The corn smut fungus, Ustilago maydis, is a global pathogen responsible for 
extensive agricultural losses. Control of corn smut using traditional breeding 
has met with limited success because natural resistance to U. maydis is organ 
specific and involves numerous maize genes. Here, we present a transgenic 
approach by constitutively expressing the Totivirus antifungal protein KP4, in 
maize. Transgenic maize plants expressed high levels of KP4 with no apparent 
negative impact on plant development and displayed robust resistance to 
U. maydis challenges to both the stem and ear tissues in the greenhouse. More 
broadly, these results demonstrate that a high level of organ independent fungal 
resistance can be afforded by transgenic expression of this family of antifungal 
proteins.