Migrations and displacements of Phytophthora infestans populations in East Asian countries

Two clonal lineages of Phytophthora infestans were detected in a sample of 124 isolates collected in China, Japan, Korea, the Philippines, and Taiwan. All isolates were analyzed for mating type, genetic variation at two allozyme loci, glucose-6-phosphate isomerase (Gpi), and peptidase (Pep), nuclear DNA fingerprint as detected with probe RG57, and mitochondrial DNA haplotypc. One clonal line-age (A1 mating type, 86/100 for Gpi, and 92/100 for Pep) was detected in all five countries and was identical to -a genotype found throughout the world, previously designated as US-1. The other genotype, JP-1, was A2 mating type, 100/100 for Gpi and 96/96 for Pep. This genotype has been detected only in recent samples from Korea and Japan, where it is now the predominant genotype