A gene encoding a putative GABA aminotransferase (ugatA) was isolated from the basidiomyceteUstilago maydis via heterologous hybridization to the GABA aminotransferase gene (gatA) ofAspergillus nidulans. The derived amino-acid sequence ofugatA shows strong identity throughout the protein to the GABA aminotransferase enzymes fromA. nidulans andSaccharomyces cerevisiae. Northern analysis inU. maydis indicated that theugatA transcript is inducible by the -amino acids GABA and -alanine, and is not subject to nitrogen catabolite repression. With the use ofugatA promoter-lacZ fusion constructs, it was demonstrated that the removal of sequences located approximately 250 by 5 to the translational start site ofugatA (including multiple copies of a 7-bp direct repeat) resulted in the loss of induction by -amino acids. While theugatA gene under the control of theA. nidulans gatA promoter was able to fully complement agatA ^– phenotype inA. nidulans, the full-lengthugatA gene was not, suggesting a lack of expression from theU. maydis promoter inA. nidulans. AU. maydis strain with a gene disruption at theugatA locus showed decreased growth on -alanine as a sole nitrogen source, but was able to grow on GABA as a sole nitrogen source, indicating an alternative pathway for the utilization of GABA inU. maydis.