title: A TaqMan-based real time PCR assay for specific detection and quantification of Xylella fastidiosa strains causing bacterial leaf scorch in oleander.
abstract: A TaqMan-based real-time PCR assay was developed for specific detection of strains of X. fastidiosa causing oleander leaf scorch. The assay uses primers WG-OLS-F1 and WG-OLS-R1 and the fluorescent probe WG-OLS-P1, designed based on unique sequences found only in the genome of oleander strain Ann1. The assay is specific, allowing detection of only oleander-infecting strains, not other strains of X. fastidiosa nor other plant-associated bacteria tested. The assay is also sensitive, with a detection limit of 10.4fg DNA of X. fastidiosa per reaction in vitro and in planta. The assay can also be applied to detect low numbers of X. fastidiosa in insect samples, or further developed into a multiplex real-time PCR assay to simultaneously detect and distinguish diverse strains of X. fastidiosa that may occupy the same hosts or insect vectors. Specific and sensitive detection and quantification of oleander strains of X. fastidiosa should be useful for disease diagnosis, epidemiological studies, management of oleander leaf scorch disease, and resistance screening for oleander shrubs.
authors.affiliation: Floral and Nursery Plants Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Guan
authors.forename: Jonathan
authors.initials: J
authors.lastname: Shao
authors.forename: Raghuwinder
authors.initials: R
authors.lastname: Singh
authors.forename: Robert E
authors.initials: RE
authors.lastname: Davis
authors.forename: Tingchang
authors.initials: T
authors.lastname: Zhao
authors.forename: Qi
authors.initials: Q
authors.lastname: Huang
mesh_terms: D000818:Animals; D058491:Bacterial Load / Q000379:methods*; D017931:DNA Primers / Q000235:genetics; D007313:Insecta / Q000382:microbiology; D030007:Nerium / Q000382:microbiology; D015345:Oligonucleotide Probes / Q000235:genetics; D010935:Plant Diseases / Q000382:microbiology; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D044167:Xylella / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D017931:DNA Primers; D015345:Oligonucleotide Probes