Maize Tumors Caused by Ustilago maydis Require Organ-Specific Genes in Host and Pathogen

Abstract

Tailor-Made Tumor The biotrophic smut pathogen Ustilago maydis specifically infects the important crop plant, maize. The pathogen elicits large tumors on all aerial maize organs by redirecting primordia into a tumor pathway, and maize developmental mutants can disrupt tumor progression. Skibbe et al. (p. 89 ) examined gene expression in parallel in both the host plant and the smut pathogen and found that organ-specific gene expression patterns were required in both for tumor formation. Thus, fungal pathogens may exert distinct effects on different organs and tissues in plants, perhaps explaining the diverse pathologies that can be produced in diseased plants.