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

<i>Aspergillus flavus</i> 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 <i>A. flavus</i> 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 <i>A. flavus</i> remains unclear. This study constructed <i>A. flavus arp8</i> knockout (Δ<i>arp8</i>) and complementation (Com-<i>arp8</i>) strains via homologous recombination. Subsequent research revealed that following the deletion of <i>arp8</i>, <i>A. flavus</i> 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 <i>Bombyx mori</i> Linnaeus, 1758 infection models demonstrated that Arp8 plays a crucial role in <i>A. flavus</i> ability to infect hosts. Environmental stress experiments identified Arp8 as a vital factor for <i>A. flavus</i> 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 <i>A. flavus</i> growth and development, pathogenicity, and aflatoxin synthesis, laying a foundation to illuminate the mechanisms of <i>A. flavus</i> pathogenicity and AFs production.