The histone demethylase KdmB is part of a trimeric protein complex and mediates virulence and mycotoxin production in Penicillium expansum

Epigenetic modification of chromosome structure has increasingly been associated with alterations in secondary metabolism and sporulation defects in filamentous fungal pathogens. Recently, the epigenetic reader protein SntB was shown to govern virulence, spore production and mycotoxin synthesis in the fruit pathogen Penicillium expansum. Through immunoprecipitation-coupled mass spectrometry, we found that SntB is a member of a protein complex with KdmB, a histone demethylase and the essential protein RpdA, a histone deacetylase. Deletion of kdmB phenocopied some but not all characteristics of the Delta sntB mutant. KdmB deletion strains exhibited reduced lesion development on Golden Delicious apples and this was accompanied by decreased production of patulin and citrinin in host tissue. In addition, Delta kdmB mutants were sensitive to several cell wall stressors which possibly contributed to the decreased virulence observed on apples. Slight differences in spore production and germination rates of Delta kdmB mutants in vitro did not impact overall diameter growth in culture.

Automated summary

Epigenetic modification plays an important role in secondary metabolism and sporulation in filamentous fungal pathogens. The SntB protein, along with KdmB and RpdA, is crucial for the regulation of virulence, spore production, and mycotoxin synthesis in Penicillium expansum.