 When the vacuum is released, the pressure difference forces the "Agrobacterium" suspension into the leaves through the stomata into the mesophyll tissue.This can result in nearly all of the cells in any given leaf being in contact with the bacteria.Once inside the leaf the "Agrobacterium" remains in the intercellular space and transfers the gene of interest as part of the Ti plasmid-derived T-DNA in high copy numbers into the plant cells.