Agrobacterium tumefaciens transfers a protein-DNA complex to plant cells in a process similar to bacterial conjugation; the mechanism of transfer is beginning to be unravelled by biochemical, genetic and electron microscopic studies.

A sensor protein ChvG is part of a chromosomally encoded two-component regulatory system ChvG/ChvI that is important for the virulence of Agrobacterium tumefaciens. However, it is not clear what genes ChvG regulates or what signal(s) it senses. In this communication, we demonstrate that ChvG is involved in the regulation of acid-inducible genes, including aopB and katA, residing on the circular...

For conjugation between prokaryotic Agrobacterium tumefaciens and eukaryotic Saccharomyces cerevisiae, we constructed two novel conjugative plasmids. A. tumefaciens transmitted the plasmids to S. cerevisiae with the aid of tra genes on a helper plasmid. The transmitted plasmids retained their original structure and function in transconjugant yeasts. The presence of Ti plasmid barely affected th...

Gametophore induction in moss by Agrobacterium tumefaciens was inhibited by addition of lipopolysaccharide (LPS) from A. tumefaciens. The LPS did not affect bacterial viability or appear to bind to bacterial cells. LPS from nonbinding Agrobacterium radiobacter was not effective in reducing gametophore formation. A. tumefaciens LPS, if added 24 hours after addition of viable bacterial cells, had...

Almost ten years have elapsed since the initiation of experiments on rice transformation using Agrobacterium tumefaciens. Chen et al. successfully transformed rice using this method, but transformation efficiency was low. After Hiei et al. reported high efficiency of Agrobacterium-mediated production of fertile and heritable transgenic rice plants, this technology was adopted by many laboratori...

Agrobacterium is a unique model system as well as a major biotechnological tool for genetic manipulation of plant cells. It is still unknown, however, whether host cellular factors exist that are limiting for infection, and whether their overexpression in plant cells can increase the efficiency of the infection. Here, we examined the effect of overexpression in tobacco plants of an Arabidopsis ...

Shoot regeneration in safflower (Carthamus tinctorius 'AKS 207' and 'PKV Pink') genetically transformed using Agrobacterium was used for assessing various constraints to the efficiency of transformation including infection period, virulence induction medium, co-cultivation period, bacterial titre, selection regime, and the natural phenolic compound acetosyringone. Transformation frequency was p...

The ability to recognize and predict non-sigma54 promoters in the alphaproteobacteria is not well developed. In this study, 25 experimentally verified Sinorhizobium meliloti promoter sequences were compiled and used to predict the location of other related promoters in the S. meliloti genome. Fourteen candidate predictions were targeted for verification and of these at least 12 proved to be gen...