Molecular circuit between Aspergillus nidulans transcription factors MsnA and VelB to coordinate fungal stress and developmental responses

authored by

Emmanouil Bastakis, Jennifer Gerke, Seyma Özkan, Rebekka Harting, Tanja Lienard, Christoph Sasse, Emmanouil S. Xylakis, Merle Aden, Anja Strohdiek, Gabriele Heinrich, Verena Grosse, Gerhard H. Braus

Abstract

Development and secondary metabolism of the filamentous fungus Aspergillus nidulans are tightly controlled by concerted actions of several master regulator transcription factors (TFs). The connection between fungal development and cellular stress response programs is often elusive. Here we show that the zinc finger TF MsnA, which controls salt-stress response, is a novel major regulator of fungal development. A molecular circuit among MsnA and the velvet domain regulator VelB was discovered, which mutually fosters the actions of both regulatory proteins during development. Chromatin immunoprecipitation coupled with next generation sequencing (ChIP-seq) and gene expression studies have revealed that MsnA controls the expression of several genes encoding key transcriptional regulators of asexual as well as sexual development. The double mutant of msnA with velB showed that both genes share an additive genetic relationship, under normal and salt stress conditions, with each protein to control distinct phenotypical features. In addition, MsnA directly and indirectly affects the synthesis of specific secondary metabolites relevant for fungal defense against other organisms and growth, in addition to salt-stress responses. Moreover, the expression of genes encoding the epigenetic regulators VapA, VipC and LaeA are also directly controlled by MsnA. The VapA-VipC-VapB methyltransferase signal transduction complex promotes asexual differentiation, while the VeA-VelB-LaeA complex balances light response, development and the secondary metabolism of the fungus. MsnA is therefore placed at a novel prominent position of the central regulatory network, which coordinates stress responses with the developmental and metabolic fate of the fungus.

Organisation(s)

Institute of Organic Chemistry

External Organisation(s)

University of Göttingen

Type

Article

Journal

PLoS Genetics

Volume

21

ISSN

1553-7390

Publication date

17.07.2025

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Ecology, Evolution, Behavior and Systematics, Molecular Biology, Genetics, Genetics(clinical), Cancer Research

Sustainable Development Goals

SDG 3 - Good Health and Well-being

Electronic version(s)

https://doi.org/10.1371/journal.pgen.1011578 (Access: Open)