Rapid diagnostic test to distinguish between Phytophthora ramorum populations from America and Europe
A diagnostic test was developed in the Netherlands to distinguish rapidly between populations of Phytophthora ramorum (EPPO Alert List) from America and Europe. Earlier phylogenetic studies had revealed sequence differences (single point mutation) between European and American isolates of P. ramorum in the mitochondrial Cytochrome c oxidase subunit 1 (Cox1) gene. These differences were used to develop a single-nucleotide polymorphism protocol. A total of 83 isolates from Europe and 51 from USA were screened, and all isolates were consistently and correctly allocated. This test, which was initially developed for in vitro cultures, could also be used to detect P. ramorum in plants. However, in the event that populations from USA and Europe occur in the same region and form sexual progeny, this assay could no longer be applied to distinguish these populations (mitochondrial DNA being maternally inherited in the progeny).
Kroon LPNM, Verstappen ECP, Kox LFF, Flier WG, Bonants PJM (2004) A rapid diagnostic test to distinguish between American and European populations of Phytophthora ramorum. Phytopathology, 94(6), 613-620.