Function of two secreted proteins of Ustilago maydis that negatively affect virulence and their transcriptional regulation
Final Report Abstract
In the last two years I could gather evidence that the maize pathogen U. maydis secretes the two effectors Vcp1 and Vcp2 during its pathogenic lifecycle. A considerable amount of the protein seems to be attached to the fungal cell wall but nevertheless some can be found in the supernatant. A fraction of Vcp2 could, as shown in vitro, bind specifically to phosphatidyl-inositol 5-phosphates which is exposed on plant-cell surfaces after biotic stress. This makes it likely that Vcp2 could be taken up into the cytoplasm of the plant. The functional role of the Vcp effectors is still under elucidation. Interaction partners have been isolated by pull-down experiments and yeast-two hybrid screens. Most of them are cytoplasmafic maize proteins further supporting a role of the Vcp proteins inside the plant cell. The functional relevance of these interactions awaits further studies. For the hypervirulence phenotype the model of Vcp1 and Vcp2 acting as weak avr genes has been postulated. While developing the Vcp project I have established several techniques. These include transient Agrobacterium tumefaciens-mediated expression of fungal effectors in N. benthamiana, transient ballistic bombardment of maize leaves, a new gatewaybased vector system for effectors. These techniques will be useful for many of my planned applications and will benefit research for all our co-workers in the department.
Publications
- Physical-chemical plant-derived signals induce differentiation in Ustilago maydis. Mol Microbiol. 2009; 71(4):895-911
Mendoza-Mendoza A, Berndt P, Djamei A, Weise C, Linne U, Marahiel M, Vranes M, Kämper J, Kahmann R
- Ustilago maydis as a pathogen. Annu Rev Phytopathol. 2009; 47:423-45
Brefort T, Doehlemann G, Mendoza-Mendoza A, Reissmann S, Djamei A, Kahmann R
