APS Homepage

POSTERS: Molecular plant-microbe interactions

Identification of novel Penicillium expansum virulence factors
Dianiris Luciano-Rosario - University of Wisconsin. Nancy Keller- University of Wisconsin

Penicillium expansum is the causative agent of blue mold of pome fruits, a post-harvest disease. The presence and further infection of this fungus in apple and pears results in significant economic loss worldwide and significant health concerns due to the production of the mycotoxin patulin in apple tissues. To date, there is no substantial host resistance to blue mold in commercial apple varieties and thus disease management relies on fungicides. Previous work has showed that CreA, a carbon catabolite repressor (CCR), is required for P. expansum virulence although its downstream regulatory pathways are yet to be elucidated. The deletion of creA resulted in a strain of P. expansum which is nearly avirulent on apple and unable to produce patulin. When comparing P. expansum WT strain and ?creA infections on apple, RNA-seq data analysis showed there are 399 differentially expressed genes in the ?creA mutant. For this study we have prioritized 36 genes that were down regulated in the ?creA mutant by selecting gene categories that seemed most likely to regulate virulence (e.g. transcription factors, transporters, and proteins with DNA binding domains). Currently, deletion strains are being generated for the selected genes. In order to assess if these genes are involved in virulence, we will screen the generated mutants by comparing their growth on apples, patulin production, and spore germination compared to a WT strain.Genetic analysis of these regulated genes may provide suitable targets for controlling blue mold of pome fruits.