The Importance of Fungi

Write a note on the importance of fungi?

IMPORTANCE OF FUNGI:

Fungi are ecologically as well as economically very important.

Ecologically Importance:

Fungi have great ecological importance as decomposers, symbionts, and bioremediators.

1) Decomposers:

Fungi, along with saprobic bacteria, play a vital role in the recycling of inorganic nutrients in the ecosystem.

Without decomposition, all the essential nutrients would soon become locked up in the form of dead animals, plants, and the wastes of the animals and plants. Therefore, the essential nutrient would be unavailable to the organisms. As a result, the life would cease.

2) Symbionts:

(i) Mycorrhizae:

Mycorrhizae fungi improve the growth of plants with which they are associated.

About 95% of all kinds of vascular plants have this association.

(ii) Lichens:

lichens growing on the rock break them, setting a stage for other organisms during the course of ecological succession.

(iii) Bioremediation:

Some fungi are also used for bioremediation(degrading/removing) environmental poisons/ pollutants by organisms.

(iv) Bioindicators:

Lichens are very good bioindicators of air quality as they are very sensitive to pollution.

3) Commercial Importance:

Fungi cause economic gain as well as losses.

Economics gains due to fungi:

1) Edible Fungi:

Certain fungi are edible. About 200 species of mushroom,(e.g. Agaricus sp), morels (e.g. Morchella esculenta), truffles (underground fruiting bodies of some Ascomycetes, e.g. Tuber sp that people find with the help of trained dogs or pigs) are common edible fungi.

Reindeer moss (a lichen, not a moss) is used as food for reindeer and some other large animals in the arctic/subarctic/boreal region.

There are some poisonous mushrooms called the toadstools, such as death cap/death angle (Amanita) and jack-O lantern mushroom.

Edible fungi (a) A common morel (Morchella esculenta).

(2) Fermenting Agent:

Certain fungi are used in the food industry because of their fermenting ability.

Yeasts (Saccharomyces cerevisia) are used in the production of bread and liquor.

Penicillium species are used for giving flavour, aroma, and characteristics colour to some cheese.

Some species of Aspergillus are used for fermenting/producing soya sauce and soya paste from the soya bean.

Citric acid is also obtained from some Aspergillus species.

Antibiotics and Drugs:

(a) Some fungi are sources of antibiotics and some other drugs. Penicillin, the first antibiotic discovered (by A. Fleming-1928) is obtained from Penicillium notatum.

(b) Lovastatin is used for lowering the blood cholestrol.

(c) Cyclosporine obtained from a soil fungus is used in organ transplanation for preventing transplant rejection.

(d) Ergotine is used to relieve one kine of headache, migraine.

(e) Griseofulvin is used to inhibit fungal growth.

(4) Dyes:

Some natural dyes obtained from lichens are used in the textile industry.

(5) Biological Research:

(a) Yeasts are heavily used in genetic/molecular biological research because of their rapid generation and rapidly increasing pool of genetic and biochemical information.

(b) Yeasts were the first eukaryotes to be used by genetic engineers. In 1983, a functional artificial chromosomes was made in Saccharomyces cerevisiae.

The same yeasts was the first eukaryote whose genomic sequence was completely studied in 1996.

(c) Yeasts are also being investigated for the production of some hormones.

(d) Pink bread mold (Neurospora) has also been used for genetic research.

Economic Losses Due to Fungi:

Fungi are responsible for plant diseases, animal diseases, and food spoilage.

Plant Diseases:

Fungi are responsible for many serious plant diseases because they produce several enzymes that can break down cellulose, lignin, and cutin. All plants are susceptible to them. Some of the plant diseases are as follows.

(i) Rusts and Smuts:

Extensive damages due to rusts and smut diseases of wheat, corn, and rise prompted mass displacement, and starvation to death of many people.

(ii) Other Diseases:

Powdery mildew (on grapes, rose and wheat, etc.), ergot of rye, red rot of sugar cane, Potato wilt, cotton root rot, apple scab, and brown rot of peaches, plums, apricots, and cherries are some other common plant diseases caused by fungi.

(iii) Wood-rotting Fungi:

Wood-rotting fungi destroy not only living trees but also structural timber.

Bracket/shelf fungi (Fig. 816) cause a lot of damage to the stored cut lumber as well as stands of timber of living trees.

Animal Diseases:

Fungi also cause certain animal diseases. Some are as follows:

(i) Ringworm and Athlete's Foot:

Ringworm and athlete's foot are superficial fungal infections caused by certain imperfect fungi.

(ii) Candidiasis or Candidosis:

Candida albicans, a yeasts, causes oral and vaginal thrush (candidiasis or candidosis).

(iii) Histoplasmosis:

Histoplasmosis is a serious infection lungs caused by inhaling spores of a fungus which is common in soil contaminated with bird's feces.

If infection spreads into blood stream and then to other organs (which is very occasional), it can be serious or even fatal.

(iv) Aspergillosis:

Aspergillus fumigatus causes aspergillosis, but only in persons with the defective immune system such as AIDS and may cause death.

(v) Aflatoxins:

Some strains of Aspergillus flavus produce carcinogenic (cancer-causing) mycotoxins (toxins produced by fungi) called aflatoxins.

Aspergillus contaminates improperly stored grains such as peanuts and corn etc and they have aflatoxins.

Milk, eggs, and meat may also have small traces of aflatoxins.

Note: Any moldy human food or animal forage produce should be discarded.

(vi) Ergotism:

Ergotism is caused by eating bread made from purple ergot-contaminated rye flour.

The poisonous material in the ergot causes nervous spasm, convulsion, Psychotic delusion, and gangrene.

Food Spoilage:

Saprobic fungi are not only useful recyclers but also cause vast damage to the food, wood, fiber and leather by decomposing them.

About 15-50% of world's fruit is lost each year due to fungal attack.

Growth on Shower Curtains:

A pink yeast (Rhodotorula) grows on shower curtains and other moist surfaces.