LAUSR

Agrobacterium-mediated transient expression in plant organs is a quick and reliable method for studying gene functions. Due to the significance of transient transformation, substantial efforts have been dedicated to developing such protocols in various plants including the model Arabidopsis thaliana. Despite the importance, a reliable protocol is still lacking in Brassicaceae due to their recalcitrance towards Agrobacterium-mediated transient transformation. We have developed protocols for transient expression in Brassica juncea (PI 211000) and tested three other Brassica sp. for the suitability of the protocol. Co-infiltration of a bacteria-derived avirulence protein AvrPto1 significantly improved expression in B. juncea cotyledonary leaves. The protocol was used successfully in studying protein localization, protein–protein interaction by co-immunoprecipitation assay and transient silencing in B. juncea indicating it to be an excellent model system for transient expression. The efficiency of the protocol varied between Brassica sp. and depended highly on the Agrobacterium strain used. The protocol would be useful in designing functional analyses of genes using transient expression in Brassicaceae, including Arabidopsis and enable inclusion of mutant lines for such studies.