Molecular mechanism of Ustilago maydis pathogenicity

Ustilago maydis can induce tumor development on all aerial organs of Zea mays L. The successful colonization of maize and tumor formation by U. maydis depends on multi-directional and multi-level interactions with the host plant and complex cell and molecular events to ensure compatibility. This review covers recent advances in the field of pathogen-host warfare, focusing on how U. maydis effectors facilitate pathogen entry into the host interior, suppress plant immune perception, and alter host physiology for pathogen benefit, as well as on the molecular processes of maize for sensing and responding to pathogen attack. In addition, key insights into the establishment of U. maydis and its host-plant interactions are described, whereby U. maydis may cause the formation of plant tumors by reprogramming plant metabolism of infected tissues and by differential expression of genes encoding effectors, hormones, sugar metabolizing enzymes, and transporters of both host and pathogen origin. Moreover, further research fields are suggested in this paper.