Application of graphene oxide in Agrobacterium-mediated genetic transformation and construction of a novel DNA delivery system for watermelon.

Graphene oxide (GO) is widely used in biotechnology. The purpose of this study was to improve the efficiency of genetic transformation by constructing a delivery system based on GO. First, GO was applied in the traditional genetic transformation scheme for watermelons. We used hydroponics and tissue culture methods to determine the optimal concentration of GO for watermelon plant growth, we then used this concentration of GO for watermelon genetic transformation and found that GO can inhibit the growth of Agrobacterium tumefaciens and promote the growth of explants. This discovery can simplify the replacement of various culture media after explant infection, improve the regeneration rate of transgenic plants, and reduce experimental costs. To improve the efficiency of genetic transformation, a polymer-functionalized graphene oxide nanoparticle (GO-PEG-PEI) nanodelivery system was constructed, and the results showed that GO-PEG-PEI can transfer pCAMBIA1300-GFP plasmids into intact plant cells. We found that sheet-like GO-PEG-PEI can effectively load GFP and form small GO-PEG-PEI-GFP complexes, which can deliver pCAMBIA1300-GFP plasmids into plant cells. This research provides a new technique for molecular breeding.