Corn Smut Fungus Uses a Peptide Hidden Inside Its Own Protein, Released by Plant Enzymes, to Sense It Has Entered a Host
Researchers reported in Nature Communications on October 9, 2026 that the corn pathogen Ustilago maydis secretes a protein, Pit2, that plant enzymes cut to release a hidden peptide, which then activates the fungal receptor Gpe1 and promotes fungal growth after the fungus enters plant tissue. Mutations that disrupted the peptide-receptor contact reduced virulence, and the system is conserved in related fungi. The authors note mechanistic similarities to mammalian GPCRs, the receptor family targeted by many peptide drugs.