Molecular introduction into barley seed growth point using plasma*

If cells at the growth point are genome-edited, all cells after cell division will be genome-edited cells, and the target plant will acquire new traits. However, the technology to introduce genome editing tools directly and non-invasively into plant cells has not yet been established. In this study, we tried to introduce molecules into the growth point of barley seeds by plasma treatment.

 Barley seeds were placed statically in a 3.5 cm dish placed on a grounded plate electrode. A needle electrode was placed above the seed, and plasma was irradiated directly to the growth point by applying a sinusoidal voltage of 11 kVpp for 20 ms. After the plasma treatment, fluorescent molecule FITC-Dextran (250 kDa) was dropped onto the seeds, and their fluorescence was observed.

 High-intensity green fluorescence was observed at the growth points. The average luminance was about eight times higher than that of the control. This result suggests that the green fluorescence was not autofluorescence but rather from the introduced FITC. Since the plasma-treated barley seeds germinated and continued growing, plasma treatment does not damage the seeds. These results suggest that the efficient and non-invasive introduction of molecules into plant growth points is achieved by the plasma treatment.