High-throughput transient transformation of Arabidopsis roots enables systematic colocalization analysis of GFP-tagged proteins.

Determination of the subcellular localization of an unknown protein is a major step towards the elucidation of its function. Lately, the expression of proteins fused to fluorescent markers has been very popular and many approaches have been proposed to express these proteins. Stable transformation using Agrobacterium tumefaciens generates stable lines for downstream experiments, but is time-consuming. If only colocalization is required, transient techniques save time and effort. Several methods for transient assays have been described including protoplast transfection, biolistic bombardment, Agrobacterium tumefaciens cocultivation and infiltration. In general colocalizations are preferentially performed in intact tissues of the same species, resembling the native situation. High transformation rates were described for cotyledons of Arabidopsis, but never for roots. Here we report that it is possible to transform Arabidopsis root epidermal cells with an efficiency that is sufficient for colocalization purposes.