Phylogenetic Inference Based on Information Theory-Based PCR Amplification

As a method for the determination of the taxonomic affinities of plant pathogens and other organisms, a set of "universalʹ polymerase chain reaction (PCR) primers which amplify a taxonotnically diverse sequence domain of 28S ribosomal DNA (rDNA) were designed. The PCR primers chosen by information-theory analysis generated PCR products using DNA templates from a wide diversity of organisms. Sequences of PCR products were then obtained which allowed phylogenetic dendrograms to be constructed. Based on the above analysis, the Oomycete pathogen Phytophthora infestans clustered with the protist Prorocentrum micans rather than with representatives of the true fungi, consistent with its designation as a •pseudofungus", Magnaponhe grisea, another important plant pathogen, clustered with the true fungi as expected. The approach described can be used with other plant pathogens to clarify phytogeny of new or ambiguously designated species.