Agrobacterium tumefaciens Chry5, which is particularly virulent on soybeans, 
induces tumors that produce a family of Amadori-type opines that includes 
deoxyfructosyl glutamine (Dfg) and its lactone, chrysopine (Chy). Cosmid clones 
mapping to the right of the known oncogenic T-region of pTiChry5 conferred 
Amadori opine production on tumors induced by the nopaline strain C58. Sequence 
analysis of DNA held in common among these cosmids identified two 25-bp, direct 
repeats flanking an 8.5-kb segment of pTiChry5. These probable border sequences 
are closely related to those of other known T-regions and define a second 
T-region of pTiChry5, called T-right (TR), that confers production of the 
Amadoriopines. The oncogenic T-left region (TL) was located precisely by 
identifying and sequencing the likely border repeats defining this segment. The 
two T-regions are separated by approximately 15 kb of plasmid DNA. Based on 
these results, we predicted that pKYRT1, a vir helper plasmid derived from 
pTiChry5, still contains all of TR and the leftmost 9 kb of TL. Consistent with 
this hypothesis, transgenic Arabidopsis thaliana plants selected for with a 
marker encoded by a binary plasmid following transformation with KYRT1 
co-inherited production of the Amadori opines at high frequency. All 
opine-positive transgenic plants also contained TR-DNA, while those plants that 
lacked TR-DNA failed to produce the opines. Moreover, A. thaliana infected with 
KYRT1 in which an nptII gene driven by the 35S promoter of Cauliflower mosaic 
virus was inserted directly into the vir helper plasmid yielded 
kanamycin-resistant transformants at a low but detectable frequency. These 
results demonstrate that pKYRT1 is not disarmed, and can transfer Ti plasmid DNA 
to plants. A new vir helper plasmid was constructed from pTiChry5 by two rounds 
of sacB-mediated selection for deletion events. This plasmid, called pKPSF2, 
lacks both of the known T-regions and their borders. pKPSF2 failed to transfer 
Ti plasmid DNA to plants, but mobilized the T-region of a binary plasmid at an 
efficiency indistinguishable from those of pKYRT1 and the nopaline-type vir 
helper plasmid pMP90.