9th Acidic Friday

9th Acidic Friday
Date: 15.10.2021 16:00
Venue: Zoom
Location: Online, Zoom

Open discussion platform of the COST action EuromicropH. This discussion series is intended to stimulate an exchange on the different aspects of how microorganisms react to low pH conditions and why people are interested to investigate this subject. 

Please register here for the upcoming meeting. To access the session, please follow the zoom link below.

15.10.2021 16:00 CEST

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Matthias Steiger, TU Wien, Austria


16:00 Welcome

16:05 Omer Barda, Agricultural Research Organization – Volcani Institute, Israel

Involvement of the pH-response regulator AcpacC in Aspergillus carbonarius pathogenicity in fruits

16:30 Elia Tomás Pejó, Fundación IMDEA Energía, Spain

YEAST4BIO COST Action: Unraveling how non-conventional yeasts can be successfully implemented in biotechnological industries for bioproducts production

This presentation is followed by a general discussion about interaction possibilities between these two COST actions.

Would you like to contribute to an upcoming Acidic Friday meeting?

Please submit your talk here.


Involvement of the pH-response regulator AcpacC in Aspergillus carbonarius pathogenicity in fruits

Omer Barda

Pathogenic fungi must respond effectively to changes in environmental pH for successful host colonization, virulence and toxigenicity. Aspergillus carbonarius is a mycotoxigenic pathogen with the ability to colonize many plant hosts and secrete ochratoxin A (OTA). In our study, we characterized the functions and addressed the role of PacC-mediated pH signaling in A. carbonarius virulence using designed pacC gene knockout mutant. pacC mutant displayed an acidity-mimicking phenotype resulting in poor growth at neutral pH, accompanied by reduced sporulation and conidial germination compared to the wild-type. The ΔAcpacC mutant was unable to effectively acidify the growth media as a direct result of diminished gluconic and citric acid production. Furthermore, loss of AcpacC resulted in significant reduction of OTA production at acidic pH. Additionally, ΔAcpacC mutant exhibited attenuated virulence compared to the wild-type toward grapes and nectarine fruits. Reintroduction of pacC gene into ΔAcpacC mutant restored the wild-type phenotype. Our results demonstrate important roles of PacC in OTA biosynthesis through limiting expression of genes in the cluster, and in pathogenicity of A. carbonarius, possibly by preventing transcription of genes important for fungal infection.

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