A new finding has elucidated the co-evolutionary arms race between fungal pathogens and their host plants. Dr. Lay-Sun Ma at the Institute of Plant and Microbial Biology, Academia Sinica and her collaborators, Dr. Yin-Ru Chiang and Dr. Chuan-Chih Hsu, disclosed how the corn smut pathogen Ustilago maydis thrives on infecting its host. The process involves a sophisticated counter defense between two structurally conserved proteins, plant pathogenesis-related PR-1 for plant defense and fungal PR-1-like (PR-1L) proteins for fungal virulence, respectively. By producing PR-1L proteins, U. maydis confers resistance to toxic plant phenolics. U. maydis also hijacks the corn protease CatB3 to release a mimetic peptide from PR-1L to counteract the immunity-triggering peptide derived from the plant PR-1. This process suppresses plant immunity, enabling successful colonization of the fungus. These findings fill the knowledge gap of fungal parasitism in crops and the co-evolutionary dynamics of PR-1L and PR-1 protein in pathogens and their hosts, enabling the strategic improvement of crops to combat fungal pathogens. This study has been published in the journal Nature Communications (September 2023).

Article link: https://www.nature.com/articles/s41467-023-41459-4