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1.
Molecules ; 26(15)2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34361545

RESUMO

In this study, using the botanical active component thiochromanone as the lead compound, a total of 32 new thiochromanone derivatives containing a carboxamide moiety were designed and synthesized and their in vitro antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas oryzae pv. oryzicolaby (Xoc), and Xanthomonas axonopodis pv. citri (Xac) were determined, as well as their in vitro antifungal activities against Botryosphaeria dothidea (B. dothidea), Phomopsis sp., and Botrytis cinerea (B. cinerea). Bioassay results demonstrated that some of the target compounds exhibited moderate to good in vitro antibacterial and antifungal activities. In particular, compound 4e revealed excellent in vitro antibacterial activity against Xoo, Xoc, and Xac, and its EC50 values of 15, 19, and 23 µg/mL, respectively, were superior to those of Bismerthiazol and Thiodiazole copper. Meanwhile, compound 3b revealed moderate in vitro antifungal activity against B. dothidea at 50 µg/mL, and the inhibition rate reached 88%, which was even better than that of Pyrimethanil, however, lower than that of Carbendazim. To the best of our knowledge, this is the first report on the antibacterial and antifungal activities of this series of novel thiochromanone derivatives containing a carboxamide moiety.


Assuntos
Botrytis/crescimento & desenvolvimento , Cromanos , Phomopsis/crescimento & desenvolvimento , Xanthomonas axonopodis/crescimento & desenvolvimento , Xanthomonas/crescimento & desenvolvimento , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Cromanos/síntese química , Cromanos/química , Cromanos/farmacologia , Relação Estrutura-Atividade
2.
Int J Mol Sci ; 22(15)2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34360756

RESUMO

This study focuses on a commercial plant elicitor based on chitooligosaccharides (BIG®), which aids in rice plant growth and disease resistance to bacterial leaf blight (BLB). When the pathogen (Xoo) vigorously attacks rice that has suffered yield losses, it can cause damage in up to 20% of the plant. Furthermore, Xoo is a seed-borne pathogen that can survive in rice seeds for an extended period. In this study, when rice seeds were soaked and sprayed with BIG®, there was a significant increase in shoot and root length, as well as plant biomass. Furthermore, BIG®-treated rice plants showed a significant reduction in BLB severity of more than 33%. Synchrotron radiation-based Fourier transform infrared (SR-FTIR) analysis was used to characterize BIG®'s mechanism in the chemical structure of rice leaves. The SR-FTIR results at 1650, 1735, and 1114 cm-1 indicated changes in biochemical components such as pectins, lignins, proteins, and celluloses. These findings demonstrated that commercial BIG® not only increased rice growth but also induced resistance to BLB. The drug's target enzyme, Xoo 1075 from Xanthomonas oryzae (PDB ID: 5CY8), was analyzed for its interactions with polymer ingredients, specifically chitooligosaccharides, to gain molecular insights down to the atomic level. The results are intriguing, with a strong binding of the chitooligosaccharide polymer with the drug target, revealing 10 hydrogen bonds between the protein and polymer. Overall, the computational analysis supported the experimentally demonstrated strong binding of chitooligosaccharides to the drug target.


Assuntos
Quitina/análogos & derivados , Resistência à Doença/efeitos dos fármacos , Oryza/microbiologia , Doenças das Plantas/microbiologia , Xanthomonas/crescimento & desenvolvimento , Quitina/química , Quitina/farmacologia
3.
PLoS Pathog ; 17(8): e1009808, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34398935

RESUMO

Type IV pili (T4P) are thin and flexible filaments found on the surface of a wide range of Gram-negative bacteria that undergo cycles of extension and retraction and participate in a variety of important functions related to lifestyle, defense and pathogenesis. During pilus extensions, the PilB ATPase energizes the polymerization of pilin monomers from the inner membrane. In Xanthomonas citri, two cytosolic proteins, PilZ and the c-di-GMP receptor FimX, are involved in the regulation of T4P biogenesis through interactions with PilB. In vivo fluorescence microscopy studies show that PilB, PilZ and FimX all colocalize to the leading poles of X. citri cells during twitching motility and that this colocalization is dependent on the presence of all three proteins. We demonstrate that full-length PilB, PilZ and FimX can interact to form a stable complex as can PilB N-terminal, PilZ and FimX C-terminal fragments. We present the crystal structures of two binary complexes: i) that of the PilB N-terminal domain, encompassing sub-domains ND0 and ND1, bound to PilZ and ii) PilZ bound to the FimX EAL domain within a larger fragment containing both GGDEF and EAL domains. Evaluation of PilZ interactions with PilB and the FimX EAL domain in these and previously published structures, in conjunction with mutagenesis studies and functional assays, allow us to propose an internally consistent model for the PilB-PilZ-FimX complex and its interactions with the PilM-PilN complex in the context of the inner membrane platform of the X. citri Type IV pilus.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Fímbrias Bacterianas/metabolismo , Oxirredutases/metabolismo , Xanthomonas/metabolismo , Cristalografia por Raios X , Oxirredutases/química , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Virulência , Xanthomonas/crescimento & desenvolvimento
4.
Molecules ; 26(13)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34202405

RESUMO

The bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious rice diseases, causing huge yield losses worldwide. Several technologies and approaches have been opted to reduce the damage; however, these have had limited success. Recently, scientists have been focusing their efforts on developing efficient and environmentally friendly nanobactericides for controlling bacterial diseases in rice fields. In the present study, a scanning electron microscope (SEM), transmission electron microscope (TEM), and a confocal laser scanning microscope (CLSM) were utilized to investigate the mode of actions of ginger EOs on the cell structure of Xoo. The ginger EOs caused the cells to grow abnormally, resulting in an irregular form with hollow layers, whereas the dimethylsulfoxide (DMSO) treatment showed a typical rod shape for the Xoo cell. Ginger EOs restricted the growth and production of biofilms by reducing the number of biofilms generated as indicated by CLSM. Due to the instability, poor solubility, and durability of ginger EOs, a nanoemulsions approach was used, and a glasshouse trial was performed to assess their efficacy on BLB disease control. The in vitro antibacterial activity of the developed nanobactericides was promising at different concentration (50-125 µL/mL) tested. The efficacy was concentration-dependent. There was significant antibacterial activity recorded at higher concentrations. A glasshouse trial revealed that developed nanobactericides managed to suppress BLB disease severity effectively. Treatment at a concentration of 125 µL/mL was the best based on the suppression of disease severity index, AUDPC value, disease reduction (DR), and protection index (PI). Furthermore, findings on plant growth, physiological features, and yield parameters were significantly enhanced compared to the positive control treatment. In conclusion, the results indicated that ginger essential oils loaded-nanoemulsions are a promising alternative to synthetic antibiotics in suppressing Xoo growth, regulating the BLB disease, and enhancing rice yield under a glasshouse trial.


Assuntos
Gengibre/química , Óleos Voláteis , Oryza , Doenças das Plantas/microbiologia , Xanthomonas/crescimento & desenvolvimento , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Oryza/química , Oryza/crescimento & desenvolvimento , Oryza/microbiologia , Oryza/ultraestrutura , Xanthomonas/ultraestrutura
5.
Ecotoxicol Environ Saf ; 220: 112380, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34058676

RESUMO

Silicon (Si) is considered to be a plant growth and development regulator element as well as provide the regulatory response against various biotic stressors. However, the potential mechanism of Si enhancement to regulate plant disease resistance remains to be studied. Therefore, the current study evaluated the effects of Si application on the performance of sugarcane against Xanthomonas albilineans (Xa) infection. Si was applied exogenously (0, 3.85 and 7.70 g Si/kg soil) and the results show that plant height, stem circumference and leaf width of siliconized sugarcane have been improved, which effectively reduced the disease index (0.17-0.21) and incidence (58.2%-69.1%) after Xa infection. Lowest values of MDA (348.5 nmol g-1 FW) and H2O2 (3539.4 mmol/L) were observed in 7.70 g Si/kg soil followed by in 3.85 g Si/kg soil (MDA: 392.6 nmol g-1 FW and H2O2: 3134.6 mmol/L) than that of the control. Whereas, PAL enzyme activity (50.8 mmol/L), JA (230.2 mmol/L) and SA (2.7 ug mL-1) contents were significantly higher in 7.70 g Si/kg soil followed by in 3.85 g Si/kg soil (PAL: 46.3 mmol/L, JA: 182.7 mmol/L and SA: 2.4 ug mL-1) as compared to control. The lower MDA, H2O2 level and higher enzymatic activities were associated with the highest expression levels of their metabolic pathway associated genes i.e., ShMAPK1, ShLOX, ShPAL, ShAOS, ShAOC, ShC4H, ShCAT, Sh4CL and ShNPR1 (22.08, 15.56, 10.42, 3.35, 2.54, 2.14, 1.82, 1.67 and 1.22 folds, respectively) in 7.70 g Si/kg soil as compared to other experimental units and control. Overall, the results of current study indicates that siliconized sugarcane more actively regulates disease resistance through modulation of growth and MDA, H2O2, SA and JA associated metabolic pathways.


Assuntos
Resistência à Doença , Doenças das Plantas/microbiologia , Saccharum/efeitos dos fármacos , Silício/farmacologia , Xanthomonas , Resistência à Doença/genética , Genes de Plantas , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Redes e Vias Metabólicas/genética , Estresse Oxidativo , Doenças das Plantas/genética , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Folhas de Planta , Caules de Planta , Saccharum/crescimento & desenvolvimento , Saccharum/metabolismo , Saccharum/microbiologia , Silício/metabolismo , Solo/química , Estresse Fisiológico , Xanthomonas/crescimento & desenvolvimento
6.
J Biol Chem ; 296: 100653, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33845047

RESUMO

The transcription terminator Rho regulates many physiological processes in bacteria, such as antibiotic sensitivity, DNA repair, RNA remodeling, and so forth, and hence, is a potential antimicrobial target, which is unexplored. The bacteriophage P4 capsid protein, Psu, moonlights as a natural Rho antagonist. Here, we report the design of novel peptides based on the C-terminal region of Psu using phenotypic screening methods. The resultant 38-mer peptides, in addition to containing mutagenized Psu sequences, also contained plasmid sequences, fused to their C termini. Expression of these peptides inhibited the growth of Escherichia coli and specifically inhibited Rho-dependent termination in vivo. Peptides 16 and 33 exhibited the best Rho-inhibitory properties in vivo. Direct high-affinity binding of these two peptides to Rho also inhibited the latter's RNA-dependent ATPase and transcription termination functions in vitro. These two peptides remained functional even if eight to ten amino acids were deleted from their C termini. In silico modeling and genetic and biochemical evidence revealed that these two peptides bind to the primary RNA-binding site of the Rho hexamer near its subunit interfaces. In addition, the gene expression profiles of these peptides and Psu overlapped significantly. These peptides also inhibited the growth of Mycobacteria and inhibited the activities of Rho proteins from Mycobacterium tuberculosis, Xanthomonas, Vibrio cholerae, and Salmonella enterica. Our results showed that these novel anti-Rho peptides mimic the Rho-inhibition function of the ∼42-kDa dimeric bacteriophage P4 capsid protein, Psu. We conclude that these peptides and their C-terminal deletion derivatives could provide a basis on which to design novel antimicrobial peptides.


Assuntos
Proteínas do Capsídeo/farmacologia , Desenho de Fármacos , Proteínas de Escherichia coli/antagonistas & inibidores , Escherichia coli/metabolismo , Mycobacterium tuberculosis/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Regiões Terminadoras Genéticas , Xanthomonas/efeitos dos fármacos , Sequência de Aminoácidos , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Mycobacterium tuberculosis/crescimento & desenvolvimento , Biblioteca de Peptídeos , Plasmídeos , Ligação Proteica , Homologia de Sequência , Xanthomonas/crescimento & desenvolvimento
7.
J Microbiol Methods ; 183: 106173, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33617895

RESUMO

The efficiency of alternative preservation techniques for Xanthomonas arboricola pv pruni was studied. The preservation methods in sunflower seeds, glass beads and sterile soil were suitable for maintaining viability and productive capacity of xanthan pruni.


Assuntos
Técnicas Bacteriológicas/métodos , Preservação Biológica/métodos , Xanthomonas/química , Viabilidade Microbiana , Temperatura , Xanthomonas/crescimento & desenvolvimento
8.
J Sci Food Agric ; 101(6): 2584-2591, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33063337

RESUMO

BACKGROUND: The largest and most profitable market for citrus is the production of fresh fruit. Xanthomonas citri subsp. citri is a Gram-negative plant pathogen and the etiological agent of citrus canker, one of the major threats to citrus production worldwide. In the early stages of infection, X. citri can attach to plant surfaces by means of biofilms. Biofilm is considered an essential virulence factor, which helps tissue colonization in plants. Thus, sanitization of citrus fruit is mandatory in packinghouses before any logistic operation as packing and shipment to the market. The aim of this study was to evaluate electrolysed water (EW) as a sanitizer for the disinfection of citrus fruit in packinghouses. RESULTS: Using a protocol to monitor cell respiration we show that EW, obtained after 8 and 9 min of electrolysis, sufficed to kill X. citri when applied at a concentration of 500 µL mL-1 . Furthermore, microscopy analysis, combined with time-response growth curves, confirmed that EW affects the bacterial cytoplasmatic membrane and it leads to cell death in the first few minutes of contact. Pathogenicity tests using limes to simulate packinghouse treatment showed that EW, produced with 9 min of electrolysis, was a very effective sanitizer capable of eliminating X. citri from contaminated fruit. CONCLUSION: It was possible to conclude that EW is significantly effective as sodium hypochlorite (NaClO) at 200 ppm. Therefore, EW could be an alternative for citrus sanitization in packinghouses. © 2020 Society of Chemical Industry.


Assuntos
Citrus/microbiologia , Desinfetantes/química , Desinfetantes/farmacologia , Desinfecção/métodos , Água/química , Água/farmacologia , Biofilmes/efeitos dos fármacos , Citrus/efeitos dos fármacos , Desinfecção/instrumentação , Eletrólise , Frutas/efeitos dos fármacos , Frutas/microbiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Xanthomonas/efeitos dos fármacos , Xanthomonas/crescimento & desenvolvimento
9.
J Agric Food Chem ; 68(51): 15115-15122, 2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33289556

RESUMO

Three pairs of enantiomeric dibenzo-α-pyrone derivatives (1-3) including two pairs of new racemates (±)-alternaone A (1) and (±)-alternaone B (2) and one new enantiomer (-)-alternatiol (3), together with five known compounds (4-8) were isolated from the fungus Alternaria alternata ZHJG5. Their structures were confirmed by spectroscopic data and single-crystal X-ray diffraction analysis. All enantiomers were separated via chiral high-performance liquid chromatography, with their configurations determined by electronic circular dichroism calculation. Biogenetically, a key epoxy-rearrangement step was proposed for the formation of skeletons in 1-3; (+) 1, (-)-1, and 5 presented moderate antibacterial inhibition on phytopathogenic bacteria Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola. In the antifungal test, compounds 7 and 8 showed a moderate protective effect against Botrytis cinerea in vivo.


Assuntos
Agroquímicos/química , Agroquímicos/farmacologia , Alternaria/química , Pironas/farmacologia , Agroquímicos/metabolismo , Alternaria/metabolismo , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Cristalografia por Raios X , Pironas/química , Estereoisomerismo , Xanthomonas/efeitos dos fármacos , Xanthomonas/crescimento & desenvolvimento
10.
PLoS One ; 15(12): e0243867, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33338036

RESUMO

The causative agent of Asiatic citrus canker, the Gram-negative bacterium Xanthomonas citri subsp. citri (XAC), produces more severe symptoms and attacks a larger number of citric hosts than Xanthomonas fuscans subsp. aurantifolii XauB and XauC, the causative agents of cancrosis, a milder form of the disease. Here we report a comparative proteomic analysis of periplasmic-enriched fractions of XAC and XauB in XAM-M, a pathogenicity- inducing culture medium, for identification of differential proteins. Proteins were resolved by two-dimensional electrophoresis combined with liquid chromatography-mass spectrometry. Among the 12 proteins identified from the 4 unique spots from XAC in XAM-M (p<0.05) were phosphoglucomutase (PGM), enolase, xylose isomerase (XI), transglycosylase, NAD(P)H-dependent glycerol 3-phosphate dehydrogenase, succinyl-CoA synthetase ß subunit, 6-phosphogluconate dehydrogenase, and conserved hypothetical proteins XAC0901 and XAC0223; most of them were not detected as differential for XAC when both bacteria were grown in NB medium, a pathogenicity non-inducing medium. XauB showed a very different profile from XAC in XAM-M, presenting 29 unique spots containing proteins related to a great diversity of metabolic pathways. Preponderant expression of PGM and XI in XAC was validated by Western Blot analysis in the periplasmic-enriched fractions of both bacteria. This work shows remarkable differences between the periplasmic-enriched proteomes of XAC and XauB, bacteria that cause symptoms with distinct degrees of severity during citrus infection. The results suggest that some proteins identified in XAC can have an important role in XAC pathogenicity.


Assuntos
Proteínas de Bactérias/metabolismo , Periplasma/metabolismo , Proteômica , Xanthomonas/patogenicidade , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Carbono/metabolismo , Genes Bacterianos , Anotação de Sequência Molecular , Fosfoglucomutase/metabolismo , Reprodutibilidade dos Testes , Xanthomonas/enzimologia , Xanthomonas/genética , Xanthomonas/crescimento & desenvolvimento
11.
Int J Mol Sci ; 21(22)2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33207795

RESUMO

The Gram-negative bacterium Pseudomonas taiwanensis is a novel bacterium that uses shrimp shell waste as its sole sources of carbon and nitrogen. It is a versatile bacterium with potential for use in biological control, with activities including toxicity toward insects, fungi, and the rice pathogen Xanthomonas oryzae pv.oryzae (Xoo). In this study, the complete 5.08-Mb genome sequence of P. taiwanensis CMS was determined by a combination of NGS/Sanger sequencing and optical mapping. Comparison of optical maps of seven Pseudomonas species showed that P. taiwanensis is most closely related to P. putida KT 2400. We screened a total of 11,646 individual Tn5-transponson tagged strains to identify genes that are involved in the production and regulation of the iron-chelator pyoverdine in P. taiwanensis, which is a key anti-Xoo factor. Our results indicated that the two-component system (TCS) EnvZ/OmpR plays a positive regulatory role in the production of pyoverdine, whereas the sigma factor RpoS functions as a repressor. The knowledge of the molecular basis of the regulation of pyoverdine by P. taiwanensis provided herein will be useful for its development for use in biological control, including as an anti-Xoo agent.


Assuntos
Elementos de DNA Transponíveis , Mutagênese Insercional , Oryza/microbiologia , Doenças das Plantas/microbiologia , Pseudomonas , Controle Biológico de Vetores , Pseudomonas/genética , Pseudomonas/metabolismo , Sequenciamento Completo do Genoma , Xanthomonas/crescimento & desenvolvimento
12.
Lett Appl Microbiol ; 71(4): 420-427, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32628776

RESUMO

The present work intended to evaluate the applicability of photodynamic inactivation (PDI) of Xanthomonas citri subsp. citri with toluidine blue O (TBO), a commercial photosensitizer, as a strategy to control citrus canker. Assays were conducted with cell suspensions and biofilms, constructed either on polypropylene microtubes (in vitro assays) or on the surface of orange leaves (ex vivo assays), in the presence of TBO and under irradiation with artificial white light or natural sunlight. PDI assays using TBO alone caused a maximum 5·8 log10 reduction of X. citri viable cells in suspensions, and a much smaller inactivation (1·5 log10) in biofilms. However, concomitant use of KI potentiated the TBO photosensitization. Biofilms were inactivated down to the detection limit (>6 log10 reduction) with 5·0 µmol l-1 TBO + 10 mmol l-1 KI (in vitro) or 5·0 µmol l-1 TBO + 100 mmol l-1 KI (ex vivo) after artificial white light irradiation. Under natural sunlight, a reduction down to the detection limit of the Miles-Misra method was achieved with 50 µmol l-1 TBO and 100 mmol l-1 KI. PDI has potential to be applied in the control of citrus canker in field conditions although further studies are needed to show that there are no risks to plant physiology or fruit quality. SIGNIFICANCE AND IMPACT OF THE STUDY: Xanthomonas citri subsp. citri is a major cause of disease in citrus orchards. Because of the low efficacy and high environmental toxicity of copper-based treatments, there is growing interest on more sustainable phytosanitary approaches. Photodynamic inactivation (PDI) is being successfully used to control infectious agents and literature reports indicate that it is effective against some fungi and bacteria attacking fruit crops. The results of the present work open the perspective of using a low-cost photosensitizer and sunlight, as energy source, to control of the causative agent of citrus canker.


Assuntos
Citrus/microbiologia , Doenças das Plantas/microbiologia , Xanthomonas/crescimento & desenvolvimento , Xanthomonas/efeitos da radiação , Biofilmes/efeitos da radiação , Luz , Viabilidade Microbiana/efeitos da radiação , Folhas de Planta/microbiologia , Xanthomonas/fisiologia
13.
Lett Appl Microbiol ; 71(4): 330-336, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32506499

RESUMO

The deferred antagonism technique has been utilized for several decades for detecting antibiosis activity. Most protocols require the elimination of antibiotic-producing cells by exposing them to chloroform vapour, UV radiation or filter sterilizing the filtrate steps that require additional time and expense to complete. We provide a modified approach to current soft agar overlay practices, which involves addition of antibiotics to the soft agar overlay to inhibit growth of the producer but not the indicator strain. This technique can be used to reproducibly and efficiently screen for antibiotic production with ease. We demonstrate the effectiveness of this technique with three bacterial systems: inhibition of the bacterial spot of tomato pathogen, Xanthomonas euvesicatoria, by its pathogenic competitor Xanthomonas perforans; and inhibition of the fire blight pathogen, Erwinia amylovora, by Pantoea vagans C9-1 or Pseudomonas fluorescens A506. SIGNIFICANCE AND IMPACT OF THE STUDY: Deferred antagonism assays are used commonly to observe antibiotic production by micro-organisms. Killing or removing the producer cells prior to introduction of the indicator strain is a standard practice but requires additional time and special handling procedures. We evaluated a modification of the assay, where the overlay medium is amended with an antibiotic to which the indicator strain is resistant and the producer strain is sensitive. This modification obviates extra steps to kill the producer strain prior to overlaying with the indicator strain and provides a rapid, consistent and cost-effective method to detect antibiosis.


Assuntos
Antibiose , Erwinia amylovora/fisiologia , Técnicas Microbiológicas/métodos , Pantoea/fisiologia , Pseudomonas fluorescens/fisiologia , Xanthomonas/fisiologia , Lycopersicon esculentum/microbiologia , Doenças das Plantas/microbiologia , Xanthomonas/crescimento & desenvolvimento
14.
PLoS One ; 15(5): e0233301, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32469926

RESUMO

Bacterial spot is a destructive disease of tomato in Florida that prior to the early 1990s was caused by Xanthomonas euvesicatoria. X. perforans was first identified in Florida in 1991 and by 2006 was the only xanthomonad associated with bacterial spot disease in tomato. The ability of an X. perforans strain to outcompete X. euvesicatoria both in vitro and in vivo was at least in part associated with the production of three bacteriocins designated Bcn-A, Bcn-B, and Bcn-C. The objective of this study was to characterize the genetic determinants of these bacteriocins. Bcn-A activity was confined to one locus consisting of five ORFs of which three (ORFA, ORF2 and ORF4) were required for bacteriocin activity. The fifth ORF is predicted to encode an immunity protein to Bcn-A based on in vitro and in vivo assays. The first ORF encodes Bcn-A, a 1,398 amino acid protein, which bioinformatic analysis predicts to be a member of the RHS family of toxins. Based on results of homology modeling, we hypothesize that the amino terminus of Bcn-A interacts with a protein in the outer membrane of X. euvesicatoria. The carboxy terminus of the protein may interact with an as yet unknown protein(s) and puncture the X. euvesicatoria membrane, thereby delivering the accessory proteins into the target and causing cell death. Bcn-A appears to be activated upon secretion based on cell fractionation assays. The other two loci were each shown to be single ORFs encoding Bcn-B and Bcn-C. Both gene products possess homology toward known proteases. Proteinase activity for both Bcn-B and Bcn-C was confirmed using a milk agar assay. Bcn-B is predicted to be an ArgC-like serine protease, which was confirmed by PMSF inhibition of proteolytic activity, whereas Bcn-C has greater than 50% amino acid sequence identity to two zinc metalloproteases.


Assuntos
Proteínas de Bactérias/genética , Bacteriocinas/genética , Loci Gênicos , Lycopersicon esculentum/microbiologia , Doenças das Plantas/microbiologia , Xanthomonas/crescimento & desenvolvimento , Sequência de Aminoácidos , Proteínas de Bactérias/biossíntese , Bacteriocinas/biossíntese , Homologia de Sequência , Xanthomonas/classificação , Xanthomonas/genética , Xanthomonas/metabolismo
15.
BMC Microbiol ; 20(1): 117, 2020 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-32410647

RESUMO

BACKGROUND: Xanthomonas oryzae pv. oryzae (Xoo) can cause destructive bacterial blight in rice. As an antibacterial, resveratrol may inhibit Xoo growth. This study focused on the potential structural-activity relationship of resveratrol and its derivatives against Xoo growth, and 1H-NMR-based metabolomic analysis was applied to investigate the global metabolite changes in Xoo after resveratrol treatment. RESULTS: Resveratrol showed the strongest inhibitory effects on Xoo growth compared with its derivatives, which lacked double bonds (compounds 4-6) or hydroxyls were substituted with methoxyls (compounds 7-9). The IC50 of resveratrol against Xoo growth was 11.67 ± 0.58 µg/mL. Results indicated that the double bond of resveratrol contributed to its inhibitory effects on Xoo growth, and hydroxyls were vital for this inhibition. Interestingly, resveratrol also significantly inhibited Xoo flagellum growth. Based on 1H-NMR global metabolic analysis, a total of 30 Xoo metabolites were identified, the changes in the metabolic profile indicated that resveratrol could cause oxidative stress as well as disturb energy, purine, amino acid, and NAD+ metabolism in Xoo, resulting in the observed inhibitory effects on growth. CONCLUSIONS: This study showed that the double bond of resveratrol contributed to its inhibitory effects on Xoo growth, and hydroxyls were also the important active groups. Resveratrol could cause oxidative stress of Xoo cells, and disturb the metabolism of energy, purine, amino acid and NAD +, thus inhibit Xoo growth.


Assuntos
Antibacterianos/farmacologia , Metabolômica/métodos , Resveratrol/farmacologia , Xanthomonas/crescimento & desenvolvimento , Antibacterianos/química , Concentração Inibidora 50 , Viabilidade Microbiana/efeitos dos fármacos , Oryza/crescimento & desenvolvimento , Oryza/microbiologia , Estresse Oxidativo , Resveratrol/análogos & derivados , Resveratrol/química , Estilbenos/química , Estilbenos/farmacologia , Relação Estrutura-Atividade , Xanthomonas/efeitos dos fármacos , Xanthomonas/metabolismo
16.
J Agric Food Chem ; 68(20): 5641-5647, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32330023

RESUMO

To aid the development of novel antibacterial agents that possess a innovative mechanism of action, we built a series of novel dithiocarbamate-containing 4H-chromen-4-one derivatives. We evaluated the activities of the derivatives against three plant pathogens Xanthomonas oryzae pv oryzae (X. oryzae pv o.), Ralstonia solanacearum (R. solanacearum), and Xanthomonas axonopodis pv citri (X. axonopodis pv c.). The results of the antibacterial bioassay showed that most of the target compounds displayed good inhibitory effects against X. oryzae pv o. and X. axonopodis pv c. Remarkably, compound E6 showed the best in vitro antibacterial activity against X. axonopodis pv c., with an EC50 value of 0.11 µg/mL, which was better than those of thiodiazole copper (59.97 µg/mL) and bismerthiazol (48.93 µg/mL). Compound E14 exhibited the best in vitro antibacterial activity against X. oryzae pv o., with an EC50 value of 1.58 µg/mL, which was better than those of thiodiazole copper (83.04 µg/mL) and bismerthiazol (56.05 µg/mL). Scanning electron microscopy analysis demonstrated that compounds E6 and E14 caused the rupture or deformation of the cell membranes for X. axonopodis pv c. and X. oryzae pv o., respectively. In vivo antibacterial activity test and the defensive enzymes activity test results indicated that the compound E14 could reduce X. oryzae pv o. more effectively than thiodiazole-copper or bismerthiazol.


Assuntos
Antibacterianos/farmacologia , Tiocarbamatos/farmacologia , Antibacterianos/química , Desenho de Fármacos , Testes de Sensibilidade Microbiana , Oryza/microbiologia , Doenças das Plantas/microbiologia , Ralstonia solanacearum/efeitos dos fármacos , Ralstonia solanacearum/crescimento & desenvolvimento , Relação Estrutura-Atividade , Tiocarbamatos/química , Xanthomonas/efeitos dos fármacos , Xanthomonas/crescimento & desenvolvimento
17.
Int J Mol Sci ; 21(4)2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32093321

RESUMO

Fatty acids (FAs) have been implicated in signaling roles in plant defense responses. We previously reported that mutation or RNAi-knockdown (OsSSI2-kd) of the rice OsSSI2 gene, encoding a stearoyl acyl carrier protein FA desaturase (SACPD), remarkably enhanced resistance to blast fungus Magnaporthe oryzae and the leaf-blight bacterium Xanthomonas oryzae pv. oryzae (Xoo). Transcriptomic analysis identified six AAA-ATPase family genes (hereafter OsAAA-ATPase1-6) upregulated in the OsSSI2-kd plants, in addition to other well-known defense-related genes. Here, we report the functional analysis of OsAAA-ATPase1 in rice's defense response to M. oryzae. Recombinant OsAAA-ATPase1 synthesized in Escherichia coli showed ATPase activity. OsAAA-ATPase1 transcription was induced by exogenous treatment with a functional analogue of salicylic acid (SA), benzothiadiazole (BTH), but not by other plant hormones tested. The transcription of OsAAA-ATPase1 was also highly induced in response to M. oryzae infection in an SA-dependent manner, as gene induction was significantly attenuated in a transgenic rice line expressing a bacterial gene (nahG) encoding salicylate hydroxylase. Overexpression of OsAAA-ATPase1 significantly enhanced pathogenesis-related gene expression and the resistance to M. oryzae; conversely, RNAi-mediated suppression of this gene compromised this resistance. These results suggest that OsAAA-APTase1 plays an important role in SA-mediated defense responses against blast fungus M. oryzae.


Assuntos
Adenosina Trifosfatases/metabolismo , Resistência à Doença , Oryza , Doenças das Plantas/microbiologia , Proteínas de Plantas/metabolismo , Ácido Salicílico/metabolismo , Adenosina Trifosfatases/genética , Magnaporthe/crescimento & desenvolvimento , Oryza/enzimologia , Oryza/genética , Oryza/microbiologia , Proteínas de Plantas/genética , Xanthomonas/crescimento & desenvolvimento
18.
Talanta ; 208: 120439, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31816710

RESUMO

Marine Streptomyces is a potential source of novel bioactive natural products in medicine and agriculture. The current discrimination and screening method of Streptomyces isolates is not accurate and time-consuming, and a novel method is necessary. In this study, a protein profiling method based on an ultrahigh resolution 15 T Matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) was established and applied for differentiation and bioactivity screening of marine Streptomyces isolates. To obtain robust protein profiling, the effects of the protein extraction method, the matrix-solvent, the sample deposition mode, and the culture time of isolates on protein profiling were thoroughly studied, the optimal conditions were obtained. To evaluate the performance of the developed MALDI-FTICR MS method, MALDI-time of flight (TOF) MS and 16S rRNA were applied in parallel to analyze 25 marine Streptomyces isolates. We found that the clustering result of MALDI-FTICR MS was more similar to that of 16S rRNA than MALDI-TOF MS. And MALDI-FTICR MS could effectively indicate the antibacterial activity of Streptomyces isolates against three plant pathogenic bacteria including Xanthomonas campestris, Xanthomonas oryzae and Erwinia carotovora. Furthermore, a differential protein/peptide was defined and successfully applied to predict antibacterial activity of blind samples. This study demonstrated that MALDI-FTICR MS has great potential to discriminate and screen complex microorganisms, especially those closely related strains.


Assuntos
Proteínas de Bactérias/metabolismo , Técnicas de Tipagem Bacteriana , Proteômica/métodos , Streptomyces/classificação , Streptomyces/metabolismo , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Proteínas de Bactérias/farmacologia , Análise de Fourier , Pectobacterium/efeitos dos fármacos , Pectobacterium/crescimento & desenvolvimento , RNA Bacteriano , RNA Ribossômico 16S , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Streptomyces/genética , Xanthomonas/efeitos dos fármacos , Xanthomonas/crescimento & desenvolvimento
19.
J Agric Food Chem ; 67(50): 13904-13913, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31765135

RESUMO

A series of N-aryl-pyridine-4-one derivatives were designed and synthesized using maltol and antidesmone as lead compounds, and then their fungicidal/bactericidal activities and possible mechanism of action against Colletotrichum musae were explored. Most of these compounds exhibited significant fungicidal activity in vitro. Especially, compound 23 has more than 90% inhibitory activity against nine plant pathogenic fungi at 50 µg mL-1, which is superior to azoxystrobin. Moreover, an in vivo bioassay also demonstrated that compound 23 exhibited high-efficiency broad-spectrum antifungal activity and can effectively control postharvest diseases of mango. In addition, it was found that compounds 22 and 23 can also effectively control rice bacterial leaf blight in pot experiments, which was even more effective than zhongshengmycin. Preliminary mechanism studies revealed that compound 23 may cause cell membrane and mitochondria destruction. These findings indicate that compound 23 can be used to develop potential agrochemical fungicides and bactericides.


Assuntos
Agroquímicos/química , Agroquímicos/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Agroquímicos/síntese química , Colletotrichum/efeitos dos fármacos , Fungicidas Industriais/síntese química , Mangifera/microbiologia , Estrutura Molecular , Oryza/microbiologia , Doenças das Plantas/microbiologia , Piridinas/química , Piridinas/farmacologia , Rhizoctonia , Relação Estrutura-Atividade , Xanthomonas/efeitos dos fármacos , Xanthomonas/crescimento & desenvolvimento
20.
Electron. j. biotechnol ; 42: 30-41, Nov. 2019. tab, graf, ilus
Artigo em Inglês | LILACS | ID: biblio-1087456

RESUMO

Background: Gene expression analysis via microarray is widely used in phytobacteria to validate differential gene expression associated with virulence or to compare biological profiles of wild type and mutant strains. Here, we employed DNA microarrays to study the early stages of the infection process (24, 72 and 120 h post-inoculation) of Xanthomonas citri subsp. citri (Xac) infecting Citrus sinensis to interrogate the expression profiles of hypothetical genes. Results: Under infective conditions, 446 genes were up- and 306 downregulated. Outstanding among genes upregulated during infection were those involved in synthesizing the Type 3 Secretion System and effectors, xanthan gum and quorum-sensing induction, and flagellum synthesis and regulation. Additionally, 161 hypothetical genes were up- and 100 were downregulated, 49 of which are known to have a significant biological role. To understand hypothetical gene co-regulation or -expression, nine expression profiles including 158 genes were identified during the three infection phases. Of these, 47 hypothetical genes were identified as having expression profiles associated with at least one connected to a gene associated with adaptation and virulence. Conclusions: Expression patterns of six differentially expressed genes were validated by quantitative reverse transcription polymerase chain reaction, thus demonstrating the effectiveness of this tool in global gene expression analysis in Xac.


Assuntos
Xanthomonas/genética , Xanthomonas/patogenicidade , Citrus sinensis/microbiologia , Virulência , Xanthomonas/crescimento & desenvolvimento , Expressão Gênica , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência com Séries de Oligonucleotídeos , Transcriptoma , Sistemas de Secreção Tipo III , Genes Bacterianos
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