Vesiculation is a process employed by Gram-negative bacteria to release extracellular vesicles (EVs) into the environment. EVs from pathogenic bacteria play functions in host immune modulation, elimination of host defenses, and acquisition of nutrients from the host. Here, we observed EV production of the bacterial speck disease causal agent, Pseudomonas syringae pv. tomato (Pto) DC3000, as outer membrane vesicle release. Mass spectrometry identified 369 proteins enriched in Pto DC3000 EVs. The EV samples contained known immunomodulatory proteins and could induce plant immune responses mediated by bacterial flagellin. Having identified two biomarkers for EV detection, we provide evidence for Pto DC3000 releasing EVs during plant infection. Bioinformatic analysis of the EV-enriched proteins suggests a role for EVs in antibiotic defense and iron acquisition. Thus, our data provide insights into the strategies this pathogen may use to develop in a plant environment. IMPORTANCE The release of extracellular vesicles (EVs) into the environment is ubiquitous among bacteria. Vesiculation has been recognized as an important mechanism of bacterial pathogenesis and human disease but is poorly understood in phytopathogenic bacteria. Our research addresses the role of bacterial EVs in plant infection. In this work, we show that the causal agent of bacterial speck disease, Pseudomonas syringae pv. tomato, produces EVs during plant infection. Our data suggest that EVs may help the bacteria to adapt to environments, e.g., when iron could be limiting such as the plant apoplast, laying the foundation for studying the factors that phytopathogenic bacteria use to thrive in the plant environment.

• Klíčová slova
• Arabidopsis thaliana, EVs, NTA, PTI, Pto DC3000, extracellular vesicles, nanoparticle tracking analysis, pattern-triggered immunity, proteomics,
• MeSH
• bakteriální proteiny metabolismus   MeSH
• extracelulární vezikuly * metabolismus   MeSH
• flagelin metabolismus   MeSH
• lidé MeSH
• nemoci rostlin mikrobiologie   MeSH
• proteomika MeSH
• Pseudomonas syringae genetika   metabolismus   MeSH
• Solanum lycopersicum * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• flagelin MeSH

A total of, 78 Clostridium septicum (CLSE) isolates were screened for genes encoding: α-toxin, flagellin, and resistance to vancomycin (VANg). The isolates were also tested for their ability to form biofilm and their antibiotic susceptibility. All isolates were positive for α-toxin and flagellin genes. However, only 19 isolates (24.3%) showed prevalence for VANg. We observed the strongest capacity to form a biofilm (100%) in isolates from patients with oncologic or septic and febrile diagnoses. This percentage was also very high in patients with colitis and gastrointestinal hemorrhage (72.7%). No less than 43 isolates showed antibiotic resistance, and 21 were multidrug-resistant (MDR). Interestingly, our studies showed a correlation between antibiotic resistance and biofilm formation. A statistically significant difference was observed between biofilm-forming MDR isolates and those with low/no biofilm-forming ability. However, the most impressive observation was the correlation with mortality rate. While the overall mortality rate for CLSE infections was 16.7% (13/78), the mortality rate for patients infected with MDR isolates forming biofilm moderately or strongly reached 38.1% (8/21). This number increased even further when only infections with the biofilm-forming VANg-positive isolates were considered (61.5%; 8/13). Therefore, the ability of a VANg-positive CLSE isolate to form a biofilm has been suggested as a biomarker of poor prognosis.

• Klíčová slova
• Alpha toxin, Clostridium septicum, antibiotic resistance, biofilm, flagellin,
• MeSH
• antibakteriální látky * farmakologie   MeSH
• biofilmy MeSH
• Clostridium septicum * MeSH
• flagelin MeSH
• lidé MeSH
• mnohočetná bakteriální léková rezistence genetika   MeSH
• prognóza MeSH
• vankomycin farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky * MeSH
• flagelin MeSH
• vankomycin MeSH

Flagellin perception is a keystone of pattern-triggered immunity in plants. The recognition of this protein by a plasma membrane (PM) receptor complex is the beginning of a signaling cascade that includes protein phosphorylation and the production of reactive oxygen species (ROS). In both Arabidopsis (Arabidopsis thaliana) seedlings and suspension cells, we found that treatment with flg22, a peptide corresponding to the most conserved domain of bacterial flagellin, caused a rapid and transient decrease in the level of phosphatidylinositol (PI) 4,5-bisphosphate along with a parallel increase in phosphatidic acid (PA). In suspension cells, inhibitors of either phosphoinositide-dependent phospholipases C (PLC) or diacylglycerol kinases (DGKs) inhibited flg22-triggered PA production and the oxidative burst. In response to flg22, receptor-like kinase-deficient fls2, bak1, and bik1 mutants (FLAGELLIN SENSITIVE 2, BRASSINOSTEROID INSENSITIVE 1-associated kinase 1, and BOTRYTIS-INDUCED KINASE 1, respectively) produced less PA than wild-type (WT) plants, whereas this response did not differ in NADPH oxidase-deficient rbohD (RESPIRATORY BURST OXIDASE HOMOLOG D) plants. Among the DGK-deficient lines tested, the dgk5.1 mutant produced less PA and less ROS after flg22 treatment compared with WT seedlings. In response to flg22, dgk5.1 plants showed lower callose accumulation and impaired resistance to Pseudomonas syringae pv. tomato DC3000 hrcC-. Transcriptomics revealed that the basal expression of defense-related genes was altered in dgk5.1 seedlings compared with the WT. A GFP-DGK5 fusion protein localized to the PM, where RBOHD and PLC2 (proteins involved in plant immunity) are also located. The role of DGK5 and its enzymatic activity in flagellin signaling and fine-tuning of early immune responses in plant-microbe interactions is discussed.

• MeSH
• Arabidopsis * metabolismus   MeSH
• diacylglycerolkinasa genetika   metabolismus   MeSH
• flagelin farmakologie   genetika   MeSH
• imunita rostlin MeSH
• protein-serin-threoninkinasy MeSH
• proteiny huseníčku * genetika   metabolismus   MeSH
• Pseudomonas syringae fyziologie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BIK1 protein, Arabidopsis MeSH Prohlížeč
• diacylglycerolkinasa MeSH
• flagelin MeSH
• protein-serin-threoninkinasy MeSH
• proteiny huseníčku * MeSH
• reaktivní formy kyslíku MeSH

OBJECTIVE: The motility and genotype of the flagellin fliC and fliD genes were investigated in 82 Clostridioides difficile isolates belonging to the ribotypes (RTs): 027 (n = 41), 176 (n = 17), 023 (n = 8), 017 (n = 6) and 046 (n = 10). The reference C. difficile strains 630 and M120 were included as controls for the motility assay. METHODS: A Multiple Locus Variable-number Tandem Repeat Analysis (MLVA) was used to exclude the genetic relatedness of C. difficile isolates belonging to the same RT. The variability of the fliC and fliD genes was determined by PCR-restriction fragment length polymorphism (RFLP) analysis and Sanger sequencing. The motility assay was carried out with 0.175% BHI agar tubes and BHI solid media plates with 0.4% agar. RESULTS: The highest motility was observed in C. difficile RT023 isolates (p < 0.01), followed by RTs 027 and 176. C. difficile isolates of RTs 017 and 046 were less motile than RTs 027, 176 and 023 (p < 0.01). The fliC and fliD genes were present in all clinical isolates irrespective of the motility results. In the fliC gene analysis, four different RFLP groups were identified (I, II, VII, X). The fliC group VII was identified in two RTs (027 and 176), whereas the remaining three groups (I, II and X) belonged to a single RT 046, 017 and 023, respectively. The fliD gene analysis identified four new RFLP groups (a, b, c and d). CONCLUSIONS: C. difficile RT023 is highly motile and its motility is comparable to the hypervirulent RT027 and its genetic relative RT176.

• Klíčová slova
• Clonal complex, Clostridioides difficile, Hypervirulence, Motility, RFLP patterns, fliC and fliD genes,
• MeSH
• bakteriální proteiny genetika   MeSH
• Clostridioides difficile * genetika   MeSH
• Clostridioides MeSH
• flagelin genetika   MeSH
• genotyp MeSH
• klostridiové infekce * MeSH
• lidé MeSH
• ribotypizace MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální proteiny MeSH
• flagelin MeSH

Recognition of pathogen-associated molecular patterns (PAMPs) is crucial for plant defence against pathogen attack. The best characterized PAMP is flg22, a 22 amino acid conserved peptide from flagellin protein. In Arabidopsis thaliana, flg22 is recognized by the flagellin sensing 2 (FLS2) receptor. In this study, we focused on biotic stress responses triggered by flg22 after exposure to temporary heat stress (HS). It is important to study the reactions of plants to multiple stress conditions because plants are often exposed simultaneously to a combination of both abiotic and biotic stresses. Transient early production of reactive oxygen species (ROS) is a well-characterized response to PAMP recognition. We demonstrate the strong reduction of flg22-induced ROS production in A. thaliana after HS treatment. In addition, a decrease in FLS2 transcription and a decrease of the FLS2 presence at the plasma membrane are shown after HS. In summary, our data show the strong inhibitory effect of HS on flg22-triggered events in A. thaliana. Subsequently, temporary HS strongly decreases the resistance of A. thaliana to Pseudomonas syringae. We propose that short exposure to high temperature is a crucial abiotic stress factor that suppresses PAMP-triggered immunity, which subsequently leads to the higher susceptibility of plants to pathogens.

• Klíčová slova
• Arabidopsis thaliana, Pseudomonas syringae, PAMP-triggered immunity, flagellin sensing 2 receptor, flg22, heat stress, reactive oxygen species,
• MeSH
• alarminy metabolismus   MeSH
• Arabidopsis účinky léků   genetika   imunologie   mikrobiologie   MeSH
• flagelin farmakologie   MeSH
• genetická transkripce účinky léků   MeSH
• imunita rostlin * účinky léků   MeSH
• nemoci rostlin imunologie   mikrobiologie   MeSH
• odolnost vůči nemocem imunologie   MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• Pseudomonas syringae účinky léků   fyziologie   MeSH
• reakce na tepelný šok * účinky léků   MeSH
• regulace genové exprese u rostlin účinky léků   MeSH
• respirační vzplanutí účinky léků   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alarminy MeSH
• flagelin MeSH
• proteiny huseníčku MeSH

Turkeys and broilers have been identified as important reservoirs for Campylobacter jejuni which is of public health significance. The evaluation of the genotypes among C. jejuni strains within different reservoirs is critical for our understanding of the epidemiology of this infectious agent. The present study aimed to compare the genetic diversity and differences of C. jejuni isolates from turkeys and broilers using flagellin PCR-RFLP typing (flaA typing) technique, in terms of the ease of use and discriminatory power. Sixty C. jejuni isolates were detected biochemically and confirmed by duplex-PCR from turkeys and broilers (30 strains from each bird species). Then, a flaA gene fragment (1725 bp) of C. jejuni isolates was amplified and amplicons were digested with HpyF3I enzyme. Restriction analysis by HpyF3I gave four different flaA patterns (H1, H2, H3, H4) among all tested C. jejuni isolates. In broiler isolates, all four patterns were observed but in turkey isolates, only H2 and H4 patterns were present. The results clearly demonstrated that distribution of the flaA typing patterns differed depending on the host species (broiler/turkey). H1 and H3 flaA types are more prevalent in broiler than turkey isolates, while H2 type is significantly more prevalent within isolates from turkey (p < 0.05). The flaA typing technique by digestion with HpyF3I enzyme can almost give us a clue to the source of infection in local outbreaks.

• MeSH
• Campylobacter jejuni klasifikace   genetika   MeSH
• DNA bakterií genetika   MeSH
• flagelin genetika   MeSH
• genetická variace MeSH
• kampylobakterové infekce mikrobiologie   veterinární   MeSH
• krocani MeSH
• kur domácí MeSH
• nemoci drůbeže mikrobiologie   MeSH
• restrikční mapování veterinární   MeSH
• techniky typizace bakterií veterinární   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• DNA bakterií MeSH
• flaA protein, bacteria MeSH Prohlížeč
• flagelin MeSH

Proinflammatory cytokines play important roles in the pathogenesis of diseases caused by enterohemorrhagic Escherichia coli (EHEC) O157, but the spectrum of bacterial components involved in the proinflammatory responses is not fully understood. Here, we investigated the abilities of outer membrane vesicles (OMVs), nanoparticles released by EHEC O157 during growth, to induce production of proinflammatory cytokines in human intestinal epithelial cells. OMVs from both EHEC O157:H7 and sorbitol-fermenting (SF) EHEC O157:H- induced production of interleukin-8 (IL-8) in Caco-2, HCT-8, and HT-29 intestinal epithelial cell lines. H7 flagellin was the key IL-8-inducing component of EHEC O157:H7 OMVs, whereas cytolethal distending toxin V and O157 lipopolysaccharide (LPS) largely contributed to IL-8 production elicited by flagellin-lacking OMVs from SF EHEC O157:H-. The H7 flagellin-mediated signaling via Toll-like receptor (TLR) 5, and O157 LPS-mediated signaling via TLR4/MD-2 complex, which were followed by activation of the nuclear factor NF-κB were major pathways underlying IL-8 production induced by EHEC O157 OMVs. The proinflammatory and immunomodulatory capacities of EHEC O157 OMVs have pathogenetic implications and support the OMVs as suitable vaccine candidates.

• Klíčová slova
• Enterohemorrhagic Escherichia coli O157, Flagellin, Immunomodulation, Lipopolysaccharide, Outer membrane vesicles, Proinflammatory cytokines,
• MeSH
• buněčná membrána metabolismus   MeSH
• buňky HT-29 MeSH
• Caco-2 buňky MeSH
• epitelové buňky metabolismus   MeSH
• Escherichia coli O157 patogenita   MeSH
• faktory virulence metabolismus   MeSH
• flagelin metabolismus   MeSH
• infekce vyvolané Escherichia coli mikrobiologie   patologie   MeSH
• interleukin-8 biosyntéza   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• NF-kappa B metabolismus   MeSH
• proteiny vnější bakteriální membrány metabolismus   MeSH
• proteiny z Escherichia coli metabolismus   MeSH
• signální transdukce MeSH
• střevní sliznice cytologie   mikrobiologie   patologie   MeSH
• toll-like receptor 4 metabolismus   MeSH
• toll-like receptor 5 metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• CXCL8 protein, human MeSH Prohlížeč
• faktory virulence MeSH
• flagelin MeSH
• interleukin-8 MeSH
• NF-kappa B MeSH
• proteiny vnější bakteriální membrány MeSH
• proteiny z Escherichia coli MeSH
• TLR4 protein, human MeSH Prohlížeč
• TLR5 protein, human MeSH Prohlížeč
• toll-like receptor 4 MeSH
• toll-like receptor 5 MeSH

Biogenesis of the plant secondary cell wall involves many important aspects, such as phenolic compound deposition and often silica encrustation. Previously, we demonstrated the importance of the exocyst subunit EXO70H4 for biogenesis of the trichome secondary cell wall, namely for deposition of the autofluorescent and callose-rich cell wall layer. Here, we reveal that EXO70H4-driven cell wall biogenesis is constitutively active in the mature trichome, but also can be activated elsewhere upon pathogen attack, giving this study a broader significance with an overlap into phytopathology. To address the specificity of EXO70H4 among the EXO70 family, we complemented the exo70H4-1 mutant by 18 different Arabidopsis (Arabidopsis thaliana) EXO70 paralogs subcloned under the EXO70H4 promoter. Only EXO70H4 had the capacity to rescue the exo70H4-1 trichome phenotype. Callose deposition phenotype of exo70H4-1 mutant is caused by impaired secretion of PMR4, a callose synthase responsible for the synthesis of callose in the trichome. PMR4 colocalizes with EXO70H4 on plasma membrane microdomains that do not develop in the exo70H4-1 mutant. Using energy-dispersive x-ray microanalysis, we show that both EXO70H4- and PMR4-dependent callose deposition in the trichome are essential for cell wall silicification.

• MeSH
• Arabidopsis účinky léků   genetika   metabolismus   MeSH
• buněčná membrána účinky léků   metabolismus   MeSH
• buněčná stěna účinky léků   metabolismus   MeSH
• epidermis rostlin cytologie   účinky léků   metabolismus   MeSH
• fenotyp MeSH
• flagelin farmakologie   MeSH
• glukany MeSH
• glukosyltransferasy metabolismus   MeSH
• mutace genetika   MeSH
• oxid křemičitý metabolismus   MeSH
• podjednotky proteinů chemie   metabolismus   MeSH
• proteinové domény MeSH
• proteiny huseníčku chemie   metabolismus   MeSH
• regulace genové exprese u rostlin účinky léků   MeSH
• trichomy metabolismus   MeSH
• upregulace účinky léků   MeSH
• vezikulární transportní proteiny chemie   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1,3-beta-glucan synthase MeSH Prohlížeč
• callose MeSH Prohlížeč
• EXO70H4 protein, Arabidopsis MeSH Prohlížeč
• flagelin MeSH
• glukany MeSH
• glukosyltransferasy MeSH
• oxid křemičitý MeSH
• PMR4 protein, Arabidopsis MeSH Prohlížeč
• podjednotky proteinů MeSH
• proteiny huseníčku MeSH
• vezikulární transportní proteiny MeSH

Membrane microdomains play vital roles in the process of bacterial infection. The membrane microdomain-associated protein Flot1 acts in an endocytic pathway and is required for seedling development, however, whether Flot1 is a part of host defense mechanisms remains unknown. During an analysis of callose deposition, we found that Flot1 amiRNAi mutants exhibited defects in response to flg22. Using variable-angle total internal reflection fluorescence microscopy (VA-TIRFM), structured illumination microscopy (SIM) and fluorescence cross spectroscopy (FCS), we determined that the dynamic behavior of GFP-Flot1 in Arabidopsis thaliana cotyledon epidermal cells changed significantly in plants treated with the elicitor flg22. Moreover, we found that Flot1 was constitutively recycled via an endocytic pathway and that flg22 could promote endocytosis. Importantly, targeting of Flot1 to the late endosome/vacuole for degradation increased in response to flg22 treatment; immunoblot analysis showed that when triggered by flg22, GFP-Flot1 was gradually degraded in a time-dependent manner. Taken together, these findings support the hypothesis that the changing of dynamics and oligomeric states can promote the endocytosis and degradation of Flot1 under flg22 treatment in plant cells.

• Klíčová slova
• Dynamics, Endocytosis, Flot1, SIM, VA-TIRFM,
• MeSH
• Arabidopsis účinky léků   genetika   metabolismus   MeSH
• endocytóza účinky léků   genetika   fyziologie   MeSH
• flagelin farmakologie   MeSH
• fluorescenční mikroskopie MeSH
• geneticky modifikované rostliny genetika   metabolismus   MeSH
• kotyledon genetika   metabolismus   MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• regulace genové exprese u rostlin účinky léků   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• flagelin MeSH
• proteiny huseníčku MeSH

BACKGROUND: Microbial-associated molecular patterns activate several MAP kinases, which are major regulators of the innate immune response in Arabidopsis thaliana that induce large-scale changes in gene expression. Here, we determine whether microbial-associated molecular pattern-triggered gene expression involves modifications at the chromatin level. RESULTS: Histone acetylation and deacetylation are major regulators of microbial-associated molecular pattern-triggered gene expression and implicate the histone deacetylase HD2B in the reprogramming of defence gene expression and innate immunity. The MAP kinase MPK3 directly interacts with and phosphorylates HD2B, thereby regulating the intra-nuclear compartmentalization and function of the histone deacetylase. CONCLUSIONS: By studying a number of gene loci that undergo microbial-associated molecular pattern-dependent activation or repression, our data reveal a mechanistic model for how protein kinase signaling directly impacts chromatin reprogramming in plant defense.

• MeSH
• Arabidopsis imunologie   MeSH
• chromatin fyziologie   MeSH
• flagelin imunologie   MeSH
• fosforylace MeSH
• fyziologický stres MeSH
• histondeacetylasy metabolismus   MeSH
• histony metabolismus   MeSH
• imunita rostlin * MeSH
• mitogenem aktivované proteinkinasy kinas metabolismus   MeSH
• přirozená imunita MeSH
• proteiny huseníčku metabolismus   MeSH
• restrukturace chromatinu * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• AtMPK3 protein, Arabidopsis MeSH Prohlížeč
• chromatin MeSH
• flagelin MeSH
• histondeacetylasy MeSH
• histony MeSH
• mitogenem aktivované proteinkinasy kinas MeSH
• proteiny huseníčku MeSH