Histone post translational modifications HPTMs can affect the gene expression by rear-ranging the chromatin structure. Between these, histone methylation is one of the most studied in filamentous fungi, and different conserved domains coding for methyltrans-ferase were found in Aspergillus spp. genomes. In this work, the role of the histone methyl-transferases AcDot1 and AcRmtA in the mycotoxigenic fungus Aspergillus carbonarius was investigated, obtaining knockout or overexpression mutants through Agrobacterium tume-faciens mediated transformation (ATMT). A. carbonarius is responsible for grape-bunch rot, representing the major source of ochratoxin A (OTA) contamination on grapes. Under in vivo conditions, the deletion of Acdot1 or AcrmtA resulted in up-regulation of growth when the isolates were cultivated on a minimal medium. The influence of Acdot1 on the OTA biosynthesis was different and affected by culture conditions, while the deletion of AcrmtA always resulted in lower OTA accumulation. The expression of otaC, otaB, and otaD, key genes of the OTA biosynthetic pathway, was reduced in the ΔAcrmtA. Furthermore, both AcDot1 and AcRmtA showed a role in oxidative stress response, by modulating the growth, the conidiation and OTA biosynthesis. Neither the deletion nor the overexpres-sion of the Acdot1 or AcrmtA affected the virulence, while both the sporulation and OTA production were affected by the deletion of AcrmtA.

Angelo Agnusdei is a PhD candidate at the University of Bari granted by UE under the Program “FSE-REACT-EU, PON Research and Innovation 2014–2020”, D.M. 1061/2021 “Azione IV.5 “Dot-torati su tematiche green”, Project Code DOT1302377 (CUP: H99J21010190001). Agritech National Research Center and received funding from the European Union Next-GenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.4 – D.D. 1032 17/06/2022, CN00000022) A-R. Ballester and L. González-Candelas acknowledge the Accreditation as Center of Excellence Severo Ochoa CEX2021-001189-S funded by MICIU/AEI/10.13039/501100011033.

With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2021-001189-S)

Peer reviewed