Tobacco System for Studying Protein Colocalization and Interactions.

Transient protein expression in a heterologous system has been very useful in many research fields. As a plant expression system, tobacco has some unique advantages including big leaves, simple infiltration and transformation, high activity in expressing transgenes, and easy sampling for microscopy. Because of these advantages, tobacco system has been extensively used for many purposes, such as large-scale expression and purification of proteins of interest, protein colocalization, protein degradation, protein-protein interaction assays including co-immunoprecipitation (CoIP), fluorescence resonance energy transfer (FRET), and bimolecular fluorescence complementation (BiFC), transcription regulation, plant-pathogen interactions, and functional verification of small RNAs. A large number of publications have used this system and generated critical results to support their conclusions. The results obtained from tobacco system are highly reproducible and mostly consistent with those generated from traditional techniques, indicating its reliability. Here we describe a protocol for studying protein-protein interactions in tobacco system, which could be applied to multiple experimental purposes as the procedure of tobacco leaf infiltration is basically shared among them.