OREGON STATE UNIVERSITY

Study Outlines Findings on Evolution of Fungi

10/26/2006

CORVALLIS, Ore. – A major new study involving 35 scientific laboratories in seven countries used complex genetic analysis to provide new insights into the ancient evolution and development of fungi – a kingdom of organisms that, along with plants and animals, comprises one of the major groups of life on Earth.

Research of this type is invaluable, scientists say, because it helps answer some of the most fundamental questions about biological evolution.

In addition, fungi cause billions of dollars of economic losses as plant pathogens, lead to many human diseases, are the source of many medicines that have saved millions of lives, may have helped other life forms colonize the land, and in a symbiotic relationship allow the growth and survival of about 90 percent of all living plants.

The findings were published in the journal Nature.

“A more robust understanding of the evolutionary background and relationships in the fungi kingdom will provide a predictive framework for other areas of biology,” said Joseph Spatafora, a professor of botany and plant pathology at Oregon State University, and co-author of the study. “Fungi represent the largest group of eukaryotic microorganisms, and they affect our lives every day by performing vital ecological processes.”

“Through a more complete understanding of the fungal tree of life, we can best benefit from this amazing group of organisms,” he said.

The new findings support the thesis that fungi – which were once thought to belong to the plant kingdom – are actually more closely related to animals.

They also provide additional evidence that a type of intracellular parasite called microsporidia, which can cause human and animal disease, is actually a member of the fungi kingdom. The study also showed that while the first fungi possessed a flagellum, a motility device such as that found on sperm cells, it has been lost more than once as different fungal species colonized land and adapted to terrestrial environments during long periods of evolution.

The presence or absence of flagella is no longer seen as predictive of evolutionary relationships between fungal species, the researchers said.

Overall, the genetic analysis of these life forms, which was done with intensive computational techniques, shows that the evolution of fungi is more complex than had been understood.

Despite their importance, only about 200,000 species of fungi have been described, while scientists believe more than one million exist. Mushrooms and the yeast used in baking bread are types of fungi. So are the pathogens that cause athlete’s foot, drugs used to allow heart transplants, and the mycorrhizae that grow alongside plant roots and aid in nutrient absorption by the plant. An underground fungus that covers several acres and is over 2,000 years old has been called the oldest, largest life form on Earth.