Agroinfiltration

Agroinfiltration is a plant biotechnology method used to introduce DNA into plant tissues via Agrobacterium tumefaciens, enabling transient expression of recombinant genes without stable genome integration. It is widely used to assess gene function, protein localization, and promoter activity in a rapid and scalable way.

The technique exploits the natural ability of A. tumefaciens to transfer a piece of DNA (the T-DNA) from its Ti plasmid into plant cells. In agroinfiltration, bacteria are prepared in a suspension with a selectable density and infiltrated into leaf tissue. The bacteria transfer the T-DNA into plant cells, where the gene of interest is expressed under a chosen promoter for days to a couple of weeks, after which expression declines as tissue turns over.

Common methods include syringe infiltration of the abaxial (lower) leaf surface to introduce a suspension into intercellular spaces, and vacuum infiltration where leaves or whole seedlings are submerged in the suspension and a vacuum is applied to improve uptake. Acetosyringone or similar compounds are often added to enhance T-DNA transfer.

Agroinfiltration is used for rapid screening of constructs, transient protein production, subcellular localization studies with fluorescent tags, promoter activity assays, and functional genomics. It can also enable virus-based expression vectors for high-level protein production.

Advantages include speed, simplicity, and non-stable expression. Limitations include variability among plant species and tissues, limited expression duration, potential tissue damage, and biosafety considerations due to release of modified bacteria.

Because the technique uses disarmed bacterial strains under containment, agroinfiltration is generally considered low risk in research settings, but field release is subject to regulatory oversight.