The orchid and the mushroom

4 Jul 2020

The orchid and the mushroom
Two beings who seem to be at odds with each other. One known for its elegance, the delicacy of its flowers exposed in greenhouses, admired in the meadows, the other populating the humus, the rotting stumps, the dark undergrowth. The hidden life of mushrooms, the mycelium, reveals an unsuspected intimacy, a close link between orchids and the fungal world.
Seeds under infusion

From its first moments of life, the orchid calls for help. After flowering, a plant produces millions of seeds, so tiny and light that the wind blows them away, spreading them everywhere. Placed on poor prairie soil, in a swamp, wedged in a nook of a branch, the future orchid is so small that it has no food reserve to develop even the smallest root, the smallest cotyledon. This is where the fungus comes in. Not the Cep with its appetizing dark cap, but the mycelium, the hidden vegetative part of the fungal world. Made up of fine filaments, no more than a tenth of a hair, it cemyceliumours the seed, penetrates its cells in thin clumps, and provides it with carbon, nutrients and water. The orchid wakes up, from seed it becomes protocorm, called mycoheterotrophic because it depends on the fungus, then the plant blossoms, turns green, produces its own carbon and becomes autotrophic. And can, eventually, feed the fungus in turn.

A variety of partners throughout their lives

The orchid begins its life under fungal assistance. And it doesn't mind keeping the link longer, its partner with long mycelial filaments prospecting and providing it with water, nutrients, and a little extra sugar. A variety of fungi can be involved, with different dietary patterns. Feeding on dead organic matter, parasitizing plants or establishing symbioses, they associate with orchids. LegenreRhizoctonia is the best known of them, but the Tulasnellaceae and Ceratobasidiaceae families are not to be outdone. Studies in tropical regions, in South Africa, have shown the role of Pezizes, species close to rust. In this relationship becoming perennial, the life cycles of the partners sometimes overlap, with an annual fungus associating itself with an annual orchid, the perennials with the perennials. These associations are generally based on reciprocal exchanges, typically ensymbiosis. However, sometimes, the orchid takes advantage of them a little bit...

Mycorrhizal bridges

Orchidaceae have been shown to have the typical symbiosis mutual exchange practices. The genera Goodyera, Serapias, offer sugars to mushrooms, and receive water and mineral elements. But other orchids have quite different strategies to simplify their lives: Neottia, Corallorhiza, have a confusing behaviour. These undergrowth species never become green, devoid of leaves and chlorophyll. Their associated fungi are themselves connected to host trees, with which they develop a symbiosis. The sugars produced by the chlorophyll plant feed the fungus, and it has been shown that the same sugars reach the orchid. The fungus becomes a delivery carrier. Water, mineral elements and sugars circulate in the mycelial network, mycorrhizae interconnect the plants, and mycorrhizal bridges allow a hitherto unsuspected distribution of the territory's resources. The mycorrhizae interconnect the plants, the mycorrhizal bridges allow a distribution of the territory's resources that was previously unsuspected. The needs are provided in totality for orchids without leaves, and become a precious contribution for others, Epipactis, Limodorum, thus completing their insufficient photosynthetic production.

The orchid and the fungus, in their hidden links invisible to the naked eye, reveal an unsuspected, complex organization of ecosystems. Mycorrhizae are observed on many plants. To what extent do they intervene in the adaptation of plants to difficult environments that are too dry, too dark, too poor? How far will the discoveries on fungi and their mycelial networks, supports for cooperation, mutual aid and competition, go?


The truffle, black desire

2 Feb 2020



The truffle, black desire

The season is open. Too early according to some truffle growers in the Lot, for whom, at this period, the mushroom is not ripe enough. A rare and demanding Perigordian "Diamond", tracked down by an informed muzzle, meets those who grow it and trade it for gold.

January 3, 2020 at 5:26 PM

The black truffle of the Périgord In the Lot, 300 truffle growers exploit 2000 hectares of truffle plantations. Photo J.-D. Sudres


The season is open. We're even in the middle of it. The taste buds are getting ready for the party, for a few weeks now, the truffle is out. When you walk in the countryside near Cahors (Lot) and you see a beautiful house, you usually say: "Here, there are truffles." And the truffle is never far from the nose. It is François Delaroière who speaks best of it in La Truffe, secrets et plaisirs(Champignons magazine,hors-série, January2001): "A rustic yet subtle, powerful, intense aroma, both fresh and warm with fragrances of fresh, cut or dry herbs, wet tobacco, decaying oak leaves, roots, humus, damp earth, musk, leather, fox fur or lightly smoked charcuterie. "The journey promises to be complete.

Love at first sight

Tuber melanosporum, is the learned name of the black truffle of Périgord, this mushroom which makes the richness of lands sometimes forsaken by the good Lord. And the joy of those who appreciate the sweetness of the table and the nuances of the taste. But for this, you first need trees: oak or hazelnut trees under which the truffle will be born; a land: limestone; a climate: with Mediterranean temperatures. In the department of the Lot, all this is combined. Alain Ambialet, president of the truffle growers' union of Lalbenque, a few kilometres from Cahors, underlines it: "We are lucky to have a good soil, clay and limestone, red soils that are perfectly suited to it. There are practically no more "natural" truffles, which means that you have to plant the oaks and wait... eight years minimum, even up to fifteen or twenty years. The producers plant between 200 and 300 trees per hectare, with farms ranging from one to 30 hectares and an investment of 10,000 euros per hectare. In the Lot region, 300 farmers grow at least 2,000 hectares of truffle plantations. Jean-Paul Bataille, a retired salesman, planted more than 500 oaks in 1984 on two and a half hectares in the commune of Montcuq, 37 kilometres from Cahors. He comes from the area, his parents were winegrowers in the Lot valley. But it was only after 1968, when he was a pawn in a secondary school, that a pupil brought him a handful of truffles that he had "pricked" from his father. It was love at first sight, the smell, the taste... the truffle really "appeared" to him that day. And the idea caught on. He put it into practice when he reached retirement age...


At home, there is no smell described by François Delaroière, so you have to follow him to get to the trees under which the famous mushroom is found, because the truffle is not visible to the naked eye. It is with a dog or a pig that one can track it under the ground. The quest does not provide for the needs of a family, just to ensure an additional income. According to Jean-Paul Bataille, to make a living from it, you have to own at least 20 hectares. He explains that he had a "pitiful season in 2018" due to bad weather. This year, there was a change in the programme, at least at the beginning, with renewed optimism in September, with sufficient rainfall, but in October, when the land was submerged in two months, "it fell what normally happens over a six-month period. The stagnant water caused some truffles to perish. However, Jean-Paul Bataille had spotted quite a few "marks", the cracking that truffles cause when they are close to the surface.

The life of a truffle grower is not easy. It is necessary to maintain the truffle fields, water and prune the trees. At the end of March, the soil is stirred at a depth of about 15 centimetres in order to aerate it. Jean-Paul Bataille had to show humility because, at the beginning, he did not have enough advice, he had to do his own training, perfect his education, "peck right and left". By the way, at home, a simple butter toast with truffle shavings allows you to approach the taste of this little jewel.

We are on December 3rd, the day of the first truffle market of the season. Separated by a cordon, buyers and sellers face each other, according to a carefully studied ritual, a gesture they perform as their parents, grandparents, etc. did before them. Translated with (free version)



Future Martian habitats could be made of mushrooms...

1 Feb 2020


Future Martian habitats could be made of mushrooms...

Brice Louvet, Science Writer January 24, 2020, 11 h 35 min.

Researchers are currently studying the potential of fungi to help build the first Martian habitats. Explanations.

After the Moon, several public and private agencies are aiming to establish themselves sustainably onMars. But the Red Planet is not Earth. To live there, we will have to face many challenges. One of them will be to build new habitats specially developed to meet Martian requirements. And all ideas are good to go.

In this sense, NASA created a few years ago the Innovative Advanced Concepts (NIAC) program. The goal is to encourage the development of concepts useful for future deep-sea missions. Each successful team receives funding of $100,000 over one year. One of these projects is of particular interest to the U.S. agency. The idea is to use mycelium as a basis.

Cultivating our homes, directly on the spot

Three layers of material

Other proposed ideas

Cultivate our houses, directly on the spot

"At the moment, traditional conceptions of future Martian habitats are somewhat akin to turtle shells. In other words, we're carrying our houses on our backs," says Lynn Rothschild, who is responsible for the project, "It's a reliable plan, but with huge energy costs. Instead, we can use the lemycelium to cultivate these habitats ourselves when we get there.

The mycelium is the vegetative apparatus of fungi. It consists of a set of filaments - called hyphae - usually found in the soil. It refers to the reproductive mycelium - called the sporophore - which is responsible for the production and maturation of spores outside the soil. It is this sporophore that is commonly referred to as a "fungus".

On paper, the idea would be to be able to transport very light base structures to Mars. Dormant mycelium would also be invited on the journey. Once there, all that would be needed is to wake up these life forms with water. As they grow, they would then branch out around the previously installed structures.

"The fungi will be able to grow around this framework into a fully functional human habitat," the researcher adds.

Three layers of material

These future habitats could consist of three layers of material. Above the water ice - already present on Mars - would form the outer layer. This ice would protect the human occupants from harmful radiation.

It would also provide resources for the tiny organisms in the middle layer - photosynthetic microbes called cyanobacteria. These creatures, in turn, could produce oxygen for astronauts and nutrients for the fungal mycelium, which would then form the lower layer.

The researchers also point out that everything possible must be done to avoid the risk of contamination from Earth. Once the structure is in place, the mycelium could then be cooked, which would kill the fungus. Both the mycelium and the photosynthesizing microbes would also be genetically modified to make them unable to survive beyond the base.

In addition to the structures of Martian habitats, the mycelium could also be exploited to help filter drinking water, or to extract minerals from sewage. It could also be used to make furniture. The photo below shows us, for example, a stool made of mycelium after two weeks of growth.

Well, visually it's not very pretty, but a stool is always practical! Credits: 2018 Stanford-Brown-RISD iGEM Team

Other proposed ideas

This is just an idea, but one that is taken very seriously by NASA. Other projects have also been proposed in recent years. In 2018, for example, a team of Swiss researchers from the Swiss Federal Institute of Technology in Lausanne (EPFL) unveiled a concept for a giant igloo.

The researchers described a dome measuring around 12.5 metres high and 5 metres wide, consisting of a central living area and three airlocks leading to the outside. The structure would be made of polyethylene fibres and protected by three metres of ice. This would again protect the occupants from cosmic rays that are harmful to the human body.

An igloo on Mars. Credits: Claudio Leonardi / EPFL

More recently, the company AI SpaceFactory has proposed high and vertical structures called "Marsha". On paper, they would be made from basalt fibres (a rock found on Mars). They will also need biodegradable plastic made from plants that could be used to make them. Translated with (free version)