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Biocontrol of Candida albicans by Antagonistic Microorganisms and Bioactive Compounds. Antibiotics (Basel) 2022; 11:antibiotics11091238. [PMID: 36140017 PMCID: PMC9495215 DOI: 10.3390/antibiotics11091238] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/26/2022] [Accepted: 09/09/2022] [Indexed: 11/17/2022] Open
Abstract
Candida albicans is an endogenous opportunistic pathogenic fungus that is harmless when the host system remains stable. However, C. albicans could seriously threaten human life and health when the body’s immune function declines or the normal flora is out of balance. Due to the increasing resistance of candidiasis to existing drugs, it is important to find new strategies to help treat this type of systemic fungal disease. Biological control is considered as a promising strategy which is more friendly and safer. In this review, we compare the bacteriostatic behavior of different antagonistic microorganisms (bacteria and fungi) against C. albicans. In addition, natural products with unique structures have attracted researchers’ attention. Therefore, the bioactive nature products produced by different microorganisms and their possible inhibitory mechanisms are also reviewed. The application of biological control strategies and the discovery of new compounds with antifungal activity will reduce the resistance of C. albicans, thereby promoting the development of novel diverse antifungal drugs.
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Williams AN, Sorout N, Cameron AJ, Stavrinides J. The Integration of Genome Mining, Comparative Genomics, and Functional Genetics for Biosynthetic Gene Cluster Identification. Front Genet 2020; 11:600116. [PMID: 33343637 PMCID: PMC7744662 DOI: 10.3389/fgene.2020.600116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/11/2020] [Indexed: 11/25/2022] Open
Abstract
Antimicrobial resistance is a worldwide health crisis for which new antibiotics are needed. One strategy for antibiotic discovery is identifying unique antibiotic biosynthetic gene clusters that may produce novel compounds. The aim of this study was to demonstrate how an integrated approach that combines genome mining, comparative genomics, and functional genetics can be used to successfully identify novel biosynthetic gene clusters that produce antimicrobial natural products. Secondary metabolite clusters of an antibiotic producer are first predicted using genome mining tools, generating a list of candidates. Comparative genomic approaches are then used to identify gene suites present in the antibiotic producer that are absent in closely related non-producers. Gene sets that are common to the two lists represent leading candidates, which can then be confirmed using functional genetics approaches. To validate this strategy, we identified the genes responsible for antibiotic production in Pantoea agglomerans B025670, a strain identified in a large-scale bioactivity survey. The genome of B025670 was first mined with antiSMASH, which identified 24 candidate regions. We then used the comparative genomics platform, EDGAR, to identify genes unique to B025670 that were not present in closely related strains with contrasting antibiotic production profiles. The candidate lists generated by antiSMASH and EDGAR were compared with standalone BLAST. Among the common regions was a 14 kb cluster consisting of 14 genes with predicted enzymatic, transport, and unknown functions. Site-directed mutagenesis of the gene cluster resulted in a reduction in antimicrobial activity, suggesting involvement in antibiotic production. An integrated approach that combines genome mining, comparative genomics, and functional genetics yields a powerful, yet simple strategy for identifying potentially novel antibiotics.
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Krause K, Jung EM, Lindner J, Hardiman I, Poetschner J, Madhavan S, Matthäus C, Kai M, Menezes RC, Popp J, Svatoš A, Kothe E. Response of the wood-decay fungus Schizophyllum commune to co-occurring microorganisms. PLoS One 2020; 15:e0232145. [PMID: 32324822 PMCID: PMC7179906 DOI: 10.1371/journal.pone.0232145] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/07/2020] [Indexed: 02/02/2023] Open
Abstract
Microorganisms are constantly interacting in a given environment by a constant exchange of signaling molecules. In timber, wood-decay fungi will come into contact with other fungi and bacteria. In naturally bleached wood, dark, pigmented lines arising from confrontation of two fungi often hint at such interactions. The metabolites (and pigment) exchange was investigated using the lignicolous basidiomycete Schizophyllum commune, and co-occurring fungi and bacteria inoculated directly on sterilized wood, or on media. In interactions with competitive wood degrading fungi, yeasts or bacteria, different competition strategies and communication types were observed, and stress reactions, as well as competitor-induced enzymes or pigments were analyzed. Melanin, indole, flavonoids and carotenoids were shown to be induced in S. commune interactions. The induced genes included multi-copper oxidases lcc1, lcc2, mco1, mco2, mco3 and mco4, possibly involved in both pigment production and lignin degradation typical for wood bleaching by wood-decay fungi.
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Affiliation(s)
- Katrin Krause
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Elke-Martina Jung
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Julia Lindner
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Imam Hardiman
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | | | - Soumya Madhavan
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Christian Matthäus
- Leibniz Institute of Photonic Technology, Jena, Germany
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Jena, Germany
| | - Marco Kai
- Research Group Mass Spectrometry, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Riya Christina Menezes
- Research Group Mass Spectrometry, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Jürgen Popp
- Leibniz Institute of Photonic Technology, Jena, Germany
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Jena, Germany
| | - Aleš Svatoš
- Research Group Mass Spectrometry, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Erika Kothe
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
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Identification and Characterization of pantocin wh-1, a Novel Cyclic Polypeptide Produced by Pantoea dispersa W18. Molecules 2020; 25:molecules25030485. [PMID: 31979296 PMCID: PMC7036871 DOI: 10.3390/molecules25030485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/15/2020] [Accepted: 01/22/2020] [Indexed: 12/15/2022] Open
Abstract
Pantoea dispersa W18, isolated from contaminated soil, was found to exert antimicrobial activity against Mycobacterium species, including Mycobacterium tuberculosis, an important human pathogen. Here, the anti-mycobacterial compound produced by Pantoea dispersa W18 was purified by a combination of hydrophobic interaction chromatography, cation exchange chromatography, and reverse phase HPLC. Active compounds from Pantoea dispersa W18 were identified as a natural peptide named pantocin wh-1 with a 1927 Da molecular weight. The primary structure of this compound was detected by N-terminal amino acid sequencing. The amino acid sequence of pantocin wh-1 consisted of 16 amino acid residues with a cyclic structure. The pantocin wh-1 could be inactivated by protease K, but was heat stable and unaffected by pH (2–12). However, the activity was not completely inactivated by trypsin and pepsin. This is the first report of a cyclic polypeptide purified from a strain of Pantoea dispersa.
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Williams AN, Stavrinides J. Pantoea Natural Product 3 is encoded by an eight-gene biosynthetic gene cluster and exhibits antimicrobial activity against multi-drug resistant Acinetobacter baumannii and Pseudomonas aeruginosa. Microbiol Res 2020; 234:126412. [PMID: 32062363 DOI: 10.1016/j.micres.2020.126412] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 12/22/2019] [Accepted: 01/10/2020] [Indexed: 01/08/2023]
Abstract
Multi-drug resistant Acinetobacter baumannii and Pseudomonas aeruginosa continue to pose a serious health threat worldwide. Two Pantoea agglomerans strains, 3581 and SN01080, produce an antibiotic effective against these pathogens. To identify the antibiotic biosynthetic gene clusters, independent genetic screens were conducted for each strain using a mini-Tn5 transposon, which resulted in the identification of the same conserved eight-gene cluster. We have named this antibiotic Pantoea Natural Product 3 (PNP-3). The PNP-3 biosynthetic cluster is composed of genes encoding two Major Facilitator Superfamily (MFS) transporters, an ArsR family regulator, and five predicted enzymes. The biosynthetic gene cluster is found in only a few Pantoea strains and is not present within the antiSMASH and BAGEL4 databases, suggesting it may be novel. In strain 3581, PNP-3 production is linked to pantocin A production, where loss of pantocin A production results in a larger PNP-3 zone of inhibition. To evaluate the spectrum of activity, PNP-3 producers, including several PNP-3 mutants and pantocin A site-directed mutants, were tested against a collection of clinical, drug-resistant strains of A. baumannii and P. aeruginosa, as well as, Klebsiella, Escherichia coli, Enterobacter, Staphylococcus aureus, and Streptococcus mutans. PNP-3 was found to be effective against all strains except vancomycin-resistant Enterococcus under the tested conditions. Heterologous expression of the four predicted biosynthetic genes in Erwinia amylovora resulted in antibiotic production, providing a means for future overexpression and purification. PNP-3 is a natural product that is effective against drug-resistant A. baumannii, P. aeruginosa, and enteric species for which there are currently few treatment options.
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Affiliation(s)
- Ashley N Williams
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, Saskatchewan, S4S0A2, Canada
| | - John Stavrinides
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, Saskatchewan, S4S0A2, Canada.
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Resistance to Two Vinylglycine Antibiotic Analogs Is Conferred by Inactivation of Two Separate Amino Acid Transporters in Erwinia amylovora. J Bacteriol 2019; 201:JB.00658-18. [PMID: 30745372 DOI: 10.1128/jb.00658-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/04/2019] [Indexed: 11/20/2022] Open
Abstract
Erwinia amylovora is the causal agent of fire blight of apple and pear trees. Several bacteria have been shown to produce antibiotics that antagonize E. amylovora, including pantocins, herbicolins, dapdiamides, and the vinylglycines, 4-formylaminooxyvinylglycine (FVG) and 4-aminoethoxyvinylglycine (AVG). Pantoea ananatis BRT175 was previously shown to exhibit antibiotic activity against E. amylovora via the production of Pantoea natural product 1 (PNP-1), later shown to be FVG; however, exposure of E. amylovora to FVG results in spontaneously resistant mutants. To identify the mechanism of resistance, we used genome variant analysis on spontaneous FVG-resistant mutants of E. amylovora and identified null mutations in the l-asparagine permease gene ansP Heterologous expression of ansP in normally resistant Escherichia coli was sufficient to impart FVG susceptibility, suggesting that FVG is imported through this permease. Because FVG and AVG are structurally similar, we hypothesized that resistance to AVG would also be conferred through inactivation of ansP; however, ansP mutants were not resistant to AVG. We found that spontaneously resistant Ea321 mutants also arise in the presence of AVG, with whole-genome variant analysis revealing that resistance was due to inactivation of the arginine ABC transporter permease subunit gene artQ Heterologous expression of the predicted lysE-like transporter encoded within the Pantoea ananatis BRT175 FVG biosynthetic cluster, which is likely responsible for antibiotic export, was sufficient to confer resistance to both FVG and AVG. This work highlights the important roles of amino acid transporters in antibiotic import into bacteria and the potential utility of antimicrobial amino acid analogs as antibiotics.IMPORTANCE The related antibiotics formylaminooxyvinylglycine (FVG) and aminoethoxyvinylglycine (AVG) have been shown to have activity against the fire blight pathogen Erwinia amylovora; however, E. amylovora can develop spontaneous resistance to these antibiotics. By comparing the genomes of mutants to those of the wild type, we found that inactivation of the l-asparagine transporter conferred resistance to FVG, while inactivation of the l-arginine transporter conferred resistance to AVG. We also show that the transporter encoded by the FVG biosynthetic cluster can confer resistance to both FVG and AVG. Our work indicates the important role that amino acid transporters play in the import of antibiotics and highlights the possible utility in designer antibiotics that enter the bacterial cell through amino acid transporters.
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Mamo G. Anaerobes as Sources of Bioactive Compounds and Health Promoting Tools. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2017; 156:433-464. [PMID: 27432247 DOI: 10.1007/10_2016_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Aerobic microorganisms have been sources of medicinal agents for several decades and an impressive variety of drugs have been isolated from their cultures, studied and formulated to treat or prevent diseases. On the other hand, anaerobes, which are believed to be the oldest life forms on earth and evolved remarkably diverse physiological functions, have largely been neglected as sources of bioactive compounds. However, results obtained from the limited research done so far show that anaerobes are capable of producing a range of interesting bioactive compounds that can promote human health. In fact, some of these bioactive compounds are found to be novel in their structure and/or mode of action.Anaerobes play health-promoting roles through their bioactive products as well as application of whole cells. The bioactive compounds produced by these microorganisms include antimicrobial agents and substances such as immunomodulators and vitamins. Bacteriocins produced by anaerobes have been in use as preservatives for about 40 years. Because these substances are effective at low concentrations, encounter relatively less resistance from bacteria and are safe to use, there is a growing interest in these antimicrobial agents. Moreover, several antibiotics have been reported from the cultures of anaerobes. Closthioamide and andrimid produced by Clostridium cellulolyticum and Pantoea agglomerans, respectively, are examples of novel antibiotics of anaerobe origin. The discovery of such novel bioactive compounds is expected to encourage further studies which can potentially lead to tapping of the antibiotic production potential of this fascinating group of microorganisms.Anaerobes are widely used in preparation of fermented foods and beverages. During the fermentation processes, these organisms produce a number of bioactive compounds including anticancer, antihypertensive and antioxidant substances. The well-known health promoting effect of fermented food is mostly due to these bioactive compounds. In addition to their products, whole cell anaerobes have very interesting applications for enhancing the quality of life. Probiotic anaerobes have been on the market for many years and are receiving growing acceptance as health promoters. Gut anaerobes have been used to treat patients suffering from severe Clostridium difficile infection syndromes including diarrhoea and colitis which cannot be treated by other means. Whole cell anaerobes are also studied to detect and cure cancer. In recent years, evidence is emerging that anaerobes constituting the microbiome are linked to our overall health. A dysfunctional microbiome is believed to be the cause of many diseases including cancer, allergy, infection, obesity, diabetes and several other disorders. Maintaining normal microflora is believed to alleviate some of these serious health problems. Indeed, the use of probiotics and prebiotics which favourably change the number and composition of the gut microflora is known to render a health promoting effect. Our interaction with the microbiome anaerobes is complex. In fact, not only our lives but also our identities are more closely linked to the anaerobic microbial world than we may possibly imagine. We are just at the beginning of unravelling the secret of association between the microbiome and human body, and a clear understanding of the association may bring a paradigm shift in the way we diagnose and treat diseases and disorders. This chapter highlights some of the work done on bioactive compounds and whole cell applications of the anaerobes that foster human health and improve the quality of life.
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Affiliation(s)
- Gashaw Mamo
- Biotechnology, Center for Chemistry & Chemical Engineering, Lund University, 221 00, Lund, Sweden.
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Breen S, Solomon PS, Bedon F, Vincent D. Surveying the potential of secreted antimicrobial peptides to enhance plant disease resistance. FRONTIERS IN PLANT SCIENCE 2015; 6:900. [PMID: 26579150 PMCID: PMC4621407 DOI: 10.3389/fpls.2015.00900] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/09/2015] [Indexed: 05/20/2023]
Abstract
Antimicrobial peptides (AMPs) are natural products found across diverse taxa as part of the innate immune system against pathogen attacks. Some AMPs are synthesized through the canonical gene expression machinery and are called ribosomal AMPs. Other AMPs are assembled by modular enzymes generating nonribosomal AMPs and harbor unusual structural diversity. Plants synthesize an array of AMPs, yet are still subject to many pathogen invasions. Crop breeding programs struggle to release new cultivars in which complete disease resistance is achieved, and usually such resistance becomes quickly overcome by the targeted pathogens which have a shorter generation time. AMPs could offer a solution by exploring not only plant-derived AMPs, related or unrelated to the crop of interest, but also non-plant AMPs produced by bacteria, fungi, oomycetes or animals. This review highlights some promising candidates within the plant kingdom and elsewhere, and offers some perspectives on how to identify and validate their bioactivities. Technological advances, particularly in mass spectrometry (MS) and nuclear magnetic resonance (NMR), have been instrumental in identifying and elucidating the structure of novel AMPs, especially nonribosomal peptides which cannot be identified through genomics approaches. The majority of non-plant AMPs showing potential for plant disease immunity are often tested using in vitro assays. The greatest challenge remains the functional validation of candidate AMPs in plants through transgenic experiments, particularly introducing nonribosomal AMPs into crops.
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Affiliation(s)
- Susan Breen
- Plant Sciences Division, Research School of Biology, The Australian National UniversityCanberra, ACT, Australia
| | - Peter S. Solomon
- Plant Sciences Division, Research School of Biology, The Australian National UniversityCanberra, ACT, Australia
| | - Frank Bedon
- Department of Economic Development, AgriBioBundoora, VIC, Australia
- AgriBio, La Trobe UniversityBundoora, VIC, Australia
| | - Delphine Vincent
- Department of Economic Development, AgriBioBundoora, VIC, Australia
- *Correspondence: Delphine Vincent
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Pidot SJ, Coyne S, Kloss F, Hertweck C. Antibiotics from neglected bacterial sources. Int J Med Microbiol 2014; 304:14-22. [DOI: 10.1016/j.ijmm.2013.08.011] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Sammer UF, Reiher K, Spiteller D, Wensing A, Völksch B. Assessment of the relevance of the antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine from Pantoea agglomerans biological control strains against bacterial plant pathogens. Microbiologyopen 2012; 1:438-49. [PMID: 23233458 PMCID: PMC3535389 DOI: 10.1002/mbo3.43] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 09/09/2012] [Accepted: 09/12/2012] [Indexed: 11/08/2022] Open
Abstract
The epiphyte Pantoea agglomerans 48b/90 (Pa48b) is a promising biocontrol strain against economically important bacterial pathogens such as Erwinia amylovora. Strain Pa48b produces the broad-spectrum antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine (APV) in a temperature-dependent manner. An APV-negative mutant still suppressed the E. amylovora population and fire blight disease symptoms in apple blossom experiments under greenhouse conditions, but was inferior to the Pa48b wild-type indicating the influence of APV in the antagonism. In plant experiments with the soybean pathogen Pseudomonas syringae pv. glycinea both, Pa48b and the APV-negative mutant, successfully suppressed the pathogen. Our results demonstrate that the P. agglomerans strain Pa48b is an efficient biocontrol organism against plant pathogens, and we prove its ability for fast colonization of plant surfaces over a wide temperature range.
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Affiliation(s)
- Ulrike F Sammer
- Institute for Microbiology, Microbial Communication, University of Jena, Neugasse 25, D-07743, Jena, Germany.
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Characterization of the biosynthetic operon for the antibacterial peptide herbicolin in Pantoea vagans biocontrol strain C9-1 and incidence in Pantoea species. Appl Environ Microbiol 2012; 78:4412-9. [PMID: 22504810 DOI: 10.1128/aem.07351-11] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pantoea vagans C9-1 is a biocontrol strain that produces at least two antibiotics inhibiting the growth of Erwinia amylovora, the causal agent of fire blight disease of pear and apple. One antibiotic, herbicolin I, was purified from culture filtrates of P. vagans C9-1 and determined to be 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine, also known as N(ß)-epoxysuccinamoyl-DAP-valine. A plasposon library was screened for mutants that had lost the ability to produce herbicolin I. It was shown that mutants had reduced biocontrol efficacy in immature pear assays. The biosynthetic gene cluster in P. vagans C9-1 was identified by sequencing the flanking regions of the plasposon insertion sites. The herbicolin I biosynthetic gene cluster consists of 10 coding sequences (CDS) and is located on the 166-kb plasmid pPag2. Sequence comparisons identified orthologous gene clusters in Pantoea agglomerans CU0119 and Serratia proteamaculans 568. A low incidence of detection of the biosynthetic cluster in a collection of 45 Pantoea spp. from biocontrol, environmental, and clinical origins showed that this is a rare trait among the tested strains.
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Sagar S, Gehring C, Minneman KP. Methods to Isolate and Identify New Plant Signaling Peptides. SIGNALING AND COMMUNICATION IN PLANTS 2012. [DOI: 10.1007/978-3-642-27603-3_12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Smits THM, Rezzonico F, Kamber T, Blom J, Goesmann A, Ishimaru CA, Frey JE, Stockwell VO, Duffy B. Metabolic versatility and antibacterial metabolite biosynthesis are distinguishing genomic features of the fire blight antagonist Pantoea vagans C9-1. PLoS One 2011; 6:e22247. [PMID: 21789243 PMCID: PMC3137637 DOI: 10.1371/journal.pone.0022247] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 06/17/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Pantoea vagans is a commercialized biological control agent used against the pome fruit bacterial disease fire blight, caused by Erwinia amylovora. Compared to other biocontrol agents, relatively little is currently known regarding Pantoea genetics. Better understanding of antagonist mechanisms of action and ecological fitness is critical to improving efficacy. PRINCIPAL FINDINGS Genome analysis indicated two major factors Contribute to biocontrol activity: competition for limiting substrates and antibacterial metabolite production. Pathways for utilization of a broad diversity of sugars and acquisition of iron were identified. Metabolism of sorbitol by P. vagans C9-1 may be a major metabolic feature in biocontrol of fire blight. Biosynthetic genes for the antibacterial peptide pantocin A were found on a chromosomal 28-kb genomic island, and for dapdiamide E on the plasmid pPag2. There was no evidence of potential virulence factors that could enable an animal or phytopathogenic lifestyle and no indication of any genetic-based biosafety risk in the antagonist. CONCLUSIONS Identifying key determinants contributing to disease suppression allows the development of procedures to follow their expression in planta and the genome sequence contributes to rationale risk assessment regarding the use of the biocontrol strain in agricultural systems.
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Affiliation(s)
- Theo H. M. Smits
- Swiss National Competence Center for Fire Blight, Division of Plant Protection, Agroscope Changins-Wädenswil ACW, Wädenswil, Switzerland
| | - Fabio Rezzonico
- Swiss National Competence Center for Fire Blight, Division of Plant Protection, Agroscope Changins-Wädenswil ACW, Wädenswil, Switzerland
| | - Tim Kamber
- Swiss National Competence Center for Fire Blight, Division of Plant Protection, Agroscope Changins-Wädenswil ACW, Wädenswil, Switzerland
| | - Jochen Blom
- CeBiTec, Bielefeld University, Bielefeld, Germany
| | | | - Carol A. Ishimaru
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Jürg E. Frey
- Swiss National Competence Center for Fire Blight, Division of Plant Protection, Agroscope Changins-Wädenswil ACW, Wädenswil, Switzerland
| | - Virginia O. Stockwell
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Brion Duffy
- Swiss National Competence Center for Fire Blight, Division of Plant Protection, Agroscope Changins-Wädenswil ACW, Wädenswil, Switzerland
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Hollenhorst MA, Ntai I, Badet B, Kelleher NL, Walsh CT. A head-to-head comparison of eneamide and epoxyamide inhibitors of glucosamine-6-phosphate synthase from the dapdiamide biosynthetic pathway. Biochemistry 2011; 50:3859-61. [PMID: 21520904 DOI: 10.1021/bi2004735] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The dapdiamides make up a family of antibiotics that have been presumed to be cleaved in the target cell to enzyme-inhibitory N-acyl-2,3-diaminopropionate (DAP) warheads containing two alternative electrophilic moieties. Our prior biosynthetic studies revealed that an eneamide warhead is made first and converted to an epoxyamide via a three-enzyme branch pathway. Here we provide a rationale for this logic. We report that the R,R-epoxyamide warhead is a more efficient covalent inactivator of glucosamine-6-phosphate synthase by 1 order of magnitude versus the eneamide, and this difference correlates with a >10-fold difference in antibiotic activity for the corresponding acyl-DAP dipeptides.
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Affiliation(s)
- Marie A Hollenhorst
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
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Hollenhorst MA, Bumpus SB, Matthews ML, Bollinger JM, Kelleher NL, Walsh CT. The nonribosomal peptide synthetase enzyme DdaD tethers N(β)-fumaramoyl-l-2,3-diaminopropionate for Fe(II)/α-ketoglutarate-dependent epoxidation by DdaC during dapdiamide antibiotic biosynthesis. J Am Chem Soc 2011; 132:15773-81. [PMID: 20945916 DOI: 10.1021/ja1072367] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The gene cluster from Pantoea agglomerans responsible for biosynthesis of the dapdiamide antibiotics encodes an adenylation-thiolation didomain protein, DdaD, and an Fe(II)/α-ketoglutarate-dependent dioxygenase homologue, DdaC. Here we show that DdaD, a nonribosomal peptide synthetase module, activates and sequesters N(β)-fumaramoyl-l-2,3-diaminopropionate as a covalently tethered thioester for subsequent oxidative modification of the fumaramoyl group. DdaC catalyzes Fe(II)- and α-ketoglutarate-dependent epoxidation of the covalently bound N(β)-fumaramoyl-l-2,3-diaminopropionyl-S-DdaD species to generate N(β)-epoxysuccinamoyl-DAP (DAP = 2,3-diaminopropionate) in thioester linkage to DdaD. After hydrolytic release, N(β)-epoxysuccinamoyl-DAP can be ligated to l-valine by the ATP-dependent ligase DdaF to form the natural antibiotic N(β)-epoxysuccinamoyl-DAP-Val.
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Affiliation(s)
- Marie A Hollenhorst
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Beattie GA. Water relations in the interaction of foliar bacterial pathogens with plants. ANNUAL REVIEW OF PHYTOPATHOLOGY 2011; 49:533-55. [PMID: 21438680 DOI: 10.1146/annurev-phyto-073009-114436] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
This review examines the many ways in which water influences the relations between foliar bacterial pathogens and plants. As a limited resource in aerial plant tissues, water is subject to manipulation by both plants and pathogens. A model is emerging that suggests that plants actively promote localized desiccation at the infection site and thus restrict pathogen growth as one component of defense. Similarly, many foliar pathogens manipulate water relations as one component of pathogenesis. Nonvascular pathogens do this using effectors and other molecules to alter hormonal responses and enhance intercellular watersoaking, whereas vascular pathogens use many mechanisms to cause wilt. Because of water limitations on phyllosphere surfaces, bacterial colonists, including pathogens, benefit from the protective effects of cellular aggregation, synthesis of hygroscopic polymers, and uptake and production of osmoprotective compounds. Moreover, these bacteria employ tactics for scavenging and distributing water to overcome water-driven barriers to nutrient acquisition, movement, and signal exchange on plant surfaces.
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Affiliation(s)
- Gwyn A Beattie
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa 50011-3211, USA.
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