Agrobacterium vitis strain F2/5 contains tartrate and octopine utilization plasmids which do not encode functions for tumour inhibition on grapevine

The nonvirulent, antagonistic Agrobacterium vitis strain F2/5 was tested for the presence of tartrate utilization plasmid(s) which commonly occur in virulent A. vitis isolates. Following transformation of F2/5 plasmid DNA into Agrobacterium tumefaciens UBAPF2, an approximately 220 kbp plasmid coding for tartrate utilization was isolated. This plasmid, designated pTrF2/5, was also transferred by in planta mating between F2/5 and UBAPF2 and was maintained in a stable state in A. tumefaciens under nonselective conditions. pTrF2/5 could not be allocated into the known incompatibility groups described so far in Agrobacterium. Two trans-conjugant colonies also acquired an octopine utilization plasmid named pOcF2/5 which is related to the incRh1 Ti plasmids. Neither pTr nor pOc encodes for the tumour-inhibiting ability of F2/5.