1
|
Baukova A, Bogun A, Sushkova S, Minkina T, Mandzhieva S, Alliluev I, Jatav HS, Kalinitchenko V, Rajput VD, Delegan Y. New Insights into Pseudomonas spp.-Produced Antibiotics: Genetic Regulation of Biosynthesis and Implementation in Biotechnology. Antibiotics (Basel) 2024; 13:597. [PMID: 39061279 PMCID: PMC11273644 DOI: 10.3390/antibiotics13070597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 06/20/2024] [Accepted: 06/25/2024] [Indexed: 07/28/2024] Open
Abstract
Pseudomonas bacteria are renowned for their remarkable capacity to synthesize antibiotics, namely mupirocin, gluconic acid, pyrrolnitrin, and 2,4-diacetylphloroglucinol (DAPG). While these substances are extensively employed in agricultural biotechnology to safeguard plants against harmful bacteria and fungi, their potential for human medicine and healthcare remains highly promising for common science. However, the challenge of obtaining stable producers that yield higher quantities of these antibiotics continues to be a pertinent concern in modern biotechnology. Although the interest in antibiotics of Pseudomonas bacteria has persisted over the past century, many uncertainties still surround the regulation of the biosynthetic pathways of these compounds. Thus, the present review comprehensively studies the genetic organization and regulation of the biosynthesis of these antibiotics and provides a comprehensive summary of the genetic organization of antibiotic biosynthesis pathways in pseudomonas strains, appealing to both molecular biologists and biotechnologists. In addition, attention is also paid to the application of antibiotics in plant protection.
Collapse
Affiliation(s)
- Alexandra Baukova
- Institute of Biochemistry and Physiology of Microorganisms, Federal Research Center “Pushchino Scientific Center for Biological Research of Russian Academy of Sciences” (FRC PSCBR RAS), 142290 Pushchino, Moscow Region, Russia; (A.B.); (A.B.)
- Pushchino Branch of Federal State Budgetary Educational Institution of Higher Education “Russian Biotechnology University (ROSBIOTECH)”, 142290 Pushchino, Moscow Region, Russia
| | - Alexander Bogun
- Institute of Biochemistry and Physiology of Microorganisms, Federal Research Center “Pushchino Scientific Center for Biological Research of Russian Academy of Sciences” (FRC PSCBR RAS), 142290 Pushchino, Moscow Region, Russia; (A.B.); (A.B.)
| | - Svetlana Sushkova
- Academy of Biology and Biotechnology behalf D.I. Ivanovskyi, Southern Federal University, 344006 Rostov-on-Don, Russia; (S.S.); (T.M.); (S.M.); (I.A.); (V.D.R.)
| | - Tatiana Minkina
- Academy of Biology and Biotechnology behalf D.I. Ivanovskyi, Southern Federal University, 344006 Rostov-on-Don, Russia; (S.S.); (T.M.); (S.M.); (I.A.); (V.D.R.)
| | - Saglara Mandzhieva
- Academy of Biology and Biotechnology behalf D.I. Ivanovskyi, Southern Federal University, 344006 Rostov-on-Don, Russia; (S.S.); (T.M.); (S.M.); (I.A.); (V.D.R.)
| | - Ilya Alliluev
- Academy of Biology and Biotechnology behalf D.I. Ivanovskyi, Southern Federal University, 344006 Rostov-on-Don, Russia; (S.S.); (T.M.); (S.M.); (I.A.); (V.D.R.)
| | - Hanuman Singh Jatav
- Soil Science & Agricultural Chemistry, S.K.N. Agriculture University-Jobner, Jaipur 303329, Rajasthan, India;
| | - Valery Kalinitchenko
- Institute of Fertility of Soils of South Russia, 346493 Persianovka, Rostov Region, Russia;
- All-Russian Research Institute for Phytopathology of the Russian Academy of Sciences, Institute St., 5, 143050 Big Vyazyomy, Moscow Region, Russia
| | - Vishnu D. Rajput
- Academy of Biology and Biotechnology behalf D.I. Ivanovskyi, Southern Federal University, 344006 Rostov-on-Don, Russia; (S.S.); (T.M.); (S.M.); (I.A.); (V.D.R.)
| | - Yanina Delegan
- Institute of Biochemistry and Physiology of Microorganisms, Federal Research Center “Pushchino Scientific Center for Biological Research of Russian Academy of Sciences” (FRC PSCBR RAS), 142290 Pushchino, Moscow Region, Russia; (A.B.); (A.B.)
- Academy of Biology and Biotechnology behalf D.I. Ivanovskyi, Southern Federal University, 344006 Rostov-on-Don, Russia; (S.S.); (T.M.); (S.M.); (I.A.); (V.D.R.)
| |
Collapse
|
2
|
Beck SW, Ye DY, Hwang HG, Jung GY. Stepwise Flux Optimization for Enhanced GABA Production from Acetate in Escherichia coli. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:10420-10427. [PMID: 38657224 DOI: 10.1021/acs.jafc.4c01198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Strategic allocation of metabolic flux is essential for achieving a higher production performance in genetically engineered organisms. Flux optimization between cell growth and chemical production has led to the establishment of cost-effective chemical production methods in microbial cell factories. This effect is amplified when utilizing a low-cost carbon source. γ-Aminobutyric acid (GABA), crucial in pharmaceuticals and biodegradable polymers, can be efficiently produced from acetate, a cost-effective substrate. However, a balanced distribution of acetate-derived flux is essential for optimizing the production without hindering growth. In this study, we demonstrated GABA production from acetate using Escherichia coli by focusing on optimizing the metabolic flux at isocitrate and α-ketoglutarate nodes. Through a series of flux optimizations, the final strain produced 2.54 g/L GABA from 5.91 g/L acetate in 24 h (0.43 g/g yield). These findings suggest that delicate flux balancing with the application of a cheap substrate can contribute to cost-effective production of GABA.
Collapse
Affiliation(s)
- Sun Woo Beck
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Dae-Yeol Ye
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Hyun Gyu Hwang
- Institute of Environmental and Energy Technology, Pohang University of Science and Technology, 77 Cheongam - Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Gyoo Yeol Jung
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Republic of Korea
| |
Collapse
|
3
|
Gupta P, Dash PK, Sanjay TD, Pradhan SK, Sreevathsa R, Rai R. Cloning and Molecular Characterization of the phlD Gene Involved in the Biosynthesis of "Phloroglucinol", a Compound with Antibiotic Properties from Plant Growth Promoting Bacteria Pseudomonas spp. Antibiotics (Basel) 2023; 12:antibiotics12020260. [PMID: 36830171 PMCID: PMC9952525 DOI: 10.3390/antibiotics12020260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 02/03/2023] Open
Abstract
phlD is a novel kind of polyketide synthase involved in the biosynthesis of non-volatile metabolite phloroglucinol by iteratively condensing and cyclizing three molecules of malonyl-CoA as substrate. Phloroglucinol or 2,4-diacetylphloroglucinol (DAPG) is an ecologically important rhizospheric antibiotic produced by pseudomonads; it exhibits broad spectrum anti-bacterial and anti-fungal properties, leading to disease suppression in the rhizosphere. Additionally, DAPG triggers systemic resistance in plants, stimulates root exudation, as well as induces phyto-enhancing activities in other rhizobacteria. Here, we report the cloning and analysis of the phlD gene from soil-borne gram-negative bacteria-Pseudomonas. The full-length phlD gene (from 1078 nucleotides) was successfully cloned and the structural details of the PHLD protein were analyzed in-depth via a three-dimensional topology and a refined three-dimensional model for the PHLD protein was predicted. Additionally, the stereochemical properties of the PHLD protein were analyzed by the Ramachandran plot, based on which, 94.3% of residues fell in the favored region and 5.7% in the allowed region. The generated model was validated by secondary structure prediction using PDBsum. The present study aimed to clone and characterize the DAPG-producing phlD gene to be deployed in the development of broad-spectrum biopesticides for the biocontrol of rhizospheric pathogens.
Collapse
Affiliation(s)
- Payal Gupta
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
| | - Prasanta K. Dash
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
- Correspondence: (P.K.D.); (R.R.); Tel.: +91-1125841787 (P.K.D.); Fax: +91-1125843984 (P.K.D.)
| | | | - Sharat Kumar Pradhan
- ICAR-National Rice Research Institute, Cuttack 753006, India
- Indian Council of Agriculture Research, Krishi Bhawan, New Delhi 110001, India
| | - Rohini Sreevathsa
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
| | - Rhitu Rai
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
- Correspondence: (P.K.D.); (R.R.); Tel.: +91-1125841787 (P.K.D.); Fax: +91-1125843984 (P.K.D.)
| |
Collapse
|
4
|
Lai X, Niroula D, Burrows M, Wu X, Yan Q. Identification and Characterization of Bacteria-Derived Antibiotics for the Biological Control of Pea Aphanomyces Root Rot. Microorganisms 2022; 10:microorganisms10081596. [PMID: 36014014 PMCID: PMC9416638 DOI: 10.3390/microorganisms10081596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 07/30/2022] [Accepted: 08/04/2022] [Indexed: 11/24/2022] Open
Abstract
Antibiosis has been proposed to contribute to the beneficial bacteria-mediated biocontrol against pea Aphanomyces root rot caused by the oomycete pathogen Aphanomyces euteiches. However, the antibiotics required for disease suppression remain unknown. In this study, we found that the wild type strains of Pseudomonas protegens Pf-5 and Pseudomonas fluorescens 2P24, but not their mutants that lack 2,4-diacetylphloroglucinol, strongly inhibited A. euteiches on culture plates. Purified 2,4-diacetylphloroglucinol compound caused extensive hyphal branching and stunted hyphal growth of A. euteiches. Using a GFP-based transcriptional reporter assay, we found that expression of the 2,4-diacetylphloroglucinol biosynthesis gene phlAPf-5 is activated by germinating pea seeds. The 2,4-diacetylphloroglucinol producing Pf-5 derivative, but not its 2,4-diacetylphloroglucinol non-producing mutant, reduced disease severity caused by A. euteiches on pea plants in greenhouse conditions. This is the first report that 2,4-diacetylphloroglucinol produced by strains of Pseudomonas species plays an important role in the biocontrol of pea Aphanomyces root rot.
Collapse
Affiliation(s)
- Xiao Lai
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717, USA
| | - Dhirendra Niroula
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717, USA
| | - Mary Burrows
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717, USA
| | - Xiaogang Wu
- College of Agriculture, Guangxi University, Nanning 530004, China
- Correspondence: (X.W.); (Q.Y.)
| | - Qing Yan
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717, USA
- Correspondence: (X.W.); (Q.Y.)
| |
Collapse
|
5
|
Pacheco-Moreno A, Stefanato FL, Ford JJ, Trippel C, Uszkoreit S, Ferrafiat L, Grenga L, Dickens R, Kelly N, Kingdon AD, Ambrosetti L, Nepogodiev SA, Findlay KC, Cheema J, Trick M, Chandra G, Tomalin G, Malone JG, Truman AW. Pan-genome analysis identifies intersecting roles for Pseudomonas specialized metabolites in potato pathogen inhibition. eLife 2021; 10:71900. [PMID: 34792466 PMCID: PMC8719888 DOI: 10.7554/elife.71900] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/16/2021] [Indexed: 11/29/2022] Open
Abstract
Agricultural soil harbors a diverse microbiome that can form beneficial relationships with plants, including the inhibition of plant pathogens. Pseudomonas spp. are one of the most abundant bacterial genera in the soil and rhizosphere and play important roles in promoting plant health. However, the genetic determinants of this beneficial activity are only partially understood. Here, we genetically and phenotypically characterize the Pseudomonas fluorescens population in a commercial potato field, where we identify strong correlations between specialized metabolite biosynthesis and antagonism of the potato pathogens Streptomyces scabies and Phytophthora infestans. Genetic and chemical analyses identified hydrogen cyanide and cyclic lipopeptides as key specialized metabolites associated with S. scabies inhibition, which was supported by in planta biocontrol experiments. We show that a single potato field contains a hugely diverse and dynamic population of Pseudomonas bacteria, whose capacity to produce specialized metabolites is shaped both by plant colonization and defined environmental inputs. Potato scab and blight are two major diseases which can cause heavy crop losses. They are caused, respectively, by the bacterium Streptomyces scabies and an oomycete (a fungus-like organism) known as Phytophthora infestans. Fighting these disease-causing microorganisms can involve crop management techniques – for example, ensuring that a field is well irrigated helps to keep S. scabies at bay. Harnessing biological control agents can also offer ways to control disease while respecting the environment. Biocontrol bacteria, such as Pseudomonas, can produce compounds that keep S. scabies and P. infestans in check. However, the identity of these molecules and how irrigation can influence Pseudomonas population remains unknown. To examine these questions, Pacheco-Moreno et al. sampled and isolated hundreds of Pseudomonas strains from a commercial potato field, closely examining the genomes of 69 of these. Comparing the genetic information of strains based on whether they could control the growth of S. scabies revealed that compounds known as cyclic lipopeptides are key to controlling the growth of S. scabies and P. infestans. Whether the field was irrigated also had a large impact on the strains forming the Pseudomonas population. Working out how Pseudomonas bacteria block disease could speed up the search for biological control agents. The approach developed by Pacheco-Moreno et al. could help to predict which strains might be most effective based on their genetic features. Similar experiments could also work for other combinations of plants and diseases.
Collapse
Affiliation(s)
- Alba Pacheco-Moreno
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | | | - Jonathan J Ford
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Christine Trippel
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Simon Uszkoreit
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Laura Ferrafiat
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Lucia Grenga
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Ruth Dickens
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Nathan Kelly
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Alexander Dh Kingdon
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Liana Ambrosetti
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Sergey A Nepogodiev
- Department of Biochemistry and Metabolism, John Innes Centre, Norwich, United Kingdom
| | - Kim C Findlay
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Jitender Cheema
- Department of Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom
| | - Martin Trick
- Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom
| | - Govind Chandra
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | | | - Jacob G Malone
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Andrew W Truman
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| |
Collapse
|
6
|
Li M, Ma Y, Zhang X, Zhang L, Chen X, Ye JW, Chen GQ. Tailor-Made Polyhydroxyalkanoates by Reconstructing Pseudomonas Entomophila. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2102766. [PMID: 34322928 DOI: 10.1002/adma.202102766] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/29/2021] [Indexed: 06/13/2023]
Abstract
Microbial polyhydroxyalkanoates (PHA) containing short- and medium/long-chain-length monomers, abbreviated as SCL-co-MCL/LCL PHAs, generate suitable thermal and mechanical properties. However, SCL-co-MCL/LCL PHAs with carbon chain longer than nine are difficult to synthesize due to the low specificity of PHA synthase PhaC and the lack of either SCL- or MCL/LCL monomer precursor fluxes. This study succeeds in reprogramming a β-oxidation weakened Pseudomonas entomophila containing synthesis pathways of SCL 3-hydroxybutyryl-CoA (3HB) from glucose and MCL/LCL 3-hydroxyalkanoyl-CoA from fatty acids with carbon chain lengths from 9 to 18, respectively, that are polymerized under a low specificity PhaC61-3 to form P(3HB-co-MCL/LCL 3HA) copolymers. Through rational flux-tuning approaches, the optimized recombinant P. entomophila accumulates 55 wt% poly-3-hydroxybutyrate in 8.4 g L-1 cell dry weight. Combined with weakened β-oxidation, a series of novel P(3HB-co-MCL/LCL 3HA) copolymers with over 60 wt% PHA in 9 g L-1 cell dry weight have been synthesized for the first time. P. entomophila has become a high-performing platform to generate tailor-made new SCL-co-MCL/LCL PHAs.
Collapse
Affiliation(s)
- Mengyi Li
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yueyuan Ma
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xu Zhang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Lizhan Zhang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xinyu Chen
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jian-Wen Ye
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Guo-Qiang Chen
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center of Life Sciences, Tsinghua University, Beijing, 100084, China
- MOE Key Lab of Industrial Biocatalysts, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| |
Collapse
|
7
|
Lee JY, Cha S, Lee JH, Lim HG, Noh MH, Kang CW, Jung GY. Plug-in repressor library for precise regulation of metabolic flux in Escherichia coli. Metab Eng 2021; 67:365-372. [PMID: 34333137 DOI: 10.1016/j.ymben.2021.07.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 07/10/2021] [Accepted: 07/28/2021] [Indexed: 10/20/2022]
Abstract
In metabolic engineering, enhanced production of value-added chemicals requires precise flux control between growth-essential competing and production pathways. Although advances in synthetic biology have facilitated the exploitation of a number of genetic elements for precise flux control, their use requires expensive inducers, or more importantly, needs complex and time-consuming processes to design and optimize appropriate regulator components, case-by-case. To overcome this issue, we devised the plug-in repressor libraries for target-specific flux control, in which expression levels of the repressors were diversified using degenerate 5' untranslated region (5' UTR) sequences employing the UTR Library Designer. After we validated a wide expression range of the repressor libraries, they were applied to improve the production of lycopene from glucose and 3-hydroxypropionic acid (3-HP) from acetate in Escherichia coli via precise flux rebalancing to enlarge precursor pools. Consequently, we successfully achieved optimal carbon fluxes around the precursor nodes for efficient production. The most optimized strains were observed to produce 2.59 g/L of 3-HP and 11.66 mg/L of lycopene, which were improved 16.5-fold and 2.82-fold, respectively, compared to those produced by the parental strains. These results indicate that carbon flux rebalancing using the plug-in library is a powerful strategy for efficient production of value-added chemicals in E. coli.
Collapse
Affiliation(s)
- Ji Yeon Lee
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea
| | - Sanghak Cha
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea
| | - Ji Hoon Lee
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea
| | - Hyun Gyu Lim
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea
| | - Myung Hyun Noh
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea
| | - Chae Won Kang
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea
| | - Gyoo Yeol Jung
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea; Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea.
| |
Collapse
|
8
|
Biessy A, Filion M. Phloroglucinol Derivatives in Plant-Beneficial Pseudomonas spp.: Biosynthesis, Regulation, and Functions. Metabolites 2021; 11:metabo11030182. [PMID: 33804595 PMCID: PMC8003664 DOI: 10.3390/metabo11030182] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/12/2021] [Accepted: 03/17/2021] [Indexed: 11/16/2022] Open
Abstract
Plant-beneficial Pseudomonas spp. aggressively colonize the rhizosphere and produce numerous secondary metabolites, such as 2,4-diacetylphloroglucinol (DAPG). DAPG is a phloroglucinol derivative that contributes to disease suppression, thanks to its broad-spectrum antimicrobial activity. A famous example of this biocontrol activity has been previously described in the context of wheat monoculture where a decline in take-all disease (caused by the ascomycete Gaeumannomyces tritici) has been shown to be associated with rhizosphere colonization by DAPG-producing Pseudomonas spp. In this review, we discuss the biosynthesis and regulation of phloroglucinol derivatives in the genus Pseudomonas, as well as investigate the role played by DAPG-producing Pseudomonas spp. in natural soil suppressiveness. We also tackle the mode of action of phloroglucinol derivatives, which can act as antibiotics, signalling molecules and, in some cases, even as pathogenicity factors. Finally, we discuss the genetic and genomic diversity of DAPG-producing Pseudomonas spp. as well as its importance for improving the biocontrol of plant pathogens.
Collapse
|
9
|
Guo DD, Luo LM, Ma HL, Zhang SP, Xu H, Zhang H, Wang Y, Yuan Y, Wang Z, He YX. The Regulator PltZ Regulates a Putative ABC Transporter System PltIJKNOP of Pseudomonas aeruginosa ATCC 27853 in Response to the Antimicrobial 2,4-Diacetylphloroglucinol. Front Microbiol 2020; 11:1423. [PMID: 32733400 PMCID: PMC7360687 DOI: 10.3389/fmicb.2020.01423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 06/02/2020] [Indexed: 12/27/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen commonly infecting immunocompromised patients with diseases like cystic fibrosis (CF) and cancers and has high rates of recurrence and mortality. The treatment efficacy can be significantly worsened by the multidrug resistance (MDR) of P. aeruginosa, and there is increasing evidence showing that it is easy for this pathogen to develop MDR. Here, we identified a gene cluster, pltZ-pltIJKNOP, which was originally assumed to be involved in the biosynthesis of an antimicrobial pyoluteorin, significantly contributing to the antibiotic resistance of P. aeruginosa ATCC 27853. Moreover, the TetR family regulator PltZ binds to a semi-palindromic sequence in the promoter region of the pltIJKNOP operon and recognizes the antimicrobial 2,4-diacetylphloroglucinol (2,4-DAPG), which in turn induces the expression of the pltIJKNOP operon. Using quantitative proteomics method, it was indicated that the regulator PltZ also plays an important role in maintaining metabolic hemostasis by regulating the transporting systems of amino acids, glucose, metal ions, and bacteriocins.
Collapse
Affiliation(s)
- Ding-Ding Guo
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Li-Ming Luo
- School of Pharmacy, Lanzhou University, Lanzhou, China.,Ministry of Education, Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Hai-Long Ma
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Si-Ping Zhang
- Ministry of Education, Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Hang Xu
- Ministry of Education, Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Honghua Zhang
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Yong Wang
- Ministry of Education, Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Yongna Yuan
- School of Information Science and Engineering, Lanzhou University, Lanzhou, China
| | - Zhen Wang
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Yong-Xing He
- Ministry of Education, Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| |
Collapse
|
10
|
Zhao MM, Lyu N, Wang D, Wu XG, Zhao YZ, Zhang LQ, Zhou HY. PhlG mediates the conversion of DAPG to MAPG in Pseudomonas fluorescens 2P24. Sci Rep 2020; 10:4296. [PMID: 32152338 PMCID: PMC7062750 DOI: 10.1038/s41598-020-60555-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 02/12/2020] [Indexed: 11/25/2022] Open
Abstract
The antibiotic 2,4-diacetylphoroglucinol (2,4-DAPG), produced by the Gram-negative rod-shaped bacterium Pseudomonas fluorescens 2P24, is active against various soil-borne bacterial and fungal pathogens that cause plant diseases. Biosynthesis of 2,4-DAPG is controlled by regulating expression of the phlACBD operon at the post-transcriptional level. The phlG gene is located between the phlF and phlH genes, upstream of the phlACBD biosynthetic operon. Herein, we cloned the phlG gene, generated a phlG deletion mutant, and investigated its regulatory role in 2,4-DAPG biosynthesis. The results showed that deletion of phlG had no effect on the biosynthesis of 2,4-DAPG, but it affected conversion of 2,4-DAPG to its precursor monoacetylphloroglucinol (MAPG). The global regulatory factor encoded by gacS positively regulated expression of phlG, while rsmE negatively regulated its expression. Deleting phlG did not alter the ability of the bacterium to colonise plants or promote plant growth. These results suggest that phlG collaborates with other factors to regulate production of the antibiotic 2,4-DAPG in P. fluorescens 2P24.
Collapse
Affiliation(s)
- Ming-Min Zhao
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, 010019, China
| | - Ning Lyu
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, 010019, China
| | - Dong Wang
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, 010019, China
| | - Xiao-Gang Wu
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Yuan-Zheng Zhao
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, Inner Mongolia, 010031, China
| | - Li-Qun Zhang
- College of Agriculture, Guangxi University, Nanning, 530004, China.,Key Laboratory of Plant Pathology, Ministry of Agriculture, Beijing, 100193, China
| | - Hong-You Zhou
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, 010019, China.
| |
Collapse
|
11
|
Meyer A, Saaem I, Silverman A, Varaljay VA, Mickol R, Blum S, Tobias AV, Schwalm ND, Mojadedi W, Onderko E, Bristol C, Liu S, Pratt K, Casini A, Eluere R, Moser F, Drake C, Gupta M, Kelley-Loughnane N, Lucks JP, Akingbade KL, Lux MP, Glaven S, Crookes-Goodson W, Jewett MC, Gordon DB, Voigt CA. Organism Engineering for the Bioproduction of the Triaminotrinitrobenzene (TATB) Precursor Phloroglucinol (PG). ACS Synth Biol 2019; 8:2746-2755. [PMID: 31750651 DOI: 10.1021/acssynbio.9b00393] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Organism engineering requires the selection of an appropriate chassis, editing its genome, combining traits from different source species, and controlling genes with synthetic circuits. When a strain is needed for a new target objective, for example, to produce a chemical-of-need, the best strains, genes, techniques, software, and expertise may be distributed across laboratories. Here, we report a project where we were assigned phloroglucinol (PG) as a target, and then combined unique capabilities across the United States Army, Navy, and Air Force service laboratories with the shared goal of designing an organism to produce this molecule. In addition to the laboratory strain Escherichia coli, organisms were screened from soil and seawater. Putative PG-producing enzymes were mined from a strain bank of bacteria isolated from aircraft and fuel depots. The best enzyme was introduced into the ocean strain Marinobacter atlanticus CP1 with its genome edited to redirect carbon flux from natural fatty acid ester (FAE) production. PG production was also attempted in Bacillus subtilis and Clostridium acetobutylicum. A genetic circuit was constructed in E. coli that responds to PG accumulation, which was then ported to an in vitro paper-based system that could serve as a platform for future low-cost strain screening or for in-field sensing. Collectively, these efforts show how distributed biotechnology laboratories with domain-specific expertise can be marshalled to quickly provide a solution for a targeted organism engineering project, and highlights data and material sharing protocols needed to accelerate future efforts.
Collapse
Affiliation(s)
- Adam Meyer
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Ishtiaq Saaem
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- The Foundry, 75 Ames Street, Cambridge Massachusetts 02142, United States
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Adam Silverman
- Center for Synthetic Biology, Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Vanessa A. Varaljay
- Soft Matter Materials Branch, Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, United States
| | - Rebecca Mickol
- American Society for Engineering Education, 1818 N Street NW Suite 600, Washington, D.C. 20036, United States
| | - Steven Blum
- U.S. Army Combat Capabilities Development Command Chemical Biological Center, 8198 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Alexander V. Tobias
- U.S. Army Research Laboratory, FCDD-RLS-EB, 2800 Powder Mill Road, Adelphi, Maryland 20783, United States
| | - Nathan D. Schwalm
- U.S. Army Research Laboratory, FCDD-RLS-EB, 2800 Powder Mill Road, Adelphi, Maryland 20783, United States
| | - Wais Mojadedi
- Oak Ridge Associate Universities, P.O.
Box 117, MS-29, Oak Ridge, Tennessee 37831, United States
| | - Elizabeth Onderko
- National Research Council, 500 5th Street NW, Washington, D.C. 20001, United States
| | - Cassandra Bristol
- The Foundry, 75 Ames Street, Cambridge Massachusetts 02142, United States
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Shangtao Liu
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- The Foundry, 75 Ames Street, Cambridge Massachusetts 02142, United States
| | - Katelin Pratt
- The Foundry, 75 Ames Street, Cambridge Massachusetts 02142, United States
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Arturo Casini
- The Foundry, 75 Ames Street, Cambridge Massachusetts 02142, United States
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Raissa Eluere
- The Foundry, 75 Ames Street, Cambridge Massachusetts 02142, United States
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Felix Moser
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Carrie Drake
- UES, Inc., 4401 Dayton-Xenia Road, Dayton, Ohio 45432, United States
| | - Maneesh Gupta
- Soft Matter Materials Branch, Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, United States
| | - Nancy Kelley-Loughnane
- Soft Matter Materials Branch, Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, United States
| | - Julius P. Lucks
- Center for Synthetic Biology, Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Katherine L. Akingbade
- U.S. Army Research Laboratory, FCDD-RLS-EB, 2800 Powder Mill Road, Adelphi, Maryland 20783, United States
| | - Matthew P. Lux
- U.S. Army Combat Capabilities Development Command Chemical Biological Center, 8198 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Sarah Glaven
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Wendy Crookes-Goodson
- Soft Matter Materials Branch, Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, United States
| | - Michael C. Jewett
- Center for Synthetic Biology, Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - D. Benjamin Gordon
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- The Foundry, 75 Ames Street, Cambridge Massachusetts 02142, United States
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Christopher A. Voigt
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- The Foundry, 75 Ames Street, Cambridge Massachusetts 02142, United States
| |
Collapse
|
12
|
Kenawy A, Dailin DJ, Abo-Zaid GA, Malek RA, Ambehabati KK, Zakaria KHN, Sayyed RZ, El Enshasy HA. Biosynthesis of Antibiotics by PGPR and Their Roles in Biocontrol of Plant Diseases. PLANT GROWTH PROMOTING RHIZOBACTERIA FOR SUSTAINABLE STRESS MANAGEMENT 2019:1-35. [DOI: 10.1007/978-981-13-6986-5_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
|
13
|
Li X, Gu GQ, Chen W, Gao LJ, Wu XH, Zhang LQ. The outer membrane protein OprF and the sigma factor SigX regulate antibiotic production in Pseudomonas fluorescens 2P24. Microbiol Res 2017; 206:159-167. [PMID: 29146252 DOI: 10.1016/j.micres.2017.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 09/09/2017] [Accepted: 10/15/2017] [Indexed: 10/18/2022]
Abstract
Pseudomonas fluorescens 2P24 produces 2,4-diacetylphloroglucinol (2,4-DAPG) as the major antibiotic compound that protects plants from soil-borne diseases. Expression of the 2,4-DAPG biosynthesis enzymes, which are encoded by the phlACBD locus, is under the control of a delicate regulatory network. In this study, we identified a novel role for the outer membrane protein gene oprF, in negatively regulating the 2,4-DAPG production by using random mini-Tn5 mutagentsis. A sigma factor gene sigX was located immediately upstream of the oprF gene and shown to be a positive regulator for oprF transcription and 2,4-DAPG production. Genetic analysis of an oprF and sigX double-mutant indicated that the 2,4-DAPG regulation by oprF was dependent on SigX. The sigX gene did not affect PhlA and PhlD expression, but positively regulated the level of malonyl-CoA, the substrate of 2,4-DAPG synthesis, by influencing the expression of acetyl-CoA carboxylases. Further investigations revealed that sigX transcription was induced under conditions of salt starvation or glycine addition. All these findings indicate that SigX is a novel regulator of substrate supplements for 2,4-DAPG production.
Collapse
Affiliation(s)
- Xu Li
- Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Gao-Qi Gu
- Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Wei Chen
- Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Li-Juan Gao
- Beijing Centre for Physical and Chemical Analysis, Beijing, 100089, China
| | - Xue-Hong Wu
- Department of Plant Pathology, China Agricultural University, Beijing, China; Key Laboratory of Pest Monitoring and Green Management, Ministry of Agriculture, Beijing, China
| | - Li-Qun Zhang
- Department of Plant Pathology, China Agricultural University, Beijing, China; Key Laboratory of Pest Monitoring and Green Management, Ministry of Agriculture, Beijing, China.
| |
Collapse
|
14
|
Mandryk-Litvinkovich MN, Muratova AA, Nosonova TL, Evdokimova OV, Valentovich LN, Titok MA, Kolomiets EI. Molecular genetic analysis of determinants defining synthesis of 2,4-diacetylphloroglucinol by Pseudomonas brassicacearum BIM B-446 bacteria. APPL BIOCHEM MICRO+ 2017. [DOI: 10.1134/s0003683817010124] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
15
|
Mousa WK, Raizada MN. Biodiversity of genes encoding anti-microbial traits within plant associated microbes. FRONTIERS IN PLANT SCIENCE 2015; 6:231. [PMID: 25914708 PMCID: PMC4392301 DOI: 10.3389/fpls.2015.00231] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 03/23/2015] [Indexed: 05/10/2023]
Abstract
The plant is an attractive versatile home for diverse associated microbes. A subset of these microbes produces a diversity of anti-microbial natural products including polyketides, non-ribosomal peptides, terpenoids, heterocylic nitrogenous compounds, volatile compounds, bacteriocins, and lytic enzymes. In recent years, detailed molecular analysis has led to a better understanding of the underlying genetic mechanisms. New genomic and bioinformatic tools have permitted comparisons of orthologous genes between species, leading to predictions of the associated evolutionary mechanisms responsible for diversification at the genetic and corresponding biochemical levels. The purpose of this review is to describe the biodiversity of biosynthetic genes of plant-associated bacteria and fungi that encode selected examples of antimicrobial natural products. For each compound, the target pathogen and biochemical mode of action are described, in order to draw attention to the complexity of these phenomena. We review recent information of the underlying molecular diversity and draw lessons through comparative genomic analysis of the orthologous coding sequences (CDS). We conclude by discussing emerging themes and gaps, discuss the metabolic pathways in the context of the phylogeny and ecology of their microbial hosts, and discuss potential evolutionary mechanisms that led to the diversification of biosynthetic gene clusters.
Collapse
Affiliation(s)
- Walaa K. Mousa
- Department of Plant Agriculture, University of GuelphGuelph, ON, Canada
- Department of Pharmacognosy, Faculty of Pharmacy, Mansoura UniversityMansoura, Egypt
| | - Manish N. Raizada
- Department of Plant Agriculture, University of GuelphGuelph, ON, Canada
| |
Collapse
|
16
|
Yoo YJ, Hwang JY, Shin HL, Cui H, Lee J, Yoon YJ. Characterization of negative regulatory genes for the biosynthesis of rapamycin in Streptomyces rapamycinicus and its application for improved production. J Ind Microbiol Biotechnol 2014; 42:125-35. [PMID: 25424695 DOI: 10.1007/s10295-014-1546-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 11/09/2014] [Indexed: 10/24/2022]
Abstract
Sequence analysis of the rapamycin biosynthetic gene cluster in Streptomyces rapamycinicus ATCC 29253 identified several putative regulatory genes. The deduced product of rapY, rapR, and rapS showed high sequence similarity to the TetR family transcription regulators, response regulators and histidine kinases of two-component systems, respectively. Overexpression of each of the three genes resulted in a significant reduction in rapamycin production, while in-frame deletion of rapS and rapY from the S. rapamycinicus chromosome improved the levels of rapamycin production by approximately 4.6-fold (33.9 mg l(-1)) and 3.7-fold (26.7 mg l(-1)), respectively, compared to that of the wild-type strain. Gene expression analysis by semi-quantitative reverse transcription-PCR (RT-PCR) in the wild-type and mutant strains indicated that most of the rapamycin biosynthetic genes are regulated negatively by rapS (probably through its partner response regulator RapR) and rapY. Interestingly, RapS negatively regulates the expression of the rapY gene, and in turn, rapX encoding an ABC-transporter is negatively controlled by RapY. Finally, overexpression of rapX in the rapS deletion mutant resulted in a 6.7-fold (49 mg l(-1)) increase in rapamycin production compared to that of wild-type strain. These results demonstrate the role of RapS/R and RapY as negative regulators of rapamycin biosynthesis and provide valuable information to both understand the complex regulatory mechanism in S. rapamycinicus and exploit the regulatory genes to increase the level of rapamycin production in industrial strains.
Collapse
Affiliation(s)
- Young Ji Yoo
- Department of Chemistry and Nano Science, Ewha Global Top5 Research Program, Ewha Womans University, Seoul, 120-750, Republic of Korea
| | | | | | | | | | | |
Collapse
|
17
|
Posttranscriptional regulation of 2,4-diacetylphloroglucinol production by GidA and TrmE in Pseudomonas fluorescens 2P24. Appl Environ Microbiol 2014; 80:3972-81. [PMID: 24747907 DOI: 10.1128/aem.00455-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas fluorescens 2P24 is a soilborne bacterium that synthesizes and excretes multiple antimicrobial metabolites. The polyketide compound 2,4-diacetylphloroglucinol (2,4-DAPG), synthesized by the phlACBD locus, is its major biocontrol determinant. This study investigated two mutants defective in antagonistic activity against Rhizoctonia solani. Deletion of the gidA (PM701) or trmE (PM702) gene from strain 2P24 completely inhibited the production of 2,4-DAPG and its precursors, monoacetylphloroglucinol (MAPG) and phloroglucinol (PG). The transcription of the phlA gene was not affected, but the translation of the phlA and phlD genes was reduced significantly. Two components of the Gac/Rsm pathway, RsmA and RsmE, were found to be regulated by gidA and trmE, whereas the other components, RsmX, RsmY, and RsmZ, were not. The regulation of 2,4-DAPG production by gidA and trmE, however, was independent of the Gac/Rsm pathway. Both the gidA and trmE mutants were unable to produce PG but could convert PG to MAPG and MAPG to 2,4-DAPG. Overexpression of PhlD in the gidA and trmE mutants could restore the production of PG and 2,4-DAPG. Taken together, these findings suggest that GidA and TrmE are positive regulatory elements that influence the biosynthesis of 2,4-DAPG posttranscriptionally.
Collapse
|
18
|
Barret M, Egan F, Moynihan J, Morrissey JP, Lesouhaitier O, O'Gara F. Characterization of the SPI-1 and Rsp type three secretion systems in Pseudomonas fluorescens F113. ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:377-86. [PMID: 23754718 DOI: 10.1111/1758-2229.12039] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 01/10/2013] [Indexed: 05/21/2023]
Abstract
Pseudomonas fluorescens F113 is a plant growth-promoting rhizobacterium (PGPR) isolated from the sugar beet rhizosphere. The recent annotation of the F113 genome sequence has revealed that this strain encodes a wide array of secretion systems, including two complete type three secretion systems (T3SSs) belonging to the Hrp1 and SPI-1 families. While Hrp1 T3SSs are frequently encoded in other P. fluorescens strains, the presence of a SPI-1 T3SS in a plant-beneficial bacterial strain was unexpected. In this work, the genetic organization and expression of these two T3SS loci have been analysed by a combination of transcriptional reporter fusions and transcriptome analyses. Overexpression of two transcriptional activators has shown a number of genes encoding putative T3 effectors. In addition, the influence of these two T3SSs during the interaction of P. fluorescens F113 with some bacterial predators was also assessed. Our data revealed that the transcriptional activator hilA is induced by amoeba and that the SPI-1 T3SS could potentially be involved in resistance to amoeboid grazing.
Collapse
Affiliation(s)
- Matthieu Barret
- BIOMERIT Research Centre, University College Cork, Cork, Ireland
| | | | | | | | | | | |
Collapse
|
19
|
Troppens DM, Chu M, Holcombe LJ, Gleeson O, O'Gara F, Read ND, Morrissey JP. The bacterial secondary metabolite 2,4-diacetylphloroglucinol impairs mitochondrial function and affects calcium homeostasis in Neurospora crassa. Fungal Genet Biol 2013; 56:135-46. [PMID: 23624246 DOI: 10.1016/j.fgb.2013.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 03/25/2013] [Accepted: 04/12/2013] [Indexed: 10/26/2022]
Abstract
The bacterial secondary metabolite 2,4-diacetylphloroglucinol (DAPG) is of interest as an active ingredient of biological control strains of Pseudomonas fluorescens and as a potential lead pharmaceutical molecule because of its capacity to inhibit growth of diverse microbial and non-microbial cells. The mechanism by which this occurs is unknown and in this study the filamentous fungus Neurospora crassa was used as a model to investigate the effects of DAPG on a eukaryotic cell. Colony growth, conidial germination and cell fusion assays confirmed the inhibitory nature of DAPG towards N. crassa. A number of different fluorescent dyes and fluorescent protein reporters were used to assess the effects of DAPG treatment on mitochondrial and other cellular functions. DAPG treatment led to changes in mitochondrial morphology, and rapid loss of mitochondrial membrane potential. These effects are likely to be responsible for the toxicity of DAPG. It was also found that DAPG treatment caused extracellular calcium to be taken up by conidial germlings leading to a transient increase in cytosolic free Ca(2+) with a distinct concentration dependent Ca(2+) signature.
Collapse
|
20
|
Fighting Plant Diseases Through the Application of Bacillus and Pseudomonas Strains. SOIL BIOLOGY 2013. [DOI: 10.1007/978-3-642-39317-4_9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|
21
|
Wu X, Liu J, Zhang W, Zhang L. Multiple-level regulation of 2,4-diacetylphloroglucinol production by the sigma regulator PsrA in Pseudomonas fluorescens 2P24. PLoS One 2012; 7:e50149. [PMID: 23209661 PMCID: PMC3510223 DOI: 10.1371/journal.pone.0050149] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 10/22/2012] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Pseudomonas fluorescens 2P24 is a rhizospheric bacterium that aggressively colonizes the plant roots. It produces the antibiotic 2,4-diacetylphoroglucinol (2,4-DAPG), which contributes to the protection of various crop plants against soil borne diseases caused by bacterial and fungal pathogens. The biosynthesis of 2,4-DAPG is regulated at the transcriptional level in the expression of the phlACBD operon as well as at the posttranscriptional level by the Gac/Rsm signal transduction pathway. However, the detailed mechanism of such regulation is not clear. METHODOLOGY/PRINCIPAL FINDINGS In this study, we identified a binding site for the sigma regulator PsrA in the promoter region of the phlA gene. Electrophoretic mobility shift experiments revealed direct and specific binding of PsrA to the phlA promoter region. Consistent with the fact that its binding site locates within the promoter region of phlA, PsrA negatively regulates phlA expression, and its inactivation led to significant increase in 2,4-DAPG production. Interestingly, PsrA also activates the expression of the sigma factor RpoS, which negatively regulates 2,4-DAPG production by inducing the expression of the RNA-binding protein RsmA. CONCLUSIONS/SIGNIFICANCE These results suggest that PsrA is an important regulator that modulates 2,4-DAPG biosynthesis at both transcriptional and posttranscriptional levels.
Collapse
Affiliation(s)
- Xiaogang Wu
- Department of Plant Pathology, China Agricultural University, Beijing, People's Republic of China
| | - Jiucheng Liu
- Department of Plant Pathology, China Agricultural University, Beijing, People's Republic of China
| | - Wei Zhang
- Department of Plant Pathology, China Agricultural University, Beijing, People's Republic of China
| | - Liqun Zhang
- Department of Plant Pathology, China Agricultural University, Beijing, People's Republic of China
- Key Laboratory of Plant Pathology, Ministry of Agriculture, Beijing, People's Republic of China
- * E-mail:
| |
Collapse
|
22
|
Yang F, Cao Y. Biosynthesis of phloroglucinol compounds in microorganisms--review. Appl Microbiol Biotechnol 2011; 93:487-95. [PMID: 22101786 DOI: 10.1007/s00253-011-3712-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 10/23/2011] [Accepted: 11/05/2011] [Indexed: 12/24/2022]
Abstract
Phloroglucinol derivatives are a major class of secondary metabolites of wide occurrence in biological systems. In the bacteria kingdom, these compounds can only be synthesized by some species of Pseudomonads. Pseudomonas spp. could produce 2,4-diacetylphloroglucinol (DAPG) that plays an important role in the biological control of many plant pathogens. In this review, we summarize knowledge about synthesis of phloroglucinol compounds based on the DAPG biosynthetic pathway. Recent advances that have been made in understanding phloroglucinol compound biosynthesis and regulation are highlighted. From these studies, researchers have identified the biosynthesis pathway of DAPG. Most of the genes involved in the biosynthesis pathway have been cloned and characterized. Additionally, heterologous systems of the model microorganism Escherichia coli are constructed to produce phloroglucinol. Although further work is still required, a full understanding of phloroglucinol compound biosynthesis is almost within reach. This review also suggests new directions and attempts to gain some insights for better understanding of the biosynthesis and regulation of DAPG. The combination of traditional biochemistry and molecular biology with new systems biology and synthetic biology tools will provide a better view of phloroglucinol compound biosynthesis and a greater potential of microbial production.
Collapse
Affiliation(s)
- Fang Yang
- Ningbo Institute of Material Technology & Engineering, Chinese Academy of Sciences, 315201, Ningbo, China
| | | |
Collapse
|
23
|
Abstract
Marine bacteria and fungi are of considerable importance as new promising sources of a huge number of biologically active products. Some of these marine species live in a stressful habitat, under cold, lightless and high pressure conditions. Surprisingly, a large number of species with high diversity survive under such conditions and produce fascinating and structurally complex natural products. Up till now, only a small number of microorganisms have been investigated for bioactive metabolites, yet a huge number of active substances with some of them featuring unique structural skeletons have been isolated. This review covers new biologically active natural products published recently (2007-09) and highlights the chemical potential of marine microorganisms, with focus on bioactive products as well as on their mechanisms of action.
Collapse
Affiliation(s)
- Abdessamad Debbab
- Institut für Pharmazeutische Biologie und Biotechnologie, Heinrich-Heine Universitaet Duesseldorf, Germany
| | | | | | | |
Collapse
|
24
|
He YX, Huang L, Xue Y, Fei X, Teng YB, Rubin-Pitel SB, Zhao H, Zhou CZ. Crystal structure and computational analyses provide insights into the catalytic mechanism of 2,4-diacetylphloroglucinol hydrolase PhlG from Pseudomonas fluorescens. J Biol Chem 2010; 285:4603-11. [PMID: 20018877 PMCID: PMC2836065 DOI: 10.1074/jbc.m109.044180] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 11/03/2009] [Indexed: 12/24/2022] Open
Abstract
2,4-Diacetylphloroglucinol hydrolase PhlG from Pseudomonas fluorescens catalyzes hydrolytic carbon-carbon (C-C) bond cleavage of the antibiotic 2,4-diacetylphloroglucinol to form monoacetylphloroglucinol, a rare class of reactions in chemistry and biochemistry. To investigate the catalytic mechanism of this enzyme, we determined the three-dimensional structure of PhlG at 2.0 A resolution using x-ray crystallography and MAD methods. The overall structure includes a small N-terminal domain mainly involved in dimerization and a C-terminal domain of Bet v1-like fold, which distinguishes PhlG from the classical alpha/beta-fold hydrolases. A dumbbell-shaped substrate access tunnel was identified to connect a narrow interior amphiphilic pocket to the exterior solvent. The tunnel is likely to undergo a significant conformational change upon substrate binding to the active site. Structural analysis coupled with computational docking studies, site-directed mutagenesis, and enzyme activity analysis revealed that cleavage of the 2,4-diacetylphloroglucinol C-C bond proceeds via nucleophilic attack by a water molecule, which is coordinated by a zinc ion. In addition, residues Tyr(121), Tyr(229), and Asn(132), which are predicted to be hydrogen-bonded to the hydroxyl groups and unhydrolyzed acetyl group, can finely tune and position the bound substrate in a reactive orientation. Taken together, these results revealed the active sites and zinc-dependent hydrolytic mechanism of PhlG and explained its substrate specificity as well.
Collapse
Affiliation(s)
- Yong-Xing He
- From the Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China and
| | - Liang Huang
- From the Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China and
| | - Yanyan Xue
- From the Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China and
| | - Xue Fei
- From the Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China and
| | - Yan-Bin Teng
- From the Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China and
| | | | - Huimin Zhao
- the Departments of Chemical and Biomolecular Engineering and
- Chemistry and
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Cong-Zhao Zhou
- From the Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China and
| |
Collapse
|
25
|
Tian T, Wu XG, Duan HM, Zhang LQ. The resistance-nodulation-division efflux pump EmhABC influences the production of 2,4-diacetylphloroglucinol in Pseudomonas fluorescens 2P24. MICROBIOLOGY-SGM 2009; 156:39-48. [PMID: 19833777 DOI: 10.1099/mic.0.031161-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The polyketide metabolite 2,4-diacetylphloroglucinol (2,4-DAPG) plays a major role in the biological control of soil-borne plant diseases by Pseudomonas fluorescens 2P24. Two mutants (PM810 and PM820) with increased extracellular accumulation of 2,4-DAPG were isolated using transposon mutagenesis. The disrupted genes in these two mutants shared >80 % identity with the genes of the EmhR-EmhABC resistance-nodulation-division (RND) efflux system of P. fluorescens cLP6a. The deletion of emhA (PM802), emhB (PM803) or emhC (PM804) genes in strain 2P24 increased the extracellular accumulation of 2,4-DAPG, whereas the deletion of the emhR (PM801) gene decreased the biosynthesis of 2,4-DAPG. The promoter assay confirmed the elevated transcription of emhABC in the EmhR disrupted strain (PM801) and an indirect negative regulation of 2,4-DAPG biosynthetic locus transcription by the EmhABC efflux pump. Induction by exogenous 2,4-DAPG led to remarkable differences in transcription of chromosome-borne phlA : : lacZ fusion in PM901 and PM811 (emhA(-)) strains. Additionally, the EmhABC system in strain 2P24 was involved in the resistance to a group of toxic compounds, including ampicillin, chloramphenicol, tetracycline, ethidium bromide and crystal violet. In conclusion, our results suggest that the EmhABC system is an important element that influences the production of antibiotic 2,4-DAPG and enhances resistance to toxic compounds in P. fluorescens 2P24.
Collapse
Affiliation(s)
- Tao Tian
- Department of Plant Pathology, China Agricultural University, Beijing, 100193, PR China
| | - Xiao-Gang Wu
- Department of Plant Pathology, China Agricultural University, Beijing, 100193, PR China
| | - Hui-Mei Duan
- Department of Plant Pathology, China Agricultural University, Beijing, 100193, PR China
| | - Li-Qun Zhang
- The Key Laboratory of Plant Pathology, Ministry of Agriculture, Beijing, 100193, PR China.,Department of Plant Pathology, China Agricultural University, Beijing, 100193, PR China
| |
Collapse
|
26
|
Gross H, Loper JE. Genomics of secondary metabolite production by Pseudomonas spp. Nat Prod Rep 2009; 26:1408-46. [PMID: 19844639 DOI: 10.1039/b817075b] [Citation(s) in RCA: 390] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Harald Gross
- Institute for Pharmaceutical Biology, Nussallee 6, 53115, Bonn, Germany.
| | | |
Collapse
|
27
|
Evolutionary history of the phl gene cluster in the plant-associated bacterium Pseudomonas fluorescens. Appl Environ Microbiol 2009; 75:2122-31. [PMID: 19181839 DOI: 10.1128/aem.02052-08] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas fluorescens is of agricultural and economic importance as a biological control agent largely because of its plant association and production of secondary metabolites, in particular 2,4-diacetylphloroglucinol (2,4-DAPG). This polyketide, which is encoded by the eight-gene phl cluster, has antimicrobial effects on phytopathogens, promotes amino acid exudation from plant roots, and induces systemic resistance in plants. Despite its importance, 2,4-DAPG production is limited to a subset of P. fluorescens strains. Determination of the evolution of the phl cluster and understanding the selective pressures promoting its retention or loss in lineages of P. fluorescens will help in the development of P. fluorescens as a viable and effective inoculant for application in agriculture. In this study, genomic and sequence-based approaches were integrated to reconstruct the phylogeny of P. fluorescens and the phl cluster. It was determined that 2,4-DAPG production is an ancestral trait in the species P. fluorescens but that most lineages have lost this capacity through evolution. Furthermore, intragenomic recombination has relocated the phl cluster within the P. fluorescens genome at least three times, but the integrity of the cluster has always been maintained. The possible evolutionary and functional implications for retention of the phl cluster and 2,4-DAPG production in some lineages of P. fluorescens are discussed.
Collapse
|
28
|
Russo A, Basaglia M, Casella S, Nuti MP. Pseudomonas fluorescens 134 as a Biological Control Agent (BCA) Model in Cell Immobilization Technology. Biotechnol Prog 2008; 21:309-14. [PMID: 15903270 DOI: 10.1021/bp040030w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Antifungal activity against Rhizoctonia solani was achieved in vivo through the application of Pseudomonas fluorescens strain 134 encapsulated in sodium alginate beads of different sizes (0.5, 1, and 2 mm). The activity was compared to that obtainable with chemical treatments and bead-derived liquid formulations. The latter was obtained by dissolving alginate beads of 1 and 0.5 mm in 1% Na-citrate solution before application, without any significant (P < 0.05) reduction of bacterial numbers during the dissolution process. The dry bead formulations were applied next to the seeds in plant inoculation experiments, resulting in a reduction of disease symptoms, which were markedly reduced when the liquid formulation was applied. Moreover, the rate of disease symptoms related to liquid formulations from both 1 and 0.5 mm beads was comparable (near to 10%) to that of chemical treatment. Pseudomonas fluorescens strain 134 delivered as both dry and liquid formulations was able to colonize cotton root at a population density of about 10(8) CFU/g fresh root, 15 days after sowing.
Collapse
Affiliation(s)
- Anna Russo
- Dipartimento di Chimica e Biotecnologie Agrarie, Università di Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | | | | | | |
Collapse
|
29
|
Pagès D, Sanchez L, Conrod S, Gidrol X, Fekete A, Schmitt-Kopplin P, Heulin T, Achouak W. Exploration of intraclonal adaptation mechanisms of Pseudomonas brassicacearum facing cadmium toxicity. Environ Microbiol 2008; 9:2820-35. [PMID: 17922765 PMCID: PMC2121137 DOI: 10.1111/j.1462-2920.2007.01394.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Pseudomonas brassicacearum forms phenotypic variants in vitro as well as in planta during root colonization under natural conditions, leading to subpopulations (phase I and II cells) that differ in colony morphology and production of exoenzymes/secondary metabolites. The maximal concentration of cadmium allowing both variants growth was 25 μM; however, phase II cells accumulated fivefold higher Cd than phase I cells, even though both variants showed the same growth rate and kinetics, comprising a long stasis period (50 h). The whole transcriptome analysis of both variants in response to Cd was investigated using the home-made DNA microarrays. This analysis revealed completely different adaptation mechanisms developed by each variant to withstand and grow in the presence of the toxic. A re-organization of the cell wall to limit Cd entrance was noticed for phase I cells, as genes encoding levan exopolymers were downregulated at the expense of an upregulation of genes encoding alginate, and an upregulation of transporters such as cadA, and a downregulation of copper transporters. Phase II cells were unable to prevent Cd entrance and recruited genes under the control of oxyR and soxR regulation to face osmotic and oxidant stresses generated by Cd. Putrescine and spermidine metabolism appeared to play a central role in Cd tolerance. Microarray data were validated by biological analyses such as motility, oxidative stress assay, metabolite profiling with ICR-FT/MS and UPLC, capillary electrophoresis analysis of biogenic amines.
Collapse
Affiliation(s)
- Delphine Pagès
- Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes, CEA, DSV, iBEB, LEMiRE, CNRS, Aix Marseille Universite. CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Mikani A, Etebarian HR, Aminian H, Alizadeh A. Interaction between Pseudomonas fluorescens isolates and thiabendazole in the control of gray mold of apple. Pak J Biol Sci 2007; 10:2172-2177. [PMID: 19070177 DOI: 10.3923/pjbs.2007.2172.2177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Five isolates KW, 16P, 8, 11 and 7 of Pseudomonas fluorescens and fungicide thiabendazole were evaluated for control of gray mold of apple caused by Botrytis mali. Dual culture, cell free metabolite and volatile test showed that all five isolates of Pseudomonas fluorescens tested inhibited growth of the pathogen. Inhibition varied from 28.9-85.7% in dual culture, from 62-94.6% in cell free metabolite and from 45.9-87.9% in volatile test. Apples were wounded and inoculated with a 20 microL Botrytis mali (10(5) conidia mL(-1)) combined with a range of concentration of fungicide. Thiabendazole controlled gray mold by over 83% at 5 microg mL(-1). Pseudomonas fluorescens isolates prevented B. mali decay from expanding to more than 49.4% at 20 degrees C. Thiabendazole was combined with bacteria to control gray mold of apple. Mixing of thiabendazole and bacterial isolates provide more than 90.2% control at concentrations 5 microL mL(-1) and 10(7) CFU mL(-1), respectively, on Golden delicious apples. A combination of thiabendazole and Pseudomonas fluorescens isolate 11 at concentration 10 microg mL(-1) and 1 x10(7) CFU mL(-1), respectively controlled gray mold by 100%. Thiabendazole was not bactericidal and had no effect on five isloates of Pseudomonas fluorescens.
Collapse
Affiliation(s)
- A Mikani
- Department of Plant Protection, Abourayhan Campus, University of Tehran, P.O. Box 11365/4117, Tehran, Iran
| | | | | | | |
Collapse
|
31
|
Weller DM, Landa BB, Mavrodi OV, Schroeder KL, De La Fuente L, Blouin Bankhead S, Allende Molar R, Bonsall RF, Mavrodi DV, Thomashow LS. Role of 2,4-diacetylphloroglucinol-producing fluorescent Pseudomonas spp. in the defense of plant roots. PLANT BIOLOGY (STUTTGART, GERMANY) 2007; 9:4-20. [PMID: 17058178 DOI: 10.1055/s-2006-924473] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Plants have evolved strategies of stimulating and supporting specific groups of antagonistic microorganisms in the rhizosphere as a defense against diseases caused by soilborne plant pathogens owing to a lack of genetic resistance to some of the most common and widespread soilborne pathogens. Some of the best examples of natural microbial defense of plant roots occur in disease suppressive soils. Soil suppressiveness against many different diseases has been described. Take-all is an important root disease of wheat, and soils become suppressive to take-all when wheat or barley is grown continuously in a field following a disease outbreak; this phenomenon is known as take-all decline (TAD). In Washington State, USA and The Netherlands, TAD results from the enrichment during monoculture of populations of 2,4-diacetylphloroglucinol (2,4-DAPG)-producing Pseudomonas fluorescens to a density of 10 (5) CFU/g of root, the threshold required to suppress the take-all pathogen, Gaeumannomyces graminis var. tritici. 2,4-DAPG-producing P. fluorescens also are enriched by monoculture of other crops such as pea and flax, and evidence is accumulating that 2,4-DAPG producers contribute to the defense of plant roots in many different agroecosystems. At this time, 22 distinct genotypes of 2,4-DAPG producers (designated A - T, PfY and PfZ) have been defined by whole-cell repetitive sequence-based (rep)-PCR analysis, restriction fragment length polymorphism (RFLP) analysis of PHLD, and phylogenetic analysis of PHLD, but the number of genotypes is expected to increase. The genotype of an isolate is predictive of its rhizosphere competence on wheat and pea. Multiple genotypes often occur in a single soil and the crop species grown modulates the outcome of the competition among these genotypes in the rhizosphere. 2,4-DAPG producers are highly effective biocontrol agents against a variety of plant diseases and ideally suited for serving as vectors for expressing other biocontrol traits in the rhizosphere.
Collapse
Affiliation(s)
- D M Weller
- USDA-ARS Root Disease and Biological Control Research Unit, Washington State University, P.O. Box 646430, 367 Johnson Hall, Pullman, WA 99164-6430, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Wei HL, Zhang LQ. Quorum-sensing system influences root colonization and biological control ability in Pseudomonas fluorescens 2P24. Antonie Van Leeuwenhoek 2006; 89:267-80. [PMID: 16710638 DOI: 10.1007/s10482-005-9028-8] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Accepted: 12/19/2005] [Indexed: 11/29/2022]
Abstract
Pseudomonas fluorescens 2P24 is a biocontrol agent isolated from a wheat take-all decline soil in China. This strain produces several antifungal compounds, such as 2,4-diacetylphloroglucinol (2,4-DAPG), hydrogen cyanide and siderophore(s). Our recent work revealed that strain 2P24 employs a quorum-sensing system to regulate its biocontrol activity. In this study, we identified a quorum-sensing system consisting of PcoR and PcoI of the LuxR-LuxI family from strain 2P24. Deletion of pcoI from 2P24 abolishes the production of the quorum-sensing signals, but does not detectably affect the production of antifungal metabolites. However, the mutant is significantly defective in biofilm formation, colonization on wheat rhizosphere and biocontrol ability against wheat take-all, whilst complementation of pcoI restores the biocontrol activity to the wild-type level. Our data indicate that quorum sensing is involved in regulation of biocontrol activity in P. fluorescens 2P24.
Collapse
Affiliation(s)
- Hai-Lei Wei
- Department of Plant Pathology, China Agricultural University, Beijing, P.R. China
| | | |
Collapse
|
33
|
Kiely PD, Haynes JM, Higgins CH, Franks A, Mark GL, Morrissey JP, O'Gara F. Exploiting new systems-based strategies to elucidate plant-bacterial interactions in the rhizosphere. MICROBIAL ECOLOGY 2006; 51:257-66. [PMID: 16596439 DOI: 10.1007/s00248-006-9019-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Accepted: 12/16/2005] [Indexed: 05/08/2023]
Abstract
The rhizosphere is the site of intense interactions between plant, bacterial, and fungal partners. In plant-bacterial interactions, signal molecules exuded by the plant affect both primary initiation and subsequent behavior of the bacteria in complex beneficial associations such as biocontrol. However, despite this general acceptance that plant-root exudates have an effect on the resident bacterial populations, very little is still known about the influence of these signals on bacterial gene expression and the roles of genes found to have altered expression in plant-microbial interactions. Analysis of the rhizospheric communities incorporating both established techniques, and recently developed "omic technologies" can now facilitate investigations into the molecular basis underpinning the establishment of beneficial plant-microbial interactomes in the rhizosphere. The understanding of these signaling processes, and the functions they regulate, is fundamental to understanding the basis of beneficial microbial-plant interactions, to overcoming existing limitations, and to designing improved strategies for the development of novel Pseudomonas biocontrol strains.
Collapse
Affiliation(s)
- P D Kiely
- Biomerit Research Centre, Department of Microbiology, National University of Ireland (UCC), Cork, Ireland
| | | | | | | | | | | | | |
Collapse
|
34
|
Bottiglieri M, Keel C. Characterization of PhlG, a hydrolase that specifically degrades the antifungal compound 2,4-diacetylphloroglucinol in the biocontrol agent Pseudomonas fluorescens CHA0. Appl Environ Microbiol 2006; 72:418-27. [PMID: 16391073 PMCID: PMC1352262 DOI: 10.1128/aem.72.1.418-427.2006] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The potent antimicrobial compound 2,4-diacetylphloroglucinol (DAPG) is a major determinant of biocontrol activity of plant-beneficial Pseudomonas fluorescens CHA0 against root diseases caused by fungal pathogens. The DAPG biosynthetic locus harbors the phlG gene, the function of which has not been elucidated thus far. The phlG gene is located upstream of the phlACBD biosynthetic operon, between the phlF and phlH genes which encode pathway-specific regulators. In this study, we assigned a function to PhlG as a hydrolase specifically degrades DAPG to equimolar amounts of mildly toxic monoacetylphloroglucinol (MAPG) and acetate. DAPG added to cultures of a DAPG-negative DeltaphlA mutant of strain CHA0 was completely degraded, and MAPG was temporarily accumulated. In contrast, DAPG was not degraded in cultures of a DeltaphlA DeltaphlG double mutant. To confirm the enzymatic nature of PhlG in vitro, the protein was histidine tagged, overexpressed in Escherichia coli, and purified by affinity chromatography. Purified PhlG had a molecular mass of about 40 kDa and catalyzed the degradation of DAPG to MAPG. The enzyme had a kcat of 33 s(-1) and a Km of 140 microM at 30 degrees C and pH 7. The PhlG enzyme did not degrade other compounds with structures similar to DAPG, such as MAPG and triacetylphloroglucinol, suggesting strict substrate specificity. Interestingly, PhlG activity was strongly reduced by pyoluteorin, a further antifungal compound produced by the bacterium. Expression of phlG was not influenced by the substrate DAPG or the degradation product MAPG but was subject to positive control by the GacS/GacA two-component system and to negative control by the pathway-specific regulators PhlF and PhlH.
Collapse
Affiliation(s)
- Mélanie Bottiglieri
- Département de Microbiologie Fondamentale, Bātiment de Biologie, Université de Lausanne, CH-1015 Lausanne-Dorigny, Switzerland
| | | |
Collapse
|
35
|
Brodhagen M, Paulsen I, Loper JE. Reciprocal regulation of pyoluteorin production with membrane transporter gene expression in Pseudomonas fluorescens Pf-5. Appl Environ Microbiol 2005; 71:6900-9. [PMID: 16269724 PMCID: PMC1287665 DOI: 10.1128/aem.71.11.6900-6909.2005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pyoluteorin is a chlorinated polyketide antibiotic secreted by the rhizosphere bacterium Pseudomonas fluorescens Pf-5. Genes encoding enzymes and transcriptional regulators involved in pyoluteorin production are clustered in the genome of Pf-5. Sequence analysis of genes adjacent to the known pyoluteorin biosynthetic gene cluster revealed the presence of an ABC transporter system. We disrupted two putative ABC transporter genes by inserting transcriptional fusions to an ice nucleation reporter gene. Mutations in pltI and pltJ, which are predicted to encode a membrane fusion protein and an ATP-binding cassette of the ABC transporter, respectively, greatly reduced pyoluteorin production by Pf-5. During the transition from exponential growth to stationary phase, populations of a pltI mutant were lower than those of a pltI+ strain in a culture medium containing pyoluteorin, suggesting a role for the transport system in efflux and the resistance of Pf-5 to the antibiotic. Although pltI or pltJ mutant strains displayed low pyoluteorin production, they did not accumulate proportionately more of the antibiotic intracellularly, indicating that pltI and pltJ do not encode an exclusive exporter for pyoluteorin. Transcription of the putative pyoluteorin efflux genes pltI and pltJ was enhanced by exogenous pyoluteorin. These new observations parallel an earlier finding that pyoluteorin enhances the transcription of pyoluteorin biosynthesis genes and pyoluteorin production in Pf-5. This report provides evidence of a coordination of pyoluteorin production and the transcription of genes encoding a linked transport apparatus, wherein each requires the other for optimal expression.
Collapse
Affiliation(s)
- Marion Brodhagen
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | | | | |
Collapse
|
36
|
Baehler E, Bottiglieri M, Péchy-Tarr M, Maurhofer M, Keel C. Use of green fluorescent protein-based reporters to monitor balanced production of antifungal compounds in the biocontrol agentPseudomonas fluorescensCHA0. J Appl Microbiol 2005; 99:24-38. [PMID: 15960662 DOI: 10.1111/j.1365-2672.2005.02597.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To develop reporter constructs based on stable and unstable variants of the green fluorescent protein (GFP) for monitoring balanced production of antifungal compounds that are crucial for the capacity of the root-colonizing Pseudomonas fluorescens strain CHA0 to control plant diseases caused by soil-borne pathogenic fungi. METHODS AND RESULTS Pseudomonas fluorescens CHA0 produces the three antifungal metabolites 2,4-diacetylphloroglucinol (DAPG), pyoluteorin (PLT) and pyrrolnitrin (PRN). The gfp[mut3] and gfp[AAV] reporter genes were fused to the promoter regions of the DAPG, PLT and PRN biosynthetic genes. The reporter fusions were then used to follow the kinetics of expression of the three antifungal metabolites in a microplate assay. DAPG and PLT were found to display an inverse relationship in which each metabolite activates its own biosynthesis while repressing the synthesis of the other metabolite. PRN appears not to be involved in this balance. However, the microbial and plant phenolic metabolite salicylate was found to interfere with the expression of both DAPG and PLT. CONCLUSIONS The results obtained provide evidence that P. fluorescens CHA0 may keep the antifungal compounds DAPG and PLT at a fine-tuned balance that can be affected by certain microbial and plant phenolics. SIGNIFICANCE AND IMPACT OF THE STUDY To our knowledge, the present study is the first to use stable and unstable GFP variants to study antibiotic gene expression in a biocontrol pseudomonad. The developed reporter fusions will be a highly valuable tool to study in situ expression of this bacterial biocontrol trait on plant roots, i.e. at the site of pathogen suppression.
Collapse
Affiliation(s)
- E Baehler
- Département de Microbiologie Fondamentale, Université de Lausanne, Lausanne, Switzerland
| | | | | | | | | |
Collapse
|
37
|
Brencic A, Winans SC. Detection of and response to signals involved in host-microbe interactions by plant-associated bacteria. Microbiol Mol Biol Rev 2005; 69:155-94. [PMID: 15755957 PMCID: PMC1082791 DOI: 10.1128/mmbr.69.1.155-194.2005] [Citation(s) in RCA: 190] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diverse interactions between hosts and microbes are initiated by the detection of host-released chemical signals. Detection of these signals leads to altered patterns of gene expression that culminate in specific and adaptive changes in bacterial physiology that are required for these associations. This concept was first demonstrated for the members of the family Rhizobiaceae and was later found to apply to many other plant-associated bacteria as well as to microbes that colonize human and animal hosts. The family Rhizobiaceae includes various genera of rhizobia as well as species of Agrobacterium. Rhizobia are symbionts of legumes, which fix nitrogen within root nodules, while Agrobacterium tumefaciens is a pathogen that causes crown gall tumors on a wide variety of plants. The plant-released signals that are recognized by these bacteria are low-molecular-weight, diffusible molecules and are detected by the bacteria through specific receptor proteins. Similar phenomena are observed with other plant pathogens, including Pseudomonas syringae, Ralstonia solanacearum, and Erwinia spp., although here the signals and signal receptors are not as well defined. In some cases, nutritional conditions such as iron limitation or the lack of nitrogen sources seem to provide a significant cue. While much has been learned about the process of host detection over the past 20 years, our knowledge is far from being complete. The complex nature of the plant-microbe interactions makes it extremely challenging to gain a comprehensive picture of host detection in natural environments, and thus many signals and signal recognition systems remain to be described.
Collapse
Affiliation(s)
- Anja Brencic
- Department of Microbiology, 361A Wing Hall, Cornell University, Ithaca, NY 14853, USA
| | | |
Collapse
|
38
|
Improving biocontrol activity ofPseudomonas fluorescens through chromosomal integration of 2,4-diacetylphloroglucinol biosynthesis genes. ACTA ACUST UNITED AC 2005. [DOI: 10.1007/bf03183678] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
39
|
Péchy-Tarr M, Bottiglieri M, Mathys S, Lejbølle KB, Schnider-Keel U, Maurhofer M, Keel C. RpoN (sigma54) controls production of antifungal compounds and biocontrol activity in Pseudomonas fluorescens CHA0. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2005; 18:260-272. [PMID: 15782640 DOI: 10.1094/mpmi-18-0260] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Pseudomonas fluorescens CHA0 is an effective biocontrol agent of root diseases caused by fungal pathogens. The strain produces the antibiotics 2,4-diacetylphloroglucinol (DAPG) and pyoluteorin (PLT) that make essential contributions to pathogen suppression. This study focused on the role of the sigma factor RpoN (sigma54) in regulation of antibiotic production and biocontrol activity in P. fluorescens. An rpoN in-frame-deletion mutant of CHAO had a delayed growth, was impaired in the utilization of several carbon and nitrogen sources, and was more sensitive to salt stress. The rpoN mutant was defective for flagella and displayed drastically reduced swimming and swarming motilities. Interestingly, the rpoN mutant showed a severalfold enhanced production of DAPG and expression of the biosynthetic gene phlA compared with the wild type and the mutant complemented with monocopy rpoN+. By contrast, loss of RpoN function resulted in markedly lowered PLT production and plt gene expression, suggesting that RpoN controls the balance of the two antibiotics in strain CHA0. In natural soil microcosms, the rpoN mutant was less effective in protecting cucumber from a root rot caused by Pythium ultimum. Remarkably, the mutant was not significantly impaired in its root colonization capacity, even at early stages of root infection by Pythium spp. Taken together, our results establish RpoN for the first time as a major regulator of biocontrol activity in Pseudomonas fluorescens.
Collapse
Affiliation(s)
- Maria Péchy-Tarr
- Department de Microbiologie Fondamentale, Université de Lausanne, CH-1015 Lausanne, Switzerland
| | | | | | | | | | | | | |
Collapse
|
40
|
Alemayehu D, Gordon LM, O'Mahony MM, O'Leary ND, Dobson ADW. Cloning and functional analysis by gene disruption of a novel gene involved in indigo production and fluoranthene metabolism in Pseudomonas alcaligenes PA-10. FEMS Microbiol Lett 2005; 239:285-93. [PMID: 15476978 DOI: 10.1016/j.femsle.2004.08.046] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2004] [Revised: 08/20/2004] [Accepted: 08/31/2004] [Indexed: 12/01/2022] Open
Abstract
A novel indole dioxygenase (idoA) gene has been cloned from Pseudomonas alcaligenes PA-10, based on its ability to convert indole to indigo. The chromosomally encoded idoA gene exhibits no similarity to previously cloned naphthalene dioxygenases or to aromatic oxygenases from other species at the nucleotide level. Phylogenetic analysis indicates that the idoA gene product is most similar to an acyl-CoA dehydrogenase from Novosphingobium aromaticivorans. The enzyme encoded by the idoA gene is essential for the metabolism of fluoranthene, since a mutant in which the idoA gene has been disrupted looses the ability to degrade this compound. The idoA gene appears to be constitutively expressed in PA-10, but its expression is also subject to regulation following prior exposure to salicylate and to fluoranthene degradative intermediates.
Collapse
Affiliation(s)
- D Alemayehu
- Department of Microbiology, University College Cork, National University of Ireland, Cork, Ireland
| | | | | | | | | |
Collapse
|
41
|
Abbas A, McGuire JE, Crowley D, Baysse C, Dow M, O'Gara F. The putative permease PhlE of Pseudomonas fluorescens F113 has a role in 2,4-diacetylphloroglucinol resistance and in general stress tolerance. MICROBIOLOGY-SGM 2004; 150:2443-2450. [PMID: 15256586 DOI: 10.1099/mic.0.27033-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
2,4-Diacetylphloroglucinol (PHL) is the primary determinant of the biological control activity of Pseudomonas fluorescens F113. The operon phlACBD encodes enzymes responsible for PHL biosynthesis from intermediate metabolites. The phlE gene, which is located downstream of the phlACBD operon, encodes a putative permease suggested to be a member of the major facilitator superfamily with 12 transmembrane segments. PhlE has been suggested to function in PHL export. Here the sequencing of the phlE gene from P. fluorescens F113 and the construction of a phlE null mutant, F113-D3, is reported. It is shown that F113-D3 produced less PHL than F113. The ratio of cell-associated to free PHL was not significantly different between the strains, suggesting the existence of alternative transporters for PHL. The phlE mutant was, however, significantly more sensitive to high concentrations of added PHL, implicating PhlE in PHL resistance. Furthermore, the phlE mutant was more susceptible to osmotic, oxidative and heat-shock stresses. Osmotic stress induced rapid degradation of free PHL by the bacteria. Based on these results, we propose that the role of phlE in general stress tolerance is to export toxic intermediates of PHL degradation from the cells.
Collapse
Affiliation(s)
- Abdelhamid Abbas
- BIOMERIT Research Centre, Microbiology Department, National University of Ireland, Cork, Ireland
| | - John E McGuire
- BIOMERIT Research Centre, Microbiology Department, National University of Ireland, Cork, Ireland
| | - Delores Crowley
- BIOMERIT Research Centre, Microbiology Department, National University of Ireland, Cork, Ireland
| | - Christine Baysse
- BIOMERIT Research Centre, Microbiology Department, National University of Ireland, Cork, Ireland
| | - Max Dow
- BIOMERIT Research Centre, Microbiology Department, National University of Ireland, Cork, Ireland
| | - Fergal O'Gara
- BIOMERIT Research Centre, Microbiology Department, National University of Ireland, Cork, Ireland
| |
Collapse
|
42
|
Maurhofer M, Baehler E, Notz R, Martinez V, Keel C. Cross talk between 2,4-diacetylphloroglucinol-producing biocontrol pseudomonads on wheat roots. Appl Environ Microbiol 2004; 70:1990-8. [PMID: 15066789 PMCID: PMC383149 DOI: 10.1128/aem.70.4.1990-1998.2004] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The performance of Pseudomonas biocontrol agents may be improved by applying mixtures of strains which are complementary in their capacity to suppress plant diseases. Here, we have chosen the combination of Pseudomonas fluorescens CHA0 with another well-characterized biocontrol agent, P. fluorescens Q2-87, as a model to study how these strains affect each other's expression of a biocontrol trait. In both strains, production of the antimicrobial compound 2,4-diacetylphloroglucinol (DAPG) is a crucial factor contributing to the suppression of root diseases. DAPG acts as a signaling compound inducing the expression of its own biosynthetic genes. Experimental setups were developed to investigate whether, when combining strains CHA0 and Q2-87, DAPG excreted by one strain may influence expression of DAPG-biosynthetic genes in the other strain in vitro and on the roots of wheat. DAPG production was monitored by observing the expression of lacZ fused to the biosynthetic gene phlA of the respective strain. Dual-culture assays in which the two strains were grown in liquid medium physically separated by a membrane revealed that Q2-87 but not its DAPG-negative mutant Q2-87::Tn5-1 strongly induced phlA expression in a DeltaphlA mutant of strain CHA0. In the same way, phlA expression in a Q2-87 background was induced by DAPG produced by CHA0. When coinoculated onto the roots of wheat seedlings grown under gnotobiotic conditions, strains Q2-87 and CHA0, but not their respective DAPG-negative mutants, were able to enhance phlA expression in each other. In summary, we have established that two nonrelated pseudomonads may stimulate each other in the expression of an antimicrobial compound important for biocontrol. This interpopulation communication occurs in the rhizosphere, i.e., at the site of pathogen inhibition, and is mediated by the antimicrobial compound itself acting as a signal exchanged between the two pseudomonads.
Collapse
Affiliation(s)
- Monika Maurhofer
- Institut für Pflanzenwissenschaften/Phytopathologie, Eidgenössische Technische Hochschule, CH-8092 Zürich, Switzerland
| | | | | | | | | |
Collapse
|
43
|
Mikulík K. Structure and functional properties of prokaryotic small noncoding RNAs. Folia Microbiol (Praha) 2003; 48:443-68. [PMID: 14533476 DOI: 10.1007/bf02931326] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Most biochemical, computational and genetic approaches to gene finding assume the Central Dogma and look for genes that make mRNA and have ORFs. These approaches essentially do not work for one class of genes--the noncoding RNA. In all living organisms RNA is involved in a number of essential cell processes. Functional analysis of genome sequences has largely ignored RNA genes and their structures. Different RNA species including rRNA, tRNA, mRNA and sRNA (small RNA) are important structural, transfer, informational, and regulatory molecules containing complex folded conformations that participate in recognition and catalytic processes. Noncoding RNAs play an number of important structural, catalytic and regulatory roles in the cell. The size of the sRNA genes ranges from 70 to 500 nucleotides. Several transcripts of these genes are processed by RNAases and their final products are smaller. The encoding genes are localized between two ORFs and do not overlap with ORFs on the complementary DNA strand. As aptamers, some sRNA bind small molecular components (metal ions, peptides and nucleotides). This review summarizes recent data on the functions of prokaryotic sRNAs and approaches to their identification.
Collapse
Affiliation(s)
- K Mikulík
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20 Prague, Czechia.
| |
Collapse
|
44
|
Haas D, Keel C. Regulation of antibiotic production in root-colonizing Peudomonas spp. and relevance for biological control of plant disease. ANNUAL REVIEW OF PHYTOPATHOLOGY 2003; 41:117-53. [PMID: 12730389 DOI: 10.1146/annurev.phyto.41.052002.095656] [Citation(s) in RCA: 371] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Certain strains of fluorescent pseudomonads are important biological components of agricultural soils that are suppressive to diseases caused by pathogenic fungi on crop plants. The biocontrol abilities of such strains depend essentially on aggressive root colonization, induction of systemic resistance in the plant, and the production of diffusible or volatile antifungal antibiotics. Evidence that these compounds are produced in situ is based on their chemical extraction from the rhizosphere and on the expression of antibiotic biosynthetic genes in the producer strains colonizing plant roots. Well-characterized antibiotics with biocontrol properties include phenazines, 2,4-diacetylphloroglucinol, pyoluteorin, pyrrolnitrin, lipopeptides, and hydrogen cyanide. In vitro, optimal production of these compounds occurs at high cell densities and during conditions of restricted growth, involving (i) a number of transcriptional regulators, which are mostly pathway-specific, and (ii) the GacS/GacA two-component system, which globally exerts a positive effect on the production of extracellular metabolites at a posttranscriptional level. Small untranslated RNAs have important roles in the GacS/GacA signal transduction pathway. One challenge in future biocontrol research involves development of new strategies to overcome the broad toxicity and lack of antifungal specificity displayed by most biocontrol antibiotics studied so far.
Collapse
Affiliation(s)
- Dieter Haas
- Institut de Microbiologie Fondamentale, Universite de Lausanne, CH-1015 Lausanne, Switzerland;
| | | |
Collapse
|
45
|
Landa BB, Mavrodi OV, Raaijmakers JM, McSpadden Gardener BB, Thomashow LS, Weller DM. Differential ability of genotypes of 2,4-diacetylphloroglucinol-producing Pseudomonas fluorescens strains to colonize the roots of pea plants. Appl Environ Microbiol 2002; 68:3226-37. [PMID: 12088998 PMCID: PMC126803 DOI: 10.1128/aem.68.7.3226-3237.2002] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2001] [Accepted: 04/25/2002] [Indexed: 11/20/2022] Open
Abstract
Indigenous populations of 2,4-diacetylphloroglucinol (2,4-DAPG)-producing fluorescent Pseudomonas spp. that occur naturally in suppressive soils are an enormous resource for improving biological control of plant diseases. Over 300 isolates of 2,4-DAPG-producing fluorescent Pseudomonas spp. were isolated from the rhizosphere of pea plants grown in soils that had undergone pea or wheat monoculture and were suppressive to Fusarium wilt or take-all, respectively. Representatives of seven genotypes, A, D, E, L, O, P, and Q, were isolated from both soils and identified by whole-cell repetitive sequence-based PCR (rep-PCR) with the BOXA1R primer, increasing by three (O, P, and Q) the number of genotypes identified previously among a worldwide collection of 2,4-DAPG producers. Fourteen isolates representing eight different genotypes were tested for their ability to colonize the rhizosphere of pea plants. Population densities of strains belonging to genotypes D and P were significantly greater than the densities of other genotypes and remained above log 6.0 CFU (g of root)(-1) over the entire 15-week experiment. Genetic profiles generated by rep-PCR or restriction fragment length polymorphism analysis of the 2,4-DAPG biosynthetic gene phlD were predictive of the rhizosphere competence of the introduced 2,4-DAPG-producing strains.
Collapse
Affiliation(s)
- Blanca B Landa
- Root Disease and Biological Control Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Pullman, WA 99164-6430, USA
| | | | | | | | | | | |
Collapse
|
46
|
Abbas A, Morrissey JP, Marquez PC, Sheehan MM, Delany IR, O'Gara F. Characterization of interactions between the transcriptional repressor PhlF and its binding site at the phlA promoter in Pseudomonas fluorescens F113. J Bacteriol 2002; 184:3008-16. [PMID: 12003942 PMCID: PMC135055 DOI: 10.1128/jb.184.11.3008-3016.2002] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The phlACBD genes responsible for the biosynthesis of the antifungal metabolite 2,4-diacetylphloroglucinol (PHL) by the biocontrol strain Pseudomonas fluorescens F113 are regulated at the transcriptional level by the pathway-specific repressor PhlF. Strong evidence suggests that this regulation occurs mainly in the early logarithmic phase of growth. First, the expression of the phlF gene is relatively high between 3 and 13 h of growth and relatively low thereafter, with the phlACBD operon following an opposite expression profile. Second, the kinetics of PHL biosynthesis are specifically altered in the logarithmic phase in a P. fluorescens F113 phlF mutant. The phlA-phlF intergenic region presents a complex organization in that phlACBD is transcribed from a sigma(70) RNA polymerase-dependent promoter that is likely to overlap the promoter of the divergently transcribed phlF gene. The repression by PhlF is due to its interaction with an inverted repeated sequence, phO, located downstream of the phlA transcriptional start site. Cross-linking experiments indicate that PhlF can dimerize in solution, and thus PhlF may bind phO as a dimer or higher-order complex. Furthermore, it is now demonstrated that certain regulators of PHL synthesis act by modulating PhlF binding to phO. PHL, which has previously been shown to be an autoinducer of PHL biosynthesis, interacts with PhlF to destabilize the PhlF-phO complex. Conversely, the PhlF-phO complex is stabilized by the presence of salicylate, which has been shown to be an inhibitor of phlA expression.
Collapse
Affiliation(s)
- Abdelhamid Abbas
- BIOMERIT Research Centre, National University of Ireland, Cork, Ireland
| | | | | | | | | | | |
Collapse
|
47
|
Notz R, Maurhofer M, Dubach H, Haas D, Défago G. Fusaric acid-producing strains of Fusarium oxysporum alter 2,4-diacetylphloroglucinol biosynthetic gene expression in Pseudomonas fluorescens CHA0 in vitro and in the rhizosphere of wheat. Appl Environ Microbiol 2002; 68:2229-35. [PMID: 11976092 PMCID: PMC127576 DOI: 10.1128/aem.68.5.2229-2235.2002] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The phytotoxic pathogenicity factor fusaric acid (FA) represses the production of 2,4-diacetylphloroglucinol (DAPG), a key factor in the antimicrobial activity of the biocontrol strain Pseudomonas fluorescens CHA0. FA production by 12 Fusarium oxysporum strains varied substantially. We measured the effect of FA production on expression of the phlACBDE biosynthetic operon of strain CHA0 in culture media and in the wheat rhizosphere by using a translational phlA'-'lacZ fusion. Only FA-producing F. oxysporum strains could suppress DAPG production in strain CHA0, and the FA concentration was strongly correlated with the degree of phlA repression. The repressing effect of FA on phlA'-'lacZ expression was abolished in a mutant that lacked the DAPG pathway-specific repressor PhlF. One FA-producing strain (798) and one nonproducing strain (242) of F. oxysporum were tested for their influence on phlA expression in CHA0 in the rhizosphere of wheat in a gnotobiotic system containing a sand and clay mineral-based artificial soil. F. oxysporum strain 798 (FA(+)) repressed phlA expression in CHA0 significantly, whereas strain 242 (FA(-)) did not. In the phlF mutant CHA638, phlA expression was not altered by the presence of either F. oxysporum strain 242 or 798. phlA expression levels were seven to eight times higher in strain CHA638 than in the wild-type CHA0, indicating that PhlF limits phlA expression in the wheat rhizosphere.
Collapse
Affiliation(s)
- Regina Notz
- Phytopathology Group, Institute of Plant Sciences, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland
| | | | | | | | | |
Collapse
|
48
|
Landa BB, de Werd HAE, McSpadden Gardener BB, Weller DM. Comparison of Three Methods for Monitoring Populations of Different Genotypes of 2,4-Diacetylphloroglucinol-Producing Pseudomonas fluorescens in the Rhizosphere. PHYTOPATHOLOGY 2002; 92:129-37. [PMID: 18943085 DOI: 10.1094/phyto.2002.92.2.129] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
ABSTRACT Pseudomonas fluorescens strains producing the antibiotic 2,4-diacetylphloroglucinol (DAPG) have biocontrol activity against a broad spectrum of root and seedling diseases. In this study, we determined the effect of genotype on the ability to isolate and quantify introduced 2,4-DAPG producers from the rhizosphere of wheat using three different methods: traditional dilution plating on selective media, colony hybridization followed by polymerase chain reaction (PCR), and phlD-specific PCR-based dilution endpoint assay. Regression analysis of the population densities of 10 2,4-DAPG-producing P. fluorescens, representing five genotypes, determined by the three different methods demonstrated that the relationship was linear (P < 0.001) and the techniques were very similar (i.e., slopes equal to 1.0). The phlD-specific PCR-based assay had a slightly lower limit of detection than the other two methods (log 3.3 versus log 4.0 CFU/g of fresh root weight). With the colony hybridization procedure, we observed that the phlD probe, derived from strain P. fluorescens Q8r1-96, hybridized more strongly to colonies of BOX-PCR genotypes D (strains W2-6, L5.1-96, Q8r1-96, and Q8r2-96) and K (strain F113) compared with strains of genotypes A (Pf-5 and CHA0), B (Q2-87), and L (1M1-96 and W4-4). Colony hybridization alone overestimated the actual densities of some strains, thus requiring an additional PCR step to obtain accurate estimates. In contrast, population densities estimated for three of the bacterial treatments (strains CHA0, W2-6, and Q8r2-96) with the PCR-based assay were significantly (P < 0.041) smaller by 7.6 to 9.2% and 6.4 to 9.4% than population densities detected by the dilution plating and colony hybridization techniques, respectively. In this paper, we discuss the relative advantages of the different methods for detecting 2,4-DAPG producers.
Collapse
|
49
|
Wang C, Ramette A, Punjasamarnwong P, Zala M, Natsch A, Moënne-Loccoz Y, Défago G. Cosmopolitan distribution of phlD-containing dicotyledonous crop-associated biocontrol pseudomonads of worldwide origin. FEMS Microbiol Ecol 2001. [DOI: 10.1111/j.1574-6941.2001.tb00858.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
|
50
|
Bloemberg GV, Lugtenberg BJ. Molecular basis of plant growth promotion and biocontrol by rhizobacteria. CURRENT OPINION IN PLANT BIOLOGY 2001; 4:343-50. [PMID: 11418345 DOI: 10.1016/s1369-5266(00)00183-7] [Citation(s) in RCA: 355] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Plant-growth-promoting rhizobacteria (PGPRs) are used as inoculants for biofertilization, phytostimulation and biocontrol. The interactions of PGPRs with their biotic environment, for example with plants and microorganisms, are often complex. Substantial advances in elucidating the genetic basis of the beneficial effects of PGPRs on plants have been made, some from whole-genome sequencing projects. This progress will lead to a more efficient use of these strains and possibly to their improvement by genetic modification.
Collapse
Affiliation(s)
- G V Bloemberg
- Leiden University, Institute of Molecular Plant Sciences, Wassenaarseweg 64, 2333 AL, Leiden, The Netherlands.
| | | |
Collapse
|