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Ecology

The Mysterious, Colorful World of Fungi

Text and Photos:  Javier A. Pinzón

Fungi are beautiful and fascinating; their curious structure conceals an extraordinary ability to adapt to any environment. They live in forests and large cities, in water and soil, on skin and hair, and even on metal, glass, cloth, and paper. Basically, they manage to survive anywhere on our planet.

These strange creatures play a significant role in natural cycles by breaking down dead matter into organic waste, thus returning to the environment substances that can be assimilated by plants and animals, thereby facilitating the energy cycle typical of natural ecosystems. They are the only creatures able to degrade lignin, a basic component of wood.

Fungi played a significant role in the evolution of plants on Earth thanks to their ability to develop symbiotic relationships (a close, lasting dependency between two organisms of different species) with the roots of plants. This relationship began some five hundred million years ago, and it is estimated that 95% of vascular plants possess mycorrhizae (fungi associated with the roots of plants), without which life on Earth as we know it would be impossible.

Furthermore, there are also fungi that form mutualistic relationships (interaction between different species, with each one benefiting). A good example is the ants that cultivate fungi, “planting” it for food. In other relationships, fungi help digest the cellulose consumed by herbivores and form links with the larvae of aquatic insects and marine crustaceans.

Some fungi are even more specialized: they attack insects that live buried in the soil. The affected insects abandon their usual burrows and climb trees, where they remain until they die, covered by millions of spores, which are later dispersed in air and water.

Other fungi literally trap their prey using sticky rods to attract small worms which they then catch. The harder the worm struggles to free itself, the more rods latch onto it until the worm is completely immobilized. The fungi later develop inside the worm and feed off their host.

Villains and Heroes

Fungi ruthlessly break down organic matter in nature, but this is not necessarily desirable in human environments. For example, antique manuscripts and valuable library collections must be stored in low humidity in order to keep fungi from proliferating. The mold in our homes is an illustration of how fungi work; mold is merely a growth of various types of fungi. These fungi prefer humid places, creeping up walls and along ceilings or furniture; they even grow on clothing, if it stays wet long enough.

Fungi have pathogenic capacities and can attack growing or stored vegetables, causing millions of dollars in losses. These phytopathogenic microscopic organisms feed off a host plant, causing the host to wilt if the fungi are not controlled. Coffee leaf rust is one of seven plant diseases that have caused enormous losses over the last one hundred years. It is estimated that some 30% of the coffee crop is lost in Latin America alone.

Certain fungi affect humans by causing allergies, infections, and toxic reactions. Fungal infections produce superficial or deep mycoses, and can penetrate healthy skin and destroy tissues via enzymes such as keratinase. Fungal allergies are caused by a hypersensitivity to spores or hyphae.

But not all fungi are villains. Some are actually heroes, such as those that produce antibiotics. The first-discovered, greatest, and most recognized is penicillin. Its discoverer, Alexander Fleming, noted that the Penicillium notatum fungus produced “something” that killed bacteria. This antibiotic has saved millions of human lives.  Still other types of fungi generate a large variety of products useful to medicine and industry: vitamins, enzymes, plasma substitutes, wound-healing accelerators, cancer drugs, polysaccharides, organic acids, and many more.

Their pathogenic capacity, which can be harmful under other circumstances, is put to use for pest control in the food industry. Some types of fungi infect insects or trap nematodes, while others can control the phytopathogenic fungi that infest plants.

In addition, fungi serve as a food source for humans. Button mushrooms are delicious, and truffles and oyster mushrooms are highly valued by gourmets. These creatures enrich our lives in many more ways as well. What would our mornings be without bread, which is made with yeast (a kind of fungi)? Or what would lovers of good wine or beer do without the fungus needed for the fermentation process? Many other foods must likewise undergo fermentation, such as yogurt, kumis (a fermented dairy product traditionally made from mare’s milk), and certain meat products like sausage, salami, chorizo, and pepperoni.

While fungi are neither plant nor animal, they are undoubtedly an essential part of our lives, whether as villains or heroes.