Ti-Plasmid: Targeted plant breeding

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The so-called Ti-Plasmid (Ti stands for tumour-inducing) is a small, circular DNA molecule common among bacterial pests in plants (e.g. Agrobacterium tumefaciens). The bacteria transfer the plasmid into plant cells resulting in genetic modifications that trigger the development of plant tumours. In the 1970s, Prof. Dr Marc van Montagu and Prof. Dr Jozef Schell of the Max Planck Institute for Plant Breeding Research in Cologne developed the concept of using the Ti-Plasmid to introduce novel genes into plants by replacing the gene responsible for tumour development with the desired gene.

As part of their research of the interactions of plants and soil bacteria, the two pioneers of green genetic engineering discovered that some bacteria can transfer genes to plants. Responsible for this is the Ti plasmid, which is found in particular in the soil bacterium Agrobacterium tumefaciens. Based on the research results, the scientists use the TI plasmid as vector (gene ferry) for the production of transgenic plants. To do so, they replaced the genes that were originally responsible for tumor formation with the genes of their choice. Thus, in 1983, the production of genetically modified, pest-resistant tobacco plants succeeded for the first time.

The method opened up a new area of plant breeding as it allows for the introduction of genes from other species into a plant. The method is still unsurpassed by other technologies.