Tropaeolum Tops Tobacco

The soil-born bacterium Agrobacterium tumefaciens is the only organism capable of interkingdom gene transfer. It has been employed intensively for genetic manipulation of plant cells. Transformation is accomplished through the action of both bacterial and host proteins, many of which have been identified and functionally characterised. Yet, it is still impossible to predict which plant species are easily accessible and which are recalcitrant to Agrobacterium-mediated transformation.

This paper describes an Agrobacterium-mediated transformation of Tropaeolum majus (nasturtium, order Brassicales) as a convenient, cheap and efficient transient expression system. It facilitates studies in a genetic background that is closely related to the model plant Arabidopsis. In addition, it offers an alternative and complementary method to Nicotiana leaf infiltration. The accessibility of Tropaeolum to simple and fast genetic manipulation potentially drives progress in several fields of plant research, including those aimed at biotechnological and pharmacological applications. Unlike Arabidopsis, Tropaeolum is capable of engaging in endomycorrhizal associations, and is therefore also of interest to symbiosis researchers.

Pitzschke A. (2013) Tropaeolum Tops Tobacco – Simple and Efficient Transgene Expression in the Order Brassicales. PLoS ONE 8(9): e73355. doi:10.1371/journal.pone.0073355
Transient expression systems are valuable tools in molecular biology. Agrobacterial infiltration of leaves is well-established in tobacco, but has led to limited success in the model plant Arabidopsis thaliana. An efficient expression system combining the advantages of Arabidopsis (well-characterised) and the simplicity of leaf infiltration is desirable. Here, I describe Agrobacterium tumefaciens-mediated transformation of Tropaeolum majus (nasturtium, order Brassicales) as a remarkably simple, cheap and highly efficient transient expression system. It provides the Arabidopsis community with a tool to study subcellular localisation, protein–protein interactions and reporter gene activities (e.g. luciferase, β-glucuronidase) in a genetic background that is closely related to their primary model organism. Unlike Arabidopsis, Tropaeolum is capable of engaging in endomycorrhizal associations and is therefore relevant also to symbiosis research. RNAi-based approaches are more likely to succeed than in the distantly-related Nicotiana transformation system. Tropaeolum majus was voted the “medicinal plant of the year 2013”. Conquering this plant for genetic manipulations harbours potential for biotechnological and pharmacological applications.