Impact of fungi on forest extinction eyed

Tree-killing fungi triggered by climate change decimated Earth's forests 250 million years ago, something that could happen again, a U.S. scientist says. The death of the ancient forests was part of the largest extinction of life on Earth, which occurred when today's continents were part of one supercontinent known as Pangaea. In the so-called Permian extinction some 95 percent of marine organisms and 70 percent of land organisms eventually went extinct. Cindy Looy, a University of California, Berkeley, professor of biology, says thread-like microfossils commonly preserved in Permian rock are relatives of a group of fungi, Rhizoctonia, that today is known to attack and kill plants. Today's changing climate could also lead to increased activity of pathogenic soil microbes that could accelerate the death of trees already stressed by higher temperatures and drought, Looy and her Dutch and British co-authors say. "Pathogenic fungi are important elements of all forest ecosystems," Henk Visscher of Utrecht University in the Netherlands says. ""When an entire forest becomes weakened by environmental stress factors, onslaught of damaging fungal diseases can result in large-scale tissue death and tree mortality.""