While analyzing the role of cytokinins in Nicotiana genetic tumor formation, Feng et al. (1990) have shown that tumor formation of X-ray-induced non-tumorous mutants of N. glauca × N. langsdorffii was restored either by the insertion of the A. tumefaciens ipt gene, which encodes the key enzyme of cytokinin biosynthesis, or by the addition of cytokinin. Here, TRIT1 is linked to neoplasm.