A real time loop-mediated isothermal amplification (RealAmp) assay for rapid detection of Pleurostoma richardsiae in declining olive plants

Pleurostoma richardsiae is associated with host trunk diseases, known to cause dieback, cankers and wilting of woody trees, and human infections. This fungus was isolated from wood tissues of declining olive trees and grapevines showing esca disease symptoms, in the Apulia region of Italy. Fungus detection has been based on morphological and molecular features, which are time-consuming to identify and require well-trained personnel. Improvement of Pl. richardsiae detection in olive was achieved through development of real time loop-mediated isothermal amplification targeting the intergenic spacer (IGS) region of the fungus. Specificity of the assay was confirmed using ten Pl. richardsiae strains and 36 other fungus strains of species usually isolated from declining olive trees. The achieved limit of detection was 7.5 x 10(-2) ng mu L-1 of Pl. richardsiae genomic DNA. A preliminary validation of RealAmp was also performed using material from infected olive plants artificially inoculated in a greenhouse.