PLEUROTUS ERYNGII: CHARACTERISTICS, HABITAT, CULTIVATION AND PROPERTIES - BIOLOGY - 2024

Pleurotus erymgii is a fungus belonging to the Basidiomycota phylum, also known as thistle mushroom, thanks to the fact that it grows on the dead roots of the plant called runner thistle. It was first described by the French mycologist Lucien Quélet in 1872.

It is distributed throughout the world, with its budding seasons in autumn and to a lesser extent in spring. This mushroom is widely known thanks to its flavor and its nutritional and health properties, so its consumption is highly recommended.

Specimens of Pleurotus eryngii. Source: Diego Delso

Taxonomy

The taxonomic classification of Pleurotus eryngii is as follows:

• Domain: Eukarya
• Kingdom: Fungi
• Phylum: Basidiomycota
• Class: Agaromycetes
• Order: Agaricales
• Family: Pleurotaceae
• Genus: Pleurotus
• Species: Pleurotus eryngii

General characteristics

Pleurotus eryngii is a widely known fungus, thanks to its usefulness in various fields such as culinary and health.

Like all members of the Fungi kingdom, it is a heterotrophic eukaryotic organism. This means that their genetic material is properly packaged within a structure known as the cell nucleus, which is delimited by the nuclear membrane. Likewise, it is heterotrophic because it is not capable of synthesizing its nutrients; it obtains them from decomposing organic matter.

Regarding its cellular organization, this fungus is multicellular, that is, it is made up of many cells, which have the particularity of being surrounded by a cell wall, similar to that of plant cells. That cell wall is made up of chitin.

It reproduces through spores, which are produced in a specialized structure known as a basidium.

Similarly, this mushroom is highly appreciated and its consumption is recommended, as it helps to optimize certain body functions that have to do with the immune, circulatory and nervous systems, among others.

Morphology

Taking into account that Pleurotus eryngii belongs to the basidiomycota phylum, it is not surprising then that its structure is made up of a hat and a stipe or foot. This species is not the typical little hat fungus, but it does maintain, in a general way, their structure.

In general, this type of mushroom does not usually reach a large size. The diameter of its hat is barely 3-12 cm. Likewise, when the fungus is in its early stages, that is, when it is young, the hat has a convex shape. As the fungus reaches maturity, the hat flattens out, presenting a small depression in its central area.

Likewise, in young mushrooms, the edges remain rolled, while in adult specimens the edges are thin and a little wavy, as well as a little lighter than the rest of the hat.

With regard to color, the hat does not have a single color, but covers a wide variety of shades in the brown palette. They are dark brown, light brown, ocher, and even cream.

The texture also varies with the age of the fungus. When it is young, the texture is not uniform, but feels scaly to the touch. On the contrary, when the fungus already reaches maturity, it becomes completely smooth.

The stipe or foot of the fungus is quite thick, compared to that of other basidiomycetes. It is also solid, short (about 2-3 cm) and in most cases it is eccentric. In addition to this, it lacks the characteristic ring that many of the fungi of this phylum have.

The plates of the hymenium are of the decurrent type. This means that they are not only limited to the hat, but also extend to the stipe. This is characteristic of fungi of the genus Pleurotus. They are also very tight and have a variable coloration, since specimens have been collected whose plates are white, light ocher or greyish.

Pleurotus eryngii reproduces through spores, which have rounded edges, are elongated, colorless, and smooth in texture. They are approximately 9-15 microns long by 4-6 microns wide. These spores originate from a structure known as the basidium, which is located at the level of the hymenium. Four spores are generated in each basidium.

The meat of this mushroom is, in general, white, in addition to having a certain elastic, firm and consistent consistency.

Habitat

Pleurotus eryngii is generally known as "thistle mushroom." This is because it normally grows on the roots of a plant called runner thistle, Eryngium campestre. This fungus is saprophytic, which means that it feeds on dead organic matter. Because of this, it grows on the dead roots of various plants like the one already mentioned.

Likewise, it tends to grow in areas where livestock activity is frequent, in forest clearings or in meadows, as well as in ditches and non-sown areas.

From a geographical point of view, Pleurotus eryngii is widely distributed throughout the world geography. Regarding the climatic seasons, it usually develops optimally during the autumn mainly. If the conditions are right, it can also sprout in spring.

Reproduction

The reproduction type of Pleurotus eryngii is sexual, through the dispersal of its spores.

Once the spores mature, they are released into the environment and fall on fertile ground, begin to germinate and develop. From them originates a primary mycelium that is characterized by being monokaryotic. This type of mycelium is made up of segments that contain a single nucleus that is haploid.

Subsequently, the somatogamy process occurs, in which two primary mycelia fuse to give rise to a secondary mycelium that is dikaryotic, and whose characteristic is that in each segment there are two haploid nuclei.

This secondary mycelium continues to grow and develop until it forms the basidiocarp, which is the fruiting body of the fungus.

Life cycle of a basidiomycete. Source: M. Piepenbring

At the upper end of the basidiocarp, specifically in the area known as the hat, the basidia are formed, which are the structures in which the spores of the fungus develop.

Once the basidia develop, they undergo a process known as karyogamy. This consists of the union or fusion of the two nuclei, causing the formation of a diploid basidium. This is transitory, since the basidium immediately goes through the meiosis process, generating four nuclei that are haploid.

At the end of each basidium, four protrusions are generated by budding that will eventually become known as spores. The four haploid nuclei that had been generated migrate towards these protrusions. Finally, the basidium finishes maturing, breaks and releases its spores so that they germinate again and thus give continuity to the cycle.

Culture

The cultivation of Pleurotus eryngii is quite simple and much easier than that of other types of mushrooms.

To cultivate it, the first thing is to obtain the mycelium, since this is the starting point of the process. The mycelium can be obtained through a specialized supplier, such as a laboratory.

If this is not possible, the mycelium is obtained in the following way: spores or tissue belonging to a healthy specimen are taken as fundamental elements and they are sown in a suitable culture medium for this purpose. Among the most recommended culture media is agar enriched with certain compounds such as cereals. The most widely used cereal is wheat.

Once the tissue or spores are ready in the culture medium, it must be stored under conditions of adequate temperature and humidity. The average temperature should be around 25 ° C.

Pleurotus eryngii culture. Source: Pradejoniensis

At the same time, the substrate that the fungus will require to grow must be prepared. Pleurotus eryngii requires a substrate rich in cereals. The basic element of its substrate is cereal straw such as wheat or barley. Similarly, derivatives of cereals can be included, which are rich in carbohydrates and proteins.

The substrate must be properly sterilized to eliminate possible traces of fungi, viruses and bacteria. When it is ready, the mycelium that had been previously obtained is sown, taking great care with the contamination of the environment. Finally, it is covered with a plastic bag and placed in an incubation area with controlled humidity and temperature.

The time it takes for the mycelium to develop and invade the entire substrate is approximately 15 days; After these, the plastic bag must be removed and sufficient covering soil is placed.

It is important to note that for the cultivation and production of this fungus to be successful, certain aspects such as humidity, temperature, CO ₂ concentration, light and ventilation air must be controlled.

Health properties

Pleurotus eryngii is a mushroom widely recognized for its health benefits for those who consume it.

The reason why this mushroom is so beneficial is thanks to the abundance of nutrients it has, such as potassium, vitamin B2, vitamin B3 and iodine, among others.

Stimulates the immune system

This fungus also has among its components abundant compounds known as beta-glucans and glycoproteins, which are known for the favorable effects they have on the immune system. They boost immune cells so that they can optimally fulfill their function of eliminating pathogens.

Optimizes the circulatory system

Thanks to its high potassium content, Pleurotus eryngii is a powerful regulator of blood flow, as well as blood pressure. Likewise, when combined with sodium, it helps regulate cardiac activity through the control of muscle contraction.

Regulation of the nervous system

It stimulates the oxygenating activity of cells, thereby improving the state of the cells of the nervous system, neurons.

Tissue regeneration

It has been proven that the vitamin B2 that is present in this fungus contributes greatly to stimulating the processes of tissue regeneration, especially the skin, mucous membranes, hair and nails.

Enhances the functioning of the thyroid gland

Due to the abundance of iodine in its composition, Pleurotus eryngii stimulates the proper development and functioning of the thyroid gland and, therefore, an important part of the body's metabolism.

Getting energy

Another of its components, vitamin B3, is a great aid in the conversion of compounds such as carbohydrates, fats and proteins into energy. This is very important because it provides the cells with the energy they require to successfully carry out all their functions.

References

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