DNA in the dirt
These questions are impossible to answer without first knowing which fungi are out in the world. So the researchers traveled to 26 pine forests across North America and collected 10-centimeter-deep soil cores, more than 600 in all. Within hours of collection, and with the assistance of local scientists and universities, they preserved the samples to extract and isolate the fungal DNA. The researchers then used modern genomic tools to sequence unique stretches of the environmental DNA that can be used as barcodes to identify all of the fungal species present in each sample.
The sequencing revealed more than 10,000 species of fungi, which the researchers then analyzed to determine biodiversity, distribution, and function by geographical location and soil depth. Interestingly, Peay said, there was very little overlap in the fungal species from region to region; East Coast fungi didn't show up on the West Coast or Midwest, and vice versa.
"People oftentimes assume that similar habitats in, say, North Carolina and California would have similar fungi, but this is the opposite of what we find," Peay said. "What's more interesting, despite the fact that soil fungal communities in Florida and Alaska might have no fungi in common, you find that many of the processes and the functional rates are convergent. The same jobs exist, just different species are doing them."
The team found this to be particularly true when comparing the functionality of fungi at different strata of the core samples. Even though the samples were collected thousands of miles apart, fungi near the top all performed the same task; similarly, bo
|Contact: Bjorn Carey, Stanford News Service|