First step of the protocol is to introduce a gene of interest to a strain of Agrobacterium. Subsequently the strain is grown in a liquid culture and the resulting bacteria are washed and suspended into a buffer solution. This solution is then placed in a syringe (without a needle). The tip of the syringe is pressed against the underside of a leaf while simultaneously applying gentle counterpressure to the other side of the leaf. The Agrobacterium solution is then injected into the airspaces inside the leaf through stomata, or sometimes through a tiny incission made to the underside of the leaf.
Once inside the leaf the Agrobacterium transforms the gene of interest to a portion of the plant cells. The gene is then transiently expressed. The plant can be monitored for a possible effect in the phenotype, subjected to experimental conditions or harvested and used for purification of protein of interest. Many plants can be transformed by this method, but the most common ones are Nicotiana benthamiana and Nicotiana tabacum'.'
