Avirulent Isolates of Penicillium chrysogenum to Control the Blue Mold of Apple Caused by P. expansum

Abstract

Blue mold is an economically significant postharvest disease of pome fruit that is primarily caused by Penicillium expansum. To manage this disease and sustain product quality, novel decay intervention strategies are needed that also maintain long-term efficacy. Biocontrol organisms and natural products are promising tools for managing postharvest diseases. Here, two Penicillium chrysogenum isolates, 404 and 413, were investigated as potential biocontrol agents against P. expansum in apple. Notably, 404 and 413 were non-pathogenic in apple, yet they grew vigorously in vitro when compared to the highly aggressive P. expansum R19 and Pe21 isolates. Whole-genome sequencing and species-specific barcoding identified both strains as P. chrysogenum. Each P. chrysogenum strain was inoculated in apple with the subsequent co-inoculation of R19 or Pe21 simultaneously, 3, or 7 days after prior inoculation with 404 or 413. The co-inoculation of these isolates showed reduced decay incidence and severity, with the most significant reduction from the longer establishment of P. chrysogenum. In vitro growth showed no antagonism between species, further suggesting competitive niche colonization as the mode of action for decay reduction. Both P. chrysogenum isolates had incomplete patulin gene clusters but tolerated patulin treatment. Finally, hygromycin resistance was observed for both P. chrysogenum isolates, yet they are not multiresistant to apple postharvest fungicides. Overall, we demonstrate the translative potential of P. chrysogenum to serve as an effective biocontrol agent against blue mold decay in apples, pending practical optimization and formulation.

The Near-Gapless Penicillium fuscoglaucum Genome Enables the Discovery of Lifestyle Features as an Emerging Post-Harvest Phytopathogen

“…Similar studies have used different Penicillium spp. displaying varying levels of virulence to use as practical models to investigate genes, pathways, and metabolites involved in fungal-mediated apple fruit decay [ 40 , 41 ]. Hence, this near-gapless P. fuscoglaucum Pf_T2 genome, with its high-quality assembly and annotation, will serve as a solid foundation for omics (transcriptomic, proteomic, metabolomic) and functional genetic studies (e.g., gene knockout) to investigate virulence mechanisms.…”

Exploring the Biocontrol Capability of Non-Mycotoxigenic Strains of Penicillium expansum

“…Examples include the use of Penicillium nordicum and Penicillium chrysogenum strains to mitigate the production of ochratoxin A (OTA) by P. nordicum in meat derivatives [ 21 , 22 ]. Avirulent strains of P. chrysogenum also demonstrated efficacy in controlling P. expansum in apples [ 23 ]. Additionally, various studies explored the use of Penicillium spp.…”