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Ghosh P, Chakraborty J. Exploring the role of symbiotic modifier peptidases in the legume - rhizobium symbiosis. Arch Microbiol 2024; 206:147. [PMID: 38462552 DOI: 10.1007/s00203-024-03920-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 03/12/2024]
Abstract
Legumes can establish a mutual association with soil-derived nitrogen-fixing bacteria called 'rhizobia' forming lateral root organs called root nodules. Rhizobia inside the root nodules get transformed into 'bacteroids' that can fix atmospheric nitrogen to ammonia for host plants in return for nutrients and shelter. A substantial 200 million tons of nitrogen is fixed annually through biological nitrogen fixation. Consequently, the symbiotic mechanism of nitrogen fixation is utilized worldwide for sustainable agriculture and plays a crucial role in the Earth's ecosystem. The development of effective nitrogen-fixing symbiosis between legumes and rhizobia is very specialized and requires coordinated signaling. A plethora of plant-derived nodule-specific cysteine-rich (NCR or NCR-like) peptides get actively involved in this complex and tightly regulated signaling process of symbiosis between some legumes of the IRLC (Inverted Repeat-Lacking Clade) and Dalbergioid clades and nitrogen-fixing rhizobia. Recent progress has been made in identifying two such peptidases that actively prevent bacterial differentiation, leading to symbiotic incompatibility. In this review, we outlined the functions of NCRs and two nitrogen-fixing blocking peptidases: HrrP (host range restriction peptidase) and SapA (symbiosis-associated peptidase A). SapA was identified through an overexpression screen from the Sinorhizobium meliloti 1021 core genome, whereas HrrP is inherited extra-chromosomally. Interestingly, both peptidases affect the symbiotic outcome by degrading the NCR peptides generated from the host plants. These NCR-degrading peptidases can shed light on symbiotic incompatibility, helping to elucidate the reasons behind the inefficiency of nitrogen fixation observed in certain groups of rhizobia with specific legumes.
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Affiliation(s)
- Prithwi Ghosh
- Department of Botany, Narajole Raj College, Vidyasagar University, Midnapore, 721211, India.
| | - Joydeep Chakraborty
- School of Plant Sciences and Food Security, Tel Aviv University, Tel-Aviv, Israel
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2
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Shumilina J, Soboleva A, Abakumov E, Shtark OY, Zhukov VA, Frolov A. Signaling in Legume-Rhizobia Symbiosis. Int J Mol Sci 2023; 24:17397. [PMID: 38139226 PMCID: PMC10743482 DOI: 10.3390/ijms242417397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 11/19/2023] [Accepted: 12/02/2023] [Indexed: 12/24/2023] Open
Abstract
Legumes represent an important source of food protein for human nutrition and animal feed. Therefore, sustainable production of legume crops is an issue of global importance. It is well-known that legume-rhizobia symbiosis allows an increase in the productivity and resilience of legume crops. The efficiency of this mutualistic association strongly depends on precise regulation of the complex interactions between plant and rhizobia. Their molecular dialogue represents a complex multi-staged process, each step of which is critically important for the overall success of the symbiosis. In particular, understanding the details of the molecular mechanisms behind the nodule formation and functioning might give access to new legume cultivars with improved crop productivity. Therefore, here we provide a comprehensive literature overview on the dynamics of the signaling network underlying the development of the legume-rhizobia symbiosis. Thereby, we pay special attention to the new findings in the field, as well as the principal directions of the current and prospective research. For this, here we comprehensively address the principal signaling events involved in the nodule inception, development, functioning, and senescence.
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Affiliation(s)
- Julia Shumilina
- Laboratory of Analytical Biochemistry and Biotechnology, Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia; (J.S.); (A.S.)
| | - Alena Soboleva
- Laboratory of Analytical Biochemistry and Biotechnology, Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia; (J.S.); (A.S.)
- Biological Faculty, Saint Petersburg State University, 199034 St. Petersburg, Russia;
| | - Evgeny Abakumov
- Biological Faculty, Saint Petersburg State University, 199034 St. Petersburg, Russia;
| | - Oksana Y. Shtark
- Laboratory of Genetics of Plant-Microbe Interactions, All-Russia Research Institute for Agricultural Microbiology, 196608 St. Petersburg, Russia; (O.Y.S.); (V.A.Z.)
| | - Vladimir A. Zhukov
- Laboratory of Genetics of Plant-Microbe Interactions, All-Russia Research Institute for Agricultural Microbiology, 196608 St. Petersburg, Russia; (O.Y.S.); (V.A.Z.)
| | - Andrej Frolov
- Laboratory of Analytical Biochemistry and Biotechnology, Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia; (J.S.); (A.S.)
- Biological Faculty, Saint Petersburg State University, 199034 St. Petersburg, Russia;
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3
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Gligorijević N, Mihajlov-Krstev T, Kostić M, Nikolić L, Stanković N, Nikolić V, Dinić A, Igić M, Bernstein N. Antimicrobial Properties of Silver-Modified Denture Base Resins. NANOMATERIALS 2022; 12:nano12142453. [PMID: 35889677 PMCID: PMC9317501 DOI: 10.3390/nano12142453] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/11/2022] [Accepted: 07/14/2022] [Indexed: 02/05/2023]
Abstract
The surface quality of denture base resins allows for easy colonization by microorganisms including Candida albicans and Staphylococcus aureus, which cause major diseases of the oral cavity such as denture stomatitis. The widespread use of silver nanoparticles (AgNPs) in various fields of medicine has led to research of their possible application in dentistry, mostly in the prevention of bacterial adhesion, proliferation, and biofilm formation. The aim of the study was to synthesize cold and heat-curing denture base resins modified with AgNPs and AgCl, and evaluate the potential of the modified resins to reduce the growth of C. albicans and S.aureus. The produced material was characterized by Fourier transform infrared spectroscopy (FTIR). The antimicrobial potential of the modified material was demonstrated by the disc-diffusion method, microdilution method, and a modified microdilution method (i.e., disk-diffusion method in broth with viable counting). Spectroscopy confirmed the incorporation of biocidal materials into the structure of the denture base resins. The AgCl and AgNPs modified resins showed an antimicrobial effect. The significance of the study is in the potential therapeutic effects of the modified materials for prevention and threating staphylococci and candida in elderly patients, who are in most cases denture wearers and have a greater susceptibility to develop opportunistic infections. Modified denture base resins can significantly reduce the presence of infection at the point of contact between the denture and the mucous membrane of the prosthetic restoration. Biological tests of modified denture base resins will follow.
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Affiliation(s)
- Nikola Gligorijević
- Department of Prosthodontics, Faculty of Medicine, University of Niš, 18000 Niš, Serbia; (M.K.); (M.I.)
- Correspondence: ; Tel.: +381-65-3366646
| | | | - Milena Kostić
- Department of Prosthodontics, Faculty of Medicine, University of Niš, 18000 Niš, Serbia; (M.K.); (M.I.)
| | - Ljubiša Nikolić
- Faculty of Technology, University of Niš, 16000 Leskovac, Serbia; (L.N.); (V.N.); (A.D.)
| | | | - Vesna Nikolić
- Faculty of Technology, University of Niš, 16000 Leskovac, Serbia; (L.N.); (V.N.); (A.D.)
| | - Ana Dinić
- Faculty of Technology, University of Niš, 16000 Leskovac, Serbia; (L.N.); (V.N.); (A.D.)
| | - Marko Igić
- Department of Prosthodontics, Faculty of Medicine, University of Niš, 18000 Niš, Serbia; (M.K.); (M.I.)
| | - Nirit Bernstein
- Institute of Soil Water and Environmental Sciences, Volcani Center, Rishon LeZion 7505001, Israel;
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4
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Lima RM, Rathod BB, Tiricz H, Howan DHO, Al Bouni MA, Jenei S, Tímár E, Endre G, Tóth GK, Kondorosi É. Legume Plant Peptides as Sources of Novel Antimicrobial Molecules Against Human Pathogens. Front Mol Biosci 2022; 9:870460. [PMID: 35755814 PMCID: PMC9218685 DOI: 10.3389/fmolb.2022.870460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 05/18/2022] [Indexed: 12/22/2022] Open
Abstract
Antimicrobial peptides are prominent components of the plant immune system acting against a wide variety of pathogens. Legume plants from the inverted repeat lacking clade (IRLC) have evolved a unique gene family encoding nodule-specific cysteine-rich NCR peptides acting in the symbiotic cells of root nodules, where they convert their bacterial endosymbionts into non-cultivable, polyploid nitrogen-fixing cells. NCRs are usually 30–50 amino acids long peptides having a characteristic pattern of 4 or 6 cysteines and highly divergent amino acid composition. While the function of NCRs is largely unknown, antimicrobial activity has been demonstrated for a few cationic Medicago truncatula NCR peptides against bacterial and fungal pathogens. The advantages of these plant peptides are their broad antimicrobial spectrum, fast killing modes of actions, multiple bacterial targets, and low propensity to develop resistance to them and no or low cytotoxicity to human cells. In the IRLC legumes, the number of NCR genes varies from a few to several hundred and it is possible that altogether hundreds of thousands of different NCR peptides exist. Due to the need for new antimicrobial agents, we investigated the antimicrobial potential of 104 synthetic NCR peptides from M. truncatula, M. sativa, Pisum sativum, Galega orientalis and Cicer arietinum against eight human pathogens, including ESKAPE bacteria. 50 NCRs showed antimicrobial activity with differences in the antimicrobial spectrum and effectivity. The most active peptides eliminated bacteria at concentrations from 0.8 to 3.1 μM. High isoelectric point and positive net charge were important but not the only determinants of their antimicrobial activity. Testing the activity of shorter peptide derivatives against Acinetobacter baumannii and Candida albicans led to identification of regions responsible for the antimicrobial activity and provided insight into their potential modes of action. This work provides highly potent lead molecules without hemolytic activity on human blood cells for novel antimicrobial drugs to fight against pathogens.
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Affiliation(s)
- Rui M Lima
- Institute of Plant Biology, Biological Research Centre, ELKH, Szeged, Hungary
| | | | - Hilda Tiricz
- Institute of Plant Biology, Biological Research Centre, ELKH, Szeged, Hungary
| | - Dian H O Howan
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | | | - Sándor Jenei
- Institute of Plant Biology, Biological Research Centre, ELKH, Szeged, Hungary
| | - Edit Tímár
- Institute of Plant Biology, Biological Research Centre, ELKH, Szeged, Hungary
| | - Gabriella Endre
- Institute of Plant Biology, Biological Research Centre, ELKH, Szeged, Hungary
| | - Gábor K Tóth
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Éva Kondorosi
- Institute of Plant Biology, Biological Research Centre, ELKH, Szeged, Hungary
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Huang R, Snedden WA, diCenzo GC. Reference nodule transcriptomes for Melilotus officinalis and Medicago sativa cv. Algonquin. PLANT DIRECT 2022; 6:e408. [PMID: 35774624 PMCID: PMC9219011 DOI: 10.1002/pld3.408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 05/14/2022] [Accepted: 05/19/2022] [Indexed: 05/10/2023]
Abstract
Host/symbiont compatibility is a hallmark of the symbiotic nitrogen-fixing interaction between rhizobia and legumes, mediated in part by plant-produced nodule-specific cysteine-rich (NCR) peptides and the bacterial BacA membrane protein that can act as a NCR peptide transporter. In addition, the genetic and metabolic properties supporting symbiotic nitrogen fixation often differ between compatible partners, including those sharing a common partner, highlighting the need for multiple study systems. Here, we report high-quality nodule transcriptome assemblies for Medicago sativa cv. Algonquin and Melilotus officinalis, two legumes able to form compatible symbioses with Sinorhizobium meliloti. The compressed M. sativa and M. officinalis assemblies consisted of 79,978 and 64,593 contigs, respectively, of which 33,341 and 28,278 were assigned putative annotations, respectively. As expected, the two transcriptomes showed broad similarity at a global level. We were particularly interested in the NCR peptide profiles of these plants, as these peptides drive bacterial differentiation during the symbiosis. A total of 412 and 308 NCR peptides were predicted from the M. sativa and M. officinalis transcriptomes, respectively, with approximately 9% of the transcriptome of both species consisting of NCR transcripts. Notably, transcripts encoding highly cationic NCR peptides (isoelectric point > 9.5), which are known to have antimicrobial properties, were ∼2-fold more abundant in M. sativa than in M. officinalis, and ∼27-fold more abundant when considering only NCR peptides in the six-cysteine class. We hypothesize that the difference in abundance of highly cationic NCR peptides explains our previous observation that some rhizobial bacA alleles which can support symbiosis with M. officinalis are unable to support symbiosis with M. sativa.
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Affiliation(s)
- Rui Huang
- Department of BiologyQueen's UniversityKingstonOntarioCanada
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6
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Molecular targets for antifungals in amino acid and protein biosynthetic pathways. Amino Acids 2021; 53:961-991. [PMID: 34081205 PMCID: PMC8241756 DOI: 10.1007/s00726-021-03007-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/17/2021] [Indexed: 01/22/2023]
Abstract
Fungi cause death of over 1.5 million people every year, while cutaneous mycoses are among the most common infections in the world. Mycoses vary greatly in severity, there are long-term skin (ringworm), nail or hair infections (tinea capitis), recurrent like vaginal candidiasis or severe, life-threatening systemic, multiorgan infections. In the last few years, increasing importance is attached to the health and economic problems caused by fungal pathogens. There is a growing need for improvement of the availability of antifungal drugs, decreasing their prices and reducing side effects. Searching for novel approaches in this respect, amino acid and protein biosynthesis pathways appear to be competitive. The route that leads from amino acid biosynthesis to protein folding and its activation is rich in enzymes that are descriptive of fungi. Blocking the action of those enzymes often leads to avirulence or growth inhibition. In this review, we want to trace the principal processes of fungi vitality. We present the data of genes encoding enzymes involved in amino acid and protein biosynthesis, potential molecular targets in antifungal chemotherapy, and describe the impact of inhibitors on fungal organisms.
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7
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Isozumi N, Masubuchi Y, Imamura T, Mori M, Koga H, Ohki S. Structure and antimicrobial activity of NCR169, a nodule-specific cysteine-rich peptide of Medicago truncatula. Sci Rep 2021; 11:9923. [PMID: 33972675 PMCID: PMC8110993 DOI: 10.1038/s41598-021-89485-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/21/2021] [Indexed: 11/09/2022] Open
Abstract
A model legume, Medicago truncatula, has over 600 nodule-specific cysteine-rich (NCR) peptides required for symbiosis with rhizobia. Among them, NCR169, an essential factor for establishing symbiosis, has four cysteine residues that are indispensable for its function. However, knowledge of NCR169 structure and mechanism of action is still lacking. In this study, we solved two NMR structures of NCR169 caused by different disulfide linkage patterns. We show that both structures have a consensus C-terminal β-sheet attached to an extended N-terminal region with dissimilar features; one moves widely, whereas the other is relatively stapled. We further revealed that the disulfide bonds of NCR169 contribute to its structural stability and solubility. Regarding the function, one of the NCR169 oxidized forms could bind to negatively charged bacterial phospholipids. Furthermore, the positively charged lysine-rich region of NCR169 may be responsible for its antimicrobial activity against Escherichia coli and Sinorhizobium meliloti. This active region was disordered even in the phospholipid bound state, suggesting that the disordered conformation of this region is key to its function. Morphological observations suggested the mechanism of action of NCR169 on bacteria. The present study on NCR169 provides new insights into the structure and function of NCR peptides.
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Affiliation(s)
- Noriyoshi Isozumi
- Center for Nano Materials and Technology (CNMT), Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan
| | - Yuya Masubuchi
- Center for Nano Materials and Technology (CNMT), Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan
| | - Tomohiro Imamura
- Ishikawa Prefectural University, 1-308, Suematsu, Nonoichi, Ishikawa, 921-8836, Japan
| | - Masashi Mori
- Ishikawa Prefectural University, 1-308, Suematsu, Nonoichi, Ishikawa, 921-8836, Japan
| | - Hironori Koga
- Ishikawa Prefectural University, 1-308, Suematsu, Nonoichi, Ishikawa, 921-8836, Japan
| | - Shinya Ohki
- Center for Nano Materials and Technology (CNMT), Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan.
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8
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Szerencsés B, Gácser A, Endre G, Domonkos I, Tiricz H, Vágvölgyi C, Szolomajer J, Howan DHO, Tóth GK, Pfeiffer I, Kondorosi É. Symbiotic NCR Peptide Fragments Affect the Viability, Morphology and Biofilm Formation of Candida Species. Int J Mol Sci 2021; 22:ijms22073666. [PMID: 33915930 PMCID: PMC8037406 DOI: 10.3390/ijms22073666] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/27/2021] [Accepted: 03/28/2021] [Indexed: 11/16/2022] Open
Abstract
The increasing rate of fungal infections causes global problems not only in human healthcare but agriculture as well. To combat fungal pathogens limited numbers of antifungal agents are available therefore alternative drugs are needed. Antimicrobial peptides are potent candidates because of their broad activity spectrum and their diverse mode of actions. The model legume Medicago truncatula produces >700 nodule specific cysteine-rich (NCR) peptides in symbiosis and many of them have in vitro antimicrobial activities without considerable toxicity on human cells. In this work we demonstrate the anticandidal activity of the NCR335 and NCR169 peptide derivatives against five Candida species by using the micro-dilution method, measuring inhibition of biofilm formation with the XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) assay, and assessing the morphological change of dimorphic Candida species by microscopy. We show that both the N- and C-terminal regions of NCR335 possess anticandidal activity as well as the C-terminal sequence of NCR169. The active peptides inhibit biofilm formation and the yeast-hypha transformation. Combined treatment of C. auris with peptides and fluconazole revealed synergistic interactions and reduced 2-8-fold the minimal inhibitory concentrations. Our results demonstrate that shortening NCR peptides can even enhance and broaden their anticandidal activity and therapeutic potential.
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Affiliation(s)
- Bettina Szerencsés
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (B.S.); (A.G.); (C.V.)
| | - Attila Gácser
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (B.S.); (A.G.); (C.V.)
| | - Gabriella Endre
- Biological Research Centre, Institute of Plant Biology, H-6726 Szeged, Hungary; (G.E.); (I.D.); (H.T.)
| | - Ildikó Domonkos
- Biological Research Centre, Institute of Plant Biology, H-6726 Szeged, Hungary; (G.E.); (I.D.); (H.T.)
| | - Hilda Tiricz
- Biological Research Centre, Institute of Plant Biology, H-6726 Szeged, Hungary; (G.E.); (I.D.); (H.T.)
| | - Csaba Vágvölgyi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (B.S.); (A.G.); (C.V.)
| | - János Szolomajer
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (J.S.); (D.H.O.H.); (G.K.T.)
| | - Dian H. O. Howan
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (J.S.); (D.H.O.H.); (G.K.T.)
| | - Gábor K. Tóth
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (J.S.); (D.H.O.H.); (G.K.T.)
- MTA-SZTE Biomimetic Systems Research Group, University of Szeged, H-6720 Szeged, Hungary
| | - Ilona Pfeiffer
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (B.S.); (A.G.); (C.V.)
- Correspondence: (I.P.); (É.K.)
| | - Éva Kondorosi
- Biological Research Centre, Institute of Plant Biology, H-6726 Szeged, Hungary; (G.E.); (I.D.); (H.T.)
- Correspondence: (I.P.); (É.K.)
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Ku YS, Cheng SS, Gerhardt A, Cheung MY, Contador CA, Poon LYW, Lam HM. Secretory Peptides as Bullets: Effector Peptides from Pathogens against Antimicrobial Peptides from Soybean. Int J Mol Sci 2020; 21:E9294. [PMID: 33291499 PMCID: PMC7730307 DOI: 10.3390/ijms21239294] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/24/2020] [Accepted: 12/03/2020] [Indexed: 12/24/2022] Open
Abstract
Soybean is an important crop as both human food and animal feed. However, the yield of soybean is heavily impacted by biotic stresses including insect attack and pathogen infection. Insect bites usually make the plants vulnerable to pathogen infection, which causes diseases. Fungi, oomycetes, bacteria, viruses, and nematodes are major soybean pathogens. The infection by pathogens and the defenses mounted by soybean are an interactive and dynamic process. Using fungi, oomycetes, and bacteria as examples, we will discuss the recognition of pathogens by soybean at the molecular level. In this review, we will discuss both the secretory peptides for soybean plant infection and those for pathogen inhibition. Pathogenic secretory peptides and peptides secreted by soybean and its associated microbes will be included. We will also explore the possible use of externally applied antimicrobial peptides identical to those secreted by soybean and its associated microbes as biopesticides.
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Affiliation(s)
- Yee-Shan Ku
- Centre for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Hong Kong; (Y.-S.K.); (S.-S.C.); (A.G.); (M.-Y.C.); (C.A.C.); (L.-Y.W.P.)
| | - Sau-Shan Cheng
- Centre for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Hong Kong; (Y.-S.K.); (S.-S.C.); (A.G.); (M.-Y.C.); (C.A.C.); (L.-Y.W.P.)
| | - Aisha Gerhardt
- Centre for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Hong Kong; (Y.-S.K.); (S.-S.C.); (A.G.); (M.-Y.C.); (C.A.C.); (L.-Y.W.P.)
- Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Ming-Yan Cheung
- Centre for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Hong Kong; (Y.-S.K.); (S.-S.C.); (A.G.); (M.-Y.C.); (C.A.C.); (L.-Y.W.P.)
| | - Carolina A. Contador
- Centre for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Hong Kong; (Y.-S.K.); (S.-S.C.); (A.G.); (M.-Y.C.); (C.A.C.); (L.-Y.W.P.)
| | - Lok-Yiu Winnie Poon
- Centre for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Hong Kong; (Y.-S.K.); (S.-S.C.); (A.G.); (M.-Y.C.); (C.A.C.); (L.-Y.W.P.)
| | - Hon-Ming Lam
- Centre for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Hong Kong; (Y.-S.K.); (S.-S.C.); (A.G.); (M.-Y.C.); (C.A.C.); (L.-Y.W.P.)
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10
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Velivelli SLS, Czymmek KJ, Li H, Shaw JB, Buchko GW, Shah DM. Antifungal symbiotic peptide NCR044 exhibits unique structure and multifaceted mechanisms of action that confer plant protection. Proc Natl Acad Sci U S A 2020; 117:16043-16054. [PMID: 32571919 PMCID: PMC7354933 DOI: 10.1073/pnas.2003526117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In the indeterminate nodules of a model legume Medicago truncatula, ∼700 nodule-specific cysteine-rich (NCR) peptides with conserved cysteine signature are expressed. NCR peptides are highly diverse in sequence, and some of these cationic peptides exhibit antimicrobial activity in vitro and in vivo. However, there is a lack of knowledge regarding their structural architecture, antifungal activity, and modes of action against plant fungal pathogens. Here, the three-dimensional NMR structure of the 36-amino acid NCR044 peptide was solved. This unique structure was largely disordered and highly dynamic with one four-residue α-helix and one three-residue antiparallel β-sheet stabilized by two disulfide bonds. NCR044 peptide also exhibited potent fungicidal activity against multiple plant fungal pathogens, including Botrytis cinerea and three Fusarium spp. It inhibited germination in quiescent spores of B. cinerea In germlings, it breached the fungal plasma membrane and induced reactive oxygen species. It bound to multiple bioactive phosphoinositides in vitro. Time-lapse confocal and superresolution microscopy revealed strong fungal cell wall binding, penetration of the cell membrane at discrete foci, followed by gradual loss of turgor, subsequent accumulation in the cytoplasm, and elevated levels in nucleoli of germlings. Spray-applied NCR044 significantly reduced gray mold disease symptoms caused by the fungal pathogen B. cinerea in tomato and tobacco plants, and postharvest products. Our work illustrates the antifungal activity of a structurally unique NCR peptide against plant fungal pathogens and paves the way for future development of this class of peptides as a spray-on fungistat/fungicide.
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Affiliation(s)
| | - Kirk J Czymmek
- Donald Danforth Plant Science Center, St Louis, MO 63132
- Advanced Bioimaging Laboratory, Donald Danforth Plant Science Center, St Louis, MO 63132
| | - Hui Li
- Donald Danforth Plant Science Center, St Louis, MO 63132
| | - Jared B Shaw
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99354
| | - Garry W Buchko
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99354
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164
| | - Dilip M Shah
- Donald Danforth Plant Science Center, St Louis, MO 63132;
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Lima RM, Kylarová S, Mergaert P, Kondorosi É. Unexplored Arsenals of Legume Peptides With Potential for Their Applications in Medicine and Agriculture. Front Microbiol 2020; 11:1307. [PMID: 32625188 PMCID: PMC7314904 DOI: 10.3389/fmicb.2020.01307] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 05/22/2020] [Indexed: 12/13/2022] Open
Abstract
During endosymbiosis, bacteria live intracellularly in the symbiotic organ of their host. The host controls the proliferation of endosymbionts and prevents their spread to other tissues and organs. In Rhizobium-legume symbiosis the major host effectors are secreted nodule-specific cysteine-rich (NCR) peptides, produced exclusively in the symbiotic cells. NCRs have evolved in the Inverted Repeat Lacking Clade (IRLC) of the Leguminosae family. They are secreted peptides that mediate terminal differentiation of the endosymbionts, forming polyploid, non-cultivable cells with increased membrane permeability. NCRs form an extremely large family of peptides, which have four or six conserved cysteines but otherwise highly diverse amino acid sequences, resulting in a wide variety of anionic, neutral and cationic peptides. In vitro, many synthetic NCRs have strong antimicrobial activities against both Gram-negative and Gram-positive bacteria, including the ESKAPE strains and pathogenic fungi. The spectra and minimal bactericidal and anti-fungal concentrations of NCRs differ, indicating that, in addition to their charge, the amino acid composition and sequence also play important roles in their antimicrobial activity. NCRs attack the bacteria and fungi at the cell envelope and membrane as well as intracellularly, forming interactions with multiple essential cellular machineries. NCR-like peptides with similar symbiotic functions as the NCRs also exist in other branches of the Leguminosae family. Thus, legumes provide countless and so far unexplored sources of symbiotic peptides representing an enormous resource of pharmacologically interesting molecules.
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Affiliation(s)
- Rui M Lima
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Salome Kylarová
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Peter Mergaert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Éva Kondorosi
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
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12
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Mergaert P. Role of antimicrobial peptides in controlling symbiotic bacterial populations. Nat Prod Rep 2019; 35:336-356. [PMID: 29393944 DOI: 10.1039/c7np00056a] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Covering: up to 2018 Antimicrobial peptides (AMPs) have been known for well over three decades as crucial mediators of the innate immune response in animals and plants, where they are involved in the killing of infecting microbes. However, AMPs have now also been found to be produced by eukaryotic hosts during symbiotic interactions with bacteria. These symbiotic AMPs target the symbionts and therefore have a more subtle biological role: not eliminating the microbial symbiont population but rather keeping it in check. The arsenal of AMPs and the symbionts' adaptations to resist them are in a careful balance, which contributes to the establishment of the host-microbe homeostasis. Although in many cases the biological roles of symbiotic AMPs remain elusive, for a number of symbiotic interactions, precise functions have been assigned or proposed to the AMPs, which are discussed here. The microbiota living on epithelia in animals, from the most primitive ones to the mammals, are challenged by a cocktail of AMPs that determine the specific composition of the bacterial community as well as its spatial organization. In the symbiosis of legume plants with nitrogen-fixing rhizobium bacteria, the host deploys an extremely large panel of AMPs - called nodule-specific cysteine-rich (NCR) peptides - that drive the bacteria into a terminally differentiated state and manipulate the symbiont physiology to maximize the benefit for the host. The NCR peptides are used as tools to enslave the bacterial symbionts, limiting their reproduction but keeping them metabolically active for nitrogen fixation. In the nutritional symbiotic interactions of insects and protists that have vertically transmitted bacterial symbionts with reduced genomes, symbiotic AMPs could facilitate the integration of the endosymbiont and host metabolism by favouring the flow of metabolites across the symbiont membrane through membrane permeabilization.
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Affiliation(s)
- P Mergaert
- Institute for Integrative Biology of the Cell, UMR9198, CNRS, Université Paris-Sud, CEA, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France.
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13
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Farkas A, Pap B, Kondorosi É, Maróti G. Antimicrobial Activity of NCR Plant Peptides Strongly Depends on the Test Assays. Front Microbiol 2018; 9:2600. [PMID: 30425705 PMCID: PMC6218624 DOI: 10.3389/fmicb.2018.02600] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 10/11/2018] [Indexed: 11/13/2022] Open
Abstract
The symbiosis specific NCR247 and NCR335 cationic plant peptides of Medicago truncatula have been shown to exert antimicrobial activity against a wide range of microbes. However, their antimicrobial efficiency is clearly limited by divalent cations. Here, the antibacterial and antifungal activities of NCR247 and NCR335 peptides were compared to those of the well-characterized peptide antibiotics polymyxin B and the aminoglycoside streptomycin on three model microbes, Escherichia coli, Bacillus subtilis and Saccharomyces cerevisiae as representatives of Gram-negative and Gram-positive bacteria as well as eukaryotic fungi. The aim of the study was to assess how the killing efficiency of these peptides depends on various, widely used antimicrobial susceptibility assays. Validated resazurin microdilution assay was used to determine minimal growth inhibitory concentrations in three general test media (MHB, MHBII and low-salt medium LSM). Bactericidal/fungicidal activities were determined by the commonly used drop plate assay. The natural plant peptides showed distinct characteristics, NCR247 had a generally high sensitivity for Ca2+ and Mg2+ in the medium, while NCR335 proved to be a robust and strong antimicrobial agent with comparable efficiency values to polymyxin B. Activity data were confirmed visually, both NCR247 and NCR335 treatments at minimal bactericidal concentrations induced complete disruption of the membranes and provoked cell lysis on all tested microorganisms as observed by scanning electron microscopy.
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Affiliation(s)
- Attila Farkas
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Bernadett Pap
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Éva Kondorosi
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Gergely Maróti
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary
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Kereszt A, Mergaert P, Montiel J, Endre G, Kondorosi É. Impact of Plant Peptides on Symbiotic Nodule Development and Functioning. FRONTIERS IN PLANT SCIENCE 2018; 9:1026. [PMID: 30065740 PMCID: PMC6056668 DOI: 10.3389/fpls.2018.01026] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/25/2018] [Indexed: 05/20/2023]
Abstract
Ribosomally synthesized peptides have wide ranges of functions in plants being, for example, signal molecules, transporters, alkaloids, or antimicrobial agents. Legumes are an unprecedented rich source of peptides, which are used to control the symbiosis of these plants with the nitrogen-fixing Rhizobium bacteria. Here, we discuss the function and the evolution of these peptides playing an important role in the formation or functioning of the symbiotic organs, the root nodules. We distinguish peptides that can be either cell-autonomous or secreted short-range or long-range signals, carrying messages in or between plant cells or that can act as effectors interacting with the symbiotic bacteria. Peptides are further classified according to the stage of the symbiotic process where they act. Several peptide classes, including RALF, DLV, ENOD40, and others, control Rhizobium infection and the initiation of cell divisions and the formation of nodule primordia. CLE and CEP peptides are implicated in systemic and local control of nodule initiation during autoregulation of nodulation and in response to the nutritional demands of the plant. Still other peptides act at later stages of the symbiosis. The PSK peptide is thought to be involved in the suppression of immunity in nodules and the nodule-specific cysteine-rich, GRP, and SNARP (LEED..PEED) peptide families are essential in the functioning of the nitrogen fixing root nodules. The NCRs and possibly also the GRP and SNARPs are targeted to the endosymbionts and play essential roles in the terminal differentiation of these bacteria.
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Affiliation(s)
- Attila Kereszt
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Peter Mergaert
- Institute of Integrative Biology of the Cell, UMR 9198, CNRS – CEA – Université Paris-Sud, Gif-sur-Yvette, France
| | - Jesús Montiel
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Gabriella Endre
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Éva Kondorosi
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
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Genome-Wide Sensitivity Analysis of the Microsymbiont Sinorhizobium meliloti to Symbiotically Important, Defensin-Like Host Peptides. mBio 2017; 8:mBio.01060-17. [PMID: 28765224 PMCID: PMC5539429 DOI: 10.1128/mbio.01060-17] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The model legume species Medicago truncatula expresses more than 700 nodule-specific cysteine-rich (NCR) signaling peptides that mediate the differentiation of Sinorhizobium meliloti bacteria into nitrogen-fixing bacteroids. NCR peptides are essential for a successful symbiosis in legume plants of the inverted-repeat-lacking clade (IRLC) and show similarity to mammalian defensins. In addition to signaling functions, many NCR peptides exhibit antimicrobial activity in vitro and in vivo. Bacterial resistance to these antimicrobial activities is likely to be important for symbiosis. However, the mechanisms used by S. meliloti to resist antimicrobial activity of plant peptides are poorly understood. To address this, we applied a global genetic approach using transposon mutagenesis followed by high-throughput sequencing (Tn-seq) to identify S. meliloti genes and pathways that increase or decrease bacterial competitiveness during exposure to the well-studied cationic NCR247 peptide and also to the unrelated model antimicrobial peptide polymyxin B. We identified 78 genes and several diverse pathways whose interruption alters S. meliloti resistance to NCR247. These genes encode the following: (i) cell envelope polysaccharide biosynthesis and modification proteins, (ii) inner and outer membrane proteins, (iii) peptidoglycan (PG) effector proteins, and (iv) non-membrane-associated factors such as transcriptional regulators and ribosome-associated factors. We describe a previously uncharacterized yet highly conserved peptidase, which protects S. meliloti from NCR247 and increases competitiveness during symbiosis. Additionally, we highlight a considerable number of uncharacterized genes that provide the basis for future studies to investigate the molecular basis of symbiotic development as well as chronic pathogenic interactions. Soil rhizobial bacteria enter into an ecologically and economically important symbiotic interaction with legumes, in which they differentiate into physiologically distinct bacteroids that provide essential ammonia to the plant in return for carbon sources. Plant signal peptides are essential and specific to achieve these physiological changes. These peptides show similarity to mammalian defensin peptides which are part of the first line of defense to control invading bacterial populations. A number of these legume peptides are indeed known to possess antimicrobial activity, and so far, only the bacterial BacA protein is known to protect rhizobial bacteria against their antimicrobial action. This study identified numerous additional bacterial factors that mediate protection and belong to diverse biological pathways. Our results significantly contribute to our understanding of the molecular roles of bacterial factors during legume symbioses and, second, provide insights into the mechanisms that pathogenic bacteria may use to resist the antimicrobial effects of defensins during infections.
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Morphotype of bacteroids in different legumes correlates with the number and type of symbiotic NCR peptides. Proc Natl Acad Sci U S A 2017; 114:5041-5046. [PMID: 28438996 DOI: 10.1073/pnas.1704217114] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In legume nodules, rhizobia differentiate into nitrogen-fixing forms called bacteroids, which are enclosed by a plant membrane in an organelle-like structure called the symbiosome. In the Inverted Repeat-Lacking Clade (IRLC) of legumes, this differentiation is terminal due to irreversible loss of cell division ability and is associated with genome amplification and different morphologies of the bacteroids that can be swollen, elongated, spherical, and elongated-branched, depending on the host plant. In Medicago truncatula, this process is orchestrated by nodule-specific cysteine-rich peptides (NCRs) delivered into developing bacteroids. Here, we identified the predicted NCR proteins in 10 legumes representing different subclades of the IRLC with distinct bacteroid morphotypes. Analysis of their expression and predicted sequences establishes correlations between the composition of the NCR family and the morphotypes of bacteroids. Although NCRs have a single origin, their evolution has followed different routes in individual lineages, and enrichment and diversification of cationic peptides has resulted in the ability to impose major morphological changes on the endosymbionts. The wide range of effects provoked by NCRs such as cell enlargement, membrane alterations and permeabilization, and biofilm and vesicle formation is dependent on the amino acid composition and charge of the peptides. These effects are strongly influenced by the rhizobial surface polysaccharides that affect NCR-induced differentiation and survival of rhizobia in nodule cells.
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17
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Farkas A, Maróti G, Kereszt A, Kondorosi É. Comparative Analysis of the Bacterial Membrane Disruption Effect of Two Natural Plant Antimicrobial Peptides. Front Microbiol 2017; 8:51. [PMID: 28167938 PMCID: PMC5253368 DOI: 10.3389/fmicb.2017.00051] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 01/09/2017] [Indexed: 12/27/2022] Open
Abstract
In the Medicago truncatula genome about 700 genes code for nodule-specific cysteine-rich (NCR) small peptides that are expressed in the symbiotic organ, the root nodule, where they control terminal differentiation of the endosymbiotic rhizobium bacteria to nitrogen-fixing bacteroids. Cationic NCR peptides were predicted to have antimicrobial activities. Here antibacterial activities of NCR247, NCR335, polymyxin B (PMB), and streptomycin were investigated and compared on two foodborne pathogens Salmonella enterica and Listeria monocytogenes as representatives of Gram-negative and Gram-positive bacteria. The integrity of the bacterial membrane was seriously compromised by these NCR peptides. Different localization was observed for NCR247 and NCR335 in the treated bacteria, the peptides mostly accumulated in the cytosol in S. enterica while they remained in the bacterial membrane in L. monocytogenes. Scanning electron microscopy revealed distinct membrane morphology of the peptide-treated bacteria. Complete cell disruption was induced by PMB and NCR335 in S. enterica while NCR247 treatment resulted in extensive budding observed on the cell surface of Salmonella. PMB had no effect on L. monocytogenes while NCR335 and NCR247 provoked morphological changes on this bacterium, the whole Listeria cell content was released in response to NCR335 treatment.
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Affiliation(s)
- Attila Farkas
- Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences Szeged, Hungary
| | - Gergely Maróti
- Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences Szeged, Hungary
| | - Attila Kereszt
- Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences Szeged, Hungary
| | - Éva Kondorosi
- Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences Szeged, Hungary
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18
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Mikuláss KR, Nagy K, Bogos B, Szegletes Z, Kovács E, Farkas A, Váró G, Kondorosi É, Kereszt A. Antimicrobial nodule-specific cysteine-rich peptides disturb the integrity of bacterial outer and inner membranes and cause loss of membrane potential. Ann Clin Microbiol Antimicrob 2016; 15:43. [PMID: 27465344 PMCID: PMC4964015 DOI: 10.1186/s12941-016-0159-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 07/14/2016] [Indexed: 11/22/2022] Open
Abstract
Background Certain legume plants produce a plethora of AMP-like peptides in their symbiotic cells. The cationic subgroup of the nodule-specific cysteine-rich (NCR) peptides has potent antimicrobial activity against gram-negative and gram-positive bacteria as well as unicellular and filamentous fungi. Findings It was shown by scanning and atomic force microscopies that the cationic peptides NCR335, NCR247 and Polymyxin B (PMB) affect differentially on the surfaces of Sinorhizobium meliloti bacteria. Similarly to PMB, both NCR peptides caused damages of the outer and inner membranes but at different extent and resulted in the loss of membrane potential that could be the primary reason of their antimicrobial activity. Conclusions The primary reason for bacterial cell death upon treatment with cationic NCR peptides is the loss of membrane potential. Electronic supplementary material The online version of this article (doi:10.1186/s12941-016-0159-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kata R Mikuláss
- Institute of Biochemistry, Hungarian Academy of Sciences, Temesvári körút 62, 6726, Szeged, Hungary
| | - Krisztina Nagy
- Institute of Biophysics of the Biological Research Centre, Hungarian Academy of Sciences, Temesvári körút 62, 6726, Szeged, Hungary
| | - Balázs Bogos
- Institute of Biochemistry, Hungarian Academy of Sciences, Temesvári körút 62, 6726, Szeged, Hungary.,Department of Environmental Systems Science, Institute of Integrative Biology, Group of Theoretical Biology, ETH Zürich, Universität strasse 16, CHN K18, 8092, Zurich, Switzerland
| | - Zsolt Szegletes
- Institute of Biophysics of the Biological Research Centre, Hungarian Academy of Sciences, Temesvári körút 62, 6726, Szeged, Hungary
| | - Etelka Kovács
- Institute of Biochemistry, Hungarian Academy of Sciences, Temesvári körút 62, 6726, Szeged, Hungary
| | - Attila Farkas
- Institute of Biochemistry, Hungarian Academy of Sciences, Temesvári körút 62, 6726, Szeged, Hungary
| | - György Váró
- Institute of Biophysics of the Biological Research Centre, Hungarian Academy of Sciences, Temesvári körút 62, 6726, Szeged, Hungary
| | - Éva Kondorosi
- Institute of Biochemistry, Hungarian Academy of Sciences, Temesvári körút 62, 6726, Szeged, Hungary
| | - Attila Kereszt
- Institute of Biochemistry, Hungarian Academy of Sciences, Temesvári körút 62, 6726, Szeged, Hungary.
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Lara HH, Romero-Urbina DG, Pierce C, Lopez-Ribot JL, Arellano-Jiménez MJ, Jose-Yacaman M. Effect of silver nanoparticles on Candida albicans biofilms: an ultrastructural study. J Nanobiotechnology 2015; 13:91. [PMID: 26666378 PMCID: PMC4678641 DOI: 10.1186/s12951-015-0147-8] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 11/09/2015] [Indexed: 12/02/2022] Open
Abstract
Background Candida albicans is the most common pathogenic fungus isolated in bloodstream infections in hospitalized patients, and candidiasis represents the fourth most common infection in United States hospitals, mostly due to the increasing numbers of immune- and medically-compromised patients. C. albicans has the ability to form biofilms and morphogenetic conversions between yeast and hyphal morphologies contribute to biofilm development and represent an essential virulence factor. Moreover, these attached communities of cells are surrounded by a protective exopolymeric matrix that effectively shelters Candida against the action of antifungals. Because of dismal outcomes, novel antifungal strategies, and in particular those targeting biofilms are urgently required. As fungi are eukaryotic, research and development of new antifungal agents has been difficult due to the limited number of selective targets, also leading to toxicity. Results By microwave-assisted techniques we obtained pure 1 nm spherical silver nanoparticles ideal for their potential biological applications without adding contaminants. A phenotypic assay of C. albicans demonstrated a potent dose-dependent inhibitory effect of silver nanoparticles on biofilm formation, with an IC50 of 0.089 ppm. Also silver nanoparticles demonstrated efficacy when tested against pre-formed C. albicans biofilms resulting in an IC50 of 0.48 ppm. The cytotoxicity assay resulted in a CC50 of 7.03 ppm. The ultrastructural differences visualized under SEM with silver nanoparticles treatment were changes in the surface appearance of the yeast from smooth to rough thus indicating outer cell wall damage. On the fungal pre-formed biofilm true hyphae was mostly absent, as filamentation was inhibited. TEM measurement of the cell-wall width of C. albicans after treatment resulted in significant enlargement (206 ± 11 nm) demonstrating membrane permeabilization. Conclusions Our results demonstrate that silver nanoparticles are potent inhibitors of C. albicans biofilm formation. SEM observations are consistent with an overall loss of structure of biofilms mostly due to disruption of the outer cell membrane/wall and inhibition of filamentation.TEM indicates the permeabilization of the cell wall and subsequent disruption of the structural layers of the outer fungal cell wall. The anti-biofilm effects are via cell wall disruption. Electronic supplementary material The online version of this article (doi:10.1186/s12951-015-0147-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Humberto H Lara
- Department of Physics and Astronomy, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA.
| | - Dulce G Romero-Urbina
- Department of Physics and Astronomy, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA.
| | - Christopher Pierce
- Department of Biology and South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, 78249, USA.
| | - Jose L Lopez-Ribot
- Department of Biology and South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, 78249, USA.
| | - M Josefina Arellano-Jiménez
- Department of Physics and Astronomy, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA.
| | - Miguel Jose-Yacaman
- Department of Physics and Astronomy, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA.
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Loss of the nodule-specific cysteine rich peptide, NCR169, abolishes symbiotic nitrogen fixation in the Medicago truncatula dnf7 mutant. Proc Natl Acad Sci U S A 2015; 112:15232-7. [PMID: 26401023 DOI: 10.1073/pnas.1500777112] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Host compatible rhizobia induce the formation of legume root nodules, symbiotic organs within which intracellular bacteria are present in plant-derived membrane compartments termed symbiosomes. In Medicago truncatula nodules, the Sinorhizobium microsymbionts undergo an irreversible differentiation process leading to the development of elongated polyploid noncultivable nitrogen fixing bacteroids that convert atmospheric dinitrogen into ammonia. This terminal differentiation is directed by the host plant and involves hundreds of nodule specific cysteine-rich peptides (NCRs). Except for certain in vitro activities of cationic peptides, the functional roles of individual NCR peptides in planta are not known. In this study, we demonstrate that the inability of M. truncatula dnf7 mutants to fix nitrogen is due to inactivation of a single NCR peptide, NCR169. In the absence of NCR169, bacterial differentiation was impaired and was associated with early senescence of the symbiotic cells. Introduction of the NCR169 gene into the dnf7-2/NCR169 deletion mutant restored symbiotic nitrogen fixation. Replacement of any of the cysteine residues in the NCR169 peptide with serine rendered it incapable of complementation, demonstrating an absolute requirement for all cysteines in planta. NCR169 was induced in the cell layers in which bacteroid elongation was most pronounced, and high expression persisted throughout the nitrogen-fixing nodule zone. Our results provide evidence for an essential role of NCR169 in the differentiation and persistence of nitrogen fixing bacteroids in M. truncatula.
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21
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The Absence of N-Acetyl-D-glucosamine Causes Attenuation of Virulence of Candida albicans upon Interaction with Vaginal Epithelial Cells In Vitro. BIOMED RESEARCH INTERNATIONAL 2015; 2015:398045. [PMID: 26366412 PMCID: PMC4558442 DOI: 10.1155/2015/398045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 06/15/2015] [Accepted: 07/28/2015] [Indexed: 11/28/2022]
Abstract
To better understand the molecular events underlying vulvovaginal candidiasis, we established an in vitro system. Immortalized vaginal epithelial cells were infected with live, yeast form C. albicans and C. albicans cultured in the same medium without vaginal epithelial cells were used as control. In both cases a yeast to hyphae transition was robustly induced. Whole transcriptome sequencing was used to identify specific gene expression changes in C. albicans. Numerous genes leading to a yeast to hyphae transition and hyphae specific genes were upregulated in the control hyphae and the hyphae in response to vaginal epithelial cells. Strikingly, the GlcNAc pathway was exclusively triggered by vaginal epithelial cells. Functional analysis in our in vitro system revealed that the GlcNAc biosynthesis is involved in the adherence to, and the ability to kill, vaginal epithelial cells in vitro, thus indicating the key role for this pathway in the virulence of C. albicans upon vulvovaginal candidiasis.
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Maróti G, Downie JA, Kondorosi É. Plant cysteine-rich peptides that inhibit pathogen growth and control rhizobial differentiation in legume nodules. CURRENT OPINION IN PLANT BIOLOGY 2015; 26:57-63. [PMID: 26116977 DOI: 10.1016/j.pbi.2015.05.031] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 04/13/2015] [Accepted: 05/31/2015] [Indexed: 05/25/2023]
Abstract
Plants must co-exist with both pathogenic and beneficial microbes. Antimicrobial peptides with broad antimicrobial activities represent one of the first lines of defense against pathogens. Many plant cysteine-rich peptides with potential antimicrobial properties have been predicted. Amongst them, defensins and defensin-like peptides are the most abundant and plants can express several hundreds of them. In some rhizobial-legume symbioses special defensin-like peptides, the nodule-specific cysteine-rich (NCR) peptides have evolved in those legumes whose symbiotic partner terminally differentiates. In Medicago truncatula, >700 NCRs exist and collectively act as plant effectors inducing irreversible differentiation of rhizobia to nitrogen-fixing bacteroids. Cationic NCR peptides have a broad range of potent antimicrobial activities but do not kill the endosymbionts.
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Affiliation(s)
- Gergely Maróti
- Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences, Temesvári krt. 62., Szeged 6726, Hungary
| | - J Allan Downie
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Éva Kondorosi
- Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences, Temesvári krt. 62., Szeged 6726, Hungary.
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23
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Durgo H, Klement E, Hunyadi-Gulyas E, Szucs A, Kereszt A, Medzihradszky KF, Kondorosi E. Identification of nodule-specific cysteine-rich plant peptides in endosymbiotic bacteria. Proteomics 2015; 15:2291-5. [PMID: 25690539 DOI: 10.1002/pmic.201400385] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 01/05/2015] [Accepted: 02/12/2015] [Indexed: 11/09/2022]
Abstract
The symbiosis of Medicago truncatula with Sinorhizobium meliloti or Sinorhizobium medicae soil bacteria results in the formation of root nodules where bacteria inside the plant cells are irreversibly converted to polyploid, nondividing nitrogen-fixing bacteroids. Bacteroid differentiation is host-controlled and the plant effectors are symbiosis-specific secreted plant peptides. In the M. truncatula genome there are more than 600 symbiotic peptide genes including 500 small genes coding for nodule-specific cysteine-rich (NCR) peptides. While NCR transcripts represent >5% of the nodule transcriptome, the existence of only eight NCR peptides has been demonstrated so far. The predicted NCRs are secreted peptides targeted to the endosymbionts. Correspondingly, all the eight detected peptides were present in the bacteroids. Here, we report on large-scale detection of NCR peptides from nodules and from isolated, semipurified endosymbionts at various stages of their differentiation. In total 138 NCRs were detected in the bacteroids; 38 were cationic while the majority was anionic. The presence of early NCRs in nitrogen-fixing bacteroids indicates their high stability, and their long-term maintenance suggests persisting biological roles in the bacteroids.
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Affiliation(s)
- Hajnalka Durgo
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Eva Klement
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Eva Hunyadi-Gulyas
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Attila Szucs
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Attila Kereszt
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Katalin F Medzihradszky
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary.,Department of Pharmaceutical Chemistry, University California San Francisco, CA, USA
| | - Eva Kondorosi
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
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