agrobacteriummediated

Agrobacterium-mediated transformation is a genetic engineering method that uses the bacterium Agrobacterium tumefaciens to transfer foreign DNA into the genome of a plant cell. The approach is based on the natural ability of A. tumefaciens to transfer DNA via its Ti (tumor-inducing) plasmid, a process that in nature causes crown gall disease. In biotechnology, the oncogenic genes on the Ti plasmid are removed or deactivated, and a chosen gene of interest is placed within the T-DNA region for stable integration into the plant genome.

Mechanism and components. The transfer of DNA is initiated when plant tissues are wounded and release phenolic compounds that activate virulence (vir) genes on the Ti plasmid. The T-DNA borders define the region that is transferred into the plant cell. The transferred DNA is subsequently integrated into the plant genome, typically resulting in stable, heritable modifications. The process is often facilitated by a binary vector system, in which a disarmed Ti plasmid provides virulence functions while a separate plasmid carries the T-DNA with the gene of interest and selectable markers.

Vectors and methods. Agrobacterium-mediated transformation commonly uses co-cultivation of plant explants with Agrobacterium, followed by selection for transformed cells on media containing antibiotics or herbicide. While originally more effective in dicotyledonous plants, advances have extended applicability toward some monocots and other species through optimization of conditions, virulence induction, and vector design.

Applications and considerations. The method is widely used for functional genomics, crop improvement, and recombinant protein production in plants. Advantages include relatively low copy-number insertions and simpler regulatory pathways compared with some physical methods, though random insertion can impact gene expression and stability. Safety and regulatory oversight govern its use across jurisdictions.