In the present study Aureobasidium pullulans strains L1 and L8 were shown both in vitro and in vivo to compete
for iron with Monilinia laxa through the secretion of siderophores (1.2 and 1.4 mg ml−1, respectively) and
to prevent postharvest fruit decay of peaches. The two strains reduced mycelial growth and conidial germination
of M. laxa specially in presence of lower iron concentrations (5 and 10 μg l−1 FeCl3), confirming a better
efficacy when nutrients are scarce. In in vivo assay, A. pullulans L1 and L8 strains inhibited pathogen virulence,
reducing by 83.5% and 84.4% on average respectively the peach lesion diameter for each tested iron solutions
(5, 10, 20 μg l−1 FeCl3,). The highest iron solution slowed down the antagonists’ action and conversely increase
the pathogen aggressiveness. Results shows that A. pullulans L1 and L8 strains compete with M. laxa for iron, so
revealing new biocontrol aspects. Both strains showed the capability to decrease the accumulation of iron competing
with some fungal pathogens and reducing their virulence. These results provide new perspectives for the
use of biocontrol agents in agriculture.
