Agroinfiltration of intact leaves as a method for the transient and stable transformation of saponin producing Maesa lanceolata.

UNLABELLED: A method has been developed to genetically transform the medicinal plant Maesa lanceolata. Initially, we tested conditions for transient expression of GFP-bearing constructs in agroinfiltrated leaves. Leaf tissues of M. lanceolata were infiltrated with Agrobacterium tumefaciens carrying a nuclear-targeted GFP construct to allow the quantification of the transformation efficiency. The number of transfected cells was depended on the bacterial density, bacterial strains, the co-cultivation time, and presence of acetosyringone. The transient transformation assay generated the highest ratio of transfected cells over non-transfected cells upon 5 days post-infiltration using A. tumefaciens strain LBA4404 at an OD₆₀₀ = 1.0 in the presence of 100 μM acetosyringone and in the absence of a viral suppressor construct. In a second series of experiments we set up a stable transformation protocol that resulted in the regeneration of kanamycin-resistant plants expressing nuclear GFP. This transformation protocol will be used to introduce overexpression and RNAi constructs into M. lanceolata plants that may interfere with triterpenoid saponin biosynthesis. KEY MESSAGE: We have developed a transformation protocol for saponin producing Maesa lanceolata. Using the protocol reported here, now we are able to generate the tools for the modification of saponin production.