Specific detection and identification of Xylella fastidiosa strains causing oleander leaf scorch using polymerase chain reaction.

A pair of PCR primers, QH-OLS05/QH-OLS08 specific for strains of Xylella fastidiosa causing oleander leaf scorch was developed. The primers were designed according to a DNA sequence of a randomly amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR) product unique to oleander strains. The PCR assay using primer pair QH-OLS05/QH-OLS08 allowed quick and simple detection and identification of oleander strains in cultured bacterium and infected plant samples. The assay also can be applied to insect samples. Specific detection and identification of oleander strains of X. fastidiosa by PCR is useful for epidemiologic and etiologic studies of oleander leaf scorch by identifying what plants and insect vectors harbor or carry this particular strain of X. fastidiosa, especially in locations where mixed natural infections by oleander and other strains of X. fastidiosa occur.