A chromosomally encoded two-component sensory transduction system is required for virulence of Agrobacterium tumefaciens

Abstract

While the major interest in A. tumefaciens virulence functions has focused on Ti plasmid-encoded genes, several chromosomal virulence genes have been identified and characterized. These genes encode functions required for virulence, such as the attachment ofA. tumefaciens cells to plant cells (16,48,56,76), and for induction of the vir genes by monosaccharides (6, 31). Mutations that result in reduced vir gene induction by acetosyringone have recently been described. Those in the ivr loci drastically reduce tumor-forming ability (52), while those in miaA affect virulence only slightly (24). Significantly, chromosomal virulence genes specifically involved in T-DNA processing and transport have not been identified. As well as providing information about the mechanisms of known virulence processes, analysis of chromosomal mutations can enlighten us regarding the overall physiological and biochemical requirements for virulence.In an attempt to identify additional chromosomal virulence genes, TnphoA (44) was used by Cangelosi et al. (7) to generate insertion mutations in genes which encode proteins * Corresponding author.

Truncation of Amino Acids 12–128 Causes Deregulation of the Phosphatase Activity of the Sensor Kinase KdpD of Escherichia coli

“…In ChvG from Agrobacterium tumefaciens this putative site is located in the transmitter domain (43). The unorthodox sensor kinase BvgS from Bordetella pertussis contains such a motif in its linker region.…”

A two‐component regulatory system playing a critical role in plant pathogens and endosymbionts is present in Brucella abortus and controls cell invasion and virulence

“…The GþC content of the whole sequence was similar to that observed for B. abortus chromosomal DNA (58%) (Hoyer and McCullough, 1968). A database search of the deduced amino acid sequence for the BvrR and BvrS proteins revealed a high level of identity with a two-component regulatory system of Rhizobium (Sinorhizobium) meliloti (ChvI-ExoS;Osteras et al, 1995;Cheng and Walker, 1998) and A. tumefaciens (ChvI-ChvG;Charles and Nester, 1993;Mantis and Winans, 1993). BvrR had 85% identity (89% similarity) and 83% identity (87% similarity) to the R. meliloti and A. tumefaciens ChvI respectively.…”

Bacterial degradation and decolorization of textile dyes by newly isolated Lysobacter sp.

“…Total genomic DNA of bacteria was isolated by using method of Charles and Nester (1993) with slight modifications. Pure cultures of bacteria were raised in 10 ml of nutrient broth medium for 18 -24 h to obtain cell O.D of 0.6 at 600 nm and 12,000 rpm.…”