The Experts below are selected from a list of 1554 Experts worldwide ranked by ideXlab platform
Xuehong Zhang - One of the best experts on this subject based on the ideXlab platform.
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engineering of glycerol utilization in Pseudomonas chlororaphis gp72 for enhancing phenazine 1 carboxylic acid production
World Journal of Microbiology & Biotechnology, 2020Co-Authors: Chen Song, Wei Wang, Shengjie Yue, Wenhui Liu, Yifan Zheng, Chenghao Zhang, Tongtong Feng, Xuehong ZhangAbstract:Glycerol is a by-product of biodiesel, and it has a great application prospect to be transformed to synthesize high value-added compounds. Pseudomonas chlororaphis GP72 isolated from the green pepper rhizosphere is a plant growth promoting rhizobacteria that can utilize amount of glycerol to synthesize phenazine-1-carboxylic acid (PCA). PCA has been commercially registered as “Shenqinmycin” in China due to its characteristics of preventing pepper blight and rice sheath blight. The aim of this study was to engineer glycerol utilization pathway in P. chlororaphis GP72. First, the two genes glpF and glpK from the glycerol metabolism pathway were overexpressed in GP72ANO separately. Then, the two genes were co-expressed in GP72ANO, improving PCA production from 729.4 mg/L to 993.4 mg/L at 36 h. Moreover, the shunt pathway was blocked to enhance glycerol utilization, resulting in 1493.3 mg/L PCA production. Additionally, we confirmed the inhibition of glpR on glycerol metabolism pathway in P. chlororaphis GP72. This study provides a good example for improving the utilization of glycerol to synthesize high value-added compounds in Pseudomonas.
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microbial synthesis of antibacterial phenazine 1 6 dicarboxylic acid and the role of phzg in Pseudomonas chlororaphis gp72an
Journal of Agricultural and Food Chemistry, 2020Co-Authors: Shuqi Guo, Wei Wang, Muhammad Bilal, Yining Wang, Xuehong ZhangAbstract:Pseudomonas chlororaphis have been demonstrated to be environmentally friendly biocontrol strains, and most of them can produce phenazine compounds. Phenazine-1,6-dicarboxylic acid (PDC), with a potential antibacterial activity, is generally found in Streptomyces but not in Pseudomonas. The present study aimed to explore the feasibility of PDC synthesis and the function of PhzG in Pseudomonas. A PDC producer was constructed by replacing phzG in P. chlororaphis with lphzG from Streptomyces lomondensis. Through gene deletion, common start codon changing, gene silence, and in vitro assay, our result revealed that the yield of PDC in P. chlororaphis is associated with the relative expression of phzG to phzA and phzB. In addition, it is found that PDC can be spontaneously synthesized without PhzG. This study provides an efficient way for PDC production and promotes a better understanding of PhzG function in PDC biosynthesis. Moreover, this study gives an alternative opportunity for developing new antibacterial biopesticides.
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synthesis of cinnabarinic acid by metabolically engineered Pseudomonas chlororaphis gp72
Biotechnology and Bioengineering, 2019Co-Authors: Shengjie Yue, Wei Wang, Chen Song, Peng Huang, Shuqi Guo, Xuehong ZhangAbstract:Cinnabarinic acid is a valuable phenoxazinone that has broad applications in the pharmaceutical, chemical, and dyeing industries. However, few studies have investigated the production of cinnabarinic acid or its derivatives using genetically engineered microorganisms. Herein, an efficient synthetic pathway of cinnabarinic acid was designed and constructed in Pseudomonas chlororaphis GP72 for the first tim, which was more straightforward and robust than the known eukaryotic biosynthetic pathways. First, we screened and identified trans-2,3-dihydro-3-hydroxyanthranilic acid (DHHA) dehydrogenases from Escherichia coli MG1655 (encoded by entA), Streptomyces sp. NRRL12068 (encoded by bomO) and Streptomyces chartreusis NRRL3882 (encoded by calB3 ) based on the structural similarity of the substrate and product, and the DHHA dehydrogenase encoded by calB3 was selected for the synthesis of cinnabarinic acid due to its high DHHA conversion rate. Subsequently, cinnabarinic acid was synthesized by the expression of the DHHA dehydrogenase CalB3 and the phenoxazinone synthase CotA in the DHHA-producing strain P. chlororaphis GP72, resulting in a cinnabarinic acid titer of 20.3 mg/L at 48 hr. Further fermentation optimization by the addition of Cu2+ , H2 O2 , and with adding glycerol increased cinnabarinic acid titer to 136.2 mg/L in shake flasks. The results indicate that P. chlororaphis GP72 may be engineered as a microbial cell factory to produce cinnabarinic acid or its derivatives from renewable bioresources.
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enhanced biosynthesis of arbutin by engineering shikimate pathway in Pseudomonas chlororaphis p3
Microbial Cell Factories, 2018Co-Authors: Songwei Wang, Muhammad Bilal, Wei Wang, Xuehong ZhangAbstract:Arbutin is a plant-derived glycoside with potential antioxidant, antibacterial and anti-inflammatory activities. Currently, it is mainly produced by plant extraction or enzymatic processes, which suffers from expensive processing cost and low product yield. Metabolic engineering of microbes is an increasingly powerful method for the high-level production of valuable biologicals. Since Pseudomonas chlororaphis has been widely engineered as a phenazine-producing platform organism due to its well-characterized genetics and physiology, and faster growth rate using glycerol as a renewable carbon source, it can also be engineered as the cell factory using strong shikimate pathway on the basis of synthetic biology. In this work, a plasmid-free biosynthetic pathway was constructed in P. chlororaphis P3 for elevated biosynthesis of arbutin from sustainable carbon sources. The arbutin biosynthetic pathway was expressed under the native promoter Pphz using chromosomal integration. Instead of being plasmid and inducer dependent, the metabolic engineering approach used to fine-tune the biosynthetic pathway significantly enhanced the arbutin production with a 22.4-fold increase. On the basis of medium factor optimization and mixed fed-batch fermentation of glucose and 4-hydroxybenzoic acid, the engineered P. chlororaphis P3-Ar5 strain led to the highest arbutin production of 6.79 g/L with the productivity of 0.094 g/L/h, with a 54-fold improvement over the initial strain. The results suggested that the construction of plasmid-free synthetic pathway displays a high potential for improved biosynthesis of arbutin and other shikimate pathway derived biologicals in P. chlororaphis.
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development of an efficient method for separation and purification of trans 2 3 dihydro 3 hydroxyanthranilic acid from Pseudomonas chlororaphis gp72 fermentation broth
Separation and Purification Technology, 2018Co-Authors: Shengjie Yue, Muhammad Bilal, Wei Wang, Chen Song, Peng Huang, Shuqi Guo, Xuehong ZhangAbstract:Abstract Trans -2,3-dihydro-3-hydroxyanthranilic acid (DHHA) is an important intermediate to synthesize a wide variety of secondary metabolites with potential biological activities. Recently, we engineered a biosynthetic pathway in Pseudomonas chlororaphis GP72 and optimized the batch- fermentation conditions to synthesize DHHA. Herein, we developed a proficient method for the separation and purification of DHHA from the culture extract of recombinant Pseudomonas chlororaphis GP72 by applying macroporous cation-exchange resins. The performance and absorption characteristics of six resins namely D001, HZD-2, JK006, HD-8, HZ016, and 732 were evaluated. Notably, HD-8 resin displayed the pronounced adsorption and desorption capacities for DHHA as compared to others and its equilibrium adsorption data were well-fitted to the Langmuir isotherm. Moreover, HD-8 column chromatography-based dynamic adsorption and desorption tests were carried out to standardize the operational parameters for DHHA separation and purification. Under the optimized separating conditions, the average adsorption capacity and desorption ratio of DHHA was 40.3 ± 0.7 mg/g dry resin and 86.7 ± 2.8%, respectively. The purity and recovery of DHHA was recorded to be 95.3 ± 1.2% and 83.2 ± 2.3%, respectively. Taken together, the HD-8 resin appeared as a promising adsorbent for high-level separation and purification of DHHA from the complex media. In conclusion, this method displays a high potential for separating and purifying DHHA and other bioactive compounds in high yield from the fermentation broth.
Wei Wang - One of the best experts on this subject based on the ideXlab platform.
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engineering of glycerol utilization in Pseudomonas chlororaphis gp72 for enhancing phenazine 1 carboxylic acid production
World Journal of Microbiology & Biotechnology, 2020Co-Authors: Chen Song, Wei Wang, Shengjie Yue, Wenhui Liu, Yifan Zheng, Chenghao Zhang, Tongtong Feng, Xuehong ZhangAbstract:Glycerol is a by-product of biodiesel, and it has a great application prospect to be transformed to synthesize high value-added compounds. Pseudomonas chlororaphis GP72 isolated from the green pepper rhizosphere is a plant growth promoting rhizobacteria that can utilize amount of glycerol to synthesize phenazine-1-carboxylic acid (PCA). PCA has been commercially registered as “Shenqinmycin” in China due to its characteristics of preventing pepper blight and rice sheath blight. The aim of this study was to engineer glycerol utilization pathway in P. chlororaphis GP72. First, the two genes glpF and glpK from the glycerol metabolism pathway were overexpressed in GP72ANO separately. Then, the two genes were co-expressed in GP72ANO, improving PCA production from 729.4 mg/L to 993.4 mg/L at 36 h. Moreover, the shunt pathway was blocked to enhance glycerol utilization, resulting in 1493.3 mg/L PCA production. Additionally, we confirmed the inhibition of glpR on glycerol metabolism pathway in P. chlororaphis GP72. This study provides a good example for improving the utilization of glycerol to synthesize high value-added compounds in Pseudomonas.
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microbial synthesis of antibacterial phenazine 1 6 dicarboxylic acid and the role of phzg in Pseudomonas chlororaphis gp72an
Journal of Agricultural and Food Chemistry, 2020Co-Authors: Shuqi Guo, Wei Wang, Muhammad Bilal, Yining Wang, Xuehong ZhangAbstract:Pseudomonas chlororaphis have been demonstrated to be environmentally friendly biocontrol strains, and most of them can produce phenazine compounds. Phenazine-1,6-dicarboxylic acid (PDC), with a potential antibacterial activity, is generally found in Streptomyces but not in Pseudomonas. The present study aimed to explore the feasibility of PDC synthesis and the function of PhzG in Pseudomonas. A PDC producer was constructed by replacing phzG in P. chlororaphis with lphzG from Streptomyces lomondensis. Through gene deletion, common start codon changing, gene silence, and in vitro assay, our result revealed that the yield of PDC in P. chlororaphis is associated with the relative expression of phzG to phzA and phzB. In addition, it is found that PDC can be spontaneously synthesized without PhzG. This study provides an efficient way for PDC production and promotes a better understanding of PhzG function in PDC biosynthesis. Moreover, this study gives an alternative opportunity for developing new antibacterial biopesticides.
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synthesis of cinnabarinic acid by metabolically engineered Pseudomonas chlororaphis gp72
Biotechnology and Bioengineering, 2019Co-Authors: Shengjie Yue, Wei Wang, Chen Song, Peng Huang, Shuqi Guo, Xuehong ZhangAbstract:Cinnabarinic acid is a valuable phenoxazinone that has broad applications in the pharmaceutical, chemical, and dyeing industries. However, few studies have investigated the production of cinnabarinic acid or its derivatives using genetically engineered microorganisms. Herein, an efficient synthetic pathway of cinnabarinic acid was designed and constructed in Pseudomonas chlororaphis GP72 for the first tim, which was more straightforward and robust than the known eukaryotic biosynthetic pathways. First, we screened and identified trans-2,3-dihydro-3-hydroxyanthranilic acid (DHHA) dehydrogenases from Escherichia coli MG1655 (encoded by entA), Streptomyces sp. NRRL12068 (encoded by bomO) and Streptomyces chartreusis NRRL3882 (encoded by calB3 ) based on the structural similarity of the substrate and product, and the DHHA dehydrogenase encoded by calB3 was selected for the synthesis of cinnabarinic acid due to its high DHHA conversion rate. Subsequently, cinnabarinic acid was synthesized by the expression of the DHHA dehydrogenase CalB3 and the phenoxazinone synthase CotA in the DHHA-producing strain P. chlororaphis GP72, resulting in a cinnabarinic acid titer of 20.3 mg/L at 48 hr. Further fermentation optimization by the addition of Cu2+ , H2 O2 , and with adding glycerol increased cinnabarinic acid titer to 136.2 mg/L in shake flasks. The results indicate that P. chlororaphis GP72 may be engineered as a microbial cell factory to produce cinnabarinic acid or its derivatives from renewable bioresources.
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enhanced biosynthesis of arbutin by engineering shikimate pathway in Pseudomonas chlororaphis p3
Microbial Cell Factories, 2018Co-Authors: Songwei Wang, Muhammad Bilal, Wei Wang, Xuehong ZhangAbstract:Arbutin is a plant-derived glycoside with potential antioxidant, antibacterial and anti-inflammatory activities. Currently, it is mainly produced by plant extraction or enzymatic processes, which suffers from expensive processing cost and low product yield. Metabolic engineering of microbes is an increasingly powerful method for the high-level production of valuable biologicals. Since Pseudomonas chlororaphis has been widely engineered as a phenazine-producing platform organism due to its well-characterized genetics and physiology, and faster growth rate using glycerol as a renewable carbon source, it can also be engineered as the cell factory using strong shikimate pathway on the basis of synthetic biology. In this work, a plasmid-free biosynthetic pathway was constructed in P. chlororaphis P3 for elevated biosynthesis of arbutin from sustainable carbon sources. The arbutin biosynthetic pathway was expressed under the native promoter Pphz using chromosomal integration. Instead of being plasmid and inducer dependent, the metabolic engineering approach used to fine-tune the biosynthetic pathway significantly enhanced the arbutin production with a 22.4-fold increase. On the basis of medium factor optimization and mixed fed-batch fermentation of glucose and 4-hydroxybenzoic acid, the engineered P. chlororaphis P3-Ar5 strain led to the highest arbutin production of 6.79 g/L with the productivity of 0.094 g/L/h, with a 54-fold improvement over the initial strain. The results suggested that the construction of plasmid-free synthetic pathway displays a high potential for improved biosynthesis of arbutin and other shikimate pathway derived biologicals in P. chlororaphis.
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development of an efficient method for separation and purification of trans 2 3 dihydro 3 hydroxyanthranilic acid from Pseudomonas chlororaphis gp72 fermentation broth
Separation and Purification Technology, 2018Co-Authors: Shengjie Yue, Muhammad Bilal, Wei Wang, Chen Song, Peng Huang, Shuqi Guo, Xuehong ZhangAbstract:Abstract Trans -2,3-dihydro-3-hydroxyanthranilic acid (DHHA) is an important intermediate to synthesize a wide variety of secondary metabolites with potential biological activities. Recently, we engineered a biosynthetic pathway in Pseudomonas chlororaphis GP72 and optimized the batch- fermentation conditions to synthesize DHHA. Herein, we developed a proficient method for the separation and purification of DHHA from the culture extract of recombinant Pseudomonas chlororaphis GP72 by applying macroporous cation-exchange resins. The performance and absorption characteristics of six resins namely D001, HZD-2, JK006, HD-8, HZ016, and 732 were evaluated. Notably, HD-8 resin displayed the pronounced adsorption and desorption capacities for DHHA as compared to others and its equilibrium adsorption data were well-fitted to the Langmuir isotherm. Moreover, HD-8 column chromatography-based dynamic adsorption and desorption tests were carried out to standardize the operational parameters for DHHA separation and purification. Under the optimized separating conditions, the average adsorption capacity and desorption ratio of DHHA was 40.3 ± 0.7 mg/g dry resin and 86.7 ± 2.8%, respectively. The purity and recovery of DHHA was recorded to be 95.3 ± 1.2% and 83.2 ± 2.3%, respectively. Taken together, the HD-8 resin appeared as a promising adsorbent for high-level separation and purification of DHHA from the complex media. In conclusion, this method displays a high potential for separating and purifying DHHA and other bioactive compounds in high yield from the fermentation broth.
Francisco M Cazorla - One of the best experts on this subject based on the ideXlab platform.
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aer receptors influence the Pseudomonas chlororaphis pcl1606 lifestyle
Frontiers in Microbiology, 2020Co-Authors: Francisco M Cazorla, Eva ArrebolaAbstract:Pseudomonas chlororaphis PCL1606 (PcPCL1606) is a rhizobacterium isolated from avocado roots, which is a favorable niche for its development. This strain extensively interacts with plant roots and surrounding microbes and is considered a biocontrol rhizobacterium. Genome sequencing has shown the presence of thirty-one potential methyl-accepting chemotaxis proteins (MCPs). Among these MCPs, two candidates are putative functional aerotaxis receptors, encoded at locus PCL1606_41090 (aer1-1) and locus PLC1606_20530 (aer1-2), that are homologous to the Aer receptor of Pseudomonas aeruginosa strain PaO1. Single- and double-deletion mutants in one or both genes have led to motility deficiencies in oxygen-rich areas, particularly reduced swimming motility compared with that of wildtype PcPCL1606. No differences in swarming tests were detected, and less adhesion by the aer double mutant was observed. However, the single and double mutants on avocado plant roots showed delayed biocontrol ability. During the first days of the biocontrol experiment, the aer-defective mutants also showed delayed root colonization. The current research characterizes the presence of aer transductors on P. chlororaphis. Thus, the functions of the PCL1606_41090 and PCL1606_20530 loci, corresponding to genes aer1-1 and aer1-2, respectively, are elucidated.
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The Compound 2-Hexyl, 5-Propyl Resorcinol Has a Key Role in Biofilm Formation by the Biocontrol Rhizobacterium Pseudomonas chlororaphis PCL1606.
Frontiers in Microbiology, 2019Co-Authors: Claudia E Calderon, Eva Arrebola, Sandra Tienda, Zaira Heredia-ponce, Gerardo Cárcamo-oyarce, Leo Eberl, Francisco M CazorlaAbstract:The production of the compound 2-hexyl-5-propyl resorcinol (HPR) by the biocontrol rhizobacterium Pseudomonas chlororaphis PCL1606 (PcPCL1606) is crucial for fungal antagonism and biocontrol activity that protects plants against the phytopathogenic fungus Rosellinia necatrix. The production of HPR is also involved in avocado root colonization during the biocontrol process. This pleiotrophic response prompted us to study the potential role of HPR production in biofilm formation. The swimming motility of PcPLL1606 is enhanced by the disruption of HPR production. Mutants impaired in HPR production, revealed that adhesion, colony morphology, and typical air-liquid interphase pellicles were all dependent on HPR production. The role of HPR production in biofilm architecture was also analyzed in flow chamber experiments. These experiments revealed that the HPR mutant cells had less tight unions than those producing HPR, suggesting an involvement of HPR in the production of the biofilm matrix.
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Fitness Features Involved in the Biocontrol Interaction of Pseudomonas chlororaphis With Host Plants: The Case Study of PcPCL1606
Frontiers Media S.A., 2019Co-Authors: Carmen Vida, Antonio De Vicente, Francisco M Cazorla, Eva Arrebola, Sandra TiendaAbstract:The goal of this mini review is to summarize the relevant contribution of some beneficial traits to the behavior of the species Pseudomonas chlororaphis, and using that information, to give a practical point of view using the model biocontrol strain P. chlororaphis PCL1606 (PcPCL1606). Among the group of plant-beneficial rhizobacteria, P. chlororaphis has emerged as a plant- and soil-related bacterium that is mainly known because of its biological control of phytopathogenic fungi. Many traits have been reported to be crucial during the multitrophic interaction involving the plant, the fungal pathogen and the soil environment. To explore the different biocontrol-related traits, the biocontrol rhizobacterium PcPCL1606 has been used as a model in recent studies. This bacterium is antagonistic to many phytopathogenic fungi and displays effective biocontrol against fungal phytopathogens. Antagonistic and biocontrol activities are directly related to the production of the compound 2-hexyl, 5-propyl resorcinol (HPR), despite the production of other antifungal compounds. Furthermore, PcPCL1606 has displayed additional traits regarding its fitness in soil and plant root environments such as soil survival, efficient plant root colonization, cell-to-cell interaction or promotion of plant growth
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Impact of motility and chemotaxis features of the rhizobacterium Pseudomonas chlororaphis PCL1606 on its biocontrol of avocado white root rot
International Microbiology, 2017Co-Authors: Alvaro Polonio, Carmen Vida, Antonio De Vicente, Francisco M CazorlaAbstract:The biocontrol rhizobacterium Pseudomonas chlororaphis PCL1606 has the ability to protect avocado plants against white root rot produced by the phytopathogenic fungus Rosellinia necatrix. Moreover, PCL1606 displayed direct interactions with avocado roots and the pathogenic fungus. Thus, nonmotile (flgK mutant) and non-chemotactic (cheA mutant) derivatives of PCL1606 were constructed to emphasize the importance of motility and chemotaxis in the biological behaviour of PCL1606 during the biocontrol interaction. Plate chemotaxis assay showed that PCL1606 was attracted to the single compounds tested, such as glucose, glutamate, succinate, aspartate and malate, but no chemotaxis was observed to avocado or R. necatrix exudates. Using the more sensitive capillary assay, it was reported that smaller concentrations (1 mM) of single compounds elicited high chemotactic responses, and strong attraction was confirmed to avocado and R. necatrix exudates. Finally, biocontrol experiments revealed that the cheA and fglK derivative mutants reduced root protection against R. necatrix, suggesting an important role for these biological traits in biocontrol by P. chlororaphis PCL1606. [Int Microbiol 20(2):94-104 (2017)]Keywords: Pseudomonas chlororaphis · Rosellinia necatrix · avocado white root rot · multitrophic interactions · rhizospher
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impact of motility and chemotaxis features of the rhizobacterium Pseudomonas chlororaphis pcl1606 on its biocontrol of avocado white root rot
International Microbiology, 2017Co-Authors: Alvaro Polonio, Carmen Vida, Antonio De Vicente, Francisco M CazorlaAbstract:The biocontrol rhizobacterium Pseudomonas chlororaphis PCL1606 has the ability to protect avocado plants against white root rot produced by the phytopathogenic fungus Rosellinia necatrix. Moreover, PCL1606 displayed direct interactions with avocado roots and the pathogenic fungus. Thus, nonmotile (flgK mutant) and non-chemotactic (cheA mutant) derivatives of PCL1606 were constructed to emphasize the importance of motility and chemotaxis in the biological behaviour of PCL1606 during the biocontrol interaction. Plate chemotaxis assay showed that PCL1606 was attracted to the single compounds tested, such as glucose, glutamate, succinate, aspartate and malate, but no chemotaxis was observed to avocado or R. necatrix exudates. Using the more sensitive capillary assay, it was reported that smaller concentrations (1 mM) of single compounds elicited high chemotactic responses, and strong attraction was confirmed to avocado and R. necatrix exudates. Finally, biocontrol experiments revealed that the cheA and fglK derivative mutants reduced root protection against R. necatrix, suggesting an important role for these biological traits in biocontrol by P. chlororaphis PCL1606. [Int Microbiol 20(2):94-104 (2017)]Keywords: Pseudomonas chlororaphis · Rosellinia necatrix · avocado white root rot · multitrophic interactions · rhizosphere
Anne J. Anderson - One of the best experts on this subject based on the ideXlab platform.
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insights into plant beneficial traits of probiotic Pseudomonas chlororaphis isolates
Journal of Medical Microbiology, 2020Co-Authors: Anne J. Anderson, Young Cheol KimAbstract:Pseudomonas chlororaphis isolates have been studied intensively for their beneficial traits. P. chlororaphis species function as probiotics in plants and fish, offering plants protection against microbes, nematodes and insects. In this review, we discuss the classification of P. chlororaphis isolates within four subspecies; the shared traits include the production of coloured antimicrobial phenazines, high sequence identity between housekeeping genes and similar cellular fatty acid composition. The direct antimicrobial, insecticidal and nematocidal effects of P. chlororaphis isolates are correlated with known metabolites. Other metabolites prime the plants for stress tolerance and participate in microbial cell signalling events and biofilm formation among other things. Formulations of P. chlororaphis isolates and their metabolites are currently being commercialized for agricultural use.
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polyamine is a critical determinant of Pseudomonas chlororaphis o6 for gacs dependent bacterial cell growth and biocontrol capacity
Molecular Plant Pathology, 2018Co-Authors: Ju Yeon Park, Anne J. Anderson, Beom Ryong Kang, Choongmin Ryu, Young Cheol KimAbstract:The Gac/Rsm network regulates, at the transcriptional level, many beneficial traits in biocontrol-active pseudomonads. In this study, we used Phenotype MicroArrays, followed by specific growth studies and mutational analysis, to understand how catabolism is regulated by this sensor kinase system in the biocontrol isolate Pseudomonas chlororaphis O6. The growth of a gacS mutant was decreased significantly relative to that of the wild-type on ornithine and arginine, and on the precursor of these amino acids, N-acetyl-l-glutamic acid. The gacS mutant also showed reduced production of polyamines. Expression of the genes encoding arginine decarboxylase (speA) and ornithine decarboxylases (speC) was controlled at the transcriptional level by the GacS sensor of P. chlororaphis O6. Polyamine production was reduced in the speC mutant, and was eliminated in the speAspeC mutant. The addition of exogenous polyamines to the speAspeC mutant restored the in vitro growth inhibition of two fungal pathogens, as well as the secretion of three biological control-related factors: pyrrolnitrin, protease and siderophore. These results extend our knowledge of the regulation by the Gac/Rsm network in a biocontrol pseudomonad to include polyamine synthesis. Collectively, our studies demonstrate that bacterial polyamines act as important regulators of bacterial cell growth and biocontrol potential.
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biopesticides produced by plant probiotic Pseudomonas chlororaphis isolates
Crop Protection, 2018Co-Authors: Anne J. Anderson, Young Cheol KimAbstract:Abstract Pseudomonas chlororaphis isolates are being used in agriculture as biopesticides because they provide plant protection against an array of microbial pathogens, insects and nematodes. These isolates directly control microbial pathogens, insects, and nematodes through the production of an array of metabolites. This review describes the structures, synthesis and function of the metabolites from P. chlororaphis isolates with biopesticide potential in the rhizosphere. Understanding the mechanisms involved in the efficacy of these metabolites will promote the use of these chemicals as well as the microbes that synthesize these products, in formulations for agricultural practices aiming towards sustainability of soils as well as the quality and quantity of the crop.
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Biocontrol Efficacy of Formulated Pseudomonas chlororaphis O6 against Plant Diseases and Root-Knot Nematodes
Hanrimwon Publishing Company, 2018Co-Authors: Hyo Song Nam, Anne J. Anderson, Young Cheol KimAbstract:Commercial biocontrol of microbial plant diseases and plant pests, such as nematodes, requires field-effective formulations. The isolate Pseudomonas chlororaphis O6 is a Gram-negative bacterium that controls microbial plant pathogens both directly and indirectly. This bacterium also has nematocidal activity. In this study, we report on the efficacy of a wettable powder-type formulation of P. chlororaphis O6. Culturable bacteria in the formulated product were retained at above 1 × 108 colony forming units/g after storage of the powder at 25 °C for six months. Foliar application of the diluted formulated product controlled leaf blight and gray mold in tomato. The product also displayed preventative and curative controls for root-knot nematode (Meloidogyne spp.) in tomato. Under laboratory conditions and for commercially grown melon, the control was at levels comparable to that of a standard commercial chemical nematicide. The results indicated that the wettable powder formulation product of P. chlororaphis O6 can be used for control of plant microbial pathogens and root-knot nematodes
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Extracellular Polymeric Substances of Pseudomonas chlororaphis O6 Induce Systemic Drought Tolerance in Plants
'Korean Society of Plant Pathology', 2018Co-Authors: Song Mi Cho, Anne J. Anderson, Young Cheol KimAbstract:Pseudomonas chlororaphis O6 induces systemic tolerance in plants against drought stress. A volatile, 2R, 3R-butanediol, produced by the bacterium causes partial stomatal closure, thus, limiting water loss from the plant. In this study, we report that applications of extracellular polymeric substances (EPS) from P. chlororaphis O6 to epidermal peels of leaves of Arabidopsis thaliana also reduce the size of stomatal openings. Growth of A. thaliana seedlings with applications of the EPS from P. chlororaphis O6 reduced the extent of wilting when water was withheld from the plants. Fluorescence measurements showed photosystem II was protected in the A. thaliana leaves in the water stressed EPS-exposed plants. These findings indicate that P. chlororaphis O6 has redundancy in traits associated with induction of mechanisms to limit water stress in plants
Young Cheol Kim - One of the best experts on this subject based on the ideXlab platform.
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insights into plant beneficial traits of probiotic Pseudomonas chlororaphis isolates
Journal of Medical Microbiology, 2020Co-Authors: Anne J. Anderson, Young Cheol KimAbstract:Pseudomonas chlororaphis isolates have been studied intensively for their beneficial traits. P. chlororaphis species function as probiotics in plants and fish, offering plants protection against microbes, nematodes and insects. In this review, we discuss the classification of P. chlororaphis isolates within four subspecies; the shared traits include the production of coloured antimicrobial phenazines, high sequence identity between housekeeping genes and similar cellular fatty acid composition. The direct antimicrobial, insecticidal and nematocidal effects of P. chlororaphis isolates are correlated with known metabolites. Other metabolites prime the plants for stress tolerance and participate in microbial cell signalling events and biofilm formation among other things. Formulations of P. chlororaphis isolates and their metabolites are currently being commercialized for agricultural use.
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polyamine is a critical determinant of Pseudomonas chlororaphis o6 for gacs dependent bacterial cell growth and biocontrol capacity
Molecular Plant Pathology, 2018Co-Authors: Ju Yeon Park, Anne J. Anderson, Beom Ryong Kang, Choongmin Ryu, Young Cheol KimAbstract:The Gac/Rsm network regulates, at the transcriptional level, many beneficial traits in biocontrol-active pseudomonads. In this study, we used Phenotype MicroArrays, followed by specific growth studies and mutational analysis, to understand how catabolism is regulated by this sensor kinase system in the biocontrol isolate Pseudomonas chlororaphis O6. The growth of a gacS mutant was decreased significantly relative to that of the wild-type on ornithine and arginine, and on the precursor of these amino acids, N-acetyl-l-glutamic acid. The gacS mutant also showed reduced production of polyamines. Expression of the genes encoding arginine decarboxylase (speA) and ornithine decarboxylases (speC) was controlled at the transcriptional level by the GacS sensor of P. chlororaphis O6. Polyamine production was reduced in the speC mutant, and was eliminated in the speAspeC mutant. The addition of exogenous polyamines to the speAspeC mutant restored the in vitro growth inhibition of two fungal pathogens, as well as the secretion of three biological control-related factors: pyrrolnitrin, protease and siderophore. These results extend our knowledge of the regulation by the Gac/Rsm network in a biocontrol pseudomonad to include polyamine synthesis. Collectively, our studies demonstrate that bacterial polyamines act as important regulators of bacterial cell growth and biocontrol potential.
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biopesticides produced by plant probiotic Pseudomonas chlororaphis isolates
Crop Protection, 2018Co-Authors: Anne J. Anderson, Young Cheol KimAbstract:Abstract Pseudomonas chlororaphis isolates are being used in agriculture as biopesticides because they provide plant protection against an array of microbial pathogens, insects and nematodes. These isolates directly control microbial pathogens, insects, and nematodes through the production of an array of metabolites. This review describes the structures, synthesis and function of the metabolites from P. chlororaphis isolates with biopesticide potential in the rhizosphere. Understanding the mechanisms involved in the efficacy of these metabolites will promote the use of these chemicals as well as the microbes that synthesize these products, in formulations for agricultural practices aiming towards sustainability of soils as well as the quality and quantity of the crop.
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Biocontrol Efficacy of Formulated Pseudomonas chlororaphis O6 against Plant Diseases and Root-Knot Nematodes
Hanrimwon Publishing Company, 2018Co-Authors: Hyo Song Nam, Anne J. Anderson, Young Cheol KimAbstract:Commercial biocontrol of microbial plant diseases and plant pests, such as nematodes, requires field-effective formulations. The isolate Pseudomonas chlororaphis O6 is a Gram-negative bacterium that controls microbial plant pathogens both directly and indirectly. This bacterium also has nematocidal activity. In this study, we report on the efficacy of a wettable powder-type formulation of P. chlororaphis O6. Culturable bacteria in the formulated product were retained at above 1 × 108 colony forming units/g after storage of the powder at 25 °C for six months. Foliar application of the diluted formulated product controlled leaf blight and gray mold in tomato. The product also displayed preventative and curative controls for root-knot nematode (Meloidogyne spp.) in tomato. Under laboratory conditions and for commercially grown melon, the control was at levels comparable to that of a standard commercial chemical nematicide. The results indicated that the wettable powder formulation product of P. chlororaphis O6 can be used for control of plant microbial pathogens and root-knot nematodes
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Extracellular Polymeric Substances of Pseudomonas chlororaphis O6 Induce Systemic Drought Tolerance in Plants
'Korean Society of Plant Pathology', 2018Co-Authors: Song Mi Cho, Anne J. Anderson, Young Cheol KimAbstract:Pseudomonas chlororaphis O6 induces systemic tolerance in plants against drought stress. A volatile, 2R, 3R-butanediol, produced by the bacterium causes partial stomatal closure, thus, limiting water loss from the plant. In this study, we report that applications of extracellular polymeric substances (EPS) from P. chlororaphis O6 to epidermal peels of leaves of Arabidopsis thaliana also reduce the size of stomatal openings. Growth of A. thaliana seedlings with applications of the EPS from P. chlororaphis O6 reduced the extent of wilting when water was withheld from the plants. Fluorescence measurements showed photosystem II was protected in the A. thaliana leaves in the water stressed EPS-exposed plants. These findings indicate that P. chlororaphis O6 has redundancy in traits associated with induction of mechanisms to limit water stress in plants
