Deuteromycetes - Fungus, Reproduction, Characteristics, Imperfect

Introduction to Deuteromycetes

Deuteromycetes, also called fungi imperfecti, are fungi in which the sexual stage has not been found yet. Earlier, scientists grouped them separately because there were no sexual spores produced. Instead, these fungi are identified based on their asexual spores- conidia and mode of reproduction.

Deuteromycetes are closely related belonging to different fungal groups. When scientists discover their sexual stage using advanced methods, they are placed into other groups like Ascomycetes or Basidiomycota. Even so, Deuteromycetes are very important because they help break down dead material. They are used in industries and biotechnology, and some species act as pathogenic fungi, causing diseases in plants and animals.

Why are Deuteromycetes Called "Fungi Imperfecti"?

Deuteromycetes are called fungi imperfecti because their sexual stage is either absent or not yet discovered. As a result, they cannot be classified into other well-defined fungal groups that rely on sexual reproduction. When their sexual forms are identified, they are often reclassified into Ascomycetes or Basidiomycetes.

Classification of Deuteromycetes

The group Deuteromycetes is classified into 4 orders. The four orders, along with some characteristics and some examples, are given in the table below-

Characteristics of Deuteromycetes

Deuteromycetes can be characterised on the basis of habitat, growth, pathogenicity, and their biocontrol nature. These are highlighted in the pointers below.

• Habitat Diversity: They are commonly found in soil, decaying matter, and as plant or animal pathogens, showing wide ecological adaptability.

• Rapid Growth: Many Deuteromycetes grow quickly and vigorously, which makes them dominant in environments with rich organic content.

• Plant Pathogens: Many cause serious plant diseases like leaf spots, wilts, and blights, which can affect crop yield and quality.

• Biocontrol Agents: Certain species (e.g., Trichoderma) are used as natural biocontrol agents, helping in sustainable agriculture by suppressing soil-borne diseases.

• Toxin Production: Some species produce mycotoxins, which can contaminate food and pose risks to humans and animals (e.g., Fusarium).

Diagram of Deuteromycetes Structure

The diagram below shows the structure of Deuteromycetes along with its components. Conidia are asexual, non-motile spores produced by certain fungi for reproduction. They are borne on special structures called conidiophores, which arise from the hyphae—the thread-like filaments that make up the body of a fungus and help in nutrient absorption and growth.

Examples of Deuteromycetes

Some examples of deuteromycetes are given below:-

1. Trichoderma - Used in the biocontrol of plant diseases.

2. Alternaria - Causes leaf spots in plants.

3. Colletotrichum - Causes anthracnose disease in crops.

4. Helminthosporium - Causes blight in cereal crops.

5. Fusarium - Produces microtoxins and causes wilting in plants.

6. Aspergillusn- Used in fermentation and industrial enzyme production.

7. Candida - A yeast that causes human infections.

Deuteromycetes: Economic Importance and Significance

Deuteromycetes, or fungi imperfecti, play an important role in both natural ecosystems and human activities. While many species are beneficial in industry, agriculture, and medicine, others cause serious damage to crops, stored food, and even human health. Their economic significance can be seen in the following ways:

• Decomposition and nutrient cycling – Many species act as saprophytes, decomposing organic matter and recycling nutrients in the ecosystem.

• Industrial uses – Some produce useful enzymes, organic acids, and antibiotics (e.g., Trichoderma for enzymes, Penicillium notatum in related groups for penicillin).

• Biological control agents – Certain species, like Trichoderma, are used to control plant pathogens.

• Food spoilage – Many causes spoilage of fruits, vegetables, and stored grains, leading to economic losses.

• Plant diseases – Some are serious plant pathogens, e.g., Alternaria causes leaf spots, Colletotrichum causes anthracnose.

• Medical importance – A few species are pathogenic to humans and animals, causing skin diseases like ringworm.

Deuteromycetes NEET MCQs

Q1. The imperfect fungi which are decomposers of litter and help in mineral cycling belong to :

1. Basidiomycetes

2. Phycomycetes

3. Ascomycetes

4. Deuteromycetes

Correct answer: 4) Deuteromycetes

Explanation:

Deuteromycetes, or imperfect fungi, have a branched, filamentous, and septate mycelium. They can be saprophytic, parasitic, or decomposers, which plays a vital role in nutrient cycling. Asexual reproduction occurs by the formation of conidiospores. Sexual reproduction is absent in this group, and that is why they are termed "imperfect." Many Deuteromycetes are very important decomposers of organic litter, playing a very important role in mineral cycling in ecosystems.

Hence the correct answer is Option (4) Deuteromycetes

Q2. Which one is the wrong pairing for the disease and its causal organism?

1. Black rust of wheat-Puccinia graminis

2. Loose smut of wheat-Ustilago nuda

3. Root-knot of vegetables-Meloidogyne sp

4. Late blight of potato-Alternaria solani

Correct answer: 4) Late blight of potato-Alternaria solani

Explanation:

The late blight of potatoes is a fungal disease, caused by a fungus named Phytophthora infestans. The Alenternaria solani causes early blight of potatoes. The late blight of potatoes is a fungal disease caused by Phytophthora infestans, while Alternaria solani is responsible for early blight. Late blight spreads rapidly in cool, wet conditions and leads to water-soaked lesions on leaves stems, and tubers, often resulting in plant death. It was the primary cause of the Irish Potato Famine in the 19th century. The disease spreads through infected soil, plant debris, and windborne spores. Effective control measures include resistant potato varieties, proper crop rotation, fungicide application, and eliminating infected plant material.

Hence, the correct answer is option 4) Late blight of potato-Alternaria solani

Q3. Which of the following group of fungi produces cyclosporin A

1. Imperfect Fungi

2. Sac Fungi

3. Club Fungi

4. Algal Fungi

Correct answer: 1) Imperfect Fungi

Explanation:

Trichoderma is a Deuteromycetes fungus widely used as a biological control agent against plant-pathogenic fungi due to its ability to produce antifungal compounds and enzymes that suppress fungal growth. It is commonly used in agriculture to promote plant health by improving disease resistance and enhancing soil quality.

Hence, the correct answer is option 1) Imperfect Fungi.

Also Read:

• MCQs on Deuteromycetes

• Lichens

• Bacterial Virus

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