has been recorded in

Honshu , historically known as , is the largest of the four main islands of Japan. It lies between the Pacific Ocean (east) and the Sea of Japan (west). It is the list of islands by area, seventh-largest island in the world, and the list of islands by ...

Shikoku is the smallest of the List of islands of Japan#Main islands, four main islands of Japan. It is long and between at its widest. It has a population of 3.8 million, the least populated of Japan's four main islands. It is south of Honshu ...

, and

Kyushu is the third-largest island of Japan's Japanese archipelago, four main islands and the most southerly of the four largest islands (i.e. excluding Okinawa Island, Okinawa and the other Ryukyu Islands, Ryukyu (''Nansei'') Ryukyu Islands, Islands ...

. It has a bipolar mating system.

Uses

It is considered a delicacy in Japan, where it is known as ''shōro''. Immature fruiting bodies that are still pure white inside are considered the best, and they are commonly called ''komeshōro'' (米松露/コメショウロ). After washing thoroughly with a diluted salt solution to remove debris, it is generally used as a vegetable for soup, grilled with salt, and as an ingredient in

chawanmushi is a savoury egg custard dish in Japanese cuisine. Unlike many other custards, it is usually eaten as a dish in a meal, as chawanmushi contains savory rather than sweet ingredients. The custard consists of an egg mixture seasoned with soy sauce, ...

. Techniques for the commercial cultivation of this fungus in

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. ''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as cu ...

plantations have been developed and applied with successful results in Japan and New Zealand. The fungus is used as a

soil inoculant Microbial inoculants, also known as soil inoculants or bioinoculants, are agricultural amendments that use beneficial rhizosphericic or endophytic microbes to promote plant health. Many of the microbes involved form symbiotic relationships with t ...

agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...

and

horticulture Horticulture (from ) is the art and science of growing fruits, vegetables, flowers, trees, shrubs and ornamental plants. Horticulture is commonly associated with the more professional and technical aspects of plant cultivation on a smaller and mo ...

References

External links

* {{Taxonbar, from=Q5351663 Rhizopogonaceae Fungi of Asia Fungi of New Zealand Fungi described in 1837 Taxa named by August Carl Joseph Corda Edible fungi Fungus species