ABSTRACT: Genome sequence of Xanthomonas fuscans subsp. fuscans strain 4834-R reveals that flagellar motility is not a general feature of xanthomonads.
Project description:Plant pathogenic bacteria disseminate and survive through transmission to and by seeds of hosts and non-hosts plants. To investigate the interaction between xanthomonads and developing seeds of Medicago truncatula, plants at the flower bud stage were spray inoculated until runoff with xanthomonads suspensions. Using the Medicago NimbleGen chip, a transcriptomic analysis was performed on seeds to characterize the molecular dialogue between Xanthomonas campestris pv. campestris in an incompatible situation with M. truncatula seeds and Xanthomonas alfalfae pv. alfalfae in a compatible situation at two developmental time points (16 and 32 days atfter pollination (DAP).
Project description:Plant pathogenic bacteria disseminate and survive through transmission to and by seeds of hosts and non-hosts plants. To investigate the interaction between xanthomonads and developing seeds of Medicago truncatula, plants at the M-oM-,M-^Bower bud stage were spray inoculated until runoff with xanthomonads suspensions. Using the Medicago NimbleGen chip, a transcriptomic analysis was performed on seeds to characterize the molecular dialogue between Xanthomonas campestris pv. campestris in an incompatible situation with M. truncatula seeds and Xanthomonas alfalfae pv. alfalfae in a compatible situation at two developmental time points (16 and 32 days atfter pollination (DAP). Six-condition experiment, 16dap_Mock versus 16dap_Xaa, 16dap_Mock versus 16dap_Xcc, 32dap_Mock versus 32dap_Xaa, 32dap_Mock versus 32dap_Xcc. Biological replicates: 6 controls (16dap_Mock, 32dap_Mock), 12 treatments (16dap_Xaa, 16dap_Xcc, 32dap_Xaa, 32dap_Xcc), independently grown and harvested. One replicate per array.
Project description:Vibrio cholerae is highly motile by the action of a single polar flagellum. The loss of motility reduces the infectivity of V. cholerae, demonstrating that motility is an important virulence factor. FlrC is the sigma-54-dependent positive regulator of flagellar genes. Recently, the genes VC2206 (flgP) and VC2207 (flgO) were identified as being regulated by FlrC by microarray analysis of an flrC mutant. FlgP is reported to be an outer membrane lipoprotein required for motility that functions as a colonization factor. The study reported here focuses on the characterization of flgO, the first gene in the flgOP operon. We show FlgO/P are important for motility, as these mutants have reduced motility phenotypes. The flgO/P mutant populations display fewer motile cells as well as reduced numbers of flagellated cells. The flagella produced by the flgO/P mutant strains are shorter in length than the WT flagella, which can be restored by inhibiting rotation of the flagellum. FlgO is an outer membrane protein that localizes throughout the membrane and not at the flagellar pole. Although FlgO/P do not specifically localize to the flagellum, they are required for flagellar stability. Due to the nature of these motility defects, we established that the flagellum is not sufficient for adherence, rather, motility is the essential factor required for attachment and thus colonization by V. cholerae O1 of the classical biotype. This study reveals a novel mechanism for which the OMPs FlgO and FlgP function in motility to mediate flagellar stability and influence attachment and colonization. Vibrio cholerae O395 vs. rpoN mutant
Project description:Vibrio cholerae is highly motile by the action of a single polar flagellum. The loss of motility reduces the infectivity of V. cholerae, demonstrating that motility is an important virulence factor. FlrC is the sigma-54-dependent positive regulator of flagellar genes. Recently, the genes VC2206 (flgP) and VC2207 (flgO) were identified as being regulated by FlrC by microarray analysis of an flrC mutant. FlgP is reported to be an outer membrane lipoprotein required for motility that functions as a colonization factor. The study reported here focuses on the characterization of flgO, the first gene in the flgOP operon. We show FlgO/P are important for motility, as these mutants have reduced motility phenotypes. The flgO/P mutant populations display fewer motile cells as well as reduced numbers of flagellated cells. The flagella produced by the flgO/P mutant strains are shorter in length than the WT flagella, which can be restored by inhibiting rotation of the flagellum. FlgO is an outer membrane protein that localizes throughout the membrane and not at the flagellar pole. Although FlgO/P do not specifically localize to the flagellum, they are required for flagellar stability. Due to the nature of these motility defects, we established that the flagellum is not sufficient for adherence, rather, motility is the essential factor required for attachment and thus colonization by V. cholerae O1 of the classical biotype. This study reveals a novel mechanism for which the OMPs FlgO and FlgP function in motility to mediate flagellar stability and influence attachment and colonization.
Project description:Vibrio campbellii is a gram-negative bacterial pathogen that is both free-living and a pathogen of marine organisms and exhibits swimming motility via a single, polar flagellum. Swimming motility is a critical virulence factor in V. campbellii pathogenesis, and disruption of the flagellar motor significantly decreases host mortality. However, while V. campbelli encodes homologs of flagellar and chemotaxis genes conserved by other members of the Vibrionaceae, the regulatory network governing these genes have not been explored. We systematically deleted all 63 known flagellar and chemotaxis genes in V. campbellii and examined their effects on motility compared to their homologs in other Vibrios. We specifically focused on assessing the roles of the core flagellar regulators of the flagellar regulatory hierarchy established in other Vibrios: rpoN, flrA, flrC, and fliA. Although V. campbellii transcription of flagellar and chemotaxis genes is governed by a multi-tiered regulatory hierarchy similar to other Vibrios, we observed two critical differences: the σ54-dependent regulator FlrA is dispensable for motility, and Class II gene expression is independent of σ54 regulation. Our genetic and phenotypic dissection of the V. campbellii flagellar regulatory network highlights the differences that have evolved in flagellar regulation across the Vibrionaceae.
Project description:Transcription profiling of Citrus sinensis leaves following Xanthomonas citri subsp. citri wild type and LOV mutant treatment.<br><br>Samples taken 24 h after treatments were compared.
Project description:The flagellar motor is a powerful macromolecular machine used to propel bacteria through various environments. Flagellar motility of the alpha-proteobacterium Sinorhizobium meliloti is nearly abolished in the absence of the transcriptional regulator LdtR, which is involved in peptidoglycan remodeling. We report that LdtR does not regulate motility gene transcription. Remarkably, the motility defects of the DldtR mutant can be restored by secondary mutations in the motility gene motA or a previously uncharacterized gene in the flagellar regulon, which we named motS. MotS is not essential for S. meliloti motility and may serve an accessory role in flagellar motor function. Structural modeling predicts that MotS is comprised of an N-terminal transmembrane segment, a long-disordered region, and a conserved β-sandwich domain. The C-terminus of MotS is localized in the periplasm. Genetics-based substitution of MotA with a MotAG12S variant protein also restored the ΔldtR motility defect. The MotAG12S variant causes a local polarity shift at the periphery of the MotAB stator units. We propose that MotS may be required for optimal alignment of stators in wild-type flagellar motors but becomes detrimental in cells with altered peptidoglycan. Similarly, the polarity shift in the stator units composed of MotB/MotAG12S might stabilize its interaction with altered peptidoglycan.
Project description:Common Bacterial Blight (CBB) is a major threat to bean crops caused by Xanthomonas citri pv. fuscans (Xcf). The pathogenicity of Xcf is known to be dependent upon a functional Type 3 Secretion System (T3SS), that allows the injection of numerous Type III Effectors (T3Es) into plant cells. We generated a transcriptomic dataset to compare the response of susceptible and resistant cultivars of Phaseolus vulgaris to the inoculation of the virulent strain Xcf CFBP4885 or its avirulent T3SS-defective hrcV mutant (CFBP13802). This dataset is a valuable resource to investigate the role of T3Es in subverting the cellular functions of bean.