# Chromatin Remodeling Factor Arp8 Is Involved in the Regulation of Aflatoxin Biosynthesis and Fungal Pathogenicity of Aspergillus flavus

## TL;DR

This study shows that Arp8, a chromatin remodeling protein, is important for the growth, toxin production, and ability to infect hosts in the fungus Aspergillus flavus.

## Contribution

The novel contribution is identifying Arp8's role in aflatoxin biosynthesis and pathogenicity in Aspergillus flavus.

## Key findings

- Arp8 deletion reduces conidia production by 51% and prevents sclerotia formation in A. flavus.
- Arp8 is essential for aflatoxin B1 biosynthesis and host infection in A. flavus.
- Arp8 helps A. flavus respond to environmental stresses and regulates its pathogenicity.

## Abstract

Aspergillus flavus Link, 1809 is a pathogenic fungus widely present in the environment. It can infect plants and also acts as an opportunistic pathogen affecting humans and other animals. The aflatoxins (AFs), it produces, can cause cancers such as liver cancer. Therefore, in-depth research into the pathogenic mechanisms of A. flavus is crucial. Arp8 (Actin-like protein Arp8) is a unique subunit within the chromatin remodeling complex INO80, regulating processes including chromatin remodeling. However, the biological function of Arp8 in A. flavus remains unclear. This study constructed A. flavus arp8 knockout (Δarp8) and complementation (Com-arp8) strains via homologous recombination. Subsequent research revealed that following the deletion of arp8, A. flavus exhibits a reduction of approximately 51% in conidia production, complete abrogation of sclerotia formation, and significantly impairment of aflatoxin B1 (AFB1) biosynthesis. Crop grain colonization and Bombyx mori Linnaeus, 1758 infection models demonstrated that Arp8 plays a crucial role in A. flavus ability to infect hosts. Environmental stress experiments identified Arp8 as a vital factor for A. flavus in response to various environmental stresses. Quantitative RT-PCR (qRT-PCR) analysis indicated Arp8 achieves its biological functions through corresponding regulatory factors. This study elucidates the biological functions of Arp8 in A. flavus growth and development, pathogenicity, and aflatoxin synthesis, laying a foundation to illuminate the mechanisms of A. flavus pathogenicity and AFs production.