Agrobacterium-mediated transfer of -Glucoronidase gene (gusA) to water mint (Mentha aquatica L.)

Abstract

Water mint is a medicinal aromatic perennial herb belonging to the family Labiateae. It is distributed mostly in the temperate and sub-temperate regions of the world. Water mint is valued for its multipurpose uses in the field of pharmaceuticals, cosmetics and flavoring foods. Agrobacterium-mediated gene transformation has yielded a stunning array of transgenic plants with novel properties. Transgenic mint plants with reporter genes have been obtained only in peppermint. Therefore it would be interesting to extend transformation experiments to other mint species such as Water mint. Establishing a reliable direct regeneration system is necessary in plant transformation programs. In vitro direct regeneration of Water mint was obtained from leaf disks. Best results were obtained when explants were cultured onto MS medium supplemented with 4 mg/lit BAP. Transformed plants were obtained by co-cultivation of leaf disks with Agrobacterium tumefaciens strain GV3850 harbouring a binary vector pBI121 that carried E. coli β-glucuronidase as reporter gene and nptII as selective marker gene for kanamycin resistance. The presence and expression of transgenes in transgenics was evaluated by GUS histoenzymatic assay and PCR. An overall transformation frequency of 12% was achieved. Key words: Agrobacterium tumefaciens, Mentha aquatica, transformation, β-glucuronidase gene.