Ustilago maydis is the causative agent of common smut in maize, which is characterized by tumor formation on maize leaves, ears and tassels. The infection induces host changes including the division of highly differentiated bundle sheath cells, mesophyll enlargement and carbohydrate relocation. These changes are induced by effector proteins secreted by the pathogen. However, expression of effectors depends on developmental stage of the fungus, as well as the colonized cell types. In consequence, expression of effectors with different functions within the infected tissue is not synchronized and mixed plant responses are observed. Applying optogenetics in U. maydis allows us to switch on/off the expression of effector genes of interest by shedding different wavelength light at desired conditions to synchronize the infection and tumor induction of U. maydis in planta. This will enable us to resolve the function of effectors related to different host responses, but also allows to deploy effectors as molecular tools to trigger specific changes in plant development and metabolism.
Dr. Weiliang Zuo
The Terrestrial Microbiology Lab
Institute for Plant Sciences, Cologne Biocenter
University of Cologne