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Plant Disease Nov 2022Ohio is one of the top five floriculture producers in the United States, grossing over $200 million annually (NASS 2019). Within the international floriculture trade,...
Ohio is one of the top five floriculture producers in the United States, grossing over $200 million annually (NASS 2019). Within the international floriculture trade, gladiolus cut flowers represent the fifth highest grossing crop (Ahmed et al. 2002). In September 2021, the Ornamental Crops Pathology Lab at the Ohio State University received a gladiolus ( spp.) sample of an unknown cultivar from a home garden in Franklin Co., OH where several plants had failed to grow from planted corms or were stunted and displaying symptoms of disease. Bleached, water-soaked spots with necrotic margins along the flowering stems, stunted flowers with partial necrosis, and necrotic bracts were observed on the submitted sample. Bacterial isolations were performed by surface disinfesting small sections of bract tissue from the border of a lesion by soaking in 10% bleach for 30 sec and rinsing twice in sterile water, macerating the tissue in sterile water, and streaking the suspension on nutrient agar (NA) plates. Plates were incubated at 28°C for 48 hours and the resulting colonies were purified by re-streaking a single colony on NA twice. Bacterial colony morphology on NA presented as cream-colored and shiny with an irregular form and undulate margin. Five tests were performed using one representative isolate to identify the bacterium to the genus level: (1) confirmed levan production, (2) confirmed pectinolytic activity, (3) confirmed ability to grow at 40°C, (4) inability to grow under anaerobic conditions, and (5) a negative oxidase test (Schaad et al. 2000). All test results identified the genus as . To identify to species level, gyrase subunit B () and RNA polymerase subunit D () markers were PCR amplified and sequenced using primers UP1-E/AprU, and 70F2/70R2, respectively (Maeda et al. 2006). NCBI GenBank BLASTn comparison showed that the sequence shared 99.33% identity to the type strain of (CP009323.1), while the sequence showed 99.53% identity (CP009322.1). Sequences were deposited in GenBank under accession numbers ON597852 (gyrB) and ON597853 (rpoD). To confirm pathogenicity, each of two Gladiolus communis 'Mini Elvira' potted plants were inoculated with two bacterial and two control treatments (3 leaves/treatment/plant) as follows: leaf infiltration with 1 mL of either (i) a distilled water-Tween 20 (0.03% v/v) bacterial suspension (10 cfu/mL) or (ii) a sterile water-Tween 20 suspension using a needle-less syringe; foliar spray with either (iii) the bacterial suspension or (iv) water-Tween suspension until run-off. Following inoculation, plants were covered for 24 hours with a plastic bag to increase humidity and favor infection and maintained in a greenhouse at an average temperature of 23°C. After 3 days, water-soaked, necrotic lesions were observed on the inoculated plants regardless of inoculation method, while control leaves remained asymptomatic. To fulfill Koch's postulates, bacteria were re-isolated from the lesions 7 days post-inoculation and confirmed to be identical to the original isolate based on gene sequencing. Bacterial scab of gladiolus was reported in Ohio in the late 1900s as caused by (syn. ; Ellett, 1989). To the best of our knowledge, this report represents the first molecular identification of the causal agent as . In Ohio, the pathogen has also been observed causing slippery skin on onion but not officially reported in the peer-reviewed literature. Additionally, has been reported in other parts of the United States on orchid, corn, and rice (Keith et al. 2005; Lu et al. 2007; Nandakumar et al. 2009). Given the significant role of gladiolus within Ohio's floricultural trade, as well as the ability of this pathogen to infect other regional crops, monitoring of bacterial scab is important for floriculture and field crop growers alike.
PubMed: 36366832
DOI: 10.1094/PDIS-10-22-2309-PDN -
Molecules (Basel, Switzerland) Oct 2023Glutarimide-containing polyketides exhibiting potent antitumor and antimicrobial activities were encoded via conserved module blocks in various strains that favor the...
Glutarimide-containing polyketides exhibiting potent antitumor and antimicrobial activities were encoded via conserved module blocks in various strains that favor the genomic mining of these family compounds. The bioinformatic analysis of the genome of ATCC 10248 showed a silent -AT PKS biosynthetic gene cluster (BGC) on chromosome 2 (Chr2C8), which was predicted to produce new glutarimide-containing derivatives. Then, the silent polyketide synthase gene cluster was successfully activated via in situ promoter insertion and heterologous expression. As a result, seven glutarimide-containing analogs, including five new ones, gladiofungins D-H (-), and two known gladiofungin A/gladiostatin () and (named gladiofungin C), were isolated from the fermentation of the activated mutant. Their structures were elucidated through the analysis of HR-ESI-MS and NMR spectroscopy. The structural diversities of gladiofungins may be due to the degradation of the butenolide group in gladiofungin A () during the fermentation and extraction process. Bioactivity screening showed that and had moderate anti-inflammatory activities. Thus, genome mining combined with promoter engineering and heterologous expression were proved to be effective strategies for the pathway-specific activation of the silent BGCs for the directional discovery of new natural products.
Topics: Burkholderia gladioli; Polyketides; Piperidones; Genomics; Multigene Family
PubMed: 37836780
DOI: 10.3390/molecules28196937 -
Microbiology Spectrum Mar 2023Pathogenic fungi are the main cause of yield loss and postharvest loss of crops. In recent years, some antifungal microorganisms have been exploited and applied to...
Pathogenic fungi are the main cause of yield loss and postharvest loss of crops. In recent years, some antifungal microorganisms have been exploited and applied to prevent and control pathogenic fungi. In this study, an antagonistic bacteria KRS027 isolated from the soil rhizosphere of a healthy cotton plant from an infected field was identified as Burkholderia gladioli by morphological identification, multilocus sequence analysis, and typing (MLSA-MLST) and physiobiochemical examinations. KRS027 showed broad spectrum antifungal activity against various phytopathogenic fungi by secreting soluble and volatile compounds. KRS027 also has the characteristics of plant growth promotion (PGP) including nitrogen fixation, phosphate, and potassium solubilization, production of siderophores, and various enzymes. KRS027 is not only proven safe by inoculation of tobacco leaves and hemolysis test but also could effectively protect tobacco and table grapes against gray mold disease caused by Botrytis cinerea. Furthermore, KRS027 can trigger plant immunity by inducing systemic resistance (ISR) activated by salicylic acid- (SA), jasmonic acid- (JA), and ethylene (ET)-dependent signaling pathways. The extracellular metabolites and volatile organic compounds (VOCs) of KRS027 affected the colony extension and hyphal development by downregulation of melanin biosynthesis and upregulation of vesicle transport, G protein subunit 1, mitochondrial oxidative phosphorylation, disturbance of autophagy process, and degrading the cell wall of B. cinerea. These results demonstrated that B. gladioli KRS027 would likely become a promising biocontrol and biofertilizer agent against fungal diseases, including B. cinerea, and would promote plant growth. Searching the economical, eco-friendly and efficient biological control measures is the key to protecting crops from pathogenic fungi. The species of Burkholderia genus are widespread in the natural environment, of which nonpathogenic members have been reported to have great potential for biological control agents and biofertilizers for agricultural application. Burkholderia gladioli strains, however, need more study and application in the control of pathogenic fungi, plant growth promotion, and induced systemic resistance (ISR). In this study, we found that a B. gladioli strain KRS027 has broad spectrum antifungal activity, especially in suppressing the incidence of gray mold disease caused by Botrytis cinerea, and can stimulate plant immunity response via ISR activated by salicylic acid- (SA), jasmonic acid- (JA), and ethylene (ET)-dependent signaling pathways. These results indicate that B. gladioli KRS027 may be a promising biocontrol and biofertilizer microorganism resource in agricultural applications.
PubMed: 36861984
DOI: 10.1128/spectrum.04805-22 -
Frontiers in Plant Science 2022Several microorganisms in the plant root system, especially in the rhizosphere, have their own compositions and functions. Corm rot is the most severe disease of ,...
INTRODUCTION
Several microorganisms in the plant root system, especially in the rhizosphere, have their own compositions and functions. Corm rot is the most severe disease of , leading to more than 50% mortality in field production.
METHODS
In this study, metagenomic sequencing was used to analyze microbial composition and function in the rhizosphere of for possible microbial antagonists against pathogenic .
RESULTS
The microbial diversity and composition were different in the rhizosphere from different habitats. The diversity index (Simpson index) was significantly lower in the rhizospheric soil from Chongming (Rs_CM) and degenerative rhizospheric soil from Chongming (RsD_CM) than in others. Linear discriminant analysis effect size results showed that differences among habitats were mainly at the order (Burkholderiales, Micrococcales, and Hypocreales) and genus ( and ) levels. Correlation analysis of the relative lesion area of corm rot showed that was the most negatively correlated bacterial genus (ρ = -0.7934, < 0.001), whereas was the most negatively correlated fungal genus (ρ = -0.7047, < 0.001). The relative lesion area result showed that from Qiaocheng had the highest resistance, followed by Xiuzhou and Jiande. groups with high disease resistance had abundant pathogen resistance genes, such as chitinase and β-1,3-glucanase genes, from rhizosphere microorganisms. Further, 13 bacteria and 19 fungi were isolated from rhizosphere soils, and antagonistic activity against pathogenic . was observed on potato dextrose agar medium. corm experiments confirmed that SR38, sp. SR55, SR379, and sp. SR343 displayed biocontrol activity against corm rot disease, with biocontrol efficiency of 20.26%, 31.37%, 39.22%, and 14.38%, respectively.
DISCUSSION
This study uncovers the differences in the microbial community of rhizosphere soil of with different corm rot disease resistance and reveals the role of four rhizospheric microorganisms in providing the host with resistance against corm rot. The obtained biocontrol microorganisms can also be used for application research and field management.
PubMed: 36483959
DOI: 10.3389/fpls.2022.1045147 -
Microbiology and Immunology 2003Burkholderia cocovenenans produces a lethal toxin (Bongkrekic acid) that leads to high fatality in food poisoning cases. However, B. cocovenenans was combined in...
Need to differentiate lethal toxin-producing strains of Burkholderia gladioli, which cause severe food poisoning: description of B. gladioli pathovar cocovenenans and an emended description of B. gladioli.
Burkholderia cocovenenans produces a lethal toxin (Bongkrekic acid) that leads to high fatality in food poisoning cases. However, B. cocovenenans was combined in Burkholderia gladioli in 1999. B. gladioli was originally described as a phytopathogenic bacteria that sometimes causes pneumonia in humans and that acts as an opportunistic pathogen. We thought that it was clinically dangerous to describe these two species without considering their pathogenicities. From our data of 16S rRNA sequence analysis, DNA-DNA hybridization, and fatty acid analysis, we could confirm that B. cocovenenans and B. gladioli should be categorized as a single species. However the species really weaved lethal toxin-producing strains with non-lethal strains. To emphasize that B. gladioli contains two different pathogens, we describe a new pathovar, B. gladioli pathovar cocovenenans, for the lethal toxin-producing strains. We provide characteristics that differentiate this lethal toxin-producing pathovar from other phytopathogenic pathovars within B. gladioli, together with an emended description of B. gladioli.
Topics: Animals; Bacterial Toxins; Bacterial Typing Techniques; Base Composition; Bongkrekic Acid; Burkholderia gladioli; DNA, Bacterial; DNA, Ribosomal; Fatty Acids; Foodborne Diseases; Mice; Molecular Sequence Data; Nucleic Acid Hybridization; Phenotype; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA
PubMed: 14695441
DOI: 10.1111/j.1348-0421.2003.tb03465.x -
Laboratory Animals Apr 2021An otherwise healthy two-month-old female C57BL/6J mouse presented with a left-sided head tilt. Differential diagnoses included idiopathic necrotizing arteritis,...
An otherwise healthy two-month-old female C57BL/6J mouse presented with a left-sided head tilt. Differential diagnoses included idiopathic necrotizing arteritis, bacterial otitis media/interna (, , , and ), encephalitis, an abscess, neoplasia, a congenital malformation and an accidental or iatrogenic head trauma. Magnetic resonance imaging (MRI) revealed a large space-occupying right olfactory lobe intra-axial lesion with severe secondary left-sided subfalcine herniation. Following imaging, the animal was euthanized due to poor prognosis. Histopathologic examination revealed a unilateral, full-thickness bone defect at the base of the cribriform plate and nasal conchae dysplasia, resulting in the herniation of the olfactory bulb into the nasal cavity. There was also a left midline-shift of the frontal cortex and moderate catarrhal sinusitis in the left mandibular sinus. The MRI and histopathologic changes are consistent with a congenital malformation of the nasal cavity and frontal aspect of the skull known as an ethmoidal meningoencephalocele. Encephaloceles are rare abnormalities caused by herniation of contents of the brain through a defect in the skull which occur due to disruption of the neural tube closure at the level anterior neuropore or secondary to trauma, surgical complications, cleft palate or increased intracranial pressure. The etiology is incompletely understood but hypotheses include genetics, vitamin deficiency, teratogens, infectious agents and environmental factors. Ethmoidal encephaloceles have been reported in multiple species including humans but have not been reported previously in mice. There are multiple models for spontaneous and induced craniofacial malformation in mice, but none described for ethmoidal encephaloceles.
Topics: Animals; Diagnosis, Differential; Encephalocele; Ethmoid Bone; Fatal Outcome; Female; Magnetic Resonance Imaging; Meningocele; Mice; Mice, Inbred C57BL
PubMed: 32787540
DOI: 10.1177/0023677220944449 -
Bio-protocol Jan 2018There are some bacteria which can grow and multiply at the cost of living fungal biomass. They can potentially utilize fungi as a source of nutrients to forage over...
There are some bacteria which can grow and multiply at the cost of living fungal biomass. They can potentially utilize fungi as a source of nutrients to forage over them. Such phenomenon is known as bacterial mycophagy, however, its mechanistic insights need to be explored to identify the molecules involved in mycophagy for potential utilization in controlling various fungal diseases. Recently we have demonstrated that a rice-associated bacteria strain NGJ1 exhibits mycophagous ability on several fungi, including , the necrotrophic fungal pathogen causing sheath blight disease in rice. We hereby describe our validated and efficient methods used to study strain NGJ1 interactions. These methodologies would be useful for designing assays to study the confrontation between bacteria and fungi which in turn enable discovery of novel antifungal molecules from such bacteria.
PubMed: 34179243
DOI: 10.21769/BioProtoc.2694 -
Antibiotics (Basel, Switzerland) May 2022Tebipenem-pivoxil hydrobromide, an orally bioavailable carbapenem, is currently in clinical development for the treatment of extended-spectrum β-lactamase- and...
Tebipenem-pivoxil hydrobromide, an orally bioavailable carbapenem, is currently in clinical development for the treatment of extended-spectrum β-lactamase- and AmpC-producing Enterobacterales. Previously, tebipenem was found to possess antimicrobial activity against the biothreat pathogens, and . Thus, herein, tebipenem was evaluated against a panel of 150 curated strains of complex (Bcc) and , pathogens that infect people who are immunocompromised or have cystic fibrosis. Using the provisional susceptibility breakpoint of 0.12 mg/L for tebipenem, 100% of the Bcc and . tested as being provisionally resistant to tebipenem. Bcc and . possess two inducible chromosomal β-lactamases, PenA and AmpC. Using purified PenA1 and AmpC1, model β-lactamases expressed in ATCC 17616, PenA1 was found to slowly hydrolyze tebipenem, while AmpC1 was inhibited by tebipenem with a / value of 1.9 ± 0.1 × 10 Ms. In addition, tebipenem was found to be a weak inducer of expression. The combination of the slow hydrolysis by PenA1 and weak induction of likely compromises the potency of tebipenem against Bcc and . .
PubMed: 35625319
DOI: 10.3390/antibiotics11050674 -
Molecular Microbiology Apr 2023The pentavalent organoarsenical arsinothricin (AST) is a natural product synthesized by the rhizosphere bacterium Burkholderia gladioli GSRB05. AST is a broad-spectrum...
The pentavalent organoarsenical arsinothricin (AST) is a natural product synthesized by the rhizosphere bacterium Burkholderia gladioli GSRB05. AST is a broad-spectrum antibiotic effective against human pathogens such as carbapenem-resistant Enterobacter cloacae. It is a non-proteogenic amino acid and glutamate mimetic that inhibits bacterial glutamine synthetase. The AST biosynthetic pathway is composed of a three-gene cluster, arsQML. ArsL catalyzes synthesis of reduced trivalent hydroxyarsinothricin (R-AST-OH), which is methylated by ArsM to the reduced trivalent form of AST (R-AST). In the culture medium of B. gladioli, both trivalent species appear as the corresponding pentavalent arsenicals, likely due to oxidation in air. ArsQ is an efflux permease that is proposed to transport AST or related species out of the cells, but the chemical nature of the actual transport substrate is unclear. In this study, B. gladioli arsQ was expressed in Escherichia coli and shown to confer resistance to AST and its derivatives. Cells of E. coli accumulate R-AST, and exponentially growing cells expressing arsQ take up less R-AST. The cells exhibit little transport of their pentavalent forms. Transport was independent of cellular energy and appears to be equilibrative. A homology model of ArsQ suggests that Ser320 is in the substrate binding site. A S320A mutant exhibits reduced R-AST-OH transport, suggesting that it plays a role in ArsQ function. The ArsQ permease is proposed to be an energy-independent uniporter responsible for downhill transport of the trivalent form of AST out of cells, which is oxidized extracellularly to the active form of the antibiotic.
Topics: Humans; Membrane Transport Proteins; Anti-Bacterial Agents; Escherichia coli; Arsenicals; Escherichia coli Proteins; Symporters; Biological Transport, Active
PubMed: 36785875
DOI: 10.1111/mmi.15045 -
Nanomaterials (Basel, Switzerland) Mar 2021and are seed-borne rice pathogens that cause bacterial panicle blight (BPB) disease, resulting in huge rice yield losses worldwide. However, the excessive use of...
Bioinspired Green Synthesis of Zinc Oxide Nanoparticles from a Native Strain RNT6: Characterization and Antibacterial Activity against Rice Panicle Blight Pathogens and .
and are seed-borne rice pathogens that cause bacterial panicle blight (BPB) disease, resulting in huge rice yield losses worldwide. However, the excessive use of chemical pesticides in agriculture has led to an increase in environmental toxicity. Microbe-mediated nanoparticles (NPs) have recently gained significant attention owing to their promising application in plant disease control. In the current study, we biologically synthesize zinc oxide nanoparticles (ZnONPs) from a native RNT6 strain, which was taxonomically identified using 16S rRNA gene analysis. The biosynthesis of ZnONPs in the reaction mixture was confirmed by using UV-Vis spectroscopy. Moreover, XRD, FTIR, SEM-EDS, and TEM analysis revealed the functional groups, crystalline nature, and spherical shape of ZnONPs with sizes ranging from 21 to 35 nm, respectively. Biogenic ZnONPs showed significant antibacterial activity at 50 µg mL against and with a 2.83 cm and 2.18 cm zone of inhibition, respectively, while cell numbers (measured by OD) of the two pathogens in broth culture were reduced by 71.2% and 68.1%, respectively. The ultrastructure studies revealed the morphological damage in ZnONPs-treated and cells as compared to the corresponding control. The results of this study revealed that ZnONPs could be considered as promising nanopesticides to control BPB disease in rice.
PubMed: 33808470
DOI: 10.3390/nano11040884