Berkeley - The pathogen responsible for Sudden Oak Death first got its grip in California's forests outside a nursery in Santa Cruz and at Mt. Tamalpais in Marin County before spreading out to eventually kill millions of oaks and tanoaks along the Pacific Coast, according to a new study led by researchers at the University of California, Berkeley. It provides, for the first time, evidence of how the epidemic unfolded in this state.
"In this paper, we actually reconstruct the Sudden Oak Death epidemic," said Matteo Garbelotto, UC Berkeley associate extension specialist and adjunct professor, and principal investigator of the study. "We point to where the disease was introduced in the wild and where it spread from those introduction points."
The study, scheduled to appear later this month in the online early edition of the journal Molecular Ecology, also shows that the pathogen is currently evolving in California, with mutant genotypes appearing as new areas are infested. These findings suggest that movement of infected plants between different regions where Sudden Oak Death is established should be minimized, said Garbelotto.
Garbelotto will present these findings today (Wednesday, April 16) at the annual meeting of the California Oak Mortality Task Force, a coalition of research institutions, public agencies, non-profit organizations and private industry formed to coordinate management, research, outreach and policy efforts surrounding Sudden Oak Death disease in California. Garbelotto is a member of the task force.
The researchers analyzed genetic markers of nearly 300 samples of the fungus-like pathogen, Phytophthora ramorum, taken from 14 forest stands in Humboldt, Sonoma, Marin, Santa Cruz and Monterey counties. The sites were chosen to represent the geographic range of Sudden Oak Death infestation and included newly infected areas as well as regions that had relatively old infestations. Samples from the w
|Contact: Sarah Yang|
University of California - Berkeley