A maize anthocyanin transactivator induces pigmentation in hairy roots of dicotyledonous species

Several dicotyledonous species were infected with an Agrobacterium rhizogenes binary vector harbouring the plasmid 121.Sn which contains the maize gene Sn under the constitutive promoter CaMV35S. In maize, Sn transactivates the anthocyanin pathway in different tissues. The aim of this work was to test the efficiency of this gene to regulate the anthocyanin pathway in heterologous systems and verify its suitability as a reporter gene. The pigmentation of the hairy roots was compared with hairy roots stained for beta-glucuronidase activity, which were used as a control. In two polymorphic genotypes of Lotus angustissimus, DNA integration and expression were assayed. The maize gene is competent to induce anthocyanin pigmentation in different species, but the complexity of the regulatory mechanisms of anthocyanin synthesis restricts the use of Sn as a reporter gene.