A proline iminopeptidase gene upregulated in planta by a LuxR homologue is essential for pathogenicity of Xanthomonas campestris pv. campestris

Zhang, Lili; Jia, Yantao; Wang, Li; Fang, Rongxiang

doi:10.1111/j.1365-2958.2007.05775.x

Cited by 82 publications

(85 citation statements)

References 69 publications

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“…They sense a yet-unidentified plant signal(s) being involved in inter-kingdom signaling (7, 9, 16). Well-studied examples of LuxR PA include XccR of Xanthomonas campestris binding a signal present in cabbage, OryR of X. oryzae binding a rice produced signal compound, XagR of X. axonopodis binding the soybean, rice and cabbage produced molecules, PsoR of Pseudomonas fluorescens binding the rice and wheat molecules, and NesR in Sinorhizobium meliloti (the plant response has not been determined) (7, 9, 33, 41, 44). All above-mentioned LuxR PA proteins in the corresponding bacterium play important biological roles related to plant-bacteria interactions.…”

Section: Introductionmentioning

confidence: 99%

Roles of a Solo LuxR in the Biological Control Agent Lysobacter enzymogenes Strain OH11

Qian

Venturi

et al. 2014

Phytopathology®

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Lysobacter enzymogenes is a ubiquitous plant-associated and environmentally friendly bacterium emerging as a novel biological control agent of plant disease. This bacterium produces diverse antifungal factors, such as lytic enzymes and a secondary metabolite (heat-stable antifungal factor, HSAF) having antifungal activity with novel structure and mode of action. The regulatory mechanism for biosynthesis of antifungal factors is largely unknown in L. enzymogenes. The solo LuxR proteins have been shown to be widespread, playing important roles in plant-associated bacteria. Here, we cloned and studied a solo LuxR protein, LesR from L. enzymogenes strain OH11. Overexpression, but not deletion of lesR significantly impaired HSAF biosynthesis levels and antimicrobial activities but did not show visible effect on production of major lytic enzymes. Overexpression of lesR also led to remarkably accelerated cell aggregation and induced production of a melanin-like pigment in L. enzymogenes; these two phenotyes are mediated by diffusible factor cell-cell signaling system of L. enzymogenes. The C-terminus helix-turn-helix domain was shown to be critical for several lesR-controlled functions. Overall, our study provides the first example of the roles and mechanisms of a solo LuxR protein in a plant-associated L. enzymogenes.

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Section: Introductionmentioning

confidence: 99%

Roles of a Solo LuxR in the Biological Control Agent Lysobacter enzymogenes Strain OH11

Qian

Venturi

et al. 2014

Phytopathology®

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“…We also tested a strain deficient in the gene for a putative proline iminopeptidase (orf32), an enzyme that removes the N-terminal proline from a peptide (15). Proline iminopeptidase contributes to the virulence of the plant pathogen Xanthomonas campestris and is highly active in Treponema denticola, a pathogen causing human periodontal disease (16,17). For the generation of an aspartate-auxotrophic strain, aspC was deleted.…”

Section: Generation Of Auxotrophic S Typhimurium Mutant Strainsmentioning

confidence: 99%

Role of Host Cell-Derived Amino Acids in Nutrition of Intracellular Salmonella enterica

et al. 2015

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The facultative intracellular pathogen Salmonella enterica resides in a specific membrane-bound compartment termed the Salmonella-containing vacuole (SCV). Despite being segregated from access to metabolites in the host cell cytosol, Salmonella is able to efficiently proliferate within the SCV. We set out to unravel the nutritional supply of Salmonella in the SCV with focus on amino acids. We studied the availability of amino acids by the generation of auxotrophic strains for alanine, asparagine, aspartate, glutamine, and proline in a macrophage cell line (RAW264.7) and an epithelial cell line (HeLa) and examined access to extracellular nutrients for nutrition. Auxotrophies for alanine, asparagine, or proline attenuated intracellular replication in HeLa cells, while aspartate, asparagine, or proline auxotrophies attenuated intracellular replication in RAW264.7 macrophages. The different patterns of intracellular attenuation of alanine-or aspartate-auxotrophic strains support distinct nutritional conditions in HeLa cells and RAW264.7 macrophages. Supplementation of medium with individual amino acids restored the intracellular replication of mutant strains auxotrophic for asparagine, proline, or glutamine. Similarly, a mutant strain deficient in succinate dehydrogenase was complemented by the extracellular addition of succinate. Complementation of the intracellular replication of auxotrophic Salmonella by external amino acids was possible if bacteria were proficient in the induction of Salmonella-induced filaments (SIFs) but failed in a SIF-deficient background. We propose that the ability of intracellular Salmonella to redirect host cell vesicular transport provides access of amino acids to auxotrophic strains and, more generally, is essential to continuously supply bacteria within the SCV with nutrients.T he facultative intracellular life-style is a common virulence strategy among bacterial pathogens, and intracellular lifestyles are as diverse as the diseases caused by these pathogens. While some bacteria lyse the host cell membrane compartment and initiate replication in the cytosol, others remain in a host cell-derived membrane compartment that is modified to allow intravacuolar survival and replication. To understand the lifestyle of bacterial pathogens, it is of central importance to analyze which nutritional limitations are experienced by the pathogen in its intracellular habitat and how the pathogen adapts its metabolism in order to survive and proliferate despite these limitations.Salmonella enterica is an invasive, facultative, intracellular pathogen responsible for foodborne diseases ranging from localized gastroenteritis to systemic typhoid fever. Inside mammalian host cells, S. enterica resides in a specialized membrane-bound compartment, the Salmonella-containing vacuole (SCV). The SCV is modified by the action of virulence factors of S. enterica, and the function of the type III secretion system (T3SS) encoded by Salmonella pathogenicity island 2 (SPI2) and its effector proteins is of central impor...

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“…These proteins are found in plant-associated bacteria (PAB) and show changes in one or two highly conserved amino acids of the autoinducer domain which are thought to be important for signal recognition based on structural studies on TraR (Nasser and Reverchon, 2007). These solos were first described in two species from the Xanthomonas genus (Ferluga et al, 2007; Zhang et al, 2007). Later additional proteins belonging to this group were described in other bacterial species (Patankar and Gonzalez, 2009a; Subramoni et al, 2011; Chatnaparat et al, 2012) and they are also present in bacteria associated with Populus deltoides (Schaefer et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Studies on synthetic LuxR solo hybrids

Silva

Patel

González

et al. 2015

Front. Cell. Infect. Microbiol.

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A sub-group of LuxR family of proteins that plays important roles in quorum sensing, a process of cell-cell communication, is widespread in proteobacteria. These proteins have a typical modular structure consisting of N-ter autoinducer binding and C-ter helix-turn-helix (HTH) DNA binding domains. The autoinducer binding domain recognizes signaling molecules which are most often N-acyl homoserine lactones (AHLs) but could also be other novel and yet unidentified molecules. In this study we carried out a series of specific domain swapping and promoter activation experiments as a first step to engineer synthetic signaling modules, taking advantage of the modularity and the versatile/diverse signal specificities of LuxR proteins. In our experiments the N-ter domains from different LuxR homologs were either interchanged or placed in tandem followed by a C-ter domain. The rational design of the hybrid proteins was supported by a structure-based homology modeling studies of three members of the LuxR family (i.e., LasR, RhlR, and OryR being chosen for their unique ligand binding specificities) and of selected chimeras. Our results reveal that these LuxR homologs were able to activate promoter elements that were not their usual targets; we also show that hybrid LuxR proteins retained the ability to recognize the signal specific for their N- ter autoinducer binding domain. However, the activity of hybrid LuxR proteins containing two AHL binding domains in tandem appears to depend on the organization and nature of the introduced domains. This study represents advances in the understanding of the modularity of LuxR proteins and provides additional possibilities to use hybrid proteins in both basic and applied synthetic biology based research.

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A proline iminopeptidase gene upregulated in planta by a LuxR homologue is essential for pathogenicity of Xanthomonas campestris pv. campestris

Cited by 82 publications

References 69 publications

Roles of a Solo LuxR in the Biological Control Agent Lysobacter enzymogenes Strain OH11

Roles of a Solo LuxR in the Biological Control Agent Lysobacter enzymogenes Strain OH11

Role of Host Cell-Derived Amino Acids in Nutrition of Intracellular Salmonella enterica

Studies on synthetic LuxR solo hybrids

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