The differentiation of Phytophthora species that are pathogenic on potatoes by an asymmetric PCR combined with single-strand conformation polymorphism analysis

The goal of this study was to develop a polymerase chain reaction (PCR) capable of differentiating Phytophthora species that are pathogenic on potatoes using a single primer pair. To achieve this objective, primers were derived from conserved regions flanking variable sequences in the internal transcribed spacer 1 (ITS1) of Phytophthora species. One primer pair produced a 140 bp product from P. infestans , P. erythroseptica and P. nicotianae . The PCR products were purified and used in an asymmetric PCR (A-PCR) protocol to generate single-strand DNA (ssDNA). The ssDNA of the Phytophthora potato pathogens reproducibly migrated in non-denaturing polyacrylamide gels in a species-specific manner.     

The use of an oligonucleotide that hybridizes to DNA sequences interspersed in the genome of members of the genusPhytophthora as an adjunct to morphological criteria in species identification

An oligonucleotide (primer), designed from a conserved region of the multi-allelicb locus of the basidiomycete fungusUstilago maydis, generated reproducible PCR fingerprints inPhytophthora species. The primer hybridized in a species-specific manner to nucleotide sequences interspersed in the genome of the closely related members ofPhytophthora taxonomic group IV. We recommend the use of this PCR procedure as an alternative method for resolving the close taxonomic affinity of some members of the genusPhytophthora.