Transfer of virulence in vivo and in vitro in Agrobacterium

Kerr, A.; Manigault, P; Tempé, Jacques

doi:10.1038/265560a0

Cited by 160 publications

(67 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…23). Recently evidence has been presented which indicates that transfer of tumorinducing plasmids in Agrobacterium tumefaiens may be stimulated by octopine and nopaline, tumor-specific amino acids produced by infected plants (24,25). Although there is considerable evidence for the existence of soluble factors that influence genetic exchange in many systems, we are not aware of any report of a bacterial system where a diffusible product excreted by recipients influences donors.…”

Section: Discussionmentioning

confidence: 87%

Induced cell aggregation and mating in Streptococcus faecalis: evidence for a bacterial sex pheromone.

Dunny¹,

Brown²,

Clewell³

1978

Proc. Natl. Acad. Sci. U.S.A.

507

335

View full text Add to dashboard Cite

Recipient strains of Streptococcus faecalis produce a trypsin sensitive, heat resistant, nuclease resistant factor, designated clumping-inducing agent (CIA) which causes strains carrying certain conjugative plasmids to aggregate. RNA and protein synthesis but not DNA synthesis are required for aggregation to occur. Recipient filtrates that contain CIA activity also induce donors to mate at high frequencies. Introduction of a transferable plasmid into strains producing CIA dramatically reduces the amount of CIA activity produced by the strain but allows the strain to respond to exogenously added CIA. Our data suggest that CIA represents a bacterial sex hormone (pheromone).

show abstract

Section: Discussionmentioning

confidence: 87%

Induced cell aggregation and mating in Streptococcus faecalis: evidence for a bacterial sex pheromone.

Dunny¹,

Brown²,

Clewell³

1978

Proc. Natl. Acad. Sci. U.S.A.

507

335

View full text Add to dashboard Cite

show abstract

“…Although the inducibility of Ti plasmid transfer was first demonstrated 30 years ago (13,17), virtually nothing is known about how conjugative competence, once activated, responds to the loss of inducing signals. In batch culture, removing the quormone had only a modest effect on donors harboring any of the three mutant Ti plasmids (Fig.…”

Section: Vol 190 2008 Induction and Decay Of Quorum-regulated Conjumentioning

confidence: 99%

Induction and Loss of Ti Plasmid Conjugative Competence in Response to the Acyl-Homoserine Lactone Quorum-Sensing Signal

Khan

Farrand

2008

J Bacteriol

View full text Add to dashboard Cite

Conjugative transfer of the Ti plasmids ofConjugative transfer of the Ti plasmids of Agrobacterium tumefaciens is a tightly regulated process involving two signaling systems arranged in a hierarchy. Expression of the three Ti plasmid transfer operons, traAFB, traCDG, and traI-trb, requires first a small molecule signal, the conjugative opine, which is produced by the crown gall tumors induced on susceptible plants by this phytopathogen (7,8). In addition to acting as a signal, the conjugative opine also can be catabolized by the bacteria by using functions coded for by the Ti plasmid. The conjugative opines regulate transfer by controlling the expression of a Ti plasmid operon of which TraR, the direct regulator of the three transfer operons, is a member. For example, transfer of pTiC58 is induced by the sugar phosphodiester opines agrocinopine A and agrocinopine B. In this plasmid, traR is a member of the five-gene arc operon, the expression of which is regulated by the opine-responsive repressor AccR (1). In the absence of the conjugative opines, the expression of arc is repressed. When the opines are present, as when the bacteria are colonizing an agrocinopine-producing crown gall tumor, repression by AccR is relieved, and the arc operon, including traR, is expressed.TraR, a member of the LuxR family of quorum-sensing transcription factors, activates expression of the transfer operons in response to the second signal, an acyl-homoserine lactone (acyl-HSL) (27, 34). The cognate quormone N-(3-oxooctanoyl)-L-homoserine lactone (3-oxo-C8-HSL) is produced by the bacteria themselves via the acyl-HSL synthase TraI, also encoded by the Ti plasmid (16,24). This signal transits out of and back into the cells in a stochastic fashion, and its concentration in a diffusion-limited environment increases with in-

show abstract

“…Този пренос е бил наблюдаван пай-напред in vivo в растителпяте тумори при смесени инфекции (31,32,41). In vitro обаче Тi-плазмидите не са ав топреносими.…”

Section: /Biotechnology and Bioindustry/23unclassified

“…Те могат да бъдат иНдуцирани за ко нюгативен пренос чрез добавянето на специфичен за Тi-плазмида опии (напр. актопии за октопиновите Тi плазмиди или агропин за нопалиновите) в хранител пата среда като единствен източник на азот (1,31,41). Следователно опините, добавени в средата, иНду цират както опин-катаболитните гени, така и trа-ге ните.…”

Section: /Biotechnology and Bioindustry/23unclassified

See 1 more Smart Citation