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Fengquan Liu - One of the best experts on this subject based on the ideXlab platform.
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antifungal polycyclic tetramate macrolactam hsaf is a novel oxidative stress modulator in Lysobacter Enzymogenes
Applied and Environmental Microbiology, 2021Co-Authors: Zaichun Zhou, Fengquan LiuAbstract:Polycyclic tetramate macrolactams (PoTeM) are a fast-growing family of antibiotic natural products found in phylogenetically diverse microorganisms. Surprisingly, none of the PoTeM had been investigated for potential physiological functions in their producers. Here, we used HSAF (heat-stable antifungal factor), an antifungal PoTeM from Lysobacter Enzymogenes, as a model to show that PoTeM forms complexes with iron ion, with a K a of 2.71*106 The in vivo and in vitro data showed formation of 2:1 and 3:1 complexes between HSAF and iron ions, which were confirmed by molecular mechanical and quantum mechanical calculations. HSAF protected DNA from degradation in high concentrations of iron and H2O2 or under UV radiation. HSAF mutants of L. Enzymogenes barely survived under oxidative stresses and markedly increased the production of reactive oxygen species (ROS). Exogenous addition of HSAF into the mutants significantly prevented ROS production and rescued the mutants to normal growth under the oxidative stresses. The results reveal that the function of HSAF is to protect the producer microorganism from oxidative damages, rather than as an iron-acquisition siderophore. The characteristic structure of PoTeM, 2,4-pyrrolidinedione-embedded macrolactam, may represent a new iron-chelating scaffold of microbial metabolites. Together, the study demonstrated a previously unrecognized strategy for microorganisms to modulate oxidative damages to the cells.ImportancePolycyclic tetramate macrolactams (PoTeM) are a family of structurally distinct metabolites that have been found in a large number of bacteria. Although PoTeM exhibit diverse therapeutic properties, the physiological function of PoTeM in the producer microorganisms had not been investigated. HSAF from Lysobacter Enzymogenes is an antifungal PoTeM that has been subjected to extensive studies for mechanism of biosynthesis, regulation and the antifungal activity. Using HSAF as a model system, we here showed that the characteristic structure of PoTeM, 2,4-pyrrolidinedione-embedded macrolactam, may represent a new iron-chelating scaffold of microbial metabolites. In L. Enzymogenes, HSAF functions as a small molecule modulator for oxidative damages caused by iron, H2O2 and UV light. Together, the study demonstrated a previously unrecognized strategy for microorganisms to modulate oxidative damages to the cells. HSAF represents the first member of the fast growing PoTeM family of microbial metabolites whose potential biological function has been studied.
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two functional fatty acyl coenzyme a ligases affect free fatty acid metabolism to block biosynthesis of an antifungal antibiotic in Lysobacter Enzymogenes
Applied and Environmental Microbiology, 2020Co-Authors: Rongxian Hou, Guoliang Qian, Haihong Wang, Fengquan LiuAbstract:ABSTRACT In Lysobacter Enzymogenes OH11, RpfB1 and RpfB2 were predicted to encode acyl coenzyme A (CoA) ligases. RpfB1 is located in the Rpf gene cluster. Interestingly, we found an RpfB1 homolog (RpfB2) outside this canonical gene cluster, and nothing is known about its functionality or mechanism. Here, we report that rpfB1 and rpfB2 can functionally replace EcFadD in the Escherichia colifadD mutant JW1794. RpfB activates long-chain fatty acids (n-C16:0 and n-C18:0) for the corresponding fatty acyl-CoA ligase (FCL) activity in vitro, and Glu-361 plays critical roles in the catalytic mechanism of RpfB1 and RpfB2. Deletion of rpfB1 and rpfB2 resulted in significantly increased heat-stable antifungal factor (HSAF) production, and overexpression of rpfB1 or rpfB2 completely suppressed HSAF production. Deletion of rpfB1 and rpfB2 resulted in increased L. Enzymogenes diffusible signaling factor 3 (LeDSF3) synthesis in L. Enzymogenes. Overall, our results showed that changes in intracellular free fatty acid levels significantly altered HSAF production. Our report shows that intracellular free fatty acids are required for HSAF production and that RpfB affects HSAF production via FCL activity. The global transcriptional regulator Clp directly regulated the expression of rpfB1 and rpfB2. In conclusion, these findings reveal new roles of RpfB in antibiotic biosynthesis in L. Enzymogenes. IMPORTANCE Understanding the biosynthetic and regulatory mechanisms of heat-stable antifungal factor (HSAF) could improve the yield in Lysobacter Enzymogenes. Here, we report that RpfB1 and RpfB2 encode acyl coenzyme A (CoA) ligases. Our research shows that RpfB1 and RpfB2 affect free fatty acid metabolism via fatty acyl-CoA ligase (FCL) activity to reduce the substrate for HSAF synthesis and, thereby, block HSAF production in L. Enzymogenes. Furthermore, these findings reveal new roles for the fatty acyl-CoA ligases RpfB1 and RpfB2 in antibiotic biosynthesis in L. Enzymogenes. Importantly, the novelty of this work is the finding that RpfB2 lies outside the Rpf gene cluster and plays a key role in HSAF production, which has not been reported in other diffusible signaling factor (DSF)/Rpf-producing bacteria.
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control of wheat fusarium head blight by heat stable antifungal factor hsaf from Lysobacter Enzymogenes
Plant Disease, 2019Co-Authors: Yangyang Zhao, Guoliang Qian, Fengquan Liu, Chao Cheng, Tianping Jiang, Yun ChenAbstract:Heat-stable antifungal factor (HSAF), which belongs to the polycyclic tetramate macrolactam family, was isolated from Lysobacter Enzymogenes fermentations and exhibited inhibitory activities against a wide range of fungal pathogens. In this study, the antifungal activity of HSAF against Fusarium graminearum in vitro and in vivo was investigated. A total of 50% of mycelial growth of F. graminearum was suppressed with 4.1 μg/ml of HSAF (EC50 value). HSAF treatment resulted in abnormal morphology of the hyphae, such as curling, apical swelling, and depolarized growth. Furthermore, HSAF adequately inhibited conidial germination and conidiation of F. graminearum with an inhibition rate of 100% when 1 and 6 μg/ml of HSAF were applied, respectively. HSAF caused ultrastructural changes of F. graminearum, including cell wall thickening and plasmolysis. Moreover, the application of HSAF significantly controlled Fusarium head blight in wheat caused by F. graminearum in the field. Overall, these results indicate that HSAF has potential for development as a fungicide against F. graminearum.
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signaling specificity in the c di gmp dependent network regulating antibiotic synthesis in Lysobacter
Nucleic Acids Research, 2018Co-Authors: Sen Han, Shanho Chou, Guoliang Qian, Mark Gomelsky, Cuimei Huo, Kohsin Chin, Fengquan LiuAbstract:Enzymes controlling intracellular second messengers in bacteria, such as c-di-GMP, often affect some but not other targets. How such specificity is achieved is understood only partially. Here, we present a novel mechanism that enables specific c-di-GMP-dependent inhibition of the antifungal antibiotic production. Expression of the biosynthesis operon for Heat-Stable Antifungal Factor, HSAF, in Lysobacter Enzymogenes occurs when the transcription activator Clp binds to two upstream sites. At high c-di-GMP levels, Clp binding to the lower-affinity site is compromised, which is sufficient to decrease gene expression. We identified a weak c-di-GMP phosphodiesterase, LchP, that plays a disproportionately high role in HSAF synthesis due to its ability to bind Clp. Further, Clp binding stimulates phosphodiesterase activity of LchP. An observation of a signaling complex formed by a c-di-GMP phosphodiesterase and a c-di-GMP-binding transcription factor lends support to the emerging paradigm that such signaling complexes are common in bacteria, and that bacteria and eukaryotes employ similar solutions to the specificity problem in second messenger-based signaling systems.
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Efficient production of heat-stable antifungal factor through integrating statistical optimization with a two-stage temperature control strategy in Lysobacter Enzymogenes OH11
BMC, 2018Co-Authors: Bao Tang, Cheng Sun, Yancun Zhao, Fengquan LiuAbstract:Abstract Background Heat-stable antifungal factor (HSAF) is a newly identified broad-spectrum antifungal antibiotic from the biocontrol agent Lysobacter Enzymogenes and is regarded as a potential biological pesticide, due to its novel mode of action. However, the production level of HSAF is quite low, and little research has reported on the fermentation process involved, representing huge obstacles for large-scale industrial production. Results Medium capacity, culture temperature, and fermentation time were identified as the most significant factors affecting the production of HSAF and employed for further optimization through statistical methods. Based on the analysis of kinetic parameters at different temperatures, a novel two-stage temperature control strategy was developed to improve HSAF production, in which the temperature was increased to 32 °C during the first 12 h and then switched to 26 °C until the end of fermentation. Using this strategy, the maximum HSAF production reached 440.26 ± 16.14 mg L− 1, increased by 9.93% than that of the best results from single-temperature fermentation. Moreover, the fermentation time was shortened from 58 h to 54 h, resulting in the enhancement of HSAF productivity (17.95%) and yield (9.93%). Conclusions This study provides a simple and efficient method for producing HSAF that could be feasibly applied to the industrial-scale production of HSAF
Guoliang Qian - One of the best experts on this subject based on the ideXlab platform.
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Clp is a “busy” transcription factor in the bacterial warrior, Lysobacter Enzymogenes
'Elsevier BV', 2021Co-Authors: Long Lin, Shanho Chou, Danyu Shen, Guoliang QianAbstract:Cyclic AMP receptor protein (CRP) is a well-characterized group of global transcription factors in bacteria. They are known to regulate numerous cellular processes by binding DNA and/or cAMP (a ligand called bacterial second messenger) to control target gene expression. Gram-negative Lysobacter Enzymogenes is a soilborne, plant-beneficial bacterium without flagella that can fight against filamentous fungi and oomycete. Driven by the type IV pilus (T4P) system, this bacterium moves to nearby pathogens and uses a “mobile-attack” antifungal strategy to kill them via heat-stable antifungal factor (HSAF) and abundant lyases. This strategy is controlled by a unique “busy” transcription factor Clp, which is a CRP-like protein that is inactivated by binding of c-di-GMP, another ubiquitous second messenger of bacteria. In this review, we summarize the current progress in how Clp initiates a “mobile-attack” strategy through a series of previously uncharacterized mechanisms, including binding to DNA in a unique pattern, directly interacting with or responding to various small molecules, and interacting specifically with proteins adopting distinct structure. Together, these characteristics highlight the multifunctional roles of Clp in L. Enzymogenes, a powerful bacterial warrior against fungal pathogens
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a non flagellated biocontrol bacterium employs a pilz pilb complex to provoke twitching motility associated with its predation behavior
Phytopathology Research, 2020Co-Authors: Long Lin, Shanho Chou, Danyu Shen, Sen Han, Mimi Zhou, Alex M Fulano, Guoliang QianAbstract:Lysobacter Enzymogenes OH11 is a non-flagellated, ubiquitous soil bacterium with broad-spectrum antifungal activities. Although lacking flagella, it employs another type of motile behavior, known as twitching motility that is powered by type IV pilus (T4P) to move towards neighboring crop fungal pathogens to kill them as food. At present, little is known about how this non-flagellated bacterium controls twitching motility that is crucial for its predatory lifestyle. Herein, we present a report on how a non-canonical PilZ domain, PilZLe3639, controls such motility in the non-flagellated L. Enzymogenes; it failed to bind with c-di-GMP but seemed to be required for twitching motility. Using bacterial two-hybrid and pull-down approaches, we identified PilBLe0708, one of the PilZLe3639-binding proteins that are essential for the bacterial twitching motility, could serve as an ATPase to supply energy for T4P extension. Through site-mutagenesis approaches, we identified one essential residue of PilZLe3639 that is required for its binding affinity with PilBLe0708 and its regulatory function. Besides, two critical residues within the ATPase catalytic domains of PilBLe0708 were detected to be essential for regulating twitching behavior but not involved in binding with PilZLe3639. Overall, we illustrated that the PilZ-PilB complex formation is indispensable for twitching motility in a non-flagellated bacterium.
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two functional fatty acyl coenzyme a ligases affect free fatty acid metabolism to block biosynthesis of an antifungal antibiotic in Lysobacter Enzymogenes
Applied and Environmental Microbiology, 2020Co-Authors: Rongxian Hou, Guoliang Qian, Haihong Wang, Fengquan LiuAbstract:ABSTRACT In Lysobacter Enzymogenes OH11, RpfB1 and RpfB2 were predicted to encode acyl coenzyme A (CoA) ligases. RpfB1 is located in the Rpf gene cluster. Interestingly, we found an RpfB1 homolog (RpfB2) outside this canonical gene cluster, and nothing is known about its functionality or mechanism. Here, we report that rpfB1 and rpfB2 can functionally replace EcFadD in the Escherichia colifadD mutant JW1794. RpfB activates long-chain fatty acids (n-C16:0 and n-C18:0) for the corresponding fatty acyl-CoA ligase (FCL) activity in vitro, and Glu-361 plays critical roles in the catalytic mechanism of RpfB1 and RpfB2. Deletion of rpfB1 and rpfB2 resulted in significantly increased heat-stable antifungal factor (HSAF) production, and overexpression of rpfB1 or rpfB2 completely suppressed HSAF production. Deletion of rpfB1 and rpfB2 resulted in increased L. Enzymogenes diffusible signaling factor 3 (LeDSF3) synthesis in L. Enzymogenes. Overall, our results showed that changes in intracellular free fatty acid levels significantly altered HSAF production. Our report shows that intracellular free fatty acids are required for HSAF production and that RpfB affects HSAF production via FCL activity. The global transcriptional regulator Clp directly regulated the expression of rpfB1 and rpfB2. In conclusion, these findings reveal new roles of RpfB in antibiotic biosynthesis in L. Enzymogenes. IMPORTANCE Understanding the biosynthetic and regulatory mechanisms of heat-stable antifungal factor (HSAF) could improve the yield in Lysobacter Enzymogenes. Here, we report that RpfB1 and RpfB2 encode acyl coenzyme A (CoA) ligases. Our research shows that RpfB1 and RpfB2 affect free fatty acid metabolism via fatty acyl-CoA ligase (FCL) activity to reduce the substrate for HSAF synthesis and, thereby, block HSAF production in L. Enzymogenes. Furthermore, these findings reveal new roles for the fatty acyl-CoA ligases RpfB1 and RpfB2 in antibiotic biosynthesis in L. Enzymogenes. Importantly, the novelty of this work is the finding that RpfB2 lies outside the Rpf gene cluster and plays a key role in HSAF production, which has not been reported in other diffusible signaling factor (DSF)/Rpf-producing bacteria.
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a yajq lysr like cyclic di gmp dependent system regulating biosynthesis of an antifungal antibiotic in a crop protecting bacterium Lysobacter Enzymogenes
Molecular Plant Pathology, 2020Co-Authors: Sen Han, Shanho Chou, Danyu Shen, Yuchuan Wang, Mark Gomelsky, Yonggui Gao, Guoliang QianAbstract:YajQ, a binding protein of the universal bacterial second messenger cyclic di-GMP (c-di-GMP), affects virulence in several bacterial pathogens, including Xanthomonas campestris. In this bacterium, YajQ interacts with the transcription factor LysR. Upon c-di-GMP binding, the whole c-di-GMP-YajQ-LysR complex is found to dissociate from DNA, resulting in virulence gene regulation. Here, we identify a YajQ-LysR-like system in the bacterial biocontrol agent Lysobacter Enzymogenes OH11 that secretes an antifungal antibiotic, heat-stable antifungal factor (HSAF) against crop fungal pathogens. We show that the YajQ homologue, CdgL (c-di-GMP receptor interacting with LysR) affects expression of the HSAF biosynthesis operon by interacting with the transcription activator LysR. The CdgL-LysR interaction enhances the apparent affinity of LysR to the promoter region upstream of the HSAF biosynthesis operon, which increases operon expression. Unlike the homologues CdgL (YajQ)-LysR system in X. campestris, we show that c-di-GMP binding to CdgL seems to weaken CdgL-LysR interactions and promote the release of CdgL from the LysR-DNA complex, which leads to decreased expression. Together, this study takes the YajQ-LysR-like system from bacterial pathogens to a crop-protecting bacterium that is able to regulate antifungal HSAF biosynthesis via disassembly of the c-di-GMP receptor-transcription activator complex.
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two forms of phosphomannomutase in gammaproteobacteria the overlooked membrane bound form of algc is required for twitching motility of Lysobacter Enzymogenes
Environmental Microbiology, 2019Co-Authors: Guoliang Qian, Shifang Fei, Michael Y GalperinAbstract:Lysobacter Enzymogenes, a member of Xanthomonadaceae, is a promising tool to control crop-destroying fungal pathogens. One of its key antifungal virulence factors is the type IV pili that are required for twitching motility. Transposon mutagenesis of L. Enzymogenes revealed that the production of type IV pili required the presence of the Le2152 gene, which encodes an AlgC-type phosphomannomutase/phosphoglucomutase (PMM). However, in addition to the cytoplasmic PMM domain, the Le2152 gene product contains a ~200-aa N-terminal periplasmic domain that is anchored in the membrane by two transmembrane segments and belongs to the dCache superfamily of periplasmic sensor domains. Sequence analysis identified similar membrane-anchored PMMs, encoded in conserved coaBC-dut-algC gene clusters, in a variety of gammaproteobacteria, either as the sole PMM gene in the entire genome or in addition to the gene encoding the stand-alone enzymatic domain. Previously overlooked N-terminal periplasmic sensor domains were detected in the well-characterized PMMs of Pseudomonas aeruginosa and Xanthomonas campestris, albeit not in the enzymes from Pseudomonas fluorescens, Pseudomonas putida or Azotobacter vinelandii. It appears that after the initial cloning of the enzymatically active soluble part of P. aeruginosa AlgC in 1991, all subsequent studies utilized N-terminally truncated open reading frames. The N-terminal dCache sensor domain of AlgC is predicted to modulate the PMM activity of the cytoplasmic domain in response to as yet unidentified environmental signal(s). AlgC-like membrane-bound PMMs appear to comprise yet another environmental signalling system that regulates the production of type IV pili and potentially other systems in certain gammaproteobacteria.
Donald Y. Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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Transcriptomics of the Rice Blast Fungus Magnaporthe oryzae in Response to the Bacterial Antagonist Lysobacter Enzymogenes Reveals Candidate Fungal Defense Response Genes
2016Co-Authors: Ra M. Mathioni¤a, James A Sweigard, Nrupali Patel, Donald Y. Kobayashi, Kirk J Czymmek, Nicole M. DonofrioAbstract:Plants and animals have evolved a first line of defense response to pathogens called innate or basal immunity. While basal defenses in these organisms are well studied, there is almost a complete lack of understanding of such systems in fungal species, and more specifically, how they are able to detect and mount a defense response upon pathogen attack. Hence, the goal of the present study was to understand how fungi respond to biotic stress by assessing the transcriptional profile of the rice blast pathogen, Magnaporthe oryzae, when challenged with the bacterial antagonist Lysobacter Enzymogenes. Based on microscopic observations of interactions between M. oryzae and wild-type L. Enzymogenes strain C3, we selected early and intermediate stages represented by time-points of 3 and 9 hours post-inoculation, respectively, to evaluate the fungal transcriptome using RNA-seq. For comparative purposes, we also challenged the fungus with L. Enzymogenes mutant strain DCA, previously demonstrated to be devoid of antifungal activity. A comparison of transcriptional data from fungal interactions with the wild-type bacterial strain C3 and the mutant strain DCA revealed 463 fungal genes that were down-regulated during attack by C3; of these genes, 100 were also found to be up-regulated during the interaction with DCA. Functional categorization of genes in this suite included those with roles in carbohydrate metabolism, cellular transport and stress response. On
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use of the tetrazolium salt mtt to measure cell viability effects of the bacterial antagonist Lysobacter Enzymogenes on the filamentous fungus cryphonectria parasitica
Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology, 2013Co-Authors: Nrupali Patel, Peter V. Oudemans, Bradley I. Hillman, Donald Y. KobayashiAbstract:Despite substantial interest investigating bacterial mechanisms of fungal growth inhibition, there are few methods available that quantify fungal cell death during direct interactions with bacteria. Here we describe an in vitro cell suspension assay using the tetrazolium salt MTT as a viability stain to assess direct effects of the bacterial antagonist Lysobacter Enzymogenes on hyphal cells of the filamentous fungus Cryphonectria parasitica. The effects of bacterial cell density, fungal age and the physiological state of fungal mycelia on fungal cell viability were evaluated. As expected, increased bacterial cell density correlated with reduced fungal cell viability over time. Bacterial effects on fungal cell viability were influenced by both age and physiological state of the fungal mycelium. Cells obtained from 1-week-old mycelia lost viability faster compared with those from 2-week-old mycelia. Likewise, hyphal cells obtained from the lower layer of the mycelial pellicle lost viability more quickly compared with cells from the upper layer of the mycelial pellicle. Fungal cell viability was compared between interactions with L. Enzymogenes wildtype strain C3 and a mutant strain, DCA, which was previously demonstrated to lack in vitro antifungal activity. Addition of antibiotics eliminated contributions to MTT-formazan production by bacterial cells, but not by fungal cells, demonstrating that mutant strain DCA had lost complete capacity to reduce fungal cell viability. These results indicate this cell suspension assay can be used to quantify bacterial effects on fungal cells, thus providing a reliable method to differentiate strains during bacterial/fungal interactions.
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the role of clp regulated factors in antagonism against magnaporthe poae and biological control of summer patch disease of kentucky bluegrass by Lysobacter Enzymogenes c3
Canadian Journal of Microbiology, 2005Co-Authors: Donald Y. Kobayashi, Gary Y. YuenAbstract:A global regulator was previously identified in Lysobacter Enzymogenes C3, which when mutated, resulted in strains that were greatly reduced in the expression of traits associated with fungal antagonism and devoid of biocontrol activity towards bipolaris leaf-spot of tall fescue and pythium damping-off of sugarbeet. A clp gene homologue belonging to the crp gene family was found to globally regulate enzyme production, antimicrobial activity, and biological control activity expressed by Lysobacter Enzymogenes C3 (Kobayashi et al. 2005). Here, we report on the expansion of the biocontrol range of L. Enzymogenes C3 to summer patch disease caused by Magnaporthe poae. The clp- mutant strain 5E4 was reduced in its ability to suppress summer patch disease compared with the wild-type strain C3 and was completely devoid of antifungal activity towards M. poae. Furthermore, cell suspensions of 5E4 were incapable of colonizing M. poae mycelium in a manner that was distinct for C3. Strain C3 demonstrated biosurfactant activity in cell suspensions and culture filtrates that was associated with absorption into the mycelium during the colonization process, whereas 5E4 did not. These results describe a novel interaction between bacteria and fungi that intimates a pathogenic relationship.
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mutagenesis of β 1 3 glucanase genes in Lysobacter Enzymogenes strain c3 results in reduced biological control activity toward bipolaris leaf spot of tall fescue and pythium damping off of sugar beet
Phytopathology, 2005Co-Authors: Jeffrey D Palumbo, Gary Y. Yuen, Christine C Jochum, Kristin Tatum, Donald Y. KobayashiAbstract:Palumbo, J. D., Yuen, G. Y., Jochum, C. C., Tatum, K., and Kobayashi, D. Y. 2005. Mutagenesis of β-1,3-glucanase genes in Lysobacter Enzymogenes strain C3 results in reduced biological control activity toward Bipolaris leaf spot of tall fescue and Pythium damping-off of sugar beet. Phytopathology 95:701-707. Lysobacter Enzymogenes produces extracellular lytic enzymes capable of degrading the cell walls of fungi and oomycetes. Many of these enzymes, including β-1,3-glucanases, are thought to contribute to the biological control activity expressed by several strains of the species. L. Enzymogenes strain C3 produces multiple extracellular β-1,3-glucanases encoded by the gluA, gluB, and gluC genes. Analysis of the genes indicates they are homologous to previously characterized genes in the related strain N4-7, each sharing >95% amino acid sequence identity to their respective counterparts. The gluA and gluC gene products encode enzymes belonging to family 16 glycosyl hydrolases, whereas gluB encodes an enzyme belonging to family 64. Mutational analysis indicated that the three genes accounted for the total β-1,3-glucanase activity detected in culture. Strain G123, mutated in all three glucanase genes, was reduced in its ability to grow in a minimal medium containing laminarin as a sole carbon source. Although strain G123 was not affected in antimicrobial activity toward Bipolaris sorokiniana or Pythium ultimum var. ultimum using in vitro assays, it was significantly reduced in biological control activity against Bipolaris leaf spot of tall fescue and Pythium damping-off of sugar beet. These results provide direct supportive evidence for the role of β-1,3-glucanases in biocontrol activity of L. Enzymogenes strain C3.
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a clp gene homologue belonging to the crp gene family globally regulates lytic enzyme production antimicrobial activity and biological control activity expressed by Lysobacter Enzymogenes strain c3
Applied and Environmental Microbiology, 2005Co-Authors: Donald Y. Kobayashi, Jeffrey D Palumbo, Ralph M Reedy, Junma Zhou, Gary Y. YuenAbstract:Lysobacter Enzymogenes strain C3, a biological control agent for plant diseases, produces multiple extracellular hydrolytic enzymes and displays antimicrobial activity against various fungal and oomycetous species. However, little is known about the regulation of these enzymes or their roles in antimicrobial activity and biocontrol. A study was undertaken to identify mutants of strain C3 affected in extracellular enzyme production and to evaluate their biocontrol efficacy. A single mini-Tn5-lacZ1-cat transposon mutant of L. Enzymogenes strain C3 that was globally affected in a variety of phenotypes was isolated. In this mutant, 5E4, the activities of several extracellular lytic enzymes, gliding motility, and in vitro antimicrobial activity were reduced. Characterization of 5E4 indicated that the transposon inserted in a clp gene homologue belonging to the Crp gene family of regulators. Immediately downstream was a second open reading frame similar to that encoding acetyltransferases belonging to the Gcn5-related N-acetyltransferase superfamily, which reverse transcription-PCR confirmed was cotranscribed with clp. Chromosomal deletion mutants with mutations in clp and between clp and the acetyltransferase gene verified the 5E4 mutant phenotype. The clp gene was chromosomally inserted in mutant 5E4, resulting in complemented strain P1. All mutant phenotypes were restored in P1, although the gliding motility was observed to be excessive compared with that of the wild-type strain. clp mutant strains were significantly affected in biological control of pythium damping-off of sugar beet and bipolaris leaf spot of tall fescue, which was partially or fully restored in the complemented strain P1. These results indicate that clp is a global regulatory gene that controls biocontrol traits expressed by L. Enzymogenes C3.
Chiuchung Young - One of the best experts on this subject based on the ideXlab platform.
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description of luteimonas pelagia sp nov isolated from marine sediment and emended descriptions of luteimonas aquatica luteimonas composti luteimonas mephitis Lysobacter Enzymogenes and Lysobacter panaciterrae
International Journal of Systematic and Evolutionary Microbiology, 2016Co-Authors: Shihyao Lin, Asif Hameed, Mariyam Shahina, Youcheng Liu, Yihan Hsu, Chengzhe Wen, Chiuchung YoungAbstract:An aerobic, Gram-stain-negative, non-motile, rod-shaped bacterium, designated strain CC-VAM-7T, was isolated from a marine sediment sample collected at Kending, Taiwan. The isolate grew optimally at pH 7.0 and 30 °C and in the presence of 4 % (w/v) NaCl. The most closely related strains in terms of 16S rRNA gene sequence similarity were the type strains of Luteimonas huabeiensis (95.2 %) and Lysobacter defluvii (95.0 %). Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain CC-VAM-7T clustered with members of the genus Luteimonas. Strain CC-VAM-7T possessed C15 : 1ω5c, C16 : 1ω5c, iso-C11 : 0, iso-C15 : 0, iso-C16 : 0, iso-C17 : 0, iso-C11 : 0 3-OH and summed feature 9 (10-methyl C16 : 0 and/or iso-C17 : 1ω9c) as predominant fatty acids. The polar lipid profile contained major amounts of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine and moderate amounts of an unidentified phospholipid. The genomic DNA G+C content was 73.4 mol%. Ubiquinone 8 (Q-8) was the predominant respiratory quinone. According to its distinct phylogenetic, phenotypic and chemotaxonomic features, which were in line with those of other members of the genus Luteimonas, strain CC-VAM-7T is proposed to represent a novel species within the genus Luteimonas, for which the name Luteimonas pelagia sp. nov. is proposed. The type strain is CC-VAM-7T ( = BCRC 80558T = JCM 18792T). In addition, we propose emended descriptions of Luteimonas aquatica Chou et al. 2008 , Luteimonas composti Young et al. 2007 , Luteimonas mephitis Finkmann et al. 2000 , Lysobacter Enzymogenes Christensen and Cook 1978 and Lysobacter panaciterrae Ten et al. 2009 .
Gary Y. Yuen - One of the best experts on this subject based on the ideXlab platform.
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control of cyst nematodes by Lysobacter Enzymogenes strain c3 and the role of the antibiotic hsaf in the biological control activity
Biological Control, 2018Co-Authors: Gary Y. Yuen, Charlene C Jochum, Kyle C Broderick, Carl J Chen, E P CaswellchenAbstract:Abstract Lysobacter Enzymogenes C3, a bacterial biocontrol agent of fungal and oomycetous plant pathogens, produces an antimicrobial secondary metabolite complex (HSAF) as a mechanism for its antifungal activity. In this study, strain C3 was investigated for its activity against various life history stages of Heterodera schactii, the sugarbeet cyst nematode (SBCN), and H. glycines, the soybean cyst nematode (SCN), on roots. Strain C3 was applied to the roots of cabbage, sugarbeet, and soybean grown in growth pouches, sand, and a sand-soil medium, respectively, under growth chamber conditions. Cabbage and sugarbeet roots were subsequently challenged with SBCN, while soybean roots were inoculated with SCN. Treatment of sugarbeet with C3 reduced the number of SBCN nematodes in the roots compared to the no bacteria control, while treatment of cabbage roots with the bacterium reduced numbers of SBCN cysts and eggs per plant compared to the control. Similarly, application of C3 to soybean inhibited SCN egg production relative to the control. The findings demonstrated that the bacterium has the potential to suppress nematode feeding and reproduction in the rhizosphere. In addition, HSAF production by C3 was evaluated for its role in the interactions with SCN in the soybean rhizosphere. A mutant strain of C3 defective in the key HSAF biosynthesis gene, and thus blocked in HSAF production, lacked the suppressive effects exhibited by the wildtype strain on SCN reproduction. Thus, HSAF production was shown to be an important mechanism involved in the biocontrol activity of L. Enzymogenes C3 against cyst nematodes.
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Lsp family proteins regulate antibiotic biosynthesis in Lysobacter Enzymogenes OH11
AMB Express, 2017Co-Authors: Ruping Wang, Guoliang Qian, Yangyang Zhao, Juan Zhang, Gary Y. Yuen, Fengquan LiuAbstract:Ax21 family proteins have been shown to play regulatory roles in plant- and animal-pathogenic species in the bacterial family Xanthomonadaceae, but the protein have not been investigated previously in the non-pathogenic members of this bacterial family. Lysobacter Enzymogenes, is a non-pathogenic species known for its capacity as a biocontrol agent of plant pathogens. It is also noted for the production of antimicrobial secondary metabolites, heat stable antifungal factor (HSAF) and WAP-8294A2, that have potential for agricultural and pharmaceutical applications. The species also displays type IV pili-dependent twitching motility and the production of multiple extracellular lytic enzymes as additional biocontrol-related traits. Here, we show that L. Enzymogenes strain OH11 possesses three genes widely separated in the OH11 genome that code for unique Ax21-like proteins (Lsp). By comparing the wildtype OH11 with mutant strains having a single lsp gene or a combination of lsp genes deleted, we found that each Lsp protein individually is involved in positive regulation of HSAF and WAP-8294A2 biosynthesis, but the proteins collectively do not exert additive effects in this regulation. None of the Lsp proteins were found to influence twitching motility or the production of three extracellular lytic enzymes. This study is the first to provide evidence linking Ax21-family proteins to antibiotic biosynthesis and, hence, adds new insights into the diversity of regulatory functions of Ax21 family proteins in bacteria.
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pilg is involved in the regulation of twitching motility and antifungal antibiotic biosynthesis in the biological control agent Lysobacter Enzymogenes
Phytopathology, 2015Co-Authors: Xue Zhou, Guoliang Qian, Fengquan Liu, Yuan Chen, Gary Y. YuenAbstract:Lysobacter Enzymogenes strain C3 is a gliding bacterium which produces the antifungal secondary metabolite heat-stable antifungal factor (HSAF) and type IV pilus (T4P) as important mechanisms in biological control activity against fungal pathogens. To date, the regulators that control HSAF biosynthesis and T4P-dependent twitching motility in L. Enzymogenes are poorly explored. In the present study, we addressed the role of pilG in the regulation of these two traits in L. Enzymogenes. PilG of L. Enzymogenes was found to be a response regulator, commonly known as a component of a two-component transduction system. Mutation of pilG in strain C3 abolished its ability to display spreading colony phenotype and cell movement at the colony margin, which is indicative of twitching motility; hence, PilG positively regulates twitching motility in L. Enzymogenes. Mutation of pilG also enhanced HSAF production and the transcription of its key biosynthetic gene hsaf pks/nrps, suggesting that PilG plays a negative regulatory role in HSAF biosynthesis. This finding represents the first demonstration of the regulator PilG having a role in secondary metabolite biosynthesis in bacteria. Collectively, our results suggest that key ecological functions (HSAF production and twitching motility) in L. Enzymogenes strain C3 are regulated in opposite directions by the same regulatory protein, PilG.
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an antibiotic complex from Lysobacter Enzymogenes strain c3 antimicrobial activity and role in plant disease control
Phytopathology, 2008Co-Authors: C C Jochum, Kathia Zaletarivera, Steven D Harris, Gary Y. YuenAbstract:ABSTRACT Lysobacter Enzymogenes C3 is a bacterial biological control agent that exhibits antagonism against multiple fungal pathogens. Its antifungal activity was attributed in part to lytic enzymes. In this study, a heat-stable antifungal factor (HSAF), an antibiotic complex consisting of dihydromaltophilin and structurally related macrocyclic lactams, was found to be responsible for antagonism by C3 against fungi and oomycetes in culture. HSAF in purified form exhibited inhibitory activity against a wide range of fungal and oomycetes species in vitro, inhibiting spore germination, and disrupting hyphal polarity in sensitive fungi. When applied to tall fescue leaves as a partially-purified extract, HSAF at 25 μg/ml and higher inhibited germination of conidia of Bipolaris sorokiniana compared with the control. Although application of HSAF at 12.5 μg/ml did not reduce the incidence of conidial germination, it inhibited appressorium formation and suppressed Bipolaris leaf spot development. Two mutant strain...
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the role of clp regulated factors in antagonism against magnaporthe poae and biological control of summer patch disease of kentucky bluegrass by Lysobacter Enzymogenes c3
Canadian Journal of Microbiology, 2005Co-Authors: Donald Y. Kobayashi, Gary Y. YuenAbstract:A global regulator was previously identified in Lysobacter Enzymogenes C3, which when mutated, resulted in strains that were greatly reduced in the expression of traits associated with fungal antagonism and devoid of biocontrol activity towards bipolaris leaf-spot of tall fescue and pythium damping-off of sugarbeet. A clp gene homologue belonging to the crp gene family was found to globally regulate enzyme production, antimicrobial activity, and biological control activity expressed by Lysobacter Enzymogenes C3 (Kobayashi et al. 2005). Here, we report on the expansion of the biocontrol range of L. Enzymogenes C3 to summer patch disease caused by Magnaporthe poae. The clp- mutant strain 5E4 was reduced in its ability to suppress summer patch disease compared with the wild-type strain C3 and was completely devoid of antifungal activity towards M. poae. Furthermore, cell suspensions of 5E4 were incapable of colonizing M. poae mycelium in a manner that was distinct for C3. Strain C3 demonstrated biosurfactant activity in cell suspensions and culture filtrates that was associated with absorption into the mycelium during the colonization process, whereas 5E4 did not. These results describe a novel interaction between bacteria and fungi that intimates a pathogenic relationship.
