L. Van Der Fits et al., The ternary transformation system: constitutive virG on a compatible plasmid dramatically increases Agrobacterium-mediated plant transformation, PLANT MOL B, 43(4), 2000, pp. 495-502
This paper describes a so-called ternary transformation system for plant ce
lls. We demonstrate that Agrobacterium tumefaciens strain LBA4404 supplemen
ted with a constitutive virG mutant gene (virGN54D) on a compatible plasmid
is capable of very efficient T-DNA transfer to a diverse range of plant sp
ecies. For the plant species Catharanthus roseus it is shown that increased
T-DNA transfer results in increased stable transformation frequencies. Ana
lysis of stably transformed C. roseus cell lines showed that, although the
T-DNA transfer frequency is greatly enhanced by addition of virGN54D, only
one or a few T-DNA copies are stably integrated into the plant genome. Thus
, high transformation frequencies of different plant species can be achieve
d by introduction of a ternary plasmid carrying a constitutive virG mutant
into existing A. tumefaciens strains in combination with standard binary ve
ctors.