# COMPASS subunit Bre2 regulates chromatin remodeler Arp9 to control Aspergillus flavus aflatoxin synthesis and virulence

## TL;DR

This study reveals how a key protein in a histone methyltransferase complex regulates aflatoxin production and fungal virulence in Aspergillus flavus.

## Contribution

The novel finding is that Bre2 regulates the chromatin remodeler Arp9, linking H3K4 methylation to aflatoxin biosynthesis and pathogenicity.

## Key findings

- Bre2 modulates H3K4 methylation to regulate aflatoxin biosynthesis and fungal virulence.
- Arp9 interacts with other chromatin remodeling factors to influence fungal pathogenicity.
- Arp9 modulates chromatin conformation of genes involved in secondary metabolism and virulence.

## Abstract

Aspergillus flavus, along with its notorious secondary metabolite aflatoxin B1 (AFB1), seriously endangers human health. Histone methyltransferase complex COMPASS (complex of proteins associated with Set1) plays a crucial role in regulating aflatoxin biosynthesis and virulence of A. flavus, but the underlying mechanism is unclear. Here, we find that Bre2, the key subunit of COMPASS, regulates AFB1 biosynthesis, fungal morphogenesis, and virulence through modulation of H3K4 methylation. ChIP-seq and biochemical analyses reveal that chromatin remodeling factor (CRF) Arp9 is directly targeted by Bre2, and Arp9 exerts bio-functions through interacting with the other CRFs such as RSC8, Arp7, and Sth1. ATAC-seq results indicate that Arp9 contributes to fungal pathogenicity by modulating chromatin conformation of genes that are involved in secondary metabolism, morphogenesis, and virulence. The study reveals an epigenetic signaling pathway mediated by chromatin remodeler Arp9 and provides a potential strategy for the control of pathogenic fungi and mycotoxins.

Aspergillus flavus, producing carcinogenic aflatoxin B₁ (AFB₁), contaminates crops and invades animals. The authors identify Bre2, a key COMPASS histone methyltransferase subunit, regulates AFB₁ biosynthesis and fungal pathogenesis, providing insight into potential A. flavus and AFB₁ control strategies.