title: Pathways to false-positive diagnoses using molecular genetic detection methods; Phytophthora cinnamomi a case study.
abstract: Phytophthora cinnamomi is one of the world's most invasive plant pathogens affecting ornamental plants, horticultural crops and natural ecosystems. Accurate diagnosis is very important to determine the presence or absence of this pathogen in diseased and asymptomatic plants. In previous studies, P. cinnamomi species-specific primers were designed and tested using various polymerase chain reaction (PCR) techniques including conventional PCR, nested PCR and quantitative real-time PCR. In all cases, the primers were stated to be highly specific and sensitive to P. cinnamomi. However, few of these studies tested their primers against closely related Phytophthora species (Phytophthora clade 7). In this study, we tested these purported P. cinnamomi-specific primer sets against 11 other species from clade 7 and determined their specificity; of the eight tested primer sets only three were specific to P. cinnamomi. This study demonstrated the importance of testing primers against closely related species within the same clade, and not just other species within the same genus. The findings of this study are relevant to all species-specific microbial diagnosis.
authors.forename: Manisha
authors.initials: M
authors.lastname: Kunadiya
authors.forename: Diane
authors.initials: D
authors.lastname: White
authors.forename: William A
authors.initials: WA
authors.lastname: Dunstan
authors.forename: Giles E St J
authors.initials: GESJ
authors.lastname: Hardy
authors.forename: Vera
authors.initials: V
authors.lastname: Andjic
authors.forename: Treena I
authors.initials: TI
authors.lastname: Burgess
mesh_terms: D017931:DNA Primers / Q000592:standards; D005189:False Positive Reactions; D010838:Phytophthora / Q000235:genetics* / Q000302:isolation & purification*; D010935:Plant Diseases / Q000382:microbiology*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods / Q000592:standards*; D013045:Species Specificity
chemical_list: D017931:DNA Primers
keywords: Phytophthora cinnamomi; Species-specific primers; molecular diagnostics