Functional characterization of a novel Ustilago maydis effector protein Icd1 targeting a highly conserved plant kinase to induce cell division in planta.

• Applicant: Dr. Mamoona Khan
• Subject Area: Organismic Interactions, Chemical Ecology and Microbiomes of Plant Systems
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 557819931

Plant galls result from excessive cell division and cell enlargement triggered by invading organisms. Ustilago maydis is a biotrophic plant pathogen that infects maize (Zea mays L.) and teosinte (Zea mays subsp. mexicana and Zea mays subsp. parviglumis). This fungus can infect all aerial parts of the host plant, including stems, leaves, tassels, and ears, where it locally induces cell division and expansion, leading to gall formation. Despite extensive research on U. maydis, our understanding of the effector proteins involved in its virulence, particularly those contributing to gall formation, remains limited. Here, I have identified a novel U. maydis-secreted effector protein, Icd1, which promotes cell division and proliferation when ectopically expressed in planta. Preliminary results indicate that Icd1 interacts with a highly conserved and versatile class of plant kinases, known to negatively regulate cell proliferation and division. I propose various molecular, cell biological, and genetic approaches to further validate the role of Icd1 and the conserved plant kinases in U. maydis virulence and gall formation.

• DFG Programme: Research Grants