Integrated transcriptomic and metabolomic analyses reveal TPS1 as a key regulator linking cell wall integrity to aflatoxin production in Aspergillus flavus.

Abstract

As a widely distributed opportunistic pathogen, Aspergillus flavus poses a critical challenge to global food safety, principally through the contamination of staple crops with Aflatoxin B1 (AFB1), a highly potent carcinogen and hepatotoxin that accumulates in the food chain and gravely threatens human and animal health. Trehalose-6-phosphate synthase (TPS1) serves as a metabolic gatekeeper, yet its pleiotropic roles in A. flavus morphogenesis and secondary metabolism remain undefined. Here, we demonstrate that TPS1 is indispensable for sclerotial development, stress adaptation, and aflatoxin biosynthesis. Although the TPS1 deletion mutant (ΔTPS1) retained normal vegetative growth on solid media, it exhibited altered pellet morphology in liquid culture and completely lost the ability to produce sclerotia. Physiologically, TPS1 deficiency depleted intracellular trehalose-6-phosphate (T6P) and trehalose pools, leading to compromised cell wall integrity characterized by reduced β-1,3-glucan and chitin content, anomalous septation, and remodeled surface chemistry. Crucially, the mutant showed significantly diminished AFB1 production and attenuated virulence on host substrates (maize, peanut, and onion). Integrated transcriptomic and metabolomic analyses revealed that TPS1 deletion triggered a systemic metabolic rewiring: it disrupts glycolysis, the tricarboxylic acid (TCA) cycle, and fatty acid synthesis, while redirecting flux toward the pentose phosphate pathway. This metabolic shift correlated with the transcriptional downregulation of 23 genes within the AFB1 biosynthetic cluster. Collectively, our findings establish TPS1 as a key regulator linking carbon metabolism to morphogenesis, stress response, and virulence, highlighting its potential as a novel intervention target for controlling toxigenic fungi.