Monocotyledonous plants were believed to be not transformable by the soil bacterium Agrobacterium tumefaciens until two decades ago, although convenient protocols for infection of leaf disks and subsequent regeneration of transgenic plants had been well established in a number of dicotyledonous species by then. This belief was reinforced by the fact that monocotyledons are mostly outside the ho...

objective: methanol extract of bran and unpolished grain of two traditional aromatic rice genotypes viz. kalijira and chinigura were assayed for their activity on the growth and initiation of crown-gall tumors on potato disks. materials and methods: three agrobacterium tumefaciens (a. tumefaciens) strain atsl0105, atta0112, and atac0114 were used as the tumor forming agent. collected rice was s...

A genetic analysis of Agrobacterium tumefaciens chromosomal functions required for virulence was undertaken. Large Tn5-containing cosmid clones were isolated from DNA of avirulent A. tumefaciens mutants having chromosomal Tn5 insertions and exhibiting defective attachment to plant cells. The clones from several different mutants each contained overlapping segments of a 30-kilobase A. tumefacien...

Bacteriophytochrome photoreceptors (BphPs) are a family of phytochrome-like sensor kinases that help a wide variety of bacteria respond to their light environment. In Agrobacterium tumefaciens, a unique pair of BphPs with potentially opposing roles in light sensing are present. Both AtBphPs contain an N-terminal chromophore-binding domain that covalently attaches a biliverdin chromophore. Where...

The VirB4 ATPase of Agrobacterium tumefaciens, a putative component of the T-complex transport apparatus, associates with the cytoplasmic membrane independently of other products of the Ti plasmid. VirB4 was resistant to extraction from membranes of wild-type strain A348 or a Ti-plasmidless strain expressing virB4 from an IncP replicon. To evaluate the membrane topology of VirB4, a nested delet...

Some bacteria produce and perceive quorum-sensing (QS) signals that coordinate several behaviours, including the costly processes that are exoenzyme production and plasmid transfer. In the case of plasmid transfer, the emergence of QS signal-altered invaders and their policing are poorly documented. In Agrobacterium tumefaciens, the virulence Ti-plasmid encodes both synthesis and sensing of QS-...

The ubiquitous plant pathogen Agrobacterium tumefaciens attaches efficiently to plant tissues and abiotic surfaces and can form complex biofilms. A genetic screen for mutants unable to form biofilms on PVC identified disruptions in a homologue of the exoR gene. ExoR is a predicted periplasmic protein, originally identified in Sinorhizobium meliloti, but widely conserved among alphaproteobacteri...