L1 and L8 are Aureobasidium pullulans strains previously shown to effectively act as biocontrol agents (BCA)
against fruit postharvest pathogens. Here, L1 and L8 strains were tested in vivo against Monilinia laxa of peaches
showing the ability to reduce the brown rot incidence by 95% and by 80% respectively. To develop future
bioformulation and allow commercial use of these biocontrol agents (BCAs) it is necessary to develop specific
identification tools. Since A. pullulans strains share very similar morphological features and are not distinguishable
by visual analysis, the RAPD (Random Amplified Polymorphic DNA) technique was applied to
genomic DNA of L1 and L8 and of other 40 different A. pullulans strains, and SCAR markers were developed from
a L1 and L8 specific RAPD fragment of 984 bp. These primers amplify a fragment of 137 bp exclusively in L1 and
L8, and can be used to distinguish the two yeasts strains from other A. pullulans strains with high specificity. The
droplet digital PCR, used to determine the precise limit of detection (LOD), showed that these markers allow to
detect up to 43 and 215 cells of L1 and L8 respectively.
