Phytophthora ramorum Multilocus Genotyping Database

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This site provides information on multilocus microsatellite genotypes of P. ramorum currently found in North America. Access the database: P. ramorum multilocus genotyping database.

Isolates of P. ramorum are currently placed in one of the following three clonal lineages currently recognized for P. ramorum worldwide (Grünwald et al. 2008, 2009):

Current distribution
Mating type
Europe, North America
Gardens, Woodlands, Nurseries
A1 (see #)
North America
Forests, Nurseries
North America

# Lineage EU1 is predominantly of A1 mating type with rare findings of A2 isolates in Belgium (Werres and De Merlier 2003).

Current distribution of clonal lineages in the US is shown in figure 1:

Figure 1. Current distribution of clonal lineages of P. ramorum in the US. Color coding identifying clonal lineages is identical to that in table above.

Figure 2 shows genotypic diversity in P. ramorum as of 2008 based on multilocus microsatellite analysis in the US (Grünwald et al. 2008):

Figure 2. Dendrogram showing genetic diversity in P. ramorum in the US. Clonal lineages are coded by color.


Grünwald, N. J., Goss, E. M., and Press, C. M. 2008. Phytophthora ramorum: a pathogen with a remarkably wide host range causing sudden oak death on oaks and ramorum blight on woody ornamentals. Mol. Plant Pathol. 9: 729–740.

Grünwald, N. J., Goss, E. M., Ivors,K., Garbelotto, M., Martin, F. N., Prospero, S., Hansen, E., Bonants, P. J. M., Hamelin, R. C., Chastagner, G., Werres, S., Rizzo, D. M., Abad, G., Beales, P., Bilodeau, G. J., Blomquist, C. L., Brasier, C., Brière, S. C., Chandelier, A., Davidson, J. M., Denman, S., Elliott, M., Frankel, S. J., Goheen, E. M., de Gruyter, H., Heungens, K., James, D., Kanaskie, A., McWilliams, M. G., Man in 't Veld, W., Moralejo, E., Osterbauer, N. K., Palm, M. E., Parke, J. L., Perez Sierra, A. M., Shamoun, S. F., Shishkoff, N., Tooley, P. W., Vettraino, A. M., Webber, J., and Widmer, T. L. 2009. Standardizing the nomenclature for clonal lineages of the sudden oak death pathogen, Phytophthora ramorum. Phytopathology, in press.

Werres, S., and De Merlier, D. 2003. First detection of Phytophthora ramorum mating type A2 in Europe. Plant Disease 87:1266-1266

For questions or to suggest improvements, please e-mail grunwaln <at>

Last Updated:  May 13, 2009