Control of expression of Agrobacterium vir genes by synergistic actions of phenolic signal molecules and monosaccharides.

Abstract

but does not enhance the expression of noninducible genes. Likewise, a 2-deoxy-D-glucose, a nonmetabolized sugar, is also effective. When a deletion was introduced into the virA gene in the region encoding the periplasmic portion of the VirA protein, enhancement by glucose disappeared, but vir expression was induced by acetosyringone in this mutant. These results suggest that these sugars directly enhance a signaling process initiated by phenolic inducers that results in an-increase in expression of the vir genes.

The Agrobacterium tumefaciens vir gene transcriptional activator virG is transcriptionally induced by acid pH and other stress stimuli

“…The vir genes are transcriptionally induced in response to a family of phenolic compounds produced by wounded plant cells (50, 51). Induction also requires acidic growth medium (52) and is potentiated by certain monosaccharides (3,47).Two members of the vir regulon, virA and virG, are required for vir gene induction (44,53,63) and encode proteins that are members of the family of bacterial twocomponent regulatory systems (28, 37, 42, 62). For some vir promoters, VirA and VirG are the only known regulatory proteins (34, 64), while the virC and virD promoters are also controlled by a repressor encoded by the chromosomal ros gene (5, 7).…”

“…The vir genes are transcriptionally induced in response to a family of phenolic compounds produced by wounded plant cells (50, 51). Induction also requires acidic growth medium (52) and is potentiated by certain monosaccharides (3,47).…”

Thermosensing to Adjust Bacterial Virulence in a Fluctuating Environment

“…The T-DNA is transferred and integrated into the plant genome, and uncontrolled expression of this gene cluster induces tumor formation [163,164]. The vir gene products are responsible for the processing and the transfer of the T-DNA from the bacteria into plant cells [165]. Their expression is only activated at temperatures below 32°C by a two-component system composed of the histidine kinase VirA and the response regulator VirG [166].…”

Standardization of Agrobacterium mediated genetic transformation in Indica rice cv BPT-5204

“…Acetosyringone is a phenolic compound produced during plant cell wounding that induces the transcription of Agrobacterium tumifaciens virulence genes that regulate the processing and transfer of T-DNA from A.tumifaciens to plant cells (Shimoda et al, 1990;Gelvin 2003;Tripathi et al, 2010). Higher transformation frequency is achieved by addition of acetosyringone in co-cultivation medium.…”