ARS | Publication request: TRANSFORMATION OF 12 DIFFERENT PLASMIDS INTO SOYBEAN VIA PARTICLE BOMBARDMENT

Submitted to: Plant Cell Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 14, 1995
Publication Date: N/A

Interpretive Summary: Particle bombardment, the method of introducing DNA into cells by propelling DNA-coated particles through the cell wall, is rapidly becoming the method of choice for introducing DNA into cells of crop plants to develop varieties with novel traits. One of the major limiting factors for using this technology is the lack of understanding of the nature of DNA integration events. This study demonstrated that multiple plasmids, small circular DNA molecules, can be simultaneously introduced into plant cells with no preferential incorporation. Most of the integration events occurred by plasmid-to-plasmid fusion. The results of this study indicate that it is feasible to introduce multiple genes on separate plasmids as a single-step process for efficient production of genetically engineered plants with multiple modified traits.

Technical Abstract: Particle bombardment offers a simple method for the introduction of DNA into plant cells. One of the major limiting factors for using this technology is the lack of understanding of the nature of DNA integration events. Multiple DNA fragments may be introduced on a single plasmid or on separate plasmids (cotransformation). To investigate some of the properties and limits of cotransformation, 12 different plasmids were introduced into embryogenic suspension culture tissue of soybean via particle bombardment. Southern hybridization analysis of 26 hygromycin- resistant embryogenic clones verified the presence of introduced plasmid DNAs. All of the cotransforming plasmids were present in most of the transgenic soybean clones and there was no preferential uptake and integration of any of the plasmids. The copy number of individual plasmids was approximately equal within clones, but highly variable between clones. While some clones contained as few as zero to three copies of each plasmid, other clones contained as many as 10 to 15 copies of each of the 12 different plasmids.