Agrobacterium: A disease-causing bacterium

Abstract

Abstract. The common use of Agrobacterium as a gene vector for plants has somewhat obscured the fact that this bacterium remains an important plant pathogen.

Identification of an rsh Gene from a Novosphingobium sp. Necessary for Quorum-Sensing Signal Accumulation

“…The gram-negative bacteria A. tumefaciens and Agrobacterium vitis are the causal agents of crown gall disease on a number of dicotyledonous plants and grapevine, respectively (3,36,51,55). The N-(3-oxo-octanoyl)-L-HL (3-O-C8-HL) signal of A. tumefaciens is involved in the regulation of replication and conjugal transfer of the tumor-inducing (Ti) plasmid to Ti plasmidless A. tumefaciens cells (36,55,57).…”

Grapevine Crown Gall Suppression Using Biological Control and Genetic Engineering: A Review of Recent Research

“…Wound healing processes, such as callus formation, development of graft union vascular connection, and tissue repair and remodeling in response to grafting and freeze injury, as well as physical damages caused by vineyard equipment, involve cell division and render grapevine cells competent to Agrobacterium transformation. Consequently, these are the primary sites for CG development (Creasap et al 2005, Otten et al 2008. The tumorous growth typically occurs around the graft union (Figure 2), on the lower trunk (Figure 3), and at the base and disbudded points of cuttings, as those are prevalent sites of wound healing and highly susceptible to T-DNA export.…”

“…Many proteins encoded by virulence (vir) genes play essential roles in the T-DNA transfer process. Nearly all proteins encoded by the vir region of the Ti plasmid are required for T-DNA transfer to occur (Burr and Otten 1999, Gelvin 2003, Matthysse 2006, Otten et al 2008. VirA and VirG form a two-component regulatory system.…”

“…This involves producing pathogen-free planting material by in vitro apical meristem or shoot-tip tissue culture and inhibiting bacterial infection (soil fumigation and soil solarization) (Burr et al 1988, Pu and Goodman 1993a, Burr and Otten 1999, Otten et al 2008. Other strategies to reduce CG incidence in both vineyard and nursery are heat and chemical treatments (such as hot water submersion and oxyquinoline sulfate treatments) of dormant cuttings prior to grafting (Szegedi 1995, Burr et al 1996, Burr and Otten 1999, Otten et al 2008. Breeding for grapevine CG resistance represents another approach.…”

“…According to several previous VirE2-involved T-DNA export and integration blocking studies, the increased resistance is believed to be associated with competition of the mutated VirE2 proteins with functional VirE2 proteins. Within the plant cell the competition appears to block the integration of the T-DNA into the plant cell nucleus (Burr and Otten 1999, Gelvin 2003, Matthysse 2006, Otten et al 2008. The truncated virE2 genes from A. tumefaciens strain C58 and A6 and A. vitis strain CG450 were expressed in Teleki 5C, Richter 110, and Couderc 3309 grapevine rootstocks.…”