WRKY transcription factors (TFs), which are plant-specific TFs, play significant roles in plant defense. Here, a pathogen-induced WRKY gene, namedAktWRKY12, which was the homologous gene ofAtWRKY12, was isolated fromAkebia trifoliata. TheAktWRKY12gene has a total length of 645 nucleotides and an open reading frame (ORF) encoding 214 amino acid polypeptides. The characterizations of AktWRKY12 were subsequently performed with the ExPASy online tool Compute pI/Mw, PSIPRED and SWISS-MODEL softwares. The AktWRKY12 could be classified as a member of WRKY group II-c TFs based on sequence alignment and phylogenetic analysis. The results of tissue-specific expression analysis revealed that theAktWRKY12gene was expressed in all the tested tissues, and the highest expression level was detected inA. trifoliataleaves. Subcellular localization analysis showed that AktWRKY12 was a nuclear protein. Results showed that the expression level ofAktWRKY12significantly increased inA. trifoliataleaves with pathogen infection. Furthermore, heterologous over-expression ofAktWRKY12in tobacco resulted in suppressed expression of lignin synthesis key enzyme genes. Based on our results, we speculate that AktWRKY12 might play a negative role inA. trifoliataresponding to biotic stress by regulating the expression of lignin synthesis key enzyme genes during pathogen infection.