Agrobacterium-mediated Transformation

The use of A. tumefaciens (or A. rhizogenes) as a gene vector is the method of choice for plant transformation. The development of disarmed binary vectors, in which the virulence (vir) genes are separated from the genes to be transferred (‘T-DNA’), with the latter on a small easily manipulated plasmid, made the processes of recombinant DNA manipulations more routine. The process of transfer of gene(s) of interest and selectable marker genes have been extensively reviewed, and will not be covered further here. However, one topic that deserves further discussion is that of the selectable marker genes used to identify and extract transgenic cells from the non-transgenic cells and new reporter genes used to monitor gene expression.