Conjugation factor of Agrobacterium tumefaciens regulates Ti plasmid transfer by autoinduction

@article{Piper1993ConjugationFO,
  title={Conjugation factor of Agrobacterium tumefaciens regulates Ti plasmid transfer by autoinduction},
  author={Kevin R. Piper and Susanne Beck von Bodman and Stephen K Farrand},
  journal={Nature},
  year={1993},
  volume={362},
  pages={448-450}
}
CONJUGAL transfer of Ti plasmids from Agrobacterium donors to bacterial recipients is controlled by two types of diffusible signal molecules. Induction is mediated by novel compounds, called opines, that are secreted by crown gall tumours. These neoplasias result from infection of susceptible plants by virulent agrobacteria. The second diffusible signal, called conjugation factor, is synthesized by the donor bacteria themselves. Production of this factor is induced by the opine. Here we show… 
Two Opines Control Conjugal Transfer of an Agrobacterium Plasmid by Regulating Expression of Separate Copies of the Quorum-Sensing Activator Gene traR
TLDR
It is shown that pAtK84b codes for two independently functioning copies of traR, each regulated by a different opine, thus accounting for the activation of the transfer system of this plasmid by the two opine types.
A new regulatory element modulates homoserine lactone-mediated autoinduction of Ti plasmid conjugal transfer
TLDR
It is suggested that traM functions to sequester TraR from the very small amounts of AAI produced under conditions when the agrocinopines are not present, suggesting that TraM is not a direct transcriptional regulator.
A LuxR-LuxI type regulatory system activates Agrobacterium Ti plasmid conjugal transfer in the presence of a plant tumor metabolite
TLDR
TraR-AAI-mediated activation in wild-type Agrobacterium strains was dramatically enhanced by culturing on solid media, suggesting a possible role in cell density sensing.
Quorum Sensing but Not Autoinduction of Ti Plasmid Conjugal Transfer Requires Control by the Opine Regulon and the Antiactivator TraM
TLDR
It is concluded that conjugal transfer of pTiC58 is regulated in a quorum-dependent fashion but that supercontrol of the TraR-AAI system by opines and by TraM results in a complex control process that requires not only the accumulation of AAI but also the expression of TraR and the synthesis of this protein at levels that overcome the inhibitory activity of TraM.
Co‐evolution of the agrocinopine opines and the agrocinopine‐mediated control of TraR, the quorum‐sensing activator of the Ti plasmid conjugation system
TLDR
It is demonstrated that the novel Ti plasmid pTi chry5 is induced to transfer at high frequency by extracts from tumours initiated by strain Chry5, and that the agrocinopine opines and the corresponding opine‐meditated conjugal regulatory regions of pTiChry5 and pTiC58 share a common origin.
The Agrobacterium DNA Transfer Complex
TLDR
The early reactions in the production of an ssDNA transfer intermediate (T-strand), mediated by the VirD1/D2 proteins, are chemically similar to formation of a relaxosome in bacterial conjugation.
Modulating quorum sensing by antiactivation: TraM interacts with TraR to inhibit activation of Ti plasmid conjugal transfer genes
TLDR
It is concluded that TraM and TraR interact in vivo and that this interaction is responsible for inhibition of TraR‐mediated activation.
Quorum-Dependent Mannopine-Inducible Conjugative Transfer of an Agrobacterium Opine-Catabolic Plasmid
TLDR
It is predicted that there exist wild-type agrobacterial strains harboring plasmids in which MOP induces a functional traR and, hence, conjugation, and that the anti-activator function of TraM is conserved.
Induction and Loss of Ti Plasmid Conjugative Competence in Response to the Acyl-Homoserine Lactone Quorum-Sensing Signal
ABSTRACT Conjugative transfer of the Ti plasmids of Agrobacterium tumefaciens is controlled by a quorum-sensing system composed of TraR and its signal N-(3-oxo-octanoyl)-l-homoserine lactone. This
Activity of the Agrobacterium Ti plasmid conjugal transfer regulator TraR is inhibited by the product of the traM gene
TLDR
It is shown that induction by octopine requires traR, strongly suggesting that TraR is the direct traM activator, and that TraM inhibits transcription of traA, traI, and traM.
...
...

References

SHOWING 1-10 OF 19 REFERENCES
Opine catabolism and conjugal transfer of the nopaline Ti plasmid pTiC58 are coordinately regulated by a single repressor.
TLDR
A gene from the Ti plasmid pTiC58, whose product mediates the opine-dependent regulation of conjugal transfer and catabolism of the conjugal opines, is cloned and sequenced and demonstrated that the accR-encoded function is a transcriptional repressor.
Agrobacterium conjugation and gene regulation by N-acyl-L-homoserine lactones
TLDR
The use of spectrometry shows that the conjugation factor of Agrobacterium tumefaciens is identical to synthetic N-(β-oxo-octan-l-oyl)-L-homoserine lactone and confirms that the synthetic compound is biologically active, the first example of a second messenger molecule in a bacterial conjugal system.
A diffusible compound can enhance conjugal transfer of the Ti plasmid in Agrobacterium tumefaciens
TLDR
Evidence indicates that CF is a key factor affecting transfer efficiency of pTi but is not sufficient by itself to induce transfer, and data suggest that CF might be an activator or derepressor in the conjugation system of A. tumefaciens.
Plasmid required for virulence of Agrobacterium tumefaciens
TLDR
Findings establish unequivocally that the large plasmid determines virulence in Agrobacterium tumefaciens strain C-58.
Characterization of conjugal transfer functions of Agrobacterium tumefaciens Ti plasmid pTiC58
TLDR
Results show that pTiC58 Ti plasmid conjugal transfer occurs by functions independent of those required for transfer of DNA to plant cells.
Nucleotide sequence of the regulatory locus controlling expression of bacterial genes for bioluminescence.
TLDR
A region of DNA containing a locus consisting of the luxR and luxI genes and two closely linked divergent promoters is sequenced to understand the regulation of bioluminescence.
Cloning and characterization of the Pseudomonas aeruginosa lasR gene, a transcriptional activator of elastase expression.
TLDR
Northern (RNA) analysis of total cellular RNA from PAO1, PAO-R1, and PAO -R1 containing the lasR gene on a multicopy plasmid revealed that a functionalLasR gene is required for transcription of the elastase structural gene (lasB).
A Tn3 lacZ transposon for the random generation of beta‐galactosidase gene fusions: application to the analysis of gene expression in Agrobacterium.
TLDR
Tn3‐HoHo1 can serve as a transposon mutagen and provides a new and useful system for the random generation of both transcriptional and translational lacZ gene fusions and insertion into sequences specifically contained within plasmids.
...
...