Bacteria use "horizontal" genetic transfer through chromosomes and DNA plasmids to change quickly, which is one reason that antibiotic resistance can often develop. This capability was believed to be possible, but rare, in fungi. In the new study, based on a genome-wide analysis of three Fusarium species, it was shown experimentally that complete chromosomes were being transferred between different fungal strains, along with the ability to cause infection. Various Fusarium fungi can infect both plants and humans.
In humans, fungal infections are less common than those caused by bacteria, but can be stubborn and difficult to treat in part, because fungi are far more closely related to animals, including humans, than are bacteria. That limits the types of medical treatments that can be used against them. Fungal infections are also a serious problem in people with compromised immune systems, including AIDS patients, and can be fatal.
According to Freitag, this new understanding of fungal genetics and evolution is great news.
For one thing, it may help researchers to better understand the types of fungal strains that are most apt to develop resistance to fungicides, and help crop scientists develop approaches to minimize that problem.
Fungal diseases are a major problem in crop agriculture, and billions of dollars are spent around the world every year to combat new and emerging fungal pathogens in plants, animals and humans.
On a more basic level, this study provides evidence that the "tree of life," with one trunk and many branches, is outdated. It should be replaced by a "network of life" in which many horizontal connections occur between different species.
|Contact: Michael Freitag|
Oregon State University