| 摘要 |
The productivity of modern agriculture is due, in large part, to the development of new and improved crop varieties through cross breeding of related species, which is however inherently imprecise, unpredictable, and slow. This invention permits the development of improved plants, without the limitations of classical breeding methods by providing a vector capable of being integrated into the chromosome of a plant protoplast cell. This vector, which is illustrated in Fig. 1, includes: 1) a DNA region encoding a selectable marker protein, transcription of this DNA region being under the control of a regulatory DNA sequence capable of effecting transcription in plant cells; 2) a polyadenylation site; 3) a desired heterologous gene, or a site for the insertion of such gene; and 4) DNA capable of causing the integration of the above DNA regions into a plant chromosome. The vector lacks sufficient Ti-derived DNA to cause tumor formation or the production of opines in the plant. |
