Two different PCR approaches for universal diagnosis of brown rot and identification of Monilinia spp. in stone fruit trees.

AIMS: To design a protocol for the universal diagnosis of brown rot by polymerase chain reaction (PCR) in plant material and subsequently Monilinia spp. identification. METHODS AND
RESULTS: Primers for discrimination of Monilinia spp. from other fungal genera by PCR were designed following a ribosomal DNA analysis. Discrimination among species of Monilinia was subsequently achieved by developing primers using SCAR (Sequence Characterised Amplified Region) markers obtained after a random amplified polymorphic DNA study. In addition, an internal control (IC) based on the utilization of a mimic plasmid was designed to be used in the diagnostic protocol of brown rot to recognize false negatives due to the inhibition of PCR.
CONCLUSIONS: The four sets of primers designed allowed detection and discrimination of all Monilinia spp. causing brown rot in fruit trees. Addition of an IC in each PCR reaction performed increased the reliability of the diagnostic protocol. SIGNIFICANCE AND IMPACT OF THE STUDY: The detection protocol presented here, that combined a set of universal primers and the inclusion of the plasmid pGMON as an IC for diagnosis of all Monilinia spp., and three sets of primers to discriminate the most important species of Monilinia, could be an useful and valuable tool for epidemiological studies. The method developed could be used in programmes to avoid the spread and introduction of this serious disease in new areas.