Aspergillus niger: characteristics, life cycle and disease in plants

aspergillus niger

Today we are going to talk about a type of parasite that affects plants and that has no relationship with humans. Its about Aspergillus niger. It is a fungus of the mycelial type that is formed by hyaline hyphae that are separated from each other. If we analyze its entire area of ​​distribution we see that, worldwide, it has a saprophytic life. This means that it has its life cycle surrounded in nature and does not involve humans. The fact that this parasite or can reach human tissue is a simple accident. It is not something normal in its life cycle. However, it affects many plants and even damages them.

In this article we are going to tell you everything you need to know about the fungus Aspergillus niger.

Key features

mushroom culture

mushroom culture

All species of this genus are considered opportunistic pathogens. If we analyze the invasions that generate infections by this fungus, we see that 7% of the total ones correspond to this fungus. Skin conditions are more frequent, although it can cause some opportunistic pathologies. These pathologies are beneficial from an industrial point of view. This is because the microorganism is used for the biological degradation of industrial waste composed mainly of organic matter. Thanks to this degradation, various substances and enzymes can be produced that are useful in the manufacture of many edible and inedible products.

The reproduction of these organisms It is produced asexually thanks to the fact that they are capable of producing conidia. These can be found in the soil in a large number of its natural tracts. The conidia can be left thanks to the wind to be able to perch on other surfaces. We know that contagion occurs in a general way, affecting mainly adults more than young people. In the case of humans, it is more likely to affect men than women.

The other side of the coin is that Aspergillus niger it has some beneficial uses for environmental sanitation. And it is that it helps to degrade various industrial wastes that are subsequently used for the production of useful products.

Growth and development of Aspergillus niger

aspergillus niger under the microscope

aspergillus niger under the microscope

These organisms grow in colonies that develop rapidly and are very easy to recognize with the naked eye. They have a distinctive appearance that takes on a dusty shape. When the microorganism it is younger you can see the mycelium with a white color. As it develops and reaches its adult stage, it acquires a darker tone and, finally, it acquires various colors ranging from jet black to dark brown.

The other side of the colony looks as if it were a suede fabric and has a grayish yellowish color. You can easily distinguish the Aspergillus niger of other fungi with dark colonies such as the so-called dematiaceous fungi.

If we analyze the Aspergillus niger From the microscope, we see that it has a smooth conidiophore with a slightly granular texture and a thick wall. There are abundant conidia with a variable appearance. With the microscope we can observe conidia with globose, elliptical, equinulate, warty or longitudinal forms. All conidia are usually black or dark brown in color. They cannot be seen with the human eye because it has a great density in the accumulation of black conidia.

Affection of Aspergillus niger to the plants

onion with black mold

onion with black mold

When this fungus affects plantations, a disease known as black mold arises. As with other diseases that affect crops, the Aspergillus niger begins to act mainly during the storage and transport of crops. In this case, we are going to analyze the condition in the onions. It manifests symptoms of fungal development appearing a black color under dry skin. Often times nothing may be seen on the outside. Each of the layers of the onion can harbor different groups of spores and the most affected layers begin to appear or watery. After a while, the fungus develops, giving rise to a rapid proliferation of black spores.

These what we have mentioned before in the development of hyphae. It is a fairly common fungus that is found mainly in regions with a warmer and drier climate. It does not need a lot of humidity to survive, unlike other mushrooms. Therefore, it can be found in a large amount of plant and animal waste. It is able to survive on dead or injured plants and animals. We can see it in large quantities in fruits and other agricultural products whose infection occurs in the field and during transport.

For the infection to begin, the leaves must remain moist for a minimum of about 6 hours. In the field, the soil we observe no symptoms in the plant and, at most, you can see a slight dark coloration on the neck of the onion. The fungus enters the bulb through the neck and begins to attack the layers of the onion little by little. Any damage generated by the Aspergillus niger on the onion layers and on the outside or on the roots it will serve as another entry point for the fungus to penetrate the onion.

The problems derived from this fungus begin to arise when the temperature exceeds 28 degrees. Hence, it only appears in regions with a warmer and drier climate. The appearance of Aspergillus niger It is frequently followed by a secondary infection that turns into a more moisture rot. If the rot does not occur and the bulb mushrooms and withers quickly, it is possible to prevent and treat the impediment of the expansion of this fungus. That is, you can avoid damaging the rest of the sheets or, when injured, serve as entry points for the fungus.

To avoid damage to the bulbs when the onion is being harvested, it is interesting to maintain a low humidity and temperature both at the time of harvesting and during storage and transport.

I hope that with this information you can learn more about the fungus Aspergillus niger and the affection to the plants.

Aspergillus niger: characteristics, life cycle and disease in plants

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