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Microorganisms rely on diverse ion transport and trace elements to sustain growth, development, and secondary metabolism. Manganese (Mn 2+ ) is essential for various biological processes and plays a crucial role in the metabolism of human cells, plants, and yeast. In Aspergillus flavus , we confirmed that Pmr1 localized in cis- and medial- Golgi compartments was critical in facilitating Mn 2+ transport, fungal growth, development, secondary metabolism, and glycosylation. In comparison to the wild type, the Δ pmr1 mutant displayed heightened sensitivity to environmental stress, accompanied by inhibited synthesis of aflatoxin B1, kojic acid, and a substantial reduction in pathogenicity toward peanuts and maize. Interestingly, the addition of exogenous Mn 2+ effectively rectified the developmental and secondary metabolic defects in the Δ pmr1 mutant. However, Mn 2+ supplement failed to restore the growth and development of the Δ pmr1 Δ gdt1 double mutant, which indicated that the Gdt1 compensated for the functional deficiency of pmr1 . In addition, our results showed that pmr1 knockout leads to an upregulation of O-glycosyl-N-acetylglucose (O-GlcNAc) and O-GlcNAc transferase (OGT), while Mn 2+ supplementation can restore the glycosylation in A. flavus . Collectively, this study indicates that the pmr1 regulates Mn 2+ via Golgi and maintains growth and metabolism functions of A. flavus through regulation of the glycosylation.

sfgA is known as a key negative transcriptional regulator gene of asexual sporulation and sterigmatocystin production in Aspergillus nidulans . However, here, we found that the homolog sfgA gene shows a broad and complex regulatory role in governing growth, conidiation, sclerotia formation, secondary metabolism, and environmental stress responses in Aspergillus flavus . When sfgA was deleted in A. flavus , the fungal growth was slowed, but the conidiation was significantly increased, and the sclerotia formation displayed different behavior at different temperatures, which increased at 30 °C but decreased at 36 °C. In addition, sfgA regulated aflatoxin biosynthesis in a complex way that was associated with the changes in cultured conditions, and the increased production of aflatoxin in the ∆ sfgA mutant was associated with a decrease in sclerotia size. Furthermore, the ∆ sfgA mutant exhibited sensitivity to osmotic, oxidative, and cell wall stresses but still produced dense conidia. Transcriptome data indicated that numerous development- and secondary-metabolism-related genes were expressed differently when sfgA was deleted. Additionally, we also found that sfgA functions downstream of fluG in A. flavus , which is consistent with the genetic position in FluG-mediated conidiation in A. nidulans . Collectively, sfgA plays a critical role in the development, secondary metabolism, and stress responses of A. flavus, and sfgA renders A. flavus more stable to the external environment.