1.8.27
IDENTIFICATION OF DIFFERENTIALLY EXPRESSED GENES IN USTILAGO MAYDIS-INFECTED MAIZE TISSUE

C BASSE and R KAHMANN

Institut für Genetik und Mikrobiologie der Universität München, Maria-Ward-Strasse 1a, 80638 München, Germany

Background and objectives
Ustilago maydis is a maize pathogen that induces tumours on all aerial parts of the plant. We are interested in the interaction of U. maydis with its host. In particular, we wish to understand the molecular events that allow fungal growth in planta and the events leading to tumour formation.

Results and conclusions
To achieve these goals we have screened for maize genes which are specifically expressed in tumour tissue by using the method of differential display [1]. Differential PCR fragments were cloned, sequenced and used for expression studies. Several maize genes whose expression levels were significantly altered upon tumour development in leaf and kernel tissue were isolated. Some of these genes were already known, while others have no homologues in the database. Currently, the cDNA clones of the remaining genes are being isolated. Among the genes isolated we identified two U. maydis genes which display high levels of expression only during fungal growth in planta. For these genes, promoter-gfp fusions were generated and GFP activity was monitored during the pathogen life cycle. These strains will serve as a tool to identify plant components which regulate these genes.

References
1. Liang P, Pardee AB, 1992. Science 257, 967-971.