Transient transfection of exogenous gene in plant cells using PEI-based polyplexes

초록

Agrobacterium-mediated method and gene gun delivery with particle bombardment have been mainly used for plant transformation. Agrobacterium-mediated method is simple, but can be applied only for dicotyledonous plants. On the other hand, particle bombardment system can introduce foreign genes directly into plant cells through the use of tiny DNA-coated particles, which has no limitation regarding plant species. However, the particle bombardment shows relatively low transformation efficiency and high cost. Therefore, development of high-efficiency gene delivery vectors and transformation method is required for the improvement of plant genetic engineering. In this study, transient transfection was carried out to investigate the application of polyethylenimine (PEI) nanovector for inserting exogenous gene into plant cells. PEI is a cationic polymer which can interact with anionic nucleic acids electrostatically to form PEI/DNA complexes, namely polyplexes. The polyplexes were prepared using PEI polymer to bind the expression plasmid, pMYN409-GFP. The formation of polyplexes was analyzed by agarose gel electrophoresis retardation assay. The surface characteristics of polyplexes were observed with transmission electron microscope. To confirm whether PEI-based polyplexes can enter into cultured plant cells, green fluorescent protein was used and analyzed by confocal laser scanning microscope. Recently, it was reported that PEI could bind to DNA and form stable 100-200 nm PEI-based polyplexes when the ratio between PEl and DNA was in the range of 5:1-1:4. Therefore, optimization of transfection process was performed for rice cell suspension cultures. In addition, the transfection efficiency of PEI-based polyplexes was compared with PEG. In conclusion, PEI nanovector was used for a simple transformation of foreign gene into plant cells and the results will be shown.