An expression vector for the phytopathogenic fungus, Ustilago maydis.

We have constructed an expression vector for the phytopathogenic fungus Ustilago maydis. This vector, pUXV, expresses genes located downstream from a U. maydis glyceraldehyde-3-phosphate dehydrogenase promoter. Plasmid pUXV also contains a selective marker gene conferring resistance to the antibiotic hygromycin B and a U. maydis autonomously replicating sequence, UARS, allowing high transformation efficiency. Expression of a cDNA from the toxin-encoding region of the U. maydis virus P6 in pUXV resulted in as much killing activity as from viral particles when evaluated by killer plate assay. Plasmid pUXV preserves essential sequences from pUC12 and is therefore a shuttle vector for U. maydis and Escherichia coli.