MIF-like domain containing protein orchestrates cellular differentiation and virulence in the fungal pathogen Magnaporthe oryzae .

Macrophage migration inhibitory factor (MIF) is a pleiotropic protein with chemotactic, pro-inflammatory, and growth-promoting activities first discovered in mammals. In parasites, MIF homologs are involved in immune evasion and pathogenesis. Here, we present the first comprehensive analysis of an MIF protein from the devastating plant pathogen (). The fungal genome encodes a single MIF protein (MIF1) that, unlike the human homolog, harbors multiple low-complexity regions (LCRs) and is unique to Ascomycota. Following infection, is expressed in the biotrophic phase of the fungus, and is strongly down-regulated during subsequent necrotrophic growth in leaves and roots. We show that MIF1 is secreted during plant infection, affects the production of the mycotoxin tenuazonic acid and inhibits plant cell death. Our results suggest that MIF1 is a novel key regulator of fungal virulence that maintains the balance between biotrophy and necrotrophy during the different phases of fungal infection.