Do we really need to use the recA- Agrobacterium strains?
Maybe not. However the larger your insert is the more likely it is that it will contain some “problem sequences”. If you use the recombination deficient recA- strain of A. tumefaciens you improve your chances of maintaining problem inserts. In some plant systems the recA- A. tumefaciens strains do not perform as well as the isogenic recA+ strains for transfer of a BIBAC vector alone (~ 7 kb T-DNA). However, for the 150 kb test construct the recA- strains gave a higher efficiency of transfer. Additional work is in progress. We really don’t have enough data at this point to make a strong statement concerning recA- strains – but I still recommend it.
