About the Project
Phytophthora ramorum is considered to be an emerging pathogen
that has received worldwide attention as the causal agent of Sudden Oak
Death (SOD). This pathogen was simultaneously discovered in Europe on
Rhododendron and Viburnum species (Werres et al., 2001)
and in California on tanoak (Lithocarpus densiflorus) and coast
live oak (Quercus agrifolia) (Rizzo et al., 2002). P. ramorum
was formally described as a new species in 2001 (Werres et al., 2001).
P. ramorum has received wide attention because (i) it has a large
host range, (ii) causes severe mortality of tanoak and coast live oak
in natural ecosystems, and (iii) affects many nursery hosts thus providing
this pathogen a means of dispersal throughout the US. The host range currently
includes over 41 plant species and continues to increase. Most importantly,
nursery crops offer a very effective means of dispersing the pathogen
across the country. This has happened twice with shipments of infected
camellias from California that resulted in 1.6 million potentially infected
plants detected in 175 infested sites in over 20 states (see APHIS SOD
website). Once a nursery location is found to be infected with P.
ramorum state and federal government agencies generally try to trace
infection back to an infected nursery of origin, or, if shipments have
been made, attempts to trace the infection forward to nursery or retail
operations that received shipments from an infected site. This database
provide timely information on distribution of genotypes found in North
America that can facilitate dissection of migration pathways.
Populations of P. ramorum are currently being characterized using
multilocus microsatellite genotyping following protocols developed by
Ivors et al. (2006), Prospero et al. (2007), and Garnica et al.(2006).
This searchable database provides timely information on new finds of isolates
placed in one of three clonal lineages. The database is searchable with
the pull-down fields at the top of the database page. Maintenance and
changes to the database are password protected.
Major funding for this project is provided by grant 06-IA-045 awarded
to NJ Grünwald and EM Hansen from the USFS PSW Sudden Oak Death call
Garnica DP, Pinzon AM, Quesada-Ocampo LM, et al. (2006) Survey and analysis
of microsatellites from transcript sequences in Phytophthora
species: frequency, distribution, and potential as markers for the phylum
Oomycota. BMC Genomics 7, 245.
Ivors K, Garbelotto M, Vries
IDE, et al. (2006) Microsatellite markers identify three lineages of Phytophthora
ramorum in US nurseries, yet single lineages in US forest and European
nursery populations. Molecular Ecology 15, 1493-1505.
Prospero S, Hansen EM, Grünwald
NJ, Winton LM (2007) Population structure of the sudden oak death pathogen
Phytophthora ramorum in Oregon from 2001 to 2004. Molecular Ecology,
Rizzo DM, Garbelotto M, Davidson
JM, Slaughter GW, Koike ST (2002) Phytophthora ramorum as the
cause of extensive mortality of Quercus spp. and Lithocarpus
densiflorus in California. Plant Disease 86, 205-214
Werres S, Marwitz R, Veld W,
et al. (2001) Phytophthora ramorum sp. nov., a new pathogen on
Rhododendron and Viburnum. Mycological Research 105,
For questions or to suggest
improvements, please e-mail grunwaln <at> science.oregonstate.edu.