Agrobacterium tumefaciens is a unique plant pathogenic bacterium renowned for its ability to transform plants. The integration of transferred DNA (T-DNA) and the formation of complex insertions in the genome of transgenic plants during A. tumefaciens-mediated transformation are still poorly understood. Here, we show that complex extrachromosomal T-DNA structures form in A. tumefaciens-infected ...

A metabolic network model for facultative denitrification was developed based on experimental data obtained with Agrobacterium tumefaciens. The model includes kinetic regulation at the enzyme level and transcription regulation at the enzyme synthesis level. The objective of this work was to study the key factors regulating the metabolic response of the denitrification pathway to transition from...

Kinetic, microscopic, and biochemical studies show that virulent Ti (tumor inducing)-plasmid-containing strains of Agrobacterium attach to normal tobacco and carrot tissue culture cells. Kinetic studies showed that virulent strains of A. tumefaciens attach to the plant tissue culture cells in increasing numbers during the first 1 to 2 h of incubation of the bacteria with the plant cells. Five T...

Response to changes in light conditions involves a variety of receptors that can modulate gene expression, enzyme activity and/or motility. For the study of light-regulated effects of Agrobacterium tumefaciens, we used a global analysis approach - proteomics - and compared the protein patterns of dark- and light-grown bacteria. These analyses revealed a significant reduction of FlaA and FlaB - ...

We have achieved routine transformation of maize (Zea mays) using an Agrobacterium tumefaciens standard binary (non-super binary) vector system. Immature zygotic embryos of the hybrid line Hi II were infected with A. tumefaciens strain EHA101 harboring a standard binary vector and cocultivated in the presence of 400 mg L 1 l-cysteine. Inclusion of l-cysteine in cocultivation medium lead to an i...

The taxis response of Rhodobacter sphaeroides 2.4.1 and 2.4.3, Rhodopseudomonas palustris, and Agrobacterium tumefaciens to nitrate and nitrite was evaluated by observing the macroscopic behavior of cells suspended in soft agar and incubated under various conditions. R. sphaeroides 2.4.3, which is capable of both nitrate and nitrite reduction, showed a taxis response to both nitrate and nitrite...

Virulence genes of Agrobacterium tumefaciens are under the control of positive and negative transcriptional regulators. We found that the transcriptional regulator Ros controls expression of the plant oncogene ipt, which encodes isopentenyl transferase, in A. tumefaciens. This enzyme is involved in biosynthesis of the plant growth hormone cytokinin in the host plant. An ipt promoter::cat report...

Agrobacterium tumefaciens is the causative agent of crown gall, a disease of dicotyledonous plants characterized by a tumorous phenotype. Earlier in this century, scientific interest in A. tumefaciens was based on the possibility that the study of plant tumors might reveal mechanisms that were also operating in animal neoplasia. In the recent past, the tumorous growth was shown to result from t...

The dnaKJ operon of Agrobacterium tumefaciens was cloned and sequenced and was found to be highly homologous to previously analyzed dnaKJ operons. Transcription of this operon in A. tumefaciens was stimulated by heat shock as well as by exposure to ethanol and hydrogen peroxide. There were two transcripts representing the dnaKJ operon: one containing the dnaK and dnaJ genes and the second conta...

The Brucella BvrR/BvrS two-component regulatory system is homologous to the ChvI/ChvG systems of Sinorhizobium meliloti and Agrobacterium tumefaciens necessary for endosymbiosis and pathogenicity in plants. BvrR/BvrS controls cell invasion and intracellular survival. Probing the surface of bvrR and bvrS transposon mutants with monoclonal antibodies showed all described major outer membrane prot...