Field Museum research points way to discovering other agents
CHICAGO Researchers studying medicinal, pharmacological, antibiotic, carcinogenic and food-production agents would do well to study an often-overlooked group of fungi that once had but then lost the ability to form lichen symbioses, according to a study to be published in the journal Nature June 21, 2001.
Using DNA sequence data, the scientists have determined a more accurate fungus family tree and reconstructed the evolution of the lichen symbiosis. As a result, this little-understood group of lichen-forming fungi is now recognized as being more important to humans than previously thought.
Phylogenies coupled with statistical methods that reconstruct ancestral states can help identify additional species with possible benefits and provide a better understanding of fungi that are detrimental to humans, says Franois Lutzoni, PhD, assistant curator of botany at the Field Museum and lead author of the study. This is one of many reasons why reconstructing the complete tree of life is so compelling and should be one of the main scientific endeavors of the new millennium.
This study demonstrates that lichen-forming fungi are especially important to humans by determining for the first time that several groups of non-lichen-forming fungi known to include species with beneficial and detrimental properties to humans are derived from lichen ancestors. For example, the study determines that Penicillium, from which penicillin was derived, belongs to one of these non-lichen-forming fungal lineages (Eurotiales) that originated following the loss of lichenization.
Another example is Aspergillus flavus and A. parasiticus, also members of the Eurotiales. They produce aflatoxins on various nuts and grains (including peanuts and corn) that are among the most potent carcinogenic compounds known.