Biological differences between the evolutionary lineages within Phytophthora ramorum and Phytophthora lateralis: Should the lineages be formally taxonomically designated?

Abstract

It is now generally accepted that the four evolutionary lineages of Phytophthora ramorum (informally designated NA1, NA2, EU1, and EU2) are relatively anciently divergent populations, recently introduced into Europe and North America from different, unknown geographic locations; that recombinants between them are genetically unstable and probably unfit to survive, indicating reproductive isolation; and that they differ in growth rates and aggressiveness. EU1 lineage, for example, is on average faster growing in culture and more pathogenic on Quercus rubra bark than the NA1 lineage. Our recent studies show that all four lineages can be readily discriminated in simple G x E stress tests on colony and growth behavior alone. Furthermore, the EU2 lineage is, on average, more aggressive than EU1 on larch stems, but EU1 may produce more sporangia than EU2 on larch needles.

Parent Publication

• Proceedings of the sudden oak death sixth science symposium

Citation

Brasier, Clive. 2017. Biological differences between the evolutionary lineages within Phytophthora ramorum and Phytophthora lateralis: Should the lineages be formally taxonomically designated? In: Frankel, Susan J.; Harrell, Katharine M., tech. coords. Proceedings of the sudden oak death sixth science symposium. Gen. Tech. Rep. GTR-PSW-255. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 41-42.