A novel mitochondrial regulon for Ferroptosis during fungal pathogenesis

Ferroptosis remains an underexamined iron- and lipid peroxides-driven cell death modality despite its importance to several human- and plant-diseases and to immunity thereof. Here, we utilized a range of chemical biological tools, genetic mutants and biochemical analyses to gain insights into how the fungal pathogen Magnaporthe oryzae undergoes Ferroptosis strictly in the spore cells to successfully transit to infectious development. We reveal a functional dependency between such intrinsic Ferroptosis and autophagy-mediated mitochondrial degradation. Mechanistically, the requirement of mitophagy for ferroptotic cell death was attributed to its ability to maintain a pool of metabolically active mitochondria. Pharmacological disruption of the electron transport chain or membrane potential led to complete inhibition of ferroptosis, thus simulating the loss of mitophagy phenotypes. Conversely, increased mitochondrial membrane potential in a mitophagy-defective mutant alleviated the Ferroptosis defects therein. Graded inhibition of mitochondrial Coenzyme Q (CoQ) biosynthesis with or without ferroptosis inhibitor Liproxstation-1 distinguished its antioxidant function in such regulated cell death. Membrane potential-dependent regulation of ATP synthesis and iron homeostasis, as well as dynamics of Aconitase in the Tricarboxylic acid cycle in the presence or absence of mitophagy, mitochondrial poisoning or iron chelation further linked mitochondrial metabolism to Ferroptosis. Lastly, we present an important mitochondrial bioenergetics and redox-regulatory network regulon essential for intrinsic Ferroptosis and its precise role in fungal pathogenesis leading up to the establishment of the devastating rice blast disease.