Agrobacterium

Agrobacteria:

Agrobacterium is a well studied genus of bacteria belonging to the alpha-proteobacteria group of bacteria.  They are well known for their ability to cause disease on many different species of dicotyledonous plants.  As part of the pathology on plants, virulent forms of agrobacteria are capable of transferring a segment of DNA (also called the T-DNA) from a large virulence plasmid located in the invading bacteria to a cell of an infected host plant.  The T-DNA is then integrated stably into the chromosome of the infected plant cell and the genes located on the T-DNA are expressed causing rapid reorganization and division of the cell to form tumor-like structures (A. tumefaciens or A. vitis) or over-production of roots (A. rhizogenes).

Researchers have learned from studying the disease progress of agrobacteria and have harnessed its power for its ability to introduce foreign genes into a host plant.  This transformation process usually uses a disarmed variant of agrobacteria where the native T-DNA has been removed and replaced with a T-DNA that contains target genes of interest.  This transformation process has revolutionized scientists ability to create and test new plant tissues (i.e. transgenic roots) or whole plant variants with improved disease, insect, stress resistance and improve the nutrient or biopharmaceutical compound production.

Current Agrobacterium Research Projects:

• Composite Plants - Development of methods that enable the efficient production of transgenic roots on wild-type shoots.  This methodology is used often in the lab for functional gene studies.
• Mechanisms of pathology - Research is focused on the study of genes important in the generation of hairy roots by A. rhizogenes.
• Generation of disarmed strains of agrobacteria for plant transformation - Research is focused on identifying and creating new agrobacteria variants with improved transformation capabilities.
• Biocontrol of agrobacteria - Research is focused on testing the use of biocontrol organisms (see Pseudomonas tab) for their ability to limit the development of agrobacteria based diseases.

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