RESUMO
Prochloraz has been used to control Fusarium fujikuroi, the causative pathogen of rice bakanae disease. Linkage analysis of FfCYP51 genes in the progenies obtained from crossing prochloraz moderately resistant and sensitive strains suggested that the FfCYP51B gene is involved in prochloraz resistance. Sequence comparison revealed that the prochloraz-resistant strain had an F511S or S312T/F511S substitution in FfCYP51B compared with the sensitive strains. The contribution of the S312T and F511S substitutions in FfCYP51B to prochloraz resistance was investigated by creating S/F-, T/F-, or T/S- types at 312/511 codons from the S/S-type, which is a natural moderately resistant strain, using a gene-editing technique. T/S exhibited the highest prochloraz resistance, followed by S/S-, T/F-, and S/F-types. These results indicated that the S312T and F511S substitutions in FfCYP51B had a synergistic effect on prochloraz resistance in F. fujikuroi.
Assuntos
Fusarium , Oryza , Substituição de Aminoácidos , Imidazóis/farmacologia , Oryza/genéticaRESUMO
The development of suppressive soil is an ideal strategy to sustainably combat soilborne diseases. Previously, the cultivation of Allium plants increased antagonistic bacteria populations in soil, alleviating Fusarium wilt of different crops. This study aimed to identify a compound produced by Allium plants that can induce bacteria-mediated soil suppressiveness toward Fusarium wilt. The amendment of soils with γ-glutamyl-S-allyl-l-cysteine (GSAC), a unique dipeptide abundantly detected in the root extract of Welsh onion (Allium fistulosum), significantly suppressed Fusarium wilt diseases, whereas three other commercial dipeptides had no such effects. GSAC application did not suppress the disease in sterilized soil. Furthermore, the suppressiveness of soil amended with GSAC could be transferred to sterilized soil via soil microflora transplantation. This suppressiveness was eliminated by pretreating GSAC-amended soil microflora with antibacterial antibiotics, indicating that the suppressiveness of GSAC-amended soil is generated by the activity of antagonistic bacteria. Amplicon sequencing of the 16S rRNA gene revealed that GSAC application significantly increased the relative abundance of Pseudomonas (OTU224), Burkholderia-Caballeronia-Paraburkholderia (OTU387), and Bdellovibrio (OTU1259) in soils. Surprisingly, the relative abundance of OTU224 was significantly greater in Welsh onion rhizospheres than in noncultivated soil. Pseudomonas strains corresponding to OTU224, isolated from Welsh onion rhizospheres, displayed a remarkable suppressive effect against cucumber Fusarium wilt, implying that OTU224 was involved in GSAC-mediated suppressiveness. This is the first study on the potential of GSAC as a soil microflora-manipulating agent that can enhance soil suppressiveness to Fusarium wilt. IMPORTANCE Methods for increasing soil suppressiveness via soil microflora manipulation have long been explored as an ideal strategy to protect plants from soilborne pathogens. However, viable methods offering consistent disease control effects have not yet been developed. Previously, the cultivation of Allium plants was demonstrated to induce bacteria-mediated soil suppressiveness to Fusarium wilt of different crop plants. This study discovered that the application of γ-glutamyl-S-allyl-l-cysteine, a unique dipeptide synthesized by Welsh onion, to soil enhances Fusarium wilt suppressiveness by increasing the relative abundance of indigenous antagonistic bacteria irrespective of the soil type. This finding will facilitate research supporting the development of environmentally friendly control measures for soilborne diseases.
Assuntos
Fusarium , Fusarium/genética , Solo/química , Microbiologia do Solo , Cisteína/farmacologia , RNA Ribossômico 16S/genética , Bactérias/genética , Cebolas , Pseudomonas/genética , Dipeptídeos , Doenças das Plantas/prevenção & controle , Doenças das Plantas/microbiologiaRESUMO
Fusarium fujikuroi is the pathogen of rice bakanae disease and is subclassified into gibberellin and fumonisin groups (G and F groups). Thiophanate-methyl (TM), a benzimidazole fungicide, has been used extensively to control F. fujikuroi. Previous investigation showed that F-group strains are TM sensitive (TMS), whereas most G-group strains are TM resistant (TMR) in Japan. The minimum inhibitory concentration in TMS strains was 1 to 10 µg ml-1, whereas that in TMR strains was >100 µg ml-1. E198K and F200Y mutations in ß2-tubulin were detected in TMR strains. A loop-mediated isothermal amplification-fluorescent loop primer method was developed for diagnosis of these mutations and applied to 37 TMR strains and 56 TMS strains. The results indicated that 100% of TMR strains were identified as having either the E198K mutation (41%) or the F200Y mutation (59%), whereas none of the TMS strains tested showed either mutation. We found one remarkable TMR strain in the F group that had an F200Y mutation. These results suggest that E198K and F200Y mutations in ß2-tubulin contribute to TM resistance in F. fujikuroi.
Assuntos
Fumonisinas , Fusarium , Fusarium/genética , Japão , Tiofanato/farmacologiaRESUMO
Mitsuaria sp. TWR114 is a biocontrol agent against tomato bacterial wilt (TBW). We aimed to gain genomic insights relevant to the biocontrol mechanisms and colonization ability of this strain. The draft genome size was found to be 5,632,523 bp, with a GC content of 69.5%, assembled into 1144 scaffolds. Genome annotation predicted a total of 4675 protein coding sequences (CDSs), 914 pseudogenes, 49 transfer RNAs, 3 noncoding RNAs, and 2 ribosomal RNAs. Genome analysis identified multiple CDSs associated with various pathways for the metabolism and transport of amino acids and carbohydrates, motility and chemotactic capacities, protection against stresses (oxidative, antibiotic, and phage), production of secondary metabolites, peptidases, quorum-quenching enzymes, and indole-3-acetic acid, as well as protein secretion systems and their related appendages. The genome resource will extend our understanding of the genomic features related to TWR114's biocontrol and colonization abilities and facilitate its development as a new biopesticide against TBW.
Assuntos
Agentes de Controle Biológico , Burkholderiales/genética , Genoma Bacteriano , Doenças das Plantas/prevenção & controle , Solanum lycopersicum/microbiologia , Proteínas de Bactérias/genética , Composição de Bases , Agentes de Controle Biológico/metabolismo , Burkholderiales/metabolismo , DNA Bacteriano/química , Genômica , Ácidos Indolacéticos/metabolismo , Doenças das Plantas/microbiologia , Metabolismo Secundário/genética , Estresse FisiológicoRESUMO
Fusarium fujikuroi is a pathogenic fungus that infects rice. It produces several important mycotoxins, such as fumonisins. Fumonisin production has been detected in strains of maize, strawberry, and wheat, whereas it has not been detected in strains from rice seedlings infested with bakanae disease in Japan. We investigated the genetic relationships, pathogenicity, and resistance to a fungicide, thiophanate-methyl (TM), in 51 fumonisin-producing strains and 44 nonproducing strains. Phylogenetic analyses based on amplified fragment length polymorphism (AFLP) markers and two specific genes (a combined sequence of translation elongation factor 1α [TEF1α] and RNA polymerase II second-largest subunit [RPB2]) indicated differential clustering between the fumonisin-producing and -nonproducing strains. One of the AFLP markers, EATMCAY107, was specifically present in the fumonisin-producing strains. A specific single nucleotide polymorphism (SNP) between the fumonisin-producing and nonproducing strains was also detected in RPB2, in addition to an SNP previously found in TEF1α. Gibberellin production was higher in the nonproducing than in the producing strains according to an in vitro assay, and the nonproducing strains had the strongest pathogenicity with regard to rice seedlings. TM resistance was closely correlated with the cluster of fumonisin-nonproducing strains. The results indicate that intraspecific evolution in Japanese F. fujikuroi is associated with fumonisin production and pathogenicity. Two subgroups of Japanese F. fujikuroi, designated G group and F group, were distinguished based on phylogenetic differences and the high production of gibberellin and fumonisin, respectively.IMPORTANCEFusarium fujikuroi is a pathogenic fungus that causes rice bakanae disease. Historically, this pathogen has been known as Fusarium moniliforme, along with many other species based on a broad species concept. Gibberellin, which is currently known as a plant hormone, is a virulence factor of F. fujikuroi Fumonisin is a carcinogenic mycotoxin posing a serious threat to food and feed safety. Although it has been confirmed that F. fujikuroi produces gibberellin and fumonisin, production varies among strains, and individual production has been obscured by the traditional appellation of F. moniliforme, difficulties in species identification, and variation in the assays used to determine the production of these secondary metabolites. In this study, we discovered two phylogenetic subgroups associated with fumonisin and gibberellin production in Japanese F. fujikuroi.
Assuntos
Farmacorresistência Fúngica/genética , Fumonisinas/metabolismo , Fungicidas Industriais/farmacologia , Fusarium/genética , Giberelinas/metabolismo , Polimorfismo Genético , Tiofanato/farmacologia , Fusarium/efeitos dos fármacos , Fusarium/patogenicidade , Japão , Oryza/microbiologia , Doenças das Plantas/microbiologia , VirulênciaRESUMO
Exploration of rhizobacteria of the genus Burkholderia as an under-tapped resource of bioactive molecules resulted in the isolation of two new antimicrobial 2-alkyl-4-quinolones. (E)-2-(Hept-2-en-1-yl)quinolin-4(1H)-one (1) and (E)-2-(non-2-en-1-yl)quinolin-4(1H)-one (3) were isolated from the culture broth of strain MBAF1239 together with four known alkylquinolones (2 and 4-6), pyrrolnitrin (7), and BN-227 (8). The structures of 1 and 3 were unambiguously characterized using NMR spectroscopy and mass spectrometry. Compounds 1-8 inhibited the growth of the marine bacterium Tenacibaculum maritimum, an etiological agent of skin ulcers in marine fish, offering new opportunities to develop antibacterial drugs for fish farming.
RESUMO
Low molecular weight heparin (LMWH)/protamine (P) nano/micro particles (N/MPs) (LMWH/P N/MPs) were applied as carriers for heparin-binding growth factors (GFs) and for adhesive cells including adipose-derived stromal cells (ADSCs) and bone marrow-derived mesenchymal stem cells (BMSCs). A mixture of LMWH and P yields a dispersion of N/MPs (100 nm-3 µm in diameter). LMWH/P N/MPs can be immobilized onto cell surfaces or extracellular matrix, control the release, activate GFs and protect various GFs. Furthermore, LMWH/P N/MPs can also bind to adhesive cell surfaces, inducing cells and LMWH/P N/MPs-aggregate formation. Those aggregates substantially promoted cellular viability, and induced vascularization and fibrous tissue formation in vivo. The LMWH/P N/MPs, in combination with ADSCs or BMSCs, are effective cell-carriers and are potential promising novel therapeutic agents for inducing vascularization and fibrous tissue formation in ischemic disease by transplantation of the ADSCs and LMWH/P N/MPs-aggregates. LMWH/P N/MPs can also bind to tissue culture plates and adsorb exogenous GFs or GFs from those cells. The LMWH/P N/MPs-coated matrix in the presence of GFs may provide novel biomaterials that can control cellular activity such as growth and differentiation. Furthermore, three-dimensional (3D) cultures of cells including ADSCs and BMSCs using plasma-medium gel with LMWH/P N/MPs exhibited efficient cell proliferation. Thus, LMWH/P N/MPs are an adequate carrier both for GFs and for stromal cells such as ADSCs and BMSCs, and are a functional coating matrix for their cultures.
Assuntos
Tecido Adiposo/citologia , Materiais Biocompatíveis/química , Portadores de Fármacos/química , Heparina de Baixo Peso Molecular/química , Peptídeos e Proteínas de Sinalização Intercelular/administração & dosagem , Células-Tronco Mesenquimais/citologia , Protaminas/química , Animais , Células da Medula Óssea/citologia , Técnicas de Cultura de Células/métodos , Proliferação de Células , Sobrevivência Celular , Terapia Baseada em Transplante de Células e Tecidos/métodos , Células Cultivadas , Humanos , Plasma Rico em Plaquetas/química , Ratos , Células Estromais/citologia , Células Estromais/transplante , Engenharia Tecidual/métodosRESUMO
BACKGROUND: Crush syndrome (CS) has been reported in disasters, terrorist incidents, and accidents, and the clinical and pathologic picture has gradually been clarified. Few lethal and reproducible animal models of CS with use of a quantitative load are available. A new model is needed to investigate pathologic and therapeutic aspects of this injury. MATERIALS AND METHODS: Using a device built from commercially available components, both hindlimbs of anesthetized rats were respectively compressed for 6 h using 3.6-kg blocks. The effects of trunk warming alone without compressed hindlimbs (Group A), non-warming at room temperature (Group B), whole-body warming including compressed hindlimbs (Group C), or warming of compressed hindlimbs alone (Group D) during compression were examined. Survival rates were compared and hematological and histologic analyses were performed at specific time points after compression release. RESULTS: Limb or whole-body warming significantly worsened the survival of rats. We found a much lower survival rate of 0%-10% in animals, in which the hindlimbs were warmed during compression (Groups C and D) at 12 h after compression release, compared with 90%-100% in animals without warming of the hindlimbs (Groups A and B). Groups C and D showed significantly enhanced hyperkalemia at ≥4 h after compression release and all blood samples from dead cases showed hyperkalemia (>10 mEq/L). CONCLUSIONS: We developed a new lethal and reproducible rat CS model with a quantitative load. This study found that warming of compressed limbs worsened the survival rate and significantly enhanced hyperkalemia, apparently leading to cardiac arrest.
Assuntos
Síndrome de Esmagamento/etiologia , Modelos Animais de Doenças , Temperatura , Animais , Temperatura Corporal , Síndrome de Esmagamento/sangue , Síndrome de Esmagamento/patologia , Membro Posterior/fisiologia , Masculino , Músculo Esquelético/patologia , Potássio/sangue , Ratos , Ratos Sprague-Dawley , Análise de SobrevidaRESUMO
Streptomyces sp. strain MBCN152-1, isolated from cabbage, has potential as a biocontrol agent for Alternaria brassicicola on cabbage seedlings. The present study examined its mode of action. Light microscopy showed that appressorium formation by A. brassicicola was significantly suppressed on cabbage seedlings bacterized with MBCN152-1. Furthermore, scanning electron microscopy revealed that the mycelia of MBCN152-1, which were epiphytically growing on the cotyledon leaves of cabbage seedlings, intensively coiled around the germinating conidia of A. brassicicola. In vitro co-culture experiments demonstrated that MBCN152-1 is an aggressive mycoparasite of A. brassicicola, but not of A. brassicae or Colletotrichum higginsianum. Biocontrol experiments indicated that MBCN152-1 did not control diseases caused by A. brassicae or C. higginsianum. These results suggest that mycoparasitism is the primary mode of action for MBCN152-1. This is the first study to clearly demonstrate the significance of mycoparasitism in the biocontrol efficacy of endophytic Streptomyces.
Assuntos
Brassica , Streptomyces , Alternaria , Doenças das Plantas/prevenção & controle , PlântulaRESUMO
Members of the Fusarium graminearum species complex (Fg complex) are the primary pathogens that cause Fusarium head blight in wheat and barley. Fg complex members grow poorly on Fusarium oxysporum-selective media, such as Komada and Fo-G2, that have also been used for the isolation of other Fusarium species. Therefore, Komada medium was modified as FG medium for the isolation of Fg complex members. However, the production of pentachloronitrobenzene that is the most effective component of FG medium is discontinued and new media is required for the selective isolation of Fg complex members. In addition, the rapid diagnosis of isolated fungi is useful for the disease control. Novel tools have been developed for isolating and characterizing Fg complex members. FG21, a semi-selective medium for isolating Fg complex members, was developed using potato dextrose agar. Furthermore, a dipstick DNA chromatography assay was developed both to identify Fusarium graminearum sensu stricto and Fusarium asiaticum in the Fg complex and their trichothecene mycotoxin types. The easier isolation and characterization of Fg complex members in Japan was attained by the combined use of FG21 medium and the dipstick DNA chromatography assay.
RESUMO
To identify Lysinibacillus strains with the potential to function as plant biostimulants, we screened 10 previously isolated Lysinibacillus strains from the rhizosphere and soil for their plant growth-promoting (PGP) effects. In vitro tests showed that all strains produced indole-3-acetic acid. In primary screening, the PGP effects of these strains were assessed on spinach seedlings grown on Jiffy-7 pellets; strains GIC31, GIC41, and GIC51 markedly promoted shoot growth. In secondary screening, the PGP efficacies of these three strains were examined using spinach seedlings grown in pots under controlled conditions. Only GIC41 exerted consistent and significant PGP effects; therefore, it was selected for subsequent experiments. The results of 6-week glasshouse experiments revealed that GIC41 markedly increased shoot dry weight by ca. 12-49% over that of the control. The impact of fertilization levels on the PGP efficacy of GIC41 was investigated using pot experiments. The application of a specific level of fertilizer was required for the induction of sufficient PGP effects by this strain. The phylogenetic ana-lysis based on the 16S rDNA sequence identified GIC41 as L. xylanilyticus. Collectively, these results show the potential of strain GIC41 to function as a plant biostimulant.
Assuntos
Bacillaceae , Microbiologia do Solo , Spinacia oleracea/crescimento & desenvolvimento , Bacillaceae/fisiologia , Filogenia , RNA Ribossômico 16S/genética , Rizosfera , Plântula , Spinacia oleracea/microbiologiaRESUMO
BACKGROUND: Induced resistance against several plant pathogens was reported using different beneficial plant growth-promoting microorganisms. The potential of five fungal isolates, Trichoderma harzianum GT 3-2, Fusarium equiseti GF 18-3, F. equiseti GF 19-1, Phoma sp. GS 10-1 and Phoma sp. GS 14-1, to stimulate tomato growth and resistance against bacterial speck disease caused by Pseudomonas syringae pathovar (pv.) tomato DC3000 was evaluated. RESULTS: Based on the results of disease severity and growth promotion experiments, GF 18-3 exhibited the best results among all fungal isolates. Treatment with barley grain inocula (BGI) and culture filtrate (CF) of the isolates promoted tomato growth and suppressed the pathogen in pot trials. Furthermore, expressions of the pathogenesis-related genes (PR-1, ß-1,3-glucanase A, ß-1,3-glucanase B and LOX) were relatively higher than the control in the leaves of tomato plants treated with both BGI and CF. The transcription levels remained consistently higher than the control plants for 6 days post-inoculation with pathogen. CONCLUSION: Taken together, the results indicate that the tested fungal isolates have the potential to promote tomato growth and induce systemic resistance against the bacterial speck disease. Analysis of certain PR gene expression revealed significant activation in both BGI and CF treatments, leading to stimulated resistance against the pathogen. © 2021 Society of Chemical Industry.
Assuntos
Fusarium , Solanum lycopersicum , Fusarium/genética , Hypocreales , Doenças das Plantas , Pseudomonas syringae , RizosferaRESUMO
Cucumber mosaic virus (CMV) is a very serious hazard to vegetable production worldwide. This study is focused on evaluation of resistance stimulated by the plant growth-promoting fungus, Phoma sp. GS8-3, or nanosilica against CMV under pot and field conditions. The specific aim was to illustrate the mechanism of resistance stimulated by GS8-3 against CMV using microarray technology. Treatments with GS8-3 as well as nanosilica significantly decreased CMV severity and titer in tobacco and cucumber under pot and field conditions, respectively. Growth characters of tobacco and cucumber were significantly increased due to GS8-3 inoculation followed by nanosilica compared with control and BTH treatments. Microarray results showed highly upregulation of defense-related genes expression specially those related to heat shock proteins. Therefore, GS8-3 as well as nanosilica is suitable to serve as effective inducers against CMV in cucumber plants.
Assuntos
Ascomicetos , Cucumis sativus , Cucumovirus , Regulação da Expressão Gênica de Plantas , Doenças das Plantas , NicotianaRESUMO
The present study aimed to investigate the potential of simple sugars for use as protection agents in the control of tomato bacterial wilt caused by Ralstonia pseudosolanacearum. Based on the sugar assimilation patterns of the pathogen, four unassimilable sugars (L-arabinose, maltose, D-raffinose, and D-ribose) were selected from 10 representative sugars present in tomato root exudates. These sugars were evaluated for their effects on bacterial wilt using a tomato seedling bioassay. The application of 0.25% L-arabinose significantly reduced disease severity and was, thus, selected as a candidate for further evaluations in a pot experiment under glasshouse conditions. The results obtained showed that the disease suppressive effects of L-arabinose slightly increased at higher concentrations; drench treatments at 0.1, 0.25, and 0.5% reduced disease severity by ca. 48, 70, and 87%, respectively. The drench treatment with 0.5% L-arabinose significantly reduced the pathogen population in the rhizosphere and stem tissues of tomato plants without any antibacterial activity. Real-time reverse-transcription PCR revealed that the expression of salicylic acid-dependent and ethylene-dependent defense genes was significantly enhanced in the stem tissues of L-arabinose-treated tomato plants following the pathogen inoculation. These results suggest that soil drenching with L-arabinose effectively suppresses tomato bacterial wilt by preventing pathogen proliferation in the rhizosphere and stem tissues of tomato plants. This is the first study to report the potential of L-arabinose as a safe, eco-friendly, and cost-effective plant protection agent for the control of tomato bacterial wilt.
Assuntos
Arabinose/farmacologia , Doenças das Plantas/prevenção & controle , Ralstonia/efeitos dos fármacos , Solanum lycopersicum/microbiologia , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia , Ralstonia/crescimento & desenvolvimento , Microbiologia do SoloRESUMO
Anthracnose caused by Glomerella cingulata is one of the most devastating diseases of strawberry in Japan, particularly during its nursery period in the summer. In this study, we aimed to isolate and screen endophytic actinobacteria, to identify potential biocontrol agents capable of suppressing strawberry anthracnose. A total of 226 actinobacteria were successfully isolated from surface-sterilized strawberry tissues. In the first screening, 217 out of 226 actinobacteria isolates were studied for their suppression effect on strawberry anthracnose using a detached leaflet assay. It was discovered that isolates MBFA-172 and MBFA-227 markedly suppressed the development of anthracnose lesions. The efficacy of both isolates was then tested on two-month-old strawberry plug seedlings in a controlled environmental chamber. It was found that isolate MBFA-172 provided consistent disease suppression and was thus selected as a final candidate for further evaluation in a glasshouse experiment. Results showed that the severity as well as incidence rate of strawberry anthracnose was significantly reduced by treatment with isolate MBFA-172 compared with that of untreated control. Accordingly, the disease control efficacy provided by MBFA-172 was statistically comparable to the chemical fungicide propineb. A re-isolation experiment using a spontaneous thiostrepton-resistant mutated strain of isolate MBFA-172 revealed that it efficiently colonized the above-ground tissues of strawberry plants for at least three weeks after spray treatment. Using cultural, morphological, and physiological tests combined with 16S rRNA-based molecular analysis, MBFA-172 was identified as a moderately thermophilic Streptomyces thermocarboxydus-related species. Upon review, our results strongly indicated that MBFA-172 is a promising biocontrol agent for strawberry anthracnose.
RESUMO
The aim of the present study was to identify a strain of endophytic Bacillus species that control tomato bacterial wilt by foliar spray application. Fifty heat-tolerant endophytic bacteria were isolated from the surface-sterilized foliar tissues of symptomless tomato plants that had been pre-inoculated with the pathogen Ralstonia pseudosolanacearum. In the primary screening, we assessed the suppressive effects of a shoot-dipping treatment with bacterial strains against bacterial wilt on tomato seedlings grown on peat pellets. Bacillus sp. strains G1S3 and G4L1 significantly suppressed the incidence of tomato bacterial wilt. In subsequent pot experiments, the biocontrol efficacy of foliar spray application was examined under glasshouse conditions. G4L1 displayed consistent and significant disease suppression, and, thus, was selected as a biocontrol candidate. Moreover, the pathogen population in the stem of G4L1-treated plants was markedly smaller than that in control plants. A quantitative real-time PCR analysis revealed that the foliar spraying of tomato plants with G4L1 up-regulated the expression of PR-1a and LoxD in stem and GluB in roots upon the pathogen inoculation, implying that the induction of salicylic acid-, jasmonic acid-, and ethylene-dependent defenses was involved in the protective effects of this strain. In the re-isolation experiment, G4L1 efficiently colonized foliar tissues for at least 4| |weeks after spray application. Collectively, the present results indicate that G4L1 is a promising biocontrol agent for tomato bacterial wilt. Furthermore, to the best of our knowledge, this is the first study to report the biocontrol of bacterial wilt by the foliar spraying with an endophytic Bacillus species.
Assuntos
Bacillus/fisiologia , Doenças das Plantas/microbiologia , Ralstonia/fisiologia , Solanum lycopersicum/microbiologia , Resistência à Doença , Endófitos/crescimento & desenvolvimento , Endófitos/isolamento & purificação , Endófitos/fisiologia , Solanum lycopersicum/genética , Solanum lycopersicum/imunologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Folhas de Planta/genética , Folhas de Planta/imunologia , Folhas de Planta/microbiologia , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologiaRESUMO
There exist two small heat shock proteins (sHsps) in the fission yeast, Schizosaccharomyces pombe (S. pombe), whose expressions are highly induced by heat stress. We have previously expressed, purified, and characterized one of the sHsps, SpHsp16.0. In this study, we examined the other sHsp, SpHsp15.8. It suppressed the thermal aggregation of citrate synthase (CS) from porcine heart and dithiothreitol-induced aggregation of insulin from bovine pancreas with very high efficiency. Almost one SpHsp15.8 subunit was sufficient to protect one protein molecule from aggregation. Like SpHsp16.0, SpHsp15.8 dissociated into small oligomers and then interacted with denatured substrate proteins. SpHsp16.0 exhibited a clear enthalpy change for denaturation occurring over 60 degrees C in differential scanning calorimetry (DSC). However, we could not observe any significant enthalpy change in the DSC of SpHsp15.8. The difference is likely to be caused by the adhesive characteristics of SpHsp15.8. The oligomer dissociation of SpHsp15.8 and SpHsp16.0 and their interactions with denatured substrate proteins were studied by fluorescence polarization analysis (FPA). Both sHsps exhibited a temperature-dependent decrease of fluorescence polarization, which correlates with the dissociation of large oligomers to small oligomers. The dissociation of the SpHsp15.8 oligomer began at about 35 degrees C and proceeded gradually. On the contrary, the SpHsp16.0 oligomer was stable up to approximately 45 degrees C, but then dissociated into small oligomers abruptly at this temperature. Interestingly, SpHsp16.0 is likely to interact with denatured CS in the dissociated state, while SpHsp15.8 is likely to interact with CS in a large complex. These results suggest that S. pombe utilizes two sHsps that function in different manners, probably to cope with a wide range of temperatures and various denatured proteins.
Assuntos
Proteínas de Choque Térmico Pequenas/química , Proteínas de Choque Térmico Pequenas/metabolismo , Proteínas de Choque Térmico/química , Proteínas de Choque Térmico/metabolismo , Proteínas de Schizosaccharomyces pombe/química , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/química , Animais , Varredura Diferencial de Calorimetria , Citrato (si)-Sintase/metabolismo , Polarização de Fluorescência , Regulação Fúngica da Expressão Gênica , Temperatura Alta , Chaperonas Moleculares/metabolismo , Conformação Proteica , Desnaturação Proteica , Schizosaccharomyces/metabolismoRESUMO
Fusarium fujikuroi, a member of the Fusarium fujikuroi species complex, stands out as a rice bakanae disease pathogen with a high production of gibberellic acid. Not all, but some F. fujikuroi strains are known to produce a carcinogenic mycotoxin fumonisin. Fumonisin biosynthesis is dependent on the FUM cluster composed of 16 FUM genes. The FUM cluster was detected not only from a fumonisin producing strain, but also from a fumonisin nonproducing strain that does not produce a detectable level of fumonisin. Genetic mapping indicated the causative mutation(s) of fumonisin nonproduction is present in the FUM cluster of the fumonisin nonproducing strain. Comparative analyses of FUM genes between the fumonisin producing and the nonproducing strains and gene complementation indicated that causative mutation of fumonisin nonproduction is not a single occurrence and the mutations are distributed in FUM21 and FUM7. Our research revealed a natural variation in the FUM cluster involving fumonisin production difference in F. fujikuroi.
Assuntos
Fumonisinas/metabolismo , Fusarium/genética , Fusarium/metabolismo , Expressão Gênica , Família Multigênica , Mutação , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Crop rotation and intercropping with Allium plants suppresses Fusarium wilt in various crops. However, the mechanisms underlying this phenomenon have not been fully elucidated. This study was designed to assess the role of microorganisms inhabiting Allium rhizospheres and antifungal compounds produced by Allium roots in Fusarium wilt suppression by Allium cultivation. Suppression of cucumber Fusarium wilt and the pathogen multiplication by Allium (Welsh onion and/or onion)-cultivated soils were eliminated by heat treatment at 60 °C, whereas those by Welsh onion-root extract were lost at 40 °C. The addition of antibacterial antibiotics eliminated the suppressive effect of Welsh onion-cultivated soil on pathogen multiplication, suggesting the contribution of antagonistic gram-negative bacteria to the soil suppressiveness. The Illumina MiSeq sequencing of 16S rRNA gene amplicons revealed that genus Flavobacterium was the predominant group that preferentially accumulated in Allium rhizospheres. Flavobacterium species recovered from the rhizosphere soils of these Allium plants suppressed Fusarium wilt on cucumber seedlings. Furthermore, confocal laser scanning microscopy revealed that Flavobacterium isolates inhibited the multiplication of the pathogen in soil. Taken together, we infer that the accumulation of antagonistic Flavobacterium species plays a key role in Fusarium wilt suppression by Allium cultivation.
Assuntos
Allium/crescimento & desenvolvimento , Cucumis sativus/crescimento & desenvolvimento , Flavobacterium/crescimento & desenvolvimento , Fusarium/crescimento & desenvolvimento , Doenças das Plantas/prevenção & controle , Allium/microbiologia , Produtos Agrícolas , Cucumis sativus/microbiologia , DNA Ribossômico/genética , Flavobacterium/genética , Flavobacterium/isolamento & purificação , Temperatura Alta , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , RNA Ribossômico 16S/genética , Microbiologia do SoloRESUMO
A 74-year-old woman underwent abdominal echography at a local clinic and a splenic mass was found. She was hospitalized for detailed examinations and treatment. Splenectomy was performed to make a definite diagnosis and for treatment because a definitive diagnosis could not be made, despite various examinations. Histopathological examination revealed that the lesion was infiltrated by polyclonal lymphoid cells and contained proliferating spindle-shaped fibroblasts without any atypical cells, so the splenic mass was diagnosed as an inflammatory pseudotumor. Because some cases of inflammatory pseudotumor can be diagnosed from the clinical course and imaging findings, this possibility should also be considered in the differential diagnosis of a splenic mass.