scholarly journals Insight in the quorum sensing-driven lifestyle of the non-pathogenic Agrobacterium tumefaciens 6N2 and the interactions with the yeast Meyerozyma guilliermondii

Genomics ◽  
2021 ◽  
Author(s):  
Elisa Violeta Bertini ◽  
Mariela Analía Torres ◽  
Thibaut Léger ◽  
Camille Garcia ◽  
Kar-Wai Hong ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Quorum Sensing ◽  
Meyerozyma Guilliermondii

scholarly journals Insight in the quorum sensing-driven lifestyle of the non-pathogenic Agrobacterium tumefaciens 6N2 and the interactions with the yeast Meyerozyma guilliermondii

2021 ◽  
Author(s):  
Elisa Violeta Bertini ◽  
Mariela Analia Torres ◽  
Thibaut Leger ◽  
Camille Garcia ◽  
Kar-Wai Hong ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Quorum Sensing ◽  
Plant Tissues ◽  
Meyerozyma Guilliermondii ◽  
Proteomic Approach ◽  
Dual Cultures ◽  
Yeast Interactions ◽  
Signal Receptors

Agrobacterium tumefaciens is considered a prominent phytopathogen, though most isolates are nonpathogenic. Agrobacteria can inhabit plant tissues interacting with other microorganisms. Yeasts are likewise part of these communities. We analyzed the quorum sensing (QS) systems of A. tumefaciens strain 6N2, and its relevance for the interaction with the yeast Meyerozyma guilliermondii, both sugarcane endophytes. We show that strain 6N2 is nonpathogenic, produces OHC8-HSL, OHC10-HSL, OC12-HSL and OHC12-HSL as QS signals, and possesses a complex QS architecture, with one truncated, two complete systems, and three additional QS-signal receptors. A proteomic approach showed differences in QS-regulated proteins between pure (64 proteins) and dual (33 proteins) cultures. Seven proteins were consistently regulated by quorum sensing in pure and dual cultures. M. guilliermondii proteins influenced by QS activity were also evaluated. Several up- and down- regulated proteins differed depending on the bacterial QS. These results show the importance of the QS regulation in the bacteria-yeast interactions.

scholarly journals Co-Dependent and Interdigitated: Dual Quorum Sensing Systems Regulate Conjugative Transfer of the Ti Plasmid and the At Megaplasmid in Agrobacterium tumefaciens 15955

2020 ◽  
Author(s):  
Ian S Barton ◽  
Justin L Eagan ◽  
Priscila A Nieves-Otero ◽  
Ian P Reynolds ◽  
Thomas G Patt ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Ti Plasmid ◽  
Conjugative Transfer ◽  
Gene Promoters ◽  
Transcription Activator ◽  
Conjugation System ◽  
Direct Production ◽  
Sensing Systems

Members of the Rhizobiaceae, often carry multiple secondary replicons in addition to the primary chromosome with compatible repABC-based replication systems. Unlike secondary chromosomes and chromids, repABC-based megaplasmids and plasmids can undergo copy number fluctuations and are capable of conjugative transfer in response to environmental signals. Several Agrobacterium tumefaciens lineages harbor three secondary repABC-based replicons, including a secondary chromosome (often linear), the Ti (tumor-inducing) plasmid and the At megaplasmid. The Ti plasmid is required for virulence and encodes a conjugative transfer (tra) system that is strictly regulated by a subset of plant-tumor released opines and a well-described acyl-homoserine lactone (AHL)-based quorum-sensing mechanism. At plasmids are generally not required for virulence, but carry genes that enhance rhizosphere survival, and these plasmids are often conjugatively proficient. We report that the At megaplasmid of the octopine-type strain A. tumefaciens 15955 encodes a quorum-controlled conjugation system that directly interacts with the paralogous quorum sensing system on the co-resident Ti plasmid. Both the pAt15955 and pTi15955 plasmids carry homologues of a TraI-type AHL synthase, a TraR-type AHL-responsive transcription activator, and a TraM-type anti-activator. The traI genes from both pTi15955 and pAt15955 can direct production of the inducing AHL (3-octanoyl-L-homoserine lactone) and together contribute to the overall AHL pool. The TraR protein encoded on each plasmid activates AHL-responsive transcription of target tra gene promoters. The pAt15955 TraR can cross-activate tra genes on the Ti plasmid as strongly as its cognate tra genes, whereas the pTi15955 TraR preferentially biased towards its own tra genes. Putative tra box elements are located upstream of target promoters, and comparing between plasmids, they are in similar locations and share an inverted repeat structure, but have distinct consensus sequences. The two AHL quorum sensing systems have a combinatorial effect on conjugative transfer of both plasmids. Overall, the interactions described here have implications for the horizontal transfer and evolutionary stability of both plasmids and, in a broad sense, are consistent with other repABC systems that often have multiple quorum-sensing controlled secondary replicons.

scholarly journals Transsexuality in the Rhizosphere: Quorum Sensing Reversibly Converts Agrobacterium tumefaciens from Phenotypically Female to Male

2009 ◽  
Vol 191 (10) ◽  
pp. 3375-3383 ◽  
Author(s):  
Hongbaek Cho ◽  
Uelinton M. Pinto ◽  
Stephen C. Winans
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Quorum Sensing ◽  
Host Cell ◽  
Ti Plasmid ◽  
Conjugative Plasmids ◽  
Acylhomoserine Lactone ◽  
Ti Plasmids ◽  
Quorum Sensing Signals

ABSTRACT Conjugative plasmids generally encode proteins that block the conjugative entry of identical or similar plasmids into the host cell, a phenomenon known as entry exclusion. Here, we demonstrate that two Ti plasmids of Agrobacterium tumefaciens encode robust entry exclusion functions. Two proteins, TrbJ and TrbK, can each mediate entry exclusion and act synergistically. The trbJ and trbK genes are included within the trb operon, which is tightly regulated by the quorum-sensing regulator TraR and the cognate acylhomoserine lactone. In the absence of quorum-sensing signals, these proteins are not significantly expressed, and cells lacking TrbJ and TrbK are efficient Ti plasmid recipients. In the presence of these signals, these strains block the entry of Ti plasmids and instead become efficient conjugal donors.

scholarly journals Rapid Screening of Quorum-Sensing Signal N-Acyl Homoserine Lactones by an In Vitro Cell-Free Assay

2008 ◽  
Vol 74 (12) ◽  
pp. 3667-3671 ◽  
Author(s):  
Tomohiro Kawaguchi ◽  
Yung Pin Chen ◽  
R. Sean Norman ◽  
Alan W. Decho
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Quorum Sensing ◽  
High Sensitivity ◽  
Homoserine Lactone ◽  
Assay System ◽  
Rapid Screening ◽  
Whole Cell ◽  
Bacterial Quorum ◽  
Whole Cell Biosensor

ABSTRACT A simple, sensitive, and rapid cell-free assay system was developed for detection of N-acyl homoserine lactone (AHL) autoinducers involved in bacterial quorum sensing (QS). The present approach improves upon previous whole-cell biosensor-based approaches in its utilization of a cell-free assay approach to conduct bioassays. The cell-free assay was derived from the AHL biosensor bacterium Agrobacterium tumefaciens NTL4(pCF218)(pCF372), allowing the expression of β-galactosidase upon addition of exogenous AHLs. We have shown that β-galactosidase expression is possible in cell-free solution [lysate from Agrobacterium tumefaciens NTL4(pCF218)(pCF372) culture]. Assay detection limits with the use of chromogenic substrate X-Gal (5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside) ranged from approximately 100 nM to 300 nM depending on the specific AHL. Replacement (of X-Gal) with the luminescent substrate Beta-Glo increased sensitivity to AHLs by 10-fold. A major advantage of the cell-free assay system is elimination of time-consuming steps for biosensor cell culture conditioning, which are required prior to whole-cell bioassays. This significantly reduced assay times from greater than 24 h to less than 3 h, while maintaining high sensitivity. Assay lysate may be prepared in bulk and stored (−80°C) over 6 months for future use. Finally, the present protocol may be adapted for use with other biosensor strains and be used in high-throughput AHL screening of bacteria or metagenomic libraries.

scholarly journals A Pyranose-2-Phosphate Motif Is Responsible for Both Antibiotic Import and Quorum-Sensing Regulation in Agrobacterium tumefaciens

2015 ◽  
Vol 11 (8) ◽  
pp. e1005071 ◽  
Author(s):  
Abbas El Sahili ◽  
Si-Zhe Li ◽  
Julien Lang ◽  
Cornelia Virus ◽  
Sara Planamente ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Quorum Sensing

scholarly journals Transcriptome analysis revealed that a quorum sensing system regulates the transfer of the pAt megaplasmid in Agrobacterium tumefaciens

BMC Genomics ◽  
2016 ◽  
Vol 17 (1) ◽  
Author(s):  
Nadia Mhedbi-Hajri ◽  
Noura Yahiaoui ◽  
Samuel Mondy ◽  
Nathalie Hue ◽  
Franck Pélissier ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Quorum Sensing ◽  
Transcriptome Analysis ◽  
Sensing System ◽  
Quorum Sensing System

scholarly journals Complex Regulation of Arsenite Oxidation in Agrobacterium tumefaciens

2006 ◽  
Vol 188 (3) ◽  
pp. 1081-1088 ◽  
Author(s):  
Des R. Kashyap ◽  
Lina M. Botero ◽  
William L. Franck ◽  
Daniel J. Hassett ◽  
Timothy R. McDermott
Keyword(s):  
Signal Transduction ◽  
Agrobacterium Tumefaciens ◽  
Quorum Sensing ◽  
Response Regulator ◽  
Structural Features ◽  
Rt Pcr ◽  
Two Component ◽  
In The Wild ◽  
Two Component Signal Transduction ◽  
Operon Expression

ABSTRACT Seminal regulatory controls of microbial arsenite [As(III)] oxidation are described in this study. Transposon mutagenesis of Agrobacterium tumefaciens identified genes essential for As(III) oxidation, including those coding for a two-component signal transduction pair. The transposon interrupted a response regulator gene (referred to as aoxR), which encodes an ntrC-like protein and is immediately downstream of a gene (aoxS) encoding a protein with primary structural features found in sensor histidine kinases. The structural genes for As(III) oxidase (aoxAB), a c-type cytochrome (cytc 2), and molybdopterin biosynthesis (chlE) were downstream of aoxR. The mutant could not be complemented by aoxSR in trans but was complemented by a clone containing aoxS-aoxR-aoxA-aoxB-cytc 2 and consistent with reverse transcriptase (RT) PCR experiments, which demonstrated these genes are cotranscribed as an operon. Expression of aoxAB was monitored by RT-PCR and found to be up-regulated by the addition of As(III) to cell cultures. Expression of aoxAB was also controlled in a fashion consistent with quorum sensing in that (i) expression of aoxAB was absent in As(III)-unexposed early-log-phase cells but was observed in As(III)-unexposed, late-log-phase cells and (ii) treating As(III)-unexposed, early-log-phase cells with ethyl acetate extracts of As(III)-unexposed, late-log-phase culture supernatants also resulted in aoxAB induction. Under inducing conditions, aoxS expression was readily observed in the wild-type strain but significantly reduced in the mutant, indicating that AoxR is autoregulatory and at least partially controls the expression of the aox operon. In summary, regulation of A. tumefaciens As(III) oxidation is complex, apparently being controlled by As(III) exposure, a two-component signal transduction system, and quorum sensing.

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