1
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Smith P, Schuster M. The fitness benefit of pyoverdine cross-feeding by Pseudomonas protegens Pf-5. Environ Microbiol 2024; 26:e16554. [PMID: 38097191 DOI: 10.1111/1462-2920.16554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/24/2023] [Indexed: 12/20/2023]
Abstract
Under iron-limiting conditions, fluorescent pseudomonads acquire iron from the environment by secreting strain-specific, iron-chelating siderophores termed pyoverdines (PVD). The rhizosphere bacterium Pseudomonas protegens Pf-5 produces its own PVD but also can cross-feed on PVDs produced by other species. Previous work has found that Pf-5 continues to produce its own PVD when allowed to cross-feed, raising questions about the benefit of heterologous PVD utilisation. Here, we investigate this question using a defined, unidirectional P. protegens Pf-5/Pseudomonas aeruginosa PAO1 cross-feeding model. Quantifying the production of PVD in the presence of heterologous PVD produced by PAO1, we show that cross-feeding Pf-5 strains reduce the production of their own PVD, while non-cross-feeding Pf-5 strains increase the production of PVD. Measuring the fitness of cross-feeding and non-cross-feeding Pf-5 strains in triple coculture with PAO1, we find that cross-feeding provides a fitness benefit to Pf-5 when the availability of heterologous PVD is high. We conclude that cross-feeding can reduce the costs of self-PVD production and may thus aid in the colonisation of iron-limited environments that contain compatible siderophores produced by other resident microbes. Taken together, these results expand our understanding of the mechanisms of interspecific competition for iron in microbial communities.
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Affiliation(s)
- Parker Smith
- Department of Microbiology, Oregon State University, Corvallis, Oregon, USA
| | - Martin Schuster
- Department of Microbiology, Oregon State University, Corvallis, Oregon, USA
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2
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Hua LQ, Yang SQ, Xia ZF, Zeng H. Application of Sophora alopecuroides organic fertilizer changes the rhizosphere microbial community structure of melon plants and increases the fruit sugar content. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2023; 103:164-175. [PMID: 35837792 DOI: 10.1002/jsfa.12126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 07/10/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Sophora alopecuroides L. is a leguminous plant commonly found in northwest China. In Xinjiang, the fresh herb of S. alopecuroides is often applied as a green fertilizer to the rhizosphere of melon (Cucumis melo) plants at the end of their flowering period, to improve the taste of the fruits. However, the effects of S. alopecuroides-based fertilizers on the microbial community structure of soil and crop-root systems are unclear. In order to study the sweetening mechanism of the S. alopecuroides organic fertilizer, three different varieties of melon were selected. The untreated plants were used as the control (CK) group, and the plants treated with S. alopecuroides-based organic fertilizer were selected as the treatment (T) group. The physical and chemical properties, enzyme activities and microbial community structure of the rhizosphere samples were also determined, and a correlation analysis with the fruit sweetness index was conducted. RESULTS Sugar content of group T was at least 40% higher than that of group CK. The increase in fruit sugar content positively correlated with the increase in the abundance of beneficial microorganisms, including Pseudomonas, Bacillus, Mycobacterium, Burkholderia, Streptomyces, Acinetobacter, Proteobacteria, Lysobacter, Actinomycetes, Penicillium and Aspergillus. CONCLUSION Sophora alopecuroides organic fertilizer could alter the composition and function of bacterial and fungal communities and promote the growth of beneficial bacteria in the melon plant rhizosphere. Further, it could increase the content of soluble solids and sugar in the fruits to achieve a sweetening effect. This fertilizer can be applied as a fruit sweetener in melon cultivation, improving the sugar content of the fruit and consequently the sweetness. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Ling-Qi Hua
- College of Life Science, Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin of Xinjiang Production and Construction Corps, Tarim University, Xinjiang, People's Republic of China
| | - Sheng-Qiang Yang
- School of Basic Medicine, Youjiang Medical University for Nationalities, Baise, People's Republic of China
| | - Zhan-Feng Xia
- College of Life Science, Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin of Xinjiang Production and Construction Corps, Tarim University, Xinjiang, People's Republic of China
| | - Hong Zeng
- College of Life Science, Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin of Xinjiang Production and Construction Corps, Tarim University, Xinjiang, People's Republic of China
- School of Basic Medicine, Youjiang Medical University for Nationalities, Baise, People's Republic of China
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3
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Iron acquisition strategies in pseudomonads: mechanisms, ecology, and evolution. Biometals 2022:10.1007/s10534-022-00480-8. [PMID: 36508064 PMCID: PMC10393863 DOI: 10.1007/s10534-022-00480-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022]
Abstract
AbstractIron is important for bacterial growth and survival, as it is a common co-factor in essential enzymes. Although iron is very abundant in the earth crust, its bioavailability is low in most habitats because ferric iron is largely insoluble under aerobic conditions and at neutral pH. Consequently, bacteria have evolved a plethora of mechanisms to solubilize and acquire iron from environmental and host stocks. In this review, I focus on Pseudomonas spp. and first present the main iron uptake mechanisms of this taxa, which involve the direct uptake of ferrous iron via importers, the production of iron-chelating siderophores, the exploitation of siderophores produced by other microbial species, and the use of iron-chelating compounds produced by plants and animals. In the second part of this review, I elaborate on how these mechanisms affect interactions between bacteria in microbial communities, and between bacteria and their hosts. This is important because Pseudomonas spp. live in diverse communities and certain iron-uptake strategies might have evolved not only to acquire this essential nutrient, but also to gain relative advantages over competitors in the race for iron. Thus, an integrative understanding of the mechanisms of iron acquisition and the eco-evolutionary dynamics they drive at the community level might prove most useful to understand why Pseudomonas spp., in particular, and many other bacterial species, in general, have evolved such diverse iron uptake repertoires.
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4
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Figueiredo ART, Özkaya Ö, Kümmerli R, Kramer J. Siderophores drive invasion dynamics in bacterial communities through their dual role as public good versus public bad. Ecol Lett 2021; 25:138-150. [PMID: 34753204 PMCID: PMC9299690 DOI: 10.1111/ele.13912] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/21/2021] [Accepted: 10/12/2021] [Indexed: 11/30/2022]
Abstract
Microbial invasions can compromise ecosystem services and spur dysbiosis and disease in hosts. Nevertheless, the mechanisms determining invasion outcomes often remain unclear. Here, we examine the role of iron‐scavenging siderophores in driving invasions of Pseudomonas aeruginosa into resident communities of environmental pseudomonads. Siderophores can be ‘public goods’ by delivering iron to individuals possessing matching receptors; but they can also be ‘public bads’ by withholding iron from competitors lacking these receptors. Accordingly, siderophores should either promote or impede invasion, depending on their effects on invader and resident growth. Using supernatant feeding and invasion assays, we show that invasion success indeed increased when the invader could use its siderophores to inhibit (public bad) rather than stimulate (public good) resident growth. Conversely, invasion success decreased the more the invader was inhibited by the residents’ siderophores. Our findings identify siderophores as a major driver of invasion dynamics in bacterial communities under iron‐limited conditions.
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Affiliation(s)
- Alexandre R T Figueiredo
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Özhan Özkaya
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Rolf Kümmerli
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Jos Kramer
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
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5
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Two TonB-dependent transporters in Methylosinus trichosporium OB3b are responsible for uptake of different forms of methanobactin and are involved in the canonical 'copper switch'. Appl Environ Microbiol 2021; 88:e0179321. [PMID: 34669437 DOI: 10.1128/aem.01793-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Copper is an important component of methanotrophic physiology as it controls the expression and activity of alternative forms of methane monooxygenase (MMO). To collect copper, some methanotrophs secrete a chalkophore or copper-binding compound called methanobactin (MB). MB is a ribosomally synthesized post-translationally modified polypeptide (RiPP) that, after binding copper, is collected by MbnT, a TonB-dependent transporter (TBDT). Structurally different forms of MB have been characterized, and here we show that different forms of MB are collected by specific TBDTs. Further, we report that in the model methanotroph, Methylosinus trichosporium OB3b, expression of the TBDT required for uptake of a different MB made by Methylocystis sp. strain SB2 (MB-SB2), is induced in the presence of MB-SB2, suggesting that methanotrophs have developed specific machinery and regulatory systems to actively take up MB from other methanotrophs for copper collection. Moreover, the canonical "copper-switch" in Ms. trichosporium OB3b that controls expression of alternative MMOs is apparent if one of the two TBDTs required for MB-OB3b and MB-SB2 uptake is knocked out, but is disrupted if both TBDTs are knocked out. These data indicate that MB uptake, including the uptake of exogenous MB, plays an important role in the copper switch in M. trichosporium OB3b and thus overall activity. Based on these data, we propose a revised model for the "copper-switch" in this methanotroph that involves MB uptake. IMPORTANCE In this study, we demonstrate that different TonB-dependent transporters (TBDTs) in the model methanotroph Methylosinus trichosporium OB3b are responsible for uptake of either endogenous MB or exogenous MB. Interestingly, the presence of exogenous MB induces expression of its specific TBDT in M. trichosporium OB3b, suggesting that this methanotroph is able to actively take up MB produced by others. This work contributes to our understanding of how microbes collect and compete for copper, and also helps inform how such uptake coordinates the expression of different forms of methane monooxygenase. Such studies are likely to be very important to develop a better understanding of methanotrophic interactions via synthesis and secretion of secondary metabolites such as methanobactin and thus provide additional means whereby these microbes can be manipulated for a variety of environmental and industrial purposes.
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6
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Butaitė E, Kramer J, Kümmerli R. Local adaptation, geographical distance and phylogenetic relatedness: Assessing the drivers of siderophore-mediated social interactions in natural bacterial communities. J Evol Biol 2021; 34:1266-1278. [PMID: 34101930 PMCID: PMC8453950 DOI: 10.1111/jeb.13883] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/21/2021] [Accepted: 06/03/2021] [Indexed: 11/29/2022]
Abstract
In heterogenous, spatially structured habitats, individuals within populations can become adapted to the prevailing conditions in their local environment. Such local adaptation has been reported for animals and plants, and for pathogens adapting to hosts. There is increasing interest in applying the concept of local adaptation to microbial populations, especially in the context of microbe-microbe interactions. Here, we tested whether cooperation and cheating on cooperation can spur patterns of local adaptation in soil and pond communities of Pseudomonas bacteria, collected across a geographical scale of 0.5 to 50 m. We focussed on the production of pyoverdines, a group of secreted iron-scavenging siderophores that often differ among pseudomonads in their chemical structure and the receptor required for their uptake. A combination of supernatant-feeding and competition assays between isolates from four distance categories revealed tremendous variation in the extent to which pyoverdine non- and low-producers can benefit from pyoverdines secreted by producers. However, this variation was not explained by geographical distance, but primarily depended on the phylogenetic relatedness between interacting isolates. A notable exception occurred in local pond communities, where the effect of phylogenetic relatedness was eroded in supernatant assays, probably due to the horizontal transfer of receptor genes. While the latter result could be a signature of local adaptation, our results overall indicate that common ancestry and not geographical distance is the main predictor of siderophore-mediated social interactions among pseudomonads.
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Affiliation(s)
- Elena Butaitė
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Jos Kramer
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland.,Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Rolf Kümmerli
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland.,Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
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7
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Xu Z, Mandic-Mulec I, Zhang H, Liu Y, Sun X, Feng H, Xun W, Zhang N, Shen Q, Zhang R. Antibiotic Bacillomycin D Affects Iron Acquisition and Biofilm Formation in Bacillus velezensis through a Btr-Mediated FeuABC-Dependent Pathway. Cell Rep 2020; 29:1192-1202.e5. [PMID: 31665633 DOI: 10.1016/j.celrep.2019.09.061] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 05/31/2019] [Accepted: 09/19/2019] [Indexed: 02/06/2023] Open
Abstract
Bacillus spp. produce a wide range of secondary metabolites, including antibiotics, which have been well studied for their antibacterial properties but less so as signaling molecules. Previous results indicated that the lipopeptide bacillomycin D is a signal that promotes biofilm development of Bacillus velezensis SQR9. However, the mechanism behind this signaling is still unknown. Here, we show that bacillomycin D promotes biofilm development by promoting the acquisition of iron. Bacillomycin D promotes the transcription of the iron ABC transporter FeuABC by binding to its transcription factor, Btr. These actions increase intracellular iron concentration and activate the KinB-Spo0A-SinI-SinR-dependent synthesis of biofilm matrix components. We demonstrate that this strategy is beneficial for biofilm development and competition with the Pseudomonas fluorescens PF-5. Our results unravel an antibiotic-dependent signaling mechanism that links iron acquisition to biofilm development and ecological competition.
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Affiliation(s)
- Zhihui Xu
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing 210095, Jiangsu, Peoples R China
| | - Ines Mandic-Mulec
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Huihui Zhang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing 210095, Jiangsu, Peoples R China
| | - Yan Liu
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing 210095, Jiangsu, Peoples R China
| | - Xinli Sun
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing 210095, Jiangsu, Peoples R China
| | - Haichao Feng
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing 210095, Jiangsu, Peoples R China
| | - Weibing Xun
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing 210095, Jiangsu, Peoples R China
| | - Nan Zhang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing 210095, Jiangsu, Peoples R China
| | - Qirong Shen
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing 210095, Jiangsu, Peoples R China
| | - Ruifu Zhang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing 210095, Jiangsu, Peoples R China; Key Laboratory of Microbial Resource Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agriculture Sciences, Beijing, Peoples R China.
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8
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Kramer J, Özkaya Ö, Kümmerli R. Bacterial siderophores in community and host interactions. Nat Rev Microbiol 2020; 18:152-163. [PMID: 31748738 PMCID: PMC7116523 DOI: 10.1038/s41579-019-0284-4] [Citation(s) in RCA: 409] [Impact Index Per Article: 102.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2019] [Indexed: 01/06/2023]
Abstract
Iron is an essential trace element for most organisms. A common way for bacteria to acquire this nutrient is through the secretion of siderophores, which are secondary metabolites that scavenge iron from environmental stocks and deliver it to cells via specific receptors. While there has been tremendous interest in understanding the molecular basis of siderophore synthesis, uptake and regulation, questions about the ecological and evolutionary consequences of siderophore secretion have only recently received increasing attention. In this Review, we outline how eco-evolutionary questions can complement the mechanistic perspective and help to obtain a more integrated view of siderophores. In particular, we explain how secreted diffusible siderophores can affect other community members, leading to cooperative, exploitative and competitive interactions between individuals. These social interactions in turn can spur co-evolutionary arms races between strains and species, lead to ecological dependencies between them and potentially contribute to the formation of stable communities. In brief, this Review shows that siderophores are much more than just iron carriers: they are important mediators of interactions between members of microbial assemblies and the eukaryotic hosts they inhabit.
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Affiliation(s)
- Jos Kramer
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Özhan Özkaya
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Rolf Kümmerli
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland.
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9
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Arginine Biosynthesis Modulates Pyoverdine Production and Release in Pseudomonas putida as Part of the Mechanism of Adaptation to Oxidative Stress. J Bacteriol 2019; 201:JB.00454-19. [PMID: 31451546 DOI: 10.1128/jb.00454-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 08/22/2019] [Indexed: 12/28/2022] Open
Abstract
Iron is essential for most life forms. Under iron-limiting conditions, many bacteria produce and release siderophores-molecules with high affinity for iron-which are then transported into the cell in their iron-bound form, allowing incorporation of the metal into a wide range of cellular processes. However, free iron can also be a source of reactive oxygen species that cause DNA, protein, and lipid damage. Not surprisingly, iron capture is finely regulated and linked to oxidative-stress responses. Here, we provide evidence indicating that in the plant-beneficial bacterium Pseudomonas putida KT2440, the amino acid l-arginine is a metabolic connector between iron capture and oxidative stress. Mutants defective in arginine biosynthesis show reduced production and release of the siderophore pyoverdine and altered expression of certain pyoverdine-related genes, resulting in higher sensitivity to iron limitation. Although the amino acid is not part of the siderophore side chain, addition of exogenous l-arginine restores pyoverdine release in the mutants, and increased pyoverdine production is observed in the presence of polyamines (agmatine and spermidine), of which arginine is a precursor. Spermidine also has a protective role against hydrogen peroxide in P. putida, whereas defects in arginine and pyoverdine synthesis result in increased production of reactive oxygen species.IMPORTANCE The results of this study show a previously unidentified connection between arginine metabolism, siderophore turnover, and oxidative stress in Pseudomonas putida Although the precise molecular mechanisms involved have yet to be characterized in full detail, our data are consistent with a model in which arginine biosynthesis and the derived pathway leading to polyamine production function as a homeostasis mechanism that helps maintain the balance between iron uptake and oxidative-stress response systems.
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10
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Zhao XF, Hao YQ, Zhang DY, Zhang QG. Local biotic interactions drive species-specific divergence in soil bacterial communities. ISME JOURNAL 2019; 13:2846-2855. [PMID: 31358911 DOI: 10.1038/s41396-019-0477-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 06/23/2019] [Accepted: 07/05/2019] [Indexed: 11/09/2022]
Abstract
It is well accepted that environmental heterogeneity and dispersal are key factors determining soil bacterial community composition, yet little is known about the role of local biotic interactions. Here we address this issue with an abundance-manipulation experiment that was conducted in a semiarid grassland. We manually increased the abundance of six randomly chosen resident bacterial species in separate, closed, communities and allowed the communities to recover in situ for 1 year. The single episode of increase in the abundance of different species drove species-specific community divergence accompanied by a decline in local diversity. Four of the six added species caused a decrease in the abundance of their closely related species, suggesting an important role of interspecific competition in driving the observed community divergence. Our results also suggested a lack of effective population regulations to force the relative abundance of manipulated species to revert to original level, which would allow persistence of the divergence among soil bacterial communities. We concluded that biotic interactions were important in determining soil bacterial community composition, which could result in substantial variation in soil bacterial community composition in abiotically homogenous environment.
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Affiliation(s)
- Xin-Feng Zhao
- School of Life Sciences, South China Normal University, Guangzhou, 510631, Guangdong, China.,State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, Beijing Normal University, Beijing, 100875, China
| | - Yi-Qi Hao
- School of Life Sciences, South China Normal University, Guangzhou, 510631, Guangdong, China. .,State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, Beijing Normal University, Beijing, 100875, China.
| | - Da-Yong Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, Beijing Normal University, Beijing, 100875, China
| | - Quan-Guo Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, Beijing Normal University, Beijing, 100875, China
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11
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Jing X, Cui Q, Li X, Yin J, Ravichandran V, Pan D, Fu J, Tu Q, Wang H, Bian X, Zhang Y. Engineering Pseudomonas protegens Pf-5 to improve its antifungal activity and nitrogen fixation. Microb Biotechnol 2018; 13:118-133. [PMID: 30461205 PMCID: PMC6984399 DOI: 10.1111/1751-7915.13335] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 10/21/2018] [Accepted: 10/21/2018] [Indexed: 11/26/2022] Open
Abstract
In agricultural production, sustainability is currently one of the most significant concerns. The genetic modification of plant growth‐promoting rhizobacteria may provide a novel way to use natural bacteria as microbial inoculants. In this study, the root‐colonizing strain Pseudomonas protegens Pf‐5 was genetically modified to act as a biocontrol agent and biofertilizer with biological nitrogen fixation activity. Genetic inactivation of retS enhanced the production of 2,4‐diacetylphloroglucinol, which contributed for the enhanced antifungal activity. Then, the entire nitrogenase island with native promoter from Pseudomonas stutzeri DSM4166 was introduced into a retS mutant strain for expression. Root colonization patterns assessed via confocal laser scanning microscopy confirmed that GFP‐tagged bacterial were mainly located on root surfaces and at the junctions between epidermal root cells. Moreover, under pathogen and N‐limited double treatment conditions, the fresh weights of seedlings inoculated with the recombinant retS mutant‐nif strain were increased compared with those of the control. In conclusion, this study has innovatively developed an eco‐friendly alternative to the agrochemicals that will benefit global plant production significantly.
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Affiliation(s)
- Xiaoshu Jing
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, 266237, Qingdao, China
| | - Qingwen Cui
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, 266237, Qingdao, China
| | - Xiaochen Li
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, 266237, Qingdao, China
| | - Jia Yin
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, 266237, Qingdao, China
| | - Vinothkannan Ravichandran
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, 266237, Qingdao, China
| | - Deng Pan
- Jinan Yian Biology Institute, Shandong Yian Biological Engineering Co. Ltd., Jinan, 250100, China
| | - Jun Fu
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, 266237, Qingdao, China
| | - Qiang Tu
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, 266237, Qingdao, China
| | - Hailong Wang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, 266237, Qingdao, China
| | - Xiaoying Bian
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, 266237, Qingdao, China
| | - Youming Zhang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, 266237, Qingdao, China
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12
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Butaitė E, Kramer J, Wyder S, Kümmerli R. Environmental determinants of pyoverdine production, exploitation and competition in natural Pseudomonas communities. Environ Microbiol 2018; 20:3629-3642. [PMID: 30003663 DOI: 10.1111/1462-2920.14355] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 06/20/2018] [Accepted: 06/25/2018] [Indexed: 11/28/2022]
Abstract
Many bacteria rely on the secretion of siderophores to scavenge iron from the environment. Laboratory studies revealed that abiotic and biotic factors together determine how much siderophores bacteria make, and whether siderophores can be exploited by non-producing cheaters or be deployed by producers to inhibit competitors. Here, we explore whether these insights apply to natural communities, by comparing the production of the siderophore pyoverdine among 930 Pseudomonas strains from 48 soil and pond communities. We found that pH, iron content, carbon concentration and community diversity determine pyoverdine production levels, and the extent to which strains are either stimulated or inhibited by heterologous (non-self) pyoverdines. While pyoverdine non-producers occurred in both habitats, their prevalence was higher in soils. Environmental and genetic analyses suggest that non-producers can evolve as cheaters, exploiting heterologous pyoverdine, but also due to pyoverdine disuse in environments with increased iron availability. Overall, we found that environmental factors explained between-strain variation in pyoverdine production much better in soils than in ponds, presumably because high strain mixing in ponds impedes local adaption. Our study sheds light on the complexity of natural bacterial communities, and provides first insights into the multivariate nature of siderophore-based iron acquisition and competition among environmental pseudomonads.
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Affiliation(s)
- Elena Butaitė
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Jos Kramer
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Stefan Wyder
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Rolf Kümmerli
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
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Frank SA. Receptor uptake arrays for vitamin B 12, siderophores, and glycans shape bacterial communities. Ecol Evol 2017; 7:10175-10195. [PMID: 29238546 PMCID: PMC5723603 DOI: 10.1002/ece3.3544] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/20/2017] [Accepted: 09/28/2017] [Indexed: 01/15/2023] Open
Abstract
Molecular variants of vitamin B12, siderophores, and glycans occur. To take up variant forms, bacteria may express an array of receptors. The gut microbe Bacteroides thetaiotaomicron has three different receptors to take up variants of vitamin B12 and 88 receptors to take up various glycans. The design of receptor arrays reflects key processes that shape cellular evolution. Competition may focus each species on a subset of the available nutrient diversity. Some gut bacteria can take up only a narrow range of carbohydrates, whereas species such as B. thetaiotaomicron can digest many different complex glycans. Comparison of different nutrients, habitats, and genomes provides opportunity to test hypotheses about the breadth of receptor arrays. Another important process concerns fluctuations in nutrient availability. Such fluctuations enhance the value of cellular sensors, which gain information about environmental availability and adjust receptor deployment. Bacteria often adjust receptor expression in response to fluctuations of particular carbohydrate food sources. Some species may adjust expression of uptake receptors for specific siderophores. How do cells use sensor information to control the response to fluctuations? This question about regulatory wiring relates to problems that arise in control theory and artificial intelligence. Control theory clarifies how to analyze environmental fluctuations in relation to the design of sensors and response systems. Recent advances in deep learning studies of artificial intelligence focus on the architecture of regulatory wiring and the ways in which complex control networks represent and classify environmental states. I emphasize the similar design problems that arise in cellular evolution, control theory, and artificial intelligence. I connect those broad conceptual aspects to many testable hypotheses for bacterial uptake of vitamin B12, siderophores, and glycans.
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Affiliation(s)
- Steven A. Frank
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaIrvineCAUSA
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