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Uroz S, Geisler O, Fauchery L, Lami R, Rodrigues AMS, Morin E, Leveau JHJ, Oger P. Genomic and transcriptomic characterization of the Collimonas quorum sensing genes and regulon. FEMS Microbiol Ecol 2022; 98:6679101. [PMID: 36040340 DOI: 10.1093/femsec/fiac100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 07/13/2022] [Accepted: 08/26/2022] [Indexed: 01/21/2023] Open
Abstract
Collimonads are well-adapted to nutrient-poor environments. They are known to hydrolyse chitin, produce antifungal metabolites, weather minerals, and are effective biocontrol agents protecting plants from fungal diseases. The production of N-acyl homoserine lactones (AHLs) was suggested to be a conserved trait of collimonads, but little is known about the genes that underlie this production or the genes that are controlled by AHLs. To improve our understanding of the role of AHLs in the ecology of collimonads, we carried out transcriptomic analyses, combined with chemical and functional assays, on strain Collimonas pratensis PMB3(1). The main AHLs produced by this strain were identified as 3-hydroxy-hexa- and octa-noyl-homoserine lactone. Genome analysis permitted to identify putative genes coding for the autoinducer synthase (colI) and cognate transcriptional regulator (colR). The ability to produce AHLs was lost in ΔcolI and ΔcolR mutants. Functional assays revealed that the two mutants metabolized glucose, formate, oxalate, and leucine better than the wild-type (WT) strain. Transcriptome sequencing analyses revealed an up-regulation of different metabolic pathways and of motility in the QS-mutants compared to the WT strain. Overall, our results provide insights into the role of the AHL-dependent regulation system of Collimonas in environment colonization, metabolism readjustment, and microbial interactions.
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Affiliation(s)
- Stephane Uroz
- Université de Lorraine, INRAE, UMR1136 "Interactions Arbres-Microorganismes", F-54280 Champenoux, France.,INRAE, UR1138 "Biogéochimie des écosystèmes forestiers", F-54280 Champenoux, France
| | - Océane Geisler
- Université de Lorraine, INRAE, UMR1136 "Interactions Arbres-Microorganismes", F-54280 Champenoux, France
| | - Laure Fauchery
- Université de Lorraine, INRAE, UMR1136 "Interactions Arbres-Microorganismes", F-54280 Champenoux, France
| | - Raphaël Lami
- Sorbonne Université, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM, USR3579), Fédération de Recherche FR3724, Observatoire Océanologique, 66650 Banyuls-sur-Mer, France
| | - Alice M S Rodrigues
- Sorbonne Université, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM, USR3579), Fédération de Recherche FR3724, Observatoire Océanologique, 66650 Banyuls-sur-Mer, France
| | - Emmanuelle Morin
- Université de Lorraine, INRAE, UMR1136 "Interactions Arbres-Microorganismes", F-54280 Champenoux, France
| | - Johan H J Leveau
- Department of Plant Pathology, University of California - Davis, Davis, CA 95616, United States
| | - Philippe Oger
- Université Lyon, INSA de Lyon, CNRS UMR 5240, F-69622 Villeurbanne, France
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The Prokaryotic Complex of Modern and Buried Soils on the Kamchatka Peninsula. FORESTS 2022. [DOI: 10.3390/f13071066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A prokaryotic heterotrophic mesophilic community was studied in volcanic soil samples from Kamchatka. A phylogenetic and physiological characterization of the prokaryotic complex of modern and buried soils of the Kamchatka Peninsula is given. Volcanic Paleolithic soils (2500 and 11,300 years old) and their modern equivalents were investigated. It was found that the biomass of metabolically active prokaryotes in modern volcanic and Paleolithic soils reached 50 and 40 µg/g, respectively. The proportion of archaea in the metabolically active prokaryotic complex varied from 20% to 30% and increased in variants with the application of the nitrogen-containing biopolymer chitin. The application of the additional resource to paleovolcanic soils led to an incremental increase in the proportion of metabolically active prokaryotes, which reached 50% of the total prokaryotic biomass detected, indicating the high metabolic potential of the considered soils. Phylogenetic structure characteristics of the prokaryotic metabolically active component of modern and buried volcanic soil were established by molecular biology methods (metagenomic analysis, FISH method). The phylum Proteobacteria (74%), Acidobacteria, and Actinobacteria (14% combined) were dominant in modern soils; phylum Acidobacteria (51.8%) was dominant in paleosoils, whereas Chloroflexi (21%) and Proteobacteria (9%) were subdominant. It was determined that the potential activity of the microbial hydrolytic community, as measured by the relative response to the added resource (chitin), was found to increase in a series from modern to paleovolcanic soil. It was demonstrated that several key genes of the nitrogen cycle responsible for the processes of molecular nitrogen fixation, nitrification, and denitrification (nifH, amoA, nirK) were present in both modern and buried horizons.
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Barragán-Fonseca KY, Nurfikari A, van de Zande EM, Wantulla M, van Loon JJA, de Boer W, Dicke M. Insect frass and exuviae to promote plant growth and health. TRENDS IN PLANT SCIENCE 2022; 27:646-654. [PMID: 35248491 DOI: 10.1016/j.tplants.2022.01.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/28/2021] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Beneficial soil microorganisms can contribute to biocontrol of plant pests and diseases, induce systemic resistance (ISR) against attackers, and enhance crop yield. Using organic soil amendments has been suggested to stimulate the abundance and/or activity of beneficial indigenous microbes in the soil. Residual streams from insect farming (frass and exuviae) contain chitin and other compounds that may stimulate beneficial soil microbes that have ISR and biocontrol activity. Additionally, changes in plant phenotype that are induced by beneficial microorganisms may directly influence plant-pollinator interactions, thus affecting plant reproduction. We explore the potential of insect residual streams derived from the production of insects as food and feed to promote plant growth and health, as well as their potential benefits for sustainable agriculture.
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Affiliation(s)
- Katherine Y Barragán-Fonseca
- Laboratory of Entomology, Wageningen University & Research, 6700 AA, Wageningen, The Netherlands; Grupo en Conservación y Manejo de Vida Silvestre, Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Azkia Nurfikari
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands; Soil Biology Group, Wageningen University & Research, 6700 AA Wageningen, The Netherlands
| | - Els M van de Zande
- Laboratory of Entomology, Wageningen University & Research, 6700 AA, Wageningen, The Netherlands
| | - Max Wantulla
- Laboratory of Entomology, Wageningen University & Research, 6700 AA, Wageningen, The Netherlands
| | - Joop J A van Loon
- Laboratory of Entomology, Wageningen University & Research, 6700 AA, Wageningen, The Netherlands
| | - Wietse de Boer
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, The Netherlands; Soil Biology Group, Wageningen University & Research, 6700 AA Wageningen, The Netherlands
| | - Marcel Dicke
- Laboratory of Entomology, Wageningen University & Research, 6700 AA, Wageningen, The Netherlands.
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4
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Wang B, Chu S, Liu X, Zhang D, Chai X, Yang X, Zhi Y, Chi Y, Zhou P. Changes in soil bacterial and fungal communities in response to Bacillus megaterium NCT-2 inoculation in secondary salinized soil. PeerJ 2021; 9:e12309. [PMID: 34721987 PMCID: PMC8519178 DOI: 10.7717/peerj.12309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 09/23/2021] [Indexed: 11/20/2022] Open
Abstract
Background Secondary salinized soil in greenhouses often contains excess nitrate. Inoculation of Bacillus megaterium NCT-2 with nitrate assimilation ability represents an attractive approach for soil remediation. However, the effects of NCT-2 on the structure and function of soil microbial communities have not been explored. Methods Greenhouse experiments were carried out to investigate changes in soil properties, Brassica chinensis L. growth, bacterial, and fungal community structure and function in response to NCT-2 inoculation. Results The NCT-2 inoculant significantly reduced the nitrate content in B. chinensis and inhibited the rebound of soil nitrate in the later stage. The shifts of bacterial community structure and function by NCT-2 was negligible, and a greater disturbance of soil fungal community structure and function was observed, for example the strong inhibitory effect on ectomycorrhizal fungi. These results indicated that the NCT-2 inoculant likely achieved the remediation effect in secondary salinized soil by shifting fungal community. The present findings add to the current understanding of microbial interactions in response to bacterial inoculation and can be of great significance for the application of NCT-2 inoculants in secondary salinized soil remediation.
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Affiliation(s)
- Bin Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China.,Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, China
| | - Shaohua Chu
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China.,Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaorui Liu
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China.,Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, China
| | - Dan Zhang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China.,Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaotong Chai
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China.,Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, China
| | - Xijia Yang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China.,Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, China
| | - Yuee Zhi
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China.,Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, China
| | - Yaowei Chi
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China.,Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, China
| | - Pei Zhou
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China.,Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, China
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Bioprospecting Desert Plants for Endophytic and Biostimulant Microbes: A Strategy for Enhancing Agricultural Production in a Hotter, Drier Future. BIOLOGY 2021; 10:biology10100961. [PMID: 34681060 PMCID: PMC8533330 DOI: 10.3390/biology10100961] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/18/2021] [Accepted: 09/21/2021] [Indexed: 01/14/2023]
Abstract
Simple Summary Endophytes are microbes that live inside plants without causing negative effects in their hosts. All land plants are known to have endophytes, and these endophytes have the capacity to be transferred between plants. Taking endophytes from desert plants, which grow in low-nutrient, high-stress environments, and transferring them to crop plants may alleviate some of the challenges being faced by the agricultural industry, such as increasing drought frequency and rising opposition to chemical use in agriculture. Studies have shown that desert endophytes have the capacity to increase nutrient uptake and increase plant resistance to drought and heat stress, salt stress, and pathogen attack. Currently, the agricultural industry focuses on using irrigation, chemical fertilizers, and chemical pesticides to solve such issues, which can be extremely damaging to the environment. While there is still a lot that is unknown about endophytes, particularly desert plant endophytes, current research provides evidence that desert plant endophytes could be an environmentally friendly alternative to the conventional solutions being applied today. Abstract Deserts are challenging places for plants to survive in due to low nutrient availability, drought and heat stress, water stress, and herbivory. Endophytes—microbes that colonize and infect plant tissues without causing apparent disease—may contribute to plant success in such harsh environments. Current knowledge of desert plant endophytes is limited, but studies performed so far reveal that they can improve host nutrient acquisition, increase host tolerance to abiotic stresses, and increase host resistance to biotic stresses. When considered in combination with their broad host range and high colonization rate, there is great potential for desert endophytes to be used in a commercial agricultural setting, especially as croplands face more frequent and severe droughts due to climate change and as the agricultural industry faces mounting pressure to break away from agrochemicals towards more environmentally friendly alternatives. Much is still unknown about desert endophytes, but future studies may prove fruitful for the discovery of new endophyte-based biofertilizers, biocontrol agents, and abiotic stress relievers of crops.
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Emmett BD, Lévesque-Tremblay V, Harrison MJ. Conserved and reproducible bacterial communities associate with extraradical hyphae of arbuscular mycorrhizal fungi. THE ISME JOURNAL 2021; 15:2276-2288. [PMID: 33649552 PMCID: PMC8319317 DOI: 10.1038/s41396-021-00920-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/21/2021] [Accepted: 01/29/2021] [Indexed: 01/31/2023]
Abstract
Extraradical hyphae (ERH) of arbuscular mycorrhizal fungi (AMF) extend from plant roots into the soil environment and interact with soil microbial communities. Evidence of positive and negative interactions between AMF and soil bacteria point to functionally important ERH-associated communities. To characterize communities associated with ERH and test controls on their establishment and composition, we utilized an in-growth core system containing a live soil-sand mixture that allowed manual extraction of ERH for 16S rRNA gene amplicon profiling. Across experiments and soils, consistent enrichment of members of the Betaproteobacteriales, Myxococcales, Fibrobacterales, Cytophagales, Chloroflexales, and Cellvibrionales was observed on ERH samples, while variation among samples from different soils was observed primarily at lower taxonomic ranks. The ERH-associated community was conserved between two fungal species assayed, Glomus versiforme and Rhizophagus irregularis, though R. irregularis exerted a stronger selection and showed greater enrichment for taxa in the Alphaproteobacteria and Gammaproteobacteria. A distinct community established within 14 days of hyphal access to the soil, while temporal patterns of establishment and turnover varied between taxonomic groups. Identification of a conserved ERH-associated community is consistent with the concept of an AMF microbiome and can aid the characterization of facilitative and antagonistic interactions influencing the plant-fungal symbiosis.
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Affiliation(s)
- Bryan D. Emmett
- grid.5386.8000000041936877XBoyce Thompson Institute, Ithaca, NY USA ,grid.508983.fPresent Address: USDA Agricultural Research Service, National Laboratory for Agriculture and the Environment, Ames, IA USA
| | - Véronique Lévesque-Tremblay
- grid.5386.8000000041936877XBoyce Thompson Institute, Ithaca, NY USA ,grid.146611.50000 0001 0775 5922Present Address: Laurentian Forestry Center, Canadian Forest Service, Natural Resources Canada, Quebec City, QC Canada
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Sharma S, Compant S, Franken P, Ruppel S, Ballhausen MB. It Takes Two to Tango: A Bacterial Biofilm Provides Protection against a Fungus-Feeding Bacterial Predator. Microorganisms 2021; 9:microorganisms9081566. [PMID: 34442645 PMCID: PMC8398733 DOI: 10.3390/microorganisms9081566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/15/2021] [Accepted: 07/17/2021] [Indexed: 11/23/2022] Open
Abstract
Fungus-bacterium interactions are widespread, encompass multiple interaction types from mutualism to parasitism, and have been frequent targets for microbial inoculant development. In this study, using in vitro systems combined with confocal laser scanning microscopy and real-time quantitative PCR, we test whether the nitrogen-fixing bacterium Kosakonia radicincitans can provide protection to the plant-beneficial fungus Serendipita indica, which inhabits the rhizosphere and colonizes plants as an endophyte, from the fungus-feeding bacterium Collimonas fungivorans. We show that K. radicincitans can protect fungal hyphae from bacterial feeding on solid agar medium, with probable mechanisms being quick hyphal colonization and biofilm formation. We furthermore find evidence for different feeding modes of K. radicincitans and C. fungivorans, namely “metabolite” and “hyphal feeding”, respectively. Overall, we demonstrate, to our knowledge, the first evidence for a bacterial, biofilm-based protection of fungal hyphae against attack by a fungus-feeding, bacterial predator on solid agar medium. Besides highlighting the importance of tripartite microbial interactions, we discuss implications of our results for the development and application of microbial consortium-based bioprotectants and biostimulants.
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Affiliation(s)
- Shubhangi Sharma
- Leibniz Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1, 14979 Großbeeren, Germany; (S.S.); (P.F.); (S.R.)
| | - Stéphane Compant
- AIT Austrian Institute of Technology, Center for Health and Bioresources, Konrad Lorenz Strasse 24, 3430 Tulln, Austria;
| | - Philipp Franken
- Leibniz Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1, 14979 Großbeeren, Germany; (S.S.); (P.F.); (S.R.)
- Institute of Microbiology, Friedrich Schiller University Jena, Neugasse 24, 07743 Jena, Germany
| | - Silke Ruppel
- Leibniz Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1, 14979 Großbeeren, Germany; (S.S.); (P.F.); (S.R.)
| | - Max-Bernhard Ballhausen
- Leibniz Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1, 14979 Großbeeren, Germany; (S.S.); (P.F.); (S.R.)
- Correspondence:
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Yadav SK, Das J, Kumar R, Jha G. Calcium regulates the mycophagous ability of Burkholderia gladioli strain NGJ1 in a type III secretion system-dependent manner. BMC Microbiol 2020; 20:216. [PMID: 32689944 PMCID: PMC7372643 DOI: 10.1186/s12866-020-01897-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 07/12/2020] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND A rice associated bacterium Burkholderia gladioli strain NGJ1 demonstrates mycophagy, a phenomenon wherein bacteria feed on fungi. Previously, we have reported that NGJ1 utilizes type III secretion system (T3SS) to deliver a prophage tail-like protein (Bg_9562) into fungal cells to establish mycophagy. RESULTS In this study, we report that calcium ion concentration influences the mycophagous ability of NGJ1 on Rhizoctonia solani, an important fungal pathogen. The calcium limiting condition promotes mycophagy while high calcium environment prevents it. The expression of various T3SS apparatus encoding genes of NGJ1 was induced and secretion of several potential T3SS effector proteins (including Bg_9562) into extracellular milieu was triggered under calcium limiting condition. Using LC-MS/MS proteome analysis, we identified several calcium regulated T3SS effector proteins of NGJ1. The expression of genes encoding some of these effector proteins was upregulated during mycophagous interaction of NGJ1 with R. solani. Further, mutation of one of these genes (endo-β-1, 3- glucanase) rendered the mutant NGJ1 bacterium defective in mycophagy while complementation with full length copy of the gene restored its mycophagous activity. CONCLUSION Our study provides evidence that low calcium environment triggers secretion of various T3SS effectors proteins into the extracellular milieu and suggests the importance of cocktail of these proteins in promoting mycophagy.
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Affiliation(s)
- Sunil Kumar Yadav
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Joyati Das
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Rahul Kumar
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Gopaljee Jha
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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Vurukonda SSKP, Giovanardi D, Stefani E. Plant Growth Promoting and Biocontrol Activity of Streptomyces spp. as Endophytes. Int J Mol Sci 2018; 19:E952. [PMID: 29565834 PMCID: PMC5979581 DOI: 10.3390/ijms19040952] [Citation(s) in RCA: 218] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 03/12/2018] [Accepted: 03/16/2018] [Indexed: 01/12/2023] Open
Abstract
There has been many recent studies on the use of microbial antagonists to control diseases incited by soilborne and airborne plant pathogenic bacteria and fungi, in an attempt to replace existing methods of chemical control and avoid extensive use of fungicides, which often lead to resistance in plant pathogens. In agriculture, plant growth-promoting and biocontrol microorganisms have emerged as safe alternatives to chemical pesticides. Streptomyces spp. and their metabolites may have great potential as excellent agents for controlling various fungal and bacterial phytopathogens. Streptomycetes belong to the rhizosoil microbial communities and are efficient colonizers of plant tissues, from roots to the aerial parts. They are active producers of antibiotics and volatile organic compounds, both in soil and in planta, and this feature is helpful for identifying active antagonists of plant pathogens and can be used in several cropping systems as biocontrol agents. Additionally, their ability to promote plant growth has been demonstrated in a number of crops, thus inspiring the wide application of streptomycetes as biofertilizers to increase plant productivity. The present review highlights Streptomyces spp.-mediated functional traits, such as enhancement of plant growth and biocontrol of phytopathogens.
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Affiliation(s)
| | - Davide Giovanardi
- Department of Life Sciences, University of Modena and Reggio Emilia, via Amendola 2, 42122 Reggio Emilia, Italy.
| | - Emilio Stefani
- Department of Life Sciences, University of Modena and Reggio Emilia, via Amendola 2, 42122 Reggio Emilia, Italy.
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10
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Gonzalez E, Pitre FE, Pagé AP, Marleau J, Guidi Nissim W, St-Arnaud M, Labrecque M, Joly S, Yergeau E, Brereton NJB. Trees, fungi and bacteria: tripartite metatranscriptomics of a root microbiome responding to soil contamination. MICROBIOME 2018; 6:53. [PMID: 29562928 PMCID: PMC5863371 DOI: 10.1186/s40168-018-0432-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/02/2018] [Indexed: 05/05/2023]
Abstract
BACKGROUND One method for rejuvenating land polluted with anthropogenic contaminants is through phytoremediation, the reclamation of land through the cultivation of specific crops. The capacity for phytoremediation crops, such as Salix spp., to tolerate and even flourish in contaminated soils relies on a highly complex and predominantly cryptic interacting community of microbial life. METHODS Here, Illumina HiSeq 2500 sequencing and de novo transcriptome assembly were used to observe gene expression in washed Salix purpurea cv. 'Fish Creek' roots from trees pot grown in petroleum hydrocarbon-contaminated or non-contaminated soil. All 189,849 assembled contigs were annotated without a priori assumption as to sequence origin and differential expression was assessed. RESULTS The 839 contigs differentially expressed (DE) and annotated from S. purpurea revealed substantial increases in transcripts encoding abiotic stress response equipment, such as glutathione S-transferases, in roots of contaminated trees as well as the hallmarks of fungal interaction, such as SWEET2 (Sugars Will Eventually Be Exported Transporter). A total of 8252 DE transcripts were fungal in origin, with contamination conditions resulting in a community shift from Ascomycota to Basidiomycota genera. In response to contamination, 1745 Basidiomycota transcripts increased in abundance (the majority uniquely expressed in contaminated soil) including major monosaccharide transporter MST1, primary cell wall and lamella CAZy enzymes, and an ectomycorrhiza-upregulated exo-β-1,3-glucanase (GH5). Additionally, 639 DE polycistronic transcripts from an uncharacterised Enterobacteriaceae species were uniformly in higher abundance in contamination conditions and comprised a wide spectrum of genes cryptic under laboratory conditions but considered putatively involved in eukaryotic interaction, biofilm formation and dioxygenase hydrocarbon degradation. CONCLUSIONS Fungal gene expression, representing the majority of contigs assembled, suggests out-competition of white rot Ascomycota genera (dominated by Pyronema), a sometimes ectomycorrhizal (ECM) Ascomycota (Tuber) and ECM Basidiomycota (Hebeloma) by a poorly characterised putative ECM Basidiomycota due to contamination. Root and fungal expression involved transcripts encoding carbohydrate/amino acid (C/N) dialogue whereas bacterial gene expression included the apparatus necessary for biofilm interaction and direct reduction of contamination stress, a potential bacterial currency for a role in tripartite mutualism. Unmistakable within the metatranscriptome is the degree to which the landscape of rhizospheric biology, particularly the important but predominantly uncharacterised fungal genetics, is yet to be discovered.
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Affiliation(s)
- E Gonzalez
- Canadian Center for Computational Genomics, McGill University and Genome Quebec Innovation Center, Montréal, H3A 1A4, Canada
- Department of Human Genetics, McGill University, Montreal, H3A 1B1, Canada
| | - F E Pitre
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada
- Montreal Botanical Garden, Montreal, QC, H1X 2B2, Canada
| | - A P Pagé
- Aquatic and Crop Resource Development (ACRD), National Research Council Canada, Montréal, QC, H4P 2R2, Canada
| | - J Marleau
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada
| | - W Guidi Nissim
- Department of Agri-food and Environmental Science, University of Florence, Viale delle Idee, Sesto Fiorentino, FI, Italy
| | - M St-Arnaud
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada
- Montreal Botanical Garden, Montreal, QC, H1X 2B2, Canada
| | - M Labrecque
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada
- Montreal Botanical Garden, Montreal, QC, H1X 2B2, Canada
| | - S Joly
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada
- Montreal Botanical Garden, Montreal, QC, H1X 2B2, Canada
| | - E Yergeau
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - N J B Brereton
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada.
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Gómez Expósito R, de Bruijn I, Postma J, Raaijmakers JM. Current Insights into the Role of Rhizosphere Bacteria in Disease Suppressive Soils. Front Microbiol 2017; 8:2529. [PMID: 29326674 PMCID: PMC5741648 DOI: 10.3389/fmicb.2017.02529] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 12/05/2017] [Indexed: 01/22/2023] Open
Abstract
Disease suppressive soils offer effective protection to plants against infection by soil-borne pathogens, including fungi, oomycetes, bacteria, and nematodes. The specific disease suppression that operates in these soils is, in most cases, microbial in origin. Therefore, suppressive soils are considered as a rich resource for the discovery of beneficial microorganisms with novel antimicrobial and other plant protective traits. To date, several microbial genera have been proposed as key players in disease suppressiveness of soils, but the complexity of the microbial interactions as well as the underlying mechanisms and microbial traits remain elusive for most disease suppressive soils. Recent developments in next generation sequencing and other 'omics' technologies have provided new insights into the microbial ecology of disease suppressive soils and the identification of microbial consortia and traits involved in disease suppressiveness. Here, we review the results of recent 'omics'-based studies on the microbial basis of disease suppressive soils, with specific emphasis on the role of rhizosphere bacteria in this intriguing microbiological phenomenon.
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Affiliation(s)
- Ruth Gómez Expósito
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, Netherlands
| | - Irene de Bruijn
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Joeke Postma
- Biointeractions and Plant Health, Plant Research International, Wageningen University and Research, Wageningen, Netherlands
| | - Jos M. Raaijmakers
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
- Institute of Biology, Leiden University, Leiden, Netherlands
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12
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Lira F, Berg G, Martínez JL. Double-Face Meets the Bacterial World: The Opportunistic Pathogen Stenotrophomonas maltophilia. Front Microbiol 2017; 8:2190. [PMID: 29170656 PMCID: PMC5684188 DOI: 10.3389/fmicb.2017.02190] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/25/2017] [Indexed: 11/24/2022] Open
Abstract
Most studies on bacterial virulence focus on the pathogen itself. However, it is important to recall that the in-host behavior and the virulence of bacterial pathogens constitute a complex situation that depends on both the microorganisms and the infected host. While healthy people (the community) is infected by classical pathogenic microorganisms, able to cope with the anti-infection defenses of the host, in the case of people with basal diseases, debilitated or immunodepressed, the range of pathogens able to cause infection is wider and includes the so-named opportunistic pathogens, which lack the inherent ability to cause disease in healthy hosts and rarely produce infections in the community. Some of the most relevant opportunistic pathogens, as Stenotrophomonas maltophilia, have an environmental origin and, in occasions, present interesting biotechnological properties. Consequently, it is important knowing whether S. maltophilia isolates recovered from infections constitute a specific phylogenetic branch that has evolved toward acquiring a virulent phenotype as it happens in the case of classical pathogens or rather, any member of this bacterial species is capable of producing infection and its pathogenic behavior is mainly a consequence of the host situation. To address this question, we analyzed a set of environmental and clinical S. maltophilia strains. Our results indicate that this opportunistic pathogen presents a large core genome and that the distribution of genes in general, and of known virulence determinants in particular, is similar among environmental and clinical isolates. The majority of genes not belonging to the S. maltophilia core genome are present in just one or two of the analyzed strains. This indicates that, more than speciation into different lineages (virulent and environmental), the evolution of S. maltophilia is based in the strain-specific acquisition of genes, likely involved in the adaptation of this bacterial species to different microniches. In addition, both environmental and clinical isolates present low susceptibility to several antimicrobials. Altogether our results support that S. maltophilia does not present a specific evolutionary branch toward virulence and most likely infection is mainly the consequence of the impaired anti-infective response of the infected patients.
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Affiliation(s)
- Felipe Lira
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Gabriele Berg
- Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria
| | - José L Martínez
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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Swain DM, Yadav SK, Tyagi I, Kumar R, Kumar R, Ghosh S, Das J, Jha G. A prophage tail-like protein is deployed by Burkholderia bacteria to feed on fungi. Nat Commun 2017; 8:404. [PMID: 28864820 PMCID: PMC5581363 DOI: 10.1038/s41467-017-00529-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 07/05/2017] [Indexed: 11/09/2022] Open
Abstract
Some bacteria can feed on fungi, a phenomenon known as mycophagy. Here we show that a prophage tail-like protein (Bg_9562) is essential for mycophagy in Burkholderia gladioli strain NGJ1. The purified protein causes hyphal disintegration and inhibits growth of several fungal species. Disruption of the Bg_9562 gene abolishes mycophagy. Bg_9562 is a potential effector secreted by a type III secretion system (T3SS) and is translocated into fungal mycelia during confrontation. Heterologous expression of Bg_9562 in another bacterial species, Ralstonia solanacearum, confers mycophagous ability in a T3SS-dependent manner. We propose that the ability to feed on fungi conferred by Bg_9562 may help the bacteria to survive in certain ecological niches. Furthermore, considering its broad-spectrum antifungal activity, the protein may be potentially useful in biotechnological applications to control fungal diseases.Some bacteria can feed on live fungi through unclear mechanisms. Here, the authors show that a T3SS-secreted protein, which is homologous to phage tail proteins, allows a Burkholderia gladioli strain to kill and feed on various fungal species.
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Affiliation(s)
- Durga Madhab Swain
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Sunil Kumar Yadav
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Isha Tyagi
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Rahul Kumar
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Rajeev Kumar
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Srayan Ghosh
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Joyati Das
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Gopaljee Jha
- Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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Ballhausen MB, Vandamme P, de Boer W. Trait Differentiation within the Fungus-Feeding (Mycophagous) Bacterial Genus Collimonas. PLoS One 2016; 11:e0157552. [PMID: 27309848 PMCID: PMC4911057 DOI: 10.1371/journal.pone.0157552] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 06/01/2016] [Indexed: 12/02/2022] Open
Abstract
The genus Collimonas consists of facultative, fungus-feeding (mycophagous) bacteria. To date, 3 species (C. fungivorans, C. pratensis and C. arenae) have been described and over 100 strains have been isolated from different habitats. Functional traits of Collimonas bacteria that are potentially involved in interactions with soil fungi mostly negatively (fungal inhibition e.g.), but also positively (mineral weathering e.g.), affect fungal fitness. We hypothesized that variation in such traits between Collimonas strains leads to different mycophagous bacterial feeding patterns. We investigated a) whether phylogenetically closely related Collimonas strains possess similar traits, b) how far phylogenetic resolution influences the detection of phylogenetic signal (possession of similar traits by related strains) and c) if there is a pattern of co-occurrence among the studied traits. We measured genetically encoded (nifH genes, antifungal collimomycin gene cluster e.g.) as well as phenotypically expressed traits (chitinase- and siderophore production, fungal inhibition and others) and related those to a high-resolution phylogeny (MLSA), constructed by sequencing the housekeeping genes gyrB and rpoB and concatenating those with partial 16S rDNA sequences. Additionally, high-resolution and 16S rDNA derived phylogenies were compared. We show that MLSA is superior to 16SrDNA phylogeny when analyzing trait distribution and relating it to phylogeny at fine taxonomic resolution (a single bacterial genus). We observe that several traits involved in the interaction of collimonads and their host fungus (fungal inhibition e.g.) carry phylogenetic signal. Furthermore, we compare Collimonas trait possession with sister genera like Herbaspirillum and Janthinobacterium.
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Affiliation(s)
- Max-Bernhard Ballhausen
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, the Netherlands
| | - Peter Vandamme
- Laboratory for Microbiology, Gent University, Gent, Belgium
| | - Wietse de Boer
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, the Netherlands
- Department of Soil Quality, Wageningen University, Wageningen, the Netherlands
- * E-mail:
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Berini F, Caccia S, Franzetti E, Congiu T, Marinelli F, Casartelli M, Tettamanti G. Effects of Trichoderma viride chitinases on the peritrophic matrix of Lepidoptera. PEST MANAGEMENT SCIENCE 2016; 72:980-989. [PMID: 26179981 DOI: 10.1002/ps.4078] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 06/26/2015] [Accepted: 07/07/2015] [Indexed: 06/04/2023]
Abstract
BACKGROUND The peritrophic matrix (PM) is formed by a network of chitin fibrils associated with proteins, glycoproteins and proteoglycans that lines the insect midgut. It is a physical barrier involved in digestion processes, and protects the midgut epithelium from food abrasion, pathogen infections and toxic materials. Given its fundamental role in insect physiology, the PM represents an excellent target for pest control strategies. Although a number of viral, bacterial and insect chitinolytic enzymes affecting PM integrity have already been tested, exploitation of fungal chitinases has been almost neglected. Fungal chitinases, already in use as fungal phytopathogen biocontrol agents, are known to attack the insect cuticle, but their action on the insect gut needs to be better investigated. RESULTS In the present paper, we performed a biochemical characterisation of a commercial mixture of chitinolytic enzymes derived from Trichoderma viride and analysed its in vitro and in vivo effects on the PM of the silkworm Bombyx mori, a model system among Lepidoptera. We found that these enzymes have significant in vitro effects on the structure and permeability of the PM of this insect. A bioassay supported these results and showed that the oral administration of the mixture causes PM alterations, leading to adverse consequences on larval growth and development, negatively affecting pupal weight and even inducing mortality. CONCLUSIONS This study provides an integrated experimental approach to evaluate the effects of fungal chitinases on Lepidoptera. The encouraging results obtained herein make us confident about the possible use of fungal chitinases to control lepidopteran pests.
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Affiliation(s)
- Francesca Berini
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- The Protein Factory Research Centre, Politecnico di Milano, ICRM CNR Milano and University of Insubria, Varese, Italy
| | - Silvia Caccia
- Department of Biosciences, University of Milano, Milano, Italy
- Department of Agriculture, University of Napoli Federico II, Portici, Napoli, Italy
| | - Eleonora Franzetti
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Terenzio Congiu
- Department of Surgical and Morphological Sciences, University of Insubria, Varese, Italy
| | - Flavia Marinelli
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- The Protein Factory Research Centre, Politecnico di Milano, ICRM CNR Milano and University of Insubria, Varese, Italy
| | | | - Gianluca Tettamanti
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
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16
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Song C, Schmidt R, de Jager V, Krzyzanowska D, Jongedijk E, Cankar K, Beekwilder J, van Veen A, de Boer W, van Veen JA, Garbeva P. Exploring the genomic traits of fungus-feeding bacterial genus Collimonas. BMC Genomics 2015; 16:1103. [PMID: 26704531 PMCID: PMC4690342 DOI: 10.1186/s12864-015-2289-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 12/11/2015] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Collimonas is a genus belonging to the class of Betaproteobacteria and consists mostly of soil bacteria with the ability to exploit living fungi as food source (mycophagy). Collimonas strains differ in a range of activities, including swimming motility, quorum sensing, extracellular protease activity, siderophore production, and antimicrobial activities. RESULTS In order to reveal ecological traits possibly related to Collimonas lifestyle and secondary metabolites production, we performed a comparative genomics analysis based on whole-genome sequencing of six strains representing 3 recognized species. The analysis revealed that the core genome represents 43.1 to 52.7% of the genomes of the six individual strains. These include genes coding for extracellular enzymes (chitinase, peptidase, phospholipase), iron acquisition and type II secretion systems. In the variable genome, differences were found in genes coding for secondary metabolites (e.g. tripropeptin A and volatile terpenes), several unknown orphan polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS), nonribosomal peptide synthetase (NRPS) gene clusters, a new lipopeptide and type III and type VI secretion systems. Potential roles of the latter genes in the interaction with other organisms were investigated. Mutation of a gene involved in tripropeptin A biosynthesis strongly reduced the antibacterial activity against Staphylococcus aureus, while disruption of a gene involved in the biosynthesis of the new lipopeptide had a large effect on the antifungal/oomycetal activities. CONCLUSIONS Overall our results indicated that Collimonas genomes harbour many genes encoding for novel enzymes and secondary metabolites (including terpenes) important for interactions with other organisms and revealed genomic plasticity, which reflect the behaviour, antimicrobial activity and lifestylesof Collimonas spp.
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Affiliation(s)
- Chunxu Song
- Netherlands Institute of Ecology, Department of Microbial Ecology, Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands.
| | - Ruth Schmidt
- Netherlands Institute of Ecology, Department of Microbial Ecology, Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands.
| | - Victor de Jager
- Netherlands Institute of Ecology, Department of Microbial Ecology, Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands.
| | - Dorota Krzyzanowska
- Laboratory of Biological Plant Protection, Intercollegiate Faculty of Biotechnology UG&MUG, Kladki 24, Gdansk, 80-822, Poland.
| | - Esmer Jongedijk
- Laboratory of Plant Physiology, Wageningen University, Droevendaalsesteeg 1, Wageningen, 6708 PB, The Netherlands.
| | - Katarina Cankar
- Business Unit Bioscience, Plant Research International, Wageningen University and Research Centre, Wageningen, The Netherlands.
| | - Jules Beekwilder
- Business Unit Bioscience, Plant Research International, Wageningen University and Research Centre, Wageningen, The Netherlands.
| | - Anouk van Veen
- Netherlands Institute of Ecology, Department of Microbial Ecology, Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands.
| | - Wietse de Boer
- Netherlands Institute of Ecology, Department of Microbial Ecology, Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands.
| | - Johannes A van Veen
- Netherlands Institute of Ecology, Department of Microbial Ecology, Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands.
| | - Paolina Garbeva
- Netherlands Institute of Ecology, Department of Microbial Ecology, Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands.
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17
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Ballhausen MB, van Veen JA, Hundscheid MPJ, de Boer W. Methods for Baiting and Enriching Fungus-Feeding (Mycophagous) Rhizosphere Bacteria. Front Microbiol 2015; 6:1416. [PMID: 26733962 PMCID: PMC4687392 DOI: 10.3389/fmicb.2015.01416] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 11/27/2015] [Indexed: 01/01/2023] Open
Abstract
Mycophagous soil bacteria are able to obtain nutrients from living fungal hyphae. However, with exception of the soil bacterial genus Collimonas, occurrence of this feeding strategy has not been well examined. Evaluation of the importance of mycophagy in soil bacterial communities requires targeted isolation methods. In this study, we compared two different approaches to obtain mycophagous bacteria from rhizospheric soil. A short-term method based on baiting for bacteria that can rapidly adhere to fungal hyphae and a long-term method based on the enrichment of bacteria on fungal hyphae via repeated transfer. Hyphae-adhering bacteria were isolated, identified by 16S rDNA sequencing and tested for antifungal activity and the ability to feed on fungi as the sole source of carbon. Both methods yielded a range of potentially mycophagous bacterial isolates with little phylogenetic overlap. We also found indications for feeding preferences among the potentially mycophagous bacteria. Our results indicate that mycophagy could be an important growth strategy for rhizosphere bacteria. To our surprise, we found several potential plant pathogenic bacteria among the mycophagous isolates. We discuss the possible benefits that these bacteria might gain from colonizing fungal hyphae.
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Affiliation(s)
- Max-Bernhard Ballhausen
- Department of Microbial Ecology, Netherlands Institute of EcologyWageningen, Netherlands
- Department of Plant Health, Institute for Vegetable and Ornamental CropsGroßbeeren, Germany
| | - Johannes A. van Veen
- Department of Microbial Ecology, Netherlands Institute of EcologyWageningen, Netherlands
- Institute of Biology Leiden, Leiden UniversityLeiden, Netherlands
| | - Maria P. J. Hundscheid
- Department of Microbial Ecology, Netherlands Institute of EcologyWageningen, Netherlands
| | - Wietse de Boer
- Department of Microbial Ecology, Netherlands Institute of EcologyWageningen, Netherlands
- Department of Soil Quality, Wageningen UniversityWageningen, Netherlands
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18
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Rudnick MB, van Veen JA, de Boer W. Oxalic acid: a signal molecule for fungus-feeding bacteria of the genus Collimonas? ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:709-14. [PMID: 25858310 DOI: 10.1111/1758-2229.12290] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 03/31/2015] [Indexed: 05/21/2023]
Abstract
Mycophagous (=fungus feeding) soil bacteria of the genus Collimonas have been shown to colonize and grow on hyphae of different fungal hosts as the only source of energy and carbon. The ability to exploit fungal nutrient resources might require a strategy for collimonads to sense fungi in the soil matrix. Oxalic acid is ubiquitously secreted by soil fungi, serving different purposes. In this study, we investigated the possibility that collimonads might use oxalic acid secretion to localize a fungal host and move towards it. We first confirmed earlier indications that collimonads have a very limited ability to use oxalic acid as growth substrate. In a second step, with using different assays, we show that oxalic acid triggers bacterial movement in such a way that accumulation of cells can be expected at micro-sites with high free oxalic acid concentrations. Based on these observations we propose that oxalic acid functions as a signal molecule to guide collimonads to hyphal tips, the mycelial zones that are most sensitive for mycophagous bacterial attack.
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Affiliation(s)
- M B Rudnick
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, The Netherlands
- Department of Plant Health, Institute for Vegetable and Ornamental Crops, Großbeeren/Erfurt e.V., Theodor Echtermeyer Weg 1, D-14979, Großbeeren, Germany
| | - J A van Veen
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, The Netherlands
- Institute of Biology, Leiden University, Leiden, 2333 BE, The Netherlands
| | - W de Boer
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, The Netherlands
- Department of Soil Quality, Wageningen University, Wageningen, 6708 PB, The Netherlands
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19
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de Boer W, Hundscheid MPJ, Klein Gunnewiek PJA, de Ridder-Duine AS, Thion C, van Veen JA, van der Wal A. Antifungal Rhizosphere Bacteria Can increase as Response to the Presence of Saprotrophic Fungi. PLoS One 2015; 10:e0137988. [PMID: 26393509 PMCID: PMC4578881 DOI: 10.1371/journal.pone.0137988] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 08/24/2015] [Indexed: 01/26/2023] Open
Abstract
Knowledge on the factors that determine the composition of bacterial communities in the vicinity of roots (rhizosphere) is essential to understand plant-soil interactions. Plant species identity, plant growth stage and soil properties have been indicated as major determinants of rhizosphere bacterial community composition. Here we show that the presence of saprotrophic fungi can be an additional factor steering rhizosphere bacterial community composition and functioning. We studied the impact of presence of two common fungal rhizosphere inhabitants (Mucor hiemalis and Trichoderma harzianum) on the composition of cultivable bacterial communities developing in the rhizosphere of Carex arenaria (sand sedge) in sand microcosms. Identification and phenotypic characterization of bacterial isolates revealed clear shifts in the rhizosphere bacterial community composition by the presence of two fungal strains (M. hiemalis BHB1 and T. harzianum PvdG2), whereas another M. hiemalis strain did not show this effect. Presence of both M. hiemalis BHB1 and T. harzianum PvdG2 resulted in a significant increase of chitinolytic and (in vitro) antifungal bacteria. The latter was most pronounced for M. hiemalis BHB1, an isolate from Carex roots, which stimulated the development of the bacterial genera Achromobacter and Stenotrophomonas. In vitro tests showed that these genera were strongly antagonistic against M. hiemalis but also against the plant-pathogenic fungus Rhizoctonia solani. The most likely explanation for fungal-induced shifts in the composition of rhizosphere bacteria is that bacteria are being selected which are successful in competing with fungi for root exudates. Based on the results we propose that measures increasing saprotrophic fungi in agricultural soils should be explored as an alternative approach to enhance natural biocontrol against soil-borne plant-pathogenic fungi, namely by stimulating indigenous antifungal rhizosphere bacteria.
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Affiliation(s)
- Wietse de Boer
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, the Netherlands
- Department of Soil Quality, Wageningen University, Wageningen, 6708 PB, the Netherlands
| | - Maria P. J. Hundscheid
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, the Netherlands
| | | | - Annelies S. de Ridder-Duine
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, the Netherlands
| | - Cecile Thion
- School of Biological Science, University of Aberdeen, Aberdeen, AB24 3UU, United Kingdom
| | - Johannes A. van Veen
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, the Netherlands
- Insititute of Biology, Leiden University, Leiden, 2333 BE, the Netherlands
| | - Annemieke van der Wal
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, the Netherlands
- * E-mail:
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20
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Berg G, Martinez JL. Friends or foes: can we make a distinction between beneficial and harmful strains of the Stenotrophomonas maltophilia complex? Front Microbiol 2015; 6:241. [PMID: 25873912 PMCID: PMC4379930 DOI: 10.3389/fmicb.2015.00241] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Accepted: 03/12/2015] [Indexed: 11/21/2022] Open
Abstract
Stenotrophomonas maltophilia is an emerging multi-drug-resistant global opportunistic pathogen of environmental, mainly plant-associated origin. It is also used as a biocontrol or stress protecting agent for crops in sustainable agricultural as well as in bioremediation strategies. In order to establish effective protocols to distinguish harmless from harmful strains, our discussion must take into consideration the current data available surrounding the ecology, evolution and pathogenicity of the species complex. The mutation rate was identified as one of several possible criteria for strain plasticity, but it is currently impossible to distinguish beneficial from harmful S. maltophilia strains. This may compromise the possibility of the release and application for environmental biotechnology of this bacterial species. The close relative S. rhizophila, which can be clearly differentiated from S. maltophilia, provides a harmless alternative for biotechnological applications without human health risks. This is mainly because it is unable to growth at the human body temperature, 37∘C due to the absence of heat shock genes and a potentially temperature-regulated suicide mechanism.
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Affiliation(s)
- Gabriele Berg
- Institute of Environmental Biotechnology, Graz University of Technology, Graz Austria
| | - Jose L Martinez
- Centro Nacional de Biotecnologia - Consejo Superior de Investigaciones Científicas, Madrid Spain
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21
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Poosakkannu A, Nissinen R, Kytöviita MM. Culturable endophytic microbial communities in the circumpolar grass, Deschampsia flexuosa in a sub-Arctic inland primary succession are habitat and growth stage specific. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:111-122. [PMID: 25721603 DOI: 10.1111/1758-2229.12195] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Little is known about endophytic microbes in cold climate plants and how their communities are formed.We compared culturable putative endophytic bacteria and fungi in the ecologically important circumpolargrass, Deschampsia flexuosa growing in two successional stages of subarctic sand dune (68°29′N).Sequence analyses of partial 16S rRNA and internal transcribed spacer (ITS) sequences of culturable endophytes showed that diverse bacteria and fungi inhabit different tissues of D. flexuosa. A total of 178 bacterial isolates representing seven taxonomic divisions, Alpha, Beta and Gammaproteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Acidobacteria, and 30 fungal isolates representing the phylum Ascomycota were identified. Several endophytes were affiliated with specific plant tissues or successional stages. This first report of bacterial endophytes in D. flexuosa revealed that the genus Pseudomonas is tightly associated with D. flexuosa, and encompassed 39% of the bacterial isolates, and 58% of seed isolates. Based on 16S rRNA and ITS sequence data, most of the D. flexuosa endophytes were closely related to microbes from other cold environments. The majority of seed endophytic bacterial isolates were able to solubilize organic form of phosphate suggesting that these endophytes could play a role in resource mobilization in germinating seeds in nutrient-poor habitat.
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Affiliation(s)
- Anbu Poosakkannu
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.
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22
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Bai Y, Eijsink VGH, Kielak AM, van Veen JA, de Boer W. Genomic comparison of chitinolytic enzyme systems from terrestrial and aquatic bacteria. Environ Microbiol 2014; 18:38-49. [DOI: 10.1111/1462-2920.12545] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 06/12/2014] [Indexed: 12/01/2022]
Affiliation(s)
- Yani Bai
- Department of Microbial Ecology; Netherlands Institute of Ecology (NIOO-KNAW); P.O. Box 50 Wageningen 6700 AB The Netherlands
| | - Vincent G. H. Eijsink
- Department of Chemistry, Biotechnology and Food Science; Norwegian University of Life Sciences; Aas Norway
| | - Anna M. Kielak
- Department of Microbial Ecology; Netherlands Institute of Ecology (NIOO-KNAW); P.O. Box 50 Wageningen 6700 AB The Netherlands
| | - Johannes A. van Veen
- Department of Microbial Ecology; Netherlands Institute of Ecology (NIOO-KNAW); P.O. Box 50 Wageningen 6700 AB The Netherlands
- Institute of Biology; Faculty of Science; Leiden University; Leiden The Netherlands
| | - Wietse de Boer
- Department of Microbial Ecology; Netherlands Institute of Ecology (NIOO-KNAW); P.O. Box 50 Wageningen 6700 AB The Netherlands
- Soil Quality Group; Wageningen University; P.O. Box 9101 Wageningen 6700 HB The Netherlands
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Garbeva P, Hordijk C, Gerards S, de Boer W. Volatiles produced by the mycophagous soil bacteriumCollimonas. FEMS Microbiol Ecol 2013; 87:639-49. [DOI: 10.1111/1574-6941.12252] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 11/04/2013] [Accepted: 11/11/2013] [Indexed: 12/29/2022] Open
Affiliation(s)
- Paolina Garbeva
- Department Microbial Ecology; Netherlands Institute of Ecology (NIOO-KNAW); Wageningen The Netherlands
| | - Cornelis Hordijk
- Department Microbial Ecology; Netherlands Institute of Ecology (NIOO-KNAW); Wageningen The Netherlands
| | - Saskia Gerards
- Department Microbial Ecology; Netherlands Institute of Ecology (NIOO-KNAW); Wageningen The Netherlands
| | - Wietse de Boer
- Department Microbial Ecology; Netherlands Institute of Ecology (NIOO-KNAW); Wageningen The Netherlands
- Department of Soil Quality; Wageningen University; Wageningen The Netherlands
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24
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Sakuda S, Inoue H, Nagasawa H. Novel biological activities of allosamidins. Molecules 2013; 18:6952-68. [PMID: 23765233 PMCID: PMC6269690 DOI: 10.3390/molecules18066952] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 05/27/2013] [Accepted: 06/07/2013] [Indexed: 11/23/2022] Open
Abstract
Allosamidins, which are secondary metabolites of the Streptomyces species, have chitin-mimic pseudotrisaccharide structures. They bind to catalytic centers of all family 18 chitinases and inhibit their enzymatic activity. Allosamidins have been used as chitinase inhibitors to investigate the physiological roles of chitinases in a variety of organisms. Two prominent biological activities of allosamidins were discovered, where one has anti-asthmatic activity in mammals, while the other has the chitinase-production- promoting activity in allosamidin-producing Streptomyces. In this article, recent studies on the novel biological activities of allosamidins are reviewed.
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Affiliation(s)
- Shohei Sakuda
- Department of Applied Biological Chemistry, the University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
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25
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Mela F, Fritsche K, de Boer W, van den Berg M, van Veen JA, Maharaj NN, Leveau JHJ. Comparative genomics of bacteria from the genus Collimonas: linking (dis)similarities in gene content to phenotypic variation and conservation. ENVIRONMENTAL MICROBIOLOGY REPORTS 2012; 4:424-432. [PMID: 23760828 DOI: 10.1111/j.1758-2229.2012.00336.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Collimonas is a genus of soil bacteria comprising three recognized species: C. fungivorans, C. pratensis and C. arenae. Collimonads share the ability to degrade chitin (chitinolysis), feed on living fungal hyphae (mycophagy), and dissolve minerals (weathering), but vary in their inhibition of fungi (fungistasis). To better understand this phenotypic variability, we analysed the genomic content of four strains representing three Collimonas species (Ter14, Ter6, Ter91 and Ter10) by hybridization to a microarray based on reference strain C. fungivorans Ter331. The analysis revealed genes unique to strain Ter331 (e.g. those on the extrachromosomal element pTer331) and genes present in some but not all of the tested strains. Among the latter were several candidates that may contribute to fungistasis, including genes for the production and secretion of antifungals. We hypothesize that differential possession of these genes underlies the specialization of Collimonas strains towards different fungal hosts. We identified a set of 136 genes that were common in all tested Collimonas strains, but absent from the genomes of three other members of the family Oxalobacteraceae. Predicted products of these 'Collimonas core' genes include lytic, secreted enzymes such as chitinases, peptidases, nucleases and phosphatases with a putative role in mycophagy and weathering.
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Affiliation(s)
- F Mela
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, the Netherlands Institute of Biology, Leiden University, Leiden, the Netherlands Department of Plant Pathology, University of California, Davis, CA 95616, USA
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26
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Siqueira V, Lima N. Surface Hydrophobicity of Culture and Water Biofilm of Penicillium spp. Curr Microbiol 2011; 64:93-9. [DOI: 10.1007/s00284-011-0037-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 10/07/2011] [Indexed: 11/28/2022]
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27
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Mela F, Fritsche K, de Boer W, van Veen JA, de Graaff LH, van den Berg M, Leveau JHJ. Dual transcriptional profiling of a bacterial/fungal confrontation: Collimonas fungivorans versus Aspergillus niger. ISME JOURNAL 2011; 5:1494-504. [PMID: 21614084 DOI: 10.1038/ismej.2011.29] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Interactions between bacteria and fungi cover a wide range of incentives, mechanisms and outcomes. The genus Collimonas consists of soil bacteria that are known for their antifungal activity and ability to grow at the expense of living fungi. In non-contact confrontation assays with the fungus Aspergillus niger, Collimonas fungivorans showed accumulation of biomass concomitant with inhibition of hyphal spread. Through microarray analysis of bacterial and fungal mRNA from the confrontation arena, we gained new insights into the mechanisms underlying the fungistatic effect and mycophagous phenotype of collimonads. Collimonas responded to the fungus by activating genes for the utilization of fungal-derived compounds and for production of a putative antifungal compound. In A. niger, differentially expressed genes included those involved in lipid and cell wall metabolism and cell defense, which correlated well with the hyphal deformations that were observed microscopically. Transcriptional profiles revealed distress in both partners: downregulation of ribosomal proteins and upregulation of mobile genetic elements in the bacteria and expression of endoplasmic reticulum stress and conidia-related genes in the fungus. Both partners experienced nitrogen shortage in each other's presence. Overall, our results indicate that the Collimonas/Aspergillus interaction is a complex interplay between trophism, antibiosis and competition for nutrients.
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Affiliation(s)
- Francesca Mela
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
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28
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Brooks DD, Chan R, Starks ER, Grayston SJ, Jones MD. Ectomycorrhizal hyphae structure components of the soil bacterial community for decreased phosphatase production. FEMS Microbiol Ecol 2011; 76:245-55. [PMID: 21265870 DOI: 10.1111/j.1574-6941.2011.01060.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Ectomycorrhizal fungi (EMF) provide nutrients to their hosts by means of hyphae that extend beyond nutrient-depleted rhizosphere soil. Soil bacteria may compete with EMF for nutrients or may act synergistically to enhance nutrient supply to hosts. To assess the interactions between hyphae and bacteria, two types of small, sand-filled mesh bags were incubated in a Pseudotsuga menziesii/Betula papyrifera forest. The bags allowed ingrowth by EMF (35-μm mesh) or excluded hyphae (0.5-μm mesh), while allowing migration of soil bacteria. After incubation, bacteria were isolated from bags using a method to enrich for Gram-positive bacteria. Isolates were assayed for phosphatase and N-acetyl glucosaminidase (NAGase) activities to assess the potential to access organic phosphorus and nitrogen. The average phosphatase activities were higher in exclusion than ingrowth bags, while NAGase activities did not differ. Streptomyces isolates, which are expected to be strong competitors and antagonists of EMF, were more prevalent in ingrowth bags and yet had lower phosphatase activities. Furthermore, there were no indications of antagonism between fungi and Streptomyces, as there were no increases in NAGase activities in ingrowth bags. We conclude that fungal hyphae can structure components of the soil bacterial community for decreased extracellular enzyme production.
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Affiliation(s)
- Denise D Brooks
- Faculty of Forestry, University of British Columbia, Vancouver, BC, Canada.
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29
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Leveau JHJ, Uroz S, de Boer W. The bacterial genusCollimonas: mycophagy, weathering and other adaptive solutions to life in oligotrophic soil environments. Environ Microbiol 2010; 12:281-92. [DOI: 10.1111/j.1462-2920.2009.02010.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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30
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Berg G, Egamberdieva D, Lugtenberg B, Hagemann M. Symbiotic Plant–Microbe Interactions: Stress Protection, Plant Growth Promotion, and Biocontrol by Stenotrophomonas. CELLULAR ORIGIN, LIFE IN EXTREME HABITATS AND ASTROBIOLOGY 2010. [DOI: 10.1007/978-90-481-9449-0_22] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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31
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Bending GD, Poole EJ, Whipps JM, Read DJ. Characterisation of bacteria from Pinus sylvestris-Suillus luteus mycorrhizas and their effects on root-fungus interactions and plant growth. FEMS Microbiol Ecol 2009; 39:219-27. [PMID: 19709201 DOI: 10.1111/j.1574-6941.2002.tb00924.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Bacteria from Pinus sylvestris-Suillus luteus mycorrhizas were isolated, characterised, and their effects on P. sylvestris-S. luteus interactions and plant growth investigated in vitro. The isolates formed five distinct phenotypic and physiological groups. Two of the groups, accounting for 34 of the 55 isolates, consisted of Bacillus spp., with three subgroups represented. The other groups contained Burkholderia spp., Serratia spp. and Pseudomonas spp. Representatives from each bacterial group were used in microcosm experiments to investigate bacterial effects on P. sylvestris-S. luteus interactions. Most Bacillus isolates stimulated growth of S. luteus along the P. sylvestris root, while isolates of Pseudomonas and Serratia inhibited root colonisation by the fungus. Burkholderia and Serratia isolates inhibited ectomycorrhiza formation by 97 and 41% respectively, while a single Bacillus isolate doubled the formation of first order ectomycorrhizal roots. There were no clear relationships between effects of the bacteria on root colonisation by the fungus after 4 weeks, and chitinase production or subsequent ectomycorrhiza formation. However, isolates that inhibited ectomycorrhiza formation appeared to associate preferentially with ectomycorrhizal roots. Several isolates enhanced plant growth substantially, although these effects were unrelated to either root colonisation by the fungus or ectomycorrhiza formation.
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Affiliation(s)
- Gary D Bending
- Department of Soil and Environment Sciences, Horticulture Research International, Wellesbourne, Warwick CV35 9EF, UK.
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Höppener-Ogawa S, Leveau JHJ, Hundscheid MPJ, van Veen JA, de Boer W. Impact of Collimonas bacteria on community composition of soil fungi. Environ Microbiol 2009; 11:1444-52. [PMID: 19260938 DOI: 10.1111/j.1462-2920.2009.01872.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The genus Collimonas consists of soil bacteria that have the potential to grow at the expense of living fungal hyphae. However, the consequences of this mycophagous ability for soil fungi are unknown. Here we report on the development of fungal communities after introduction of collimonads in a soil that had a low abundance of indigenous collimonads. Development of fungal communities was stimulated by addition of cellulose or by introducing plants (Plantago lanceolata). Community composition of total fungi in soil and rhizosphere and of arbuscular mycorrhizal fungi in roots was examined by PCR-DGGE. The introduction of collimonads altered the composition of all fungal communities studied but had no effects on fungal biomass increase, cellulose degrading activity or plant performance. The most likely explanation for these results is that differences in sensitivity of fungal species to the presence of collimonads result in competitive replacement of species. The lab and greenhouse experiments were complemented with a field experiment. Mesh bags containing sterile sand with or without collimonads were buried in an ex-arable field and a forest. The presence of collimonads had an effect on the composition of fungi invading these bags in the ex-arable site but not in the forest site.
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Affiliation(s)
- Sachie Höppener-Ogawa
- Centre for Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Heteren, The Netherlands
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33
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Kobayashi DY, Crouch JA. Bacterial/Fungal interactions: from pathogens to mutualistic endosymbionts. ANNUAL REVIEW OF PHYTOPATHOLOGY 2009; 47:63-82. [PMID: 19400650 DOI: 10.1146/annurev-phyto-080508-081729] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A fundamental issue in biology is the question of how bacteria initiate and maintain pathogenic relationships with eukaryotic hosts. Despite billions of years of coexistence, far less is known about bacterial/fungal interactions than the equivalent associations formed by either of these types of microorganisms with higher eukaryotes. This review highlights recent research advances in the field of bacterial/fungal interactions, and provides examples of the various forms such interactions may assume, ranging from simple antagonism and parasitism to more intimate associations of pathogenesis and endosymbiosis. Information derived from the associations of bacteria and fungi in the context of natural and agronomic ecosystems is emphasized, including interactions observed from biological control systems, endosymbiotic relationships, diseases of cultivated mushrooms, and model systems that expand our understanding of human disease. The benefits of studying these systems at the molecular level are also emphasized.
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Affiliation(s)
- Donald Y Kobayashi
- Department of Plant Biology & Pathology, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901-8520, USA.
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34
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Höppener-Ogawa S, Leveau JHJ, van Veen JA, De Boer W. Mycophagous growth of Collimonas bacteria in natural soils, impact on fungal biomass turnover and interactions with mycophagous Trichoderma fungi. ISME JOURNAL 2008; 3:190-8. [PMID: 18923455 DOI: 10.1038/ismej.2008.97] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bacteria of the genus Collimonas are widely distributed in soils, although at low densities. In the laboratory, they were shown to be mycophagous, that is, they are able to grow at the expense of living hyphae. However, so far the importance of mycophagy for growth and survival of collimonads in natural soil habitats is unknown. Using a Collimonas-specific real-time PCR assay, we show here that the invasion of field soils by fungal hyphae (Absidia sp.) resulted in a short-term, significant increase (average fourfold) of indigenous collimonads. No such responses were observed for other soil bacteria studied (Pseudomonas, Burkholderia, PCR-denaturing gradient gel electrophoresis patterns of total bacteria and Burkholderia). Hence, it appears that the stimulation of growth of Collimonas bacteria by fungal hyphae is not common among other soil bacteria. In the same field soils, Trichoderma, a fungal genus known for mycophagous (mycoparasitic) growth, increased upon introduction of Absidia hyphae. Hence, mycophagous growth by Collimonas and Trichoderma can occur in the same soils. However, in controlled experiments (sand microcosms), collimonads appeared to have a negative effect on mycophagous growth of a Trichoderma strain. The effect of mycophagous growth of collimonads on fungal biomass dynamics was studied in sand microcosms using the same Absidia sp. as a test fungus. The growth of collimonads did not cause a significant reduction in the Absidia biomass. Overall, the study indicates that mycophagous nutrition may be important for collimonads in natural soils, but the impact on fungal biomass turnover is likely to be minor.
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Affiliation(s)
- Sachie Höppener-Ogawa
- Centre for Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Heteren, The Netherlands
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35
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Fritsche K, de Boer W, Gerards S, van den Berg M, van Veen JA, Leveau JHJ. Identification and characterization of genes underlying chitinolysis in Collimonas fungivorans Ter331. FEMS Microbiol Ecol 2008; 66:123-35. [PMID: 18671744 DOI: 10.1111/j.1574-6941.2008.00547.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Through a combinatorial approach of plasposon mutagenesis, genome mining, and heterologous expression, we identified genes contributing to the chitinolytic phenotype of bacterium Collimonas fungivorans Ter331. One of five mutants with abolished ability to hydrolyze colloidal chitin carried its plasposon in the chiI gene coding for an extracellular endochitinase. Two mutants were affected in the promoter of chiP-II coding for an outer-membrane transporter of chitooligosaccharides. The remaining two mutations were linked to chitobiose/N-acetylglucosamine uptake. Thus, our model for the Collimonas chitinolytic system assumes a positive feedback regulation of chitinase activity by chitin degradation products. A second chitinase gene, chiII, coded for an exochitinase that preferentially released chitobiose from chitin analogs. Genes hexI and hexII showed coding resemblance to N-acetylglucosaminidases, and the activity of purified HexI protein towards chitin analogs suggested its role in converting chitobiose to N-acetylglucosamine. The hexI gene clustered with chiI, chiII, and chiP-II in one locus, while chitobiose/N-acetylglucosamine uptake genes colocalized in another. Both loci contained genes for conversion of N-acetylglucosamine to fructose-6-phosphate, confirming that C. fungivorans Ter331 features a complete chitin pathway. No link could be established between chitinolysis and antifungal activity of C. fungivorans Ter331, suggesting that the bacterium's reported antagonism towards fungi relies on other mechanisms.
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Affiliation(s)
- Kathrin Fritsche
- Netherlands Institute of Ecology (NIOO-KNAW), Heteren, The Netherlands
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36
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Mela F, Fritsche K, Boersma H, van Elsas JD, Bartels D, Meyer F, de Boer W, van Veen JA, Leveau JHJ. Comparative genomics of the pIPO2/pSB102 family of environmental plasmids: sequence, evolution, and ecology of pTer331 isolated from Collimonas fungivorans Ter331. FEMS Microbiol Ecol 2008; 66:45-62. [PMID: 18355297 DOI: 10.1111/j.1574-6941.2008.00472.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Plasmid pTer331 from the bacterium Collimonas fungivorans Ter331 is a new member of the pIPO2/pSB102 family of environmental plasmids. The 40 457-bp sequence of pTer331 codes for 44 putative ORFs, most of which represent genes involved in replication, partitioning and transfer of the plasmid. We confirmed that pTer331 is stably maintained in its native host. Deletion analysis identified a mini-replicon capable of replicating autonomously in Escherichia coli and Pseudomonas putida. Furthermore, plasmid pTer331 was able to mobilize and retromobilize IncQ plasmid pSM1890 at typical rates of 10(-4) and 10(-8), respectively. Analysis of the 91% DNA sequence identity between pTer331 and pIPO2 revealed functional conservation of coding sequences, the deletion of DNA fragments flanked by short direct repeats (DR), and sequence preservation of long DRs. In addition, we experimentally established that pTer331 has no obvious contribution in several of the phenotypes that are characteristic of its host C. fungivorans Ter331, including the ability to efficiently colonize plant roots. Based on our findings, we hypothesize that cryptic plasmids such as pTer331 and pIPO2 might not confer an individual advantage to bacteria, but, due to their broad-host-range and ability to retromobilize, benefit bacterial populations by accelerating the intracommunal dissemination of the mobile gene pool.
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Affiliation(s)
- Francesca Mela
- Centre for Terrestrial Ecology, Netherlands Institute of Ecology, NIOO-KNAW, Heteren, The Netherlands
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37
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Leveau JHJ, Preston GM. Bacterial mycophagy: definition and diagnosis of a unique bacterial-fungal interaction. THE NEW PHYTOLOGIST 2008; 177:859-876. [PMID: 18086226 DOI: 10.1111/j.1469-8137.2007.02325.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
This review analyses the phenomenon of bacterial mycophagy, which we define as a set of phenotypic behaviours that enable bacteria to obtain nutrients from living fungi and thus allow the conversion of fungal into bacterial biomass. We recognize three types of bacterial strategies to derive nutrition from fungi: necrotrophy, extracellular biotrophy and endocellular biotrophy. Each is characterized by a set of uniquely sequential and differently overlapping interactions with the fungal target. We offer a detailed analysis of the nature of these interactions, as well as a comprehensive overview of methodologies for assessing and quantifying their individual contributions to the mycophagy phenotype. Furthermore, we discuss future prospects for the study and exploitation of bacterial mycophagy, including the need for appropriate tools to detect bacterial mycophagy in situ in order to be able to understand, predict and possibly manipulate the way in which mycophagous bacteria affect fungal activity, turnover, and community structure in soils and other ecosystems.
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Affiliation(s)
- Johan H J Leveau
- Netherlands Institute of Ecology (NIOO-KNAW), Heteren, the Netherlands
| | - Gail M Preston
- Department of Plant Sciences, University of Oxford, Oxford, UK
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38
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Purin S, Rillig MC. Parasitism of arbuscular mycorrhizal fungi: reviewing the evidence. FEMS Microbiol Lett 2007; 279:8-14. [PMID: 18070075 DOI: 10.1111/j.1574-6968.2007.01007.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In order to understand the functioning of mycorrhizal fungi in ecosystems it is necessary to consider the full suite of possible biotic interactions in the soil. While a number of such interactions have recently been shown to be crucially important, parasitism is a highly neglected feature in the ecology of arbuscular mycorrhizal fungi (AMF). A number of studies have classified some interactions between populations of bacteria and fungi with AMF as parasitism, generating discussion about its consequences at both 'parasite' and host population levels. This paper reviews these various publications, and based on a set of criteria that are necessary to demonstrate parasitism, it was concluded that parasitism has not been conclusively shown to exist in AMF, even though some data are highly suggestive of such a relationship. The difficulties in gathering data supportive of parasitism were discussed, and hypotheses for defense were offered. This paper concludes by presenting potential consequences of AMF parasitism at the population/community levels and by discussing applied aspects.
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Affiliation(s)
- Sonia Purin
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV 26506-6108, USA.
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39
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Kamilova F, Leveau JHJ, Lugtenberg B. Collimonas fungivorans, an unpredicted in vitro but efficient in vivo biocontrol agent for the suppression of tomato foot and root rot. Environ Microbiol 2007; 9:1597-603. [PMID: 17504497 DOI: 10.1111/j.1462-2920.2007.01263.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Although bacteria from the genus Collimonas have demonstrated in vitro antifungal activity against many different fungi, they appeared inactive against the plant-pathogenic fungus Fusarium oxysporum f.sp. radicis-lycopersici (Forl), the causal agent of tomato foot and root rot (TFRR). Visualization studies using fluorescently labelled organisms showed that bacterial cells attached extensively to the fungal hyphae under nutrient-poor conditions but not in glucose-rich Armstrong medium. Collimonas fungivorans was shown to be as efficient in colonizing tomato root tips as the excellent colonizer Pseudomonas fluorescens strain WCS365. Furthermore, it appeared to colonize the same sites on the root as did the phytopathogenic fungus. Under greenhouse conditions in potting soil, C. fungivorans performed as well in biocontrol of TFRR as the well-established biocontrol strains P. fluorescens WCS365 and Pseudomonas chlororaphis PCL1391. Moreover, under biocontrol conditions, C. fungivorans did not attach to Forl hyphae colonizing plant roots. Based on these observations, we hypothesize that C. fungivorans mainly controls TFRR through a mechanism of competition for nutrients and niches rather than through its reported mycophagous properties, for which attachment of the bacteria to the fungal hyphae is assumed to be important.
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Affiliation(s)
- Faina Kamilova
- Institute of Biology, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands.
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40
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Höppener-Ogawa S, Leveau JHJ, Smant W, van Veen JA, de Boer W. Specific detection and real-time PCR quantification of potentially mycophagous bacteria belonging to the genus Collimonas in different soil ecosystems. Appl Environ Microbiol 2007; 73:4191-7. [PMID: 17483278 PMCID: PMC1932782 DOI: 10.1128/aem.00387-07] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Accepted: 04/24/2007] [Indexed: 11/20/2022] Open
Abstract
The bacterial genus Collimonas has the remarkable characteristic that it grows at the expense of living fungal hyphae under laboratory conditions. Here, we report the first field inventory of the occurrence and abundance of Collimonas in soils (n = 45) with naturally different fungal densities, which was performed in order to test the null hypothesis that there is a relationship between the presence of Collimonas and fungal biomass. Estimates of fungal densities were based on ergosterol measurements. Each soil was also characterized in terms of its physical and chemical properties and vegetation and management types. Culturable Collimonas was identified in plate-spread soil samples by its ability to clear colloidal chitin, in combination with a Collimonas-specific restriction fragment length polymorphism analysis of 16S rRNA PCR amplified from individual colonies. Using this approach, we found culturable collimonads only in (semi)natural grasslands. A real-time PCR assay for the specific quantification of Collimonas 16S rRNA in total soil DNA was developed. Collimonas was detectable in 80% of the soil samples, with densities up to 10(5) cells g(-1) (dry weight) soil. The numbers of Collimonas cells per gram of soil were consistently lowest in fungus-poor arable soils and, surprisingly, also in fungus-rich organic layers of forest soils. When all soils were included, no significant correlation was observed between the number of Collimonas cells and ergosterol-based soil fungal biomass. Based on this result, we rejected our null hypothesis, and possible explanations for this were addressed.
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Affiliation(s)
- Sachie Höppener-Ogawa
- Netherlands Institute of Ecology (NIOO-KNAW), Centre for Terrestrial Ecology, Boterhoeksestraat 48, Heteren, The Netherlands.
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Utilization of various chitinous sources for production of mycolytic enzymes by Pantoea dispersa in bench-top fermenter. Enzyme Microb Technol 2007. [DOI: 10.1016/j.enzmictec.2006.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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42
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Mucha J, Dahm H, Werner A. Influence of autoclaved saprotrophic fungal mycelia on proteolytic activity in ectomycorrhizal fungi. Antonie van Leeuwenhoek 2007; 92:137-42. [PMID: 17333458 DOI: 10.1007/s10482-006-9136-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Accepted: 12/18/2006] [Indexed: 10/23/2022]
Abstract
The production of proteolytic enzymes by several strains of ectomycorrhizal fungi i.e., Amanita muscaria (16-3), Laccaria laccata (9-12), L. laccata (9-1), Suillus bovinus (15-4), Suillus bovinus (15-3), Suillus luteus (14-7) on mycelia of Trichoderma harzianum, Trichoderma virens and Mucor hiemalis and sodium caseinate, yeast extract was evaluated. The strains of A. muscaria (16-3) and L. laccata (9-12) were characterized by the highest activity of the acidic and neutral proteases. Taking the mycelia of saprotrophic fungi into consideration, the mycelium of M. hiemalis was the best inductor for proteolytic activity. The examined ectomycorrhizal fungi exhibited higher activity of acidic proteases than neutral ones on the mycelia of saprotrophic fungi, which may imply the participation of acidic proteases in nutrition.
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Affiliation(s)
- Joanna Mucha
- Laboratory of Root System Pathology, Institute of Dendrology, Polish Academy of Science, Parkowa 5, 62-035, Kornik, Poland.
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Mougel C, Offre P, Ranjard L, Corberand T, Gamalero E, Robin C, Lemanceau P. Dynamic of the genetic structure of bacterial and fungal communities at different developmental stages of Medicago truncatula Gaertn. cv. Jemalong line J5. THE NEW PHYTOLOGIST 2006; 170:165-75. [PMID: 16539613 DOI: 10.1111/j.1469-8137.2006.01650.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The genetic structure of bacterial and fungal communities was characterized in the rhizosphere of Medicago truncatula Gaertn. cv. Jemalong line J5 at five developmental stages (three vegetative and two reproductive stages), and in three compartments (bulk soil, rhizosphere soil and root tissues). The genetic structure of microbial communities was determined by cultivation-independent methods using directly extracted DNA that was characterized by automated ribosomal intergenic spacer analysis (ARISA). Principal component analyses (PCA) indicate that, for all developmental stages, the genetic structure of microbial communities differed significantly by compartment, with a major shift in the community in root tissues corresponding to the most intimate compartment with the plant. Differences were also recorded during plant development, the most significant being observed during the transition between vegetative and reproductive stages. Throughout this period, plants were shown to establish the highest level of symbiotic association (mycorrhization, nodulation) with arbuscular mycorrhizal fungi and Rhizobia. During the reproductive stages, the dynamics of the genetic structure differed between bacterial and fungal communities. At the last reproductive stage, the genetic structure of bacterial communities became close to that recorded during the first vegetative stages, suggesting a resilience phenomenon, whereas the genetic structure of fungal communities remained different from the vegetative stages and also from the early reproductive stages, suggesting a persistence of the rhizosphere effect.
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Affiliation(s)
- C Mougel
- UMR Microbiologie et Géochimie des Sols, INRA/Université de Bourgogne, CMSE, 21065 Dijon Cedex, France.
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Ribbeck-Busch K, Roder A, Hasse D, de Boer W, Martínez JL, Hagemann M, Berg G. A molecular biological protocol to distinguish potentially human pathogenic Stenotrophomonas maltophilia from plant-associated Stenotrophomonas rhizophila. Environ Microbiol 2005; 7:1853-8. [PMID: 16232300 DOI: 10.1111/j.1462-2920.2005.00928.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In recent years, the importance of the Gram-negative bacterium Stenotrophomonas as an opportunistic pathogen as well as in biotechnology has increased. The aim of the present study was to develop new methods for distinguishing between strains closely related to the potentially human pathogenic Stenotrophomonas maltophilia and those closely related to the plant-associated Stenotrophomonas rhizophila. To accomplish this, 58 strains were characterized by 16S rDNA sequencing and amplified ribosomal DNA restriction analysis (ARDRA), and the occurrence of specific functional genes. Based on 16S rDNA sequences, an ARDRA protocol was developed which allowed differentiation between strains of the S. maltophilia and the S. rhizophila group. As it was known that only salt-treated cells of S. rhizophila were able to synthesize the compatible solute glucosylglycerol (GG), the ggpS gene responsible for GG synthesis was used for differentiation between both species and it was confirmed that it only occurred in S. rhizophila strains. As a further genetic marker the smeD gene, which is part of the genes coding for the multidrug efflux pump SmeDEF from S. maltophilia, was used. Based on the results we propose a combination of fingerprinting techniques using the 16S rDNA and the functional genes ggpS and smeD to distinguish both Stenotrophomonas species.
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Affiliation(s)
- Kathrin Ribbeck-Busch
- Microbiology, Institute of Biological Sciences, Universit of Rostock, Albert-Einstein-Str. 3, D-18051 Rostock, Germany
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Männistö MK, Häggblom MM. Characterization of psychrotolerant heterotrophic bacteria from Finnish Lapland. Syst Appl Microbiol 2005; 29:229-43. [PMID: 16564959 DOI: 10.1016/j.syapm.2005.09.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/10/2005] [Indexed: 10/25/2022]
Abstract
A total of 331 aerobic heterotrophic bacterial strains were isolated from various ecosystems of Finnish Lapland (68-69 degrees N) including forest soil, arctic alpine-tundra soil, stream water, lake and mire sediments, lichen and snow algae. Whole cell fatty acid and 16S rRNA gene sequence analysis and microscopy indicated that the isolates were dominated by Gram-negative bacteria, while only 20 Gram-positive strains were isolated. Based on 16S rRNA gene sequences the isolates were members of alpha-, beta-, gamma-Proteobacteria, Gram-positives with low G+C content, Actinobacteria and the Cytophaga/Flexibacter/Bacteroides group. More than one-third of the isolates could be tentatively identified as Pseudomonas spp. which were particularly abundant in the alpine-tundra soils where they represented 60% of all isolates. Other frequently isolated Gram-negative taxa were Burkholderia sp., Collimonas sp., Pedobacter sp., Janthinobacter sp., Duganella sp., Dyella sp. and Sphingomonas sp. Growth temperature ranges and hydrolytic enzyme activities of selected ca.100 strains were screened. The strains were psychrotolerant growing generally at temperatures ranging from 0 to 30 degrees C, as 82% of the isolates grew at 0 degrees C while only 7% grew at 35 degrees C. Protease and lipase activities at 5 degrees C were detected in more than half of the strains while approximately 20% of the strains possessed amylase and/or cellulase activities.
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Affiliation(s)
- Minna K Männistö
- Arctic Microbiology Research Group, Finnish Forest Research Institute, Rovaniemi Research Station, Eteläranta 55, 96300 Rovaniemi, Finland.
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Boer WD, Folman LB, Summerbell RC, Boddy L. Living in a fungal world: impact of fungi on soil bacterial niche development. FEMS Microbiol Rev 2004; 29:795-811. [PMID: 16102603 DOI: 10.1016/j.femsre.2004.11.005] [Citation(s) in RCA: 713] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Revised: 10/07/2004] [Accepted: 11/19/2004] [Indexed: 11/19/2022] Open
Abstract
The colonization of land by plants appears to have coincided with the appearance of mycorrhiza-like fungi. Over evolutionary time, fungi have maintained their prominent role in the formation of mycorrhizal associations. In addition, however, they have been able to occupy other terrestrial niches of which the decomposition of recalcitrant organic matter is perhaps the most remarkable. This implies that, in contrast to that of aquatic organic matter decomposition, bacteria have not been able to monopolize decomposition processes in terrestrial ecosystems. The emergence of fungi in terrestrial ecosystems must have had a strong impact on the evolution of terrestrial bacteria. On the one hand, potential decomposition niches, e.g. lignin degradation, have been lost for bacteria, whereas on the other hand the presence of fungi has itself created new bacterial niches. Confrontation between bacteria and fungi is ongoing, and from studying contemporary interactions, we can learn about the impact that fungi presently have, and have had in the past, on the ecology and evolution of terrestrial bacteria. In the first part of this review, the focus is on niche differentiation between soil bacteria and fungi involved in the decomposition of plant-derived organic matter. Bacteria and fungi are seen to compete for simple plant-derived substrates and have developed antagonistic strategies. For more recalcitrant organic substrates, e.g. cellulose and lignin, both competitive and mutualistic strategies appear to have evolved. In the second part of the review, bacterial niches with respect to the utilization of fungal-derived substrates are considered. Here, several lines of development can be recognized, ranging from mutualistic exudate-consuming bacteria that are associated with fungal surfaces to endosymbiotic and mycophagous bacteria. In some cases, there are indications of fungal specific selection in fungus-associated bacteria, and possible mechanisms for such selection are discussed.
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Affiliation(s)
- Wietse de Boer
- NIOO-Centre for Terrestrial Ecology, Department of Plant Microorganism Interactions, Heteren, The Netherlands.
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Hobel CFV, Hreggvidsson GO, Marteinsson VT, Bahrani-Mougeot F, Einarsson JM, Kristjánsson JK. Cloning, expression, and characterization of a highly thermostable family 18 chitinase from Rhodothermus marinus. Extremophiles 2004; 9:53-64. [PMID: 15583965 DOI: 10.1007/s00792-004-0422-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Accepted: 08/27/2004] [Indexed: 10/26/2022]
Abstract
A family 18 chitinase gene chiA from the thermophile Rhodothermus marinus was cloned and expressed in Escherichia coli. The gene consisted of an open reading frame of 1,131 nucleotides encoding a protein of 377 amino acids with a calculated molecular weight of 42,341 Da. The deduced ChiA was a non-modular enzyme with one unique glycoside hydrolase family 18 catalytic domain. The catalytic domain exhibited 43% amino acid identity with Bacillus circulans chitinase C. Due to poor expression of ChiA, a signal peptide-lacking mutant, chiADeltasp, was designed and used subsequently. The optimal temperature and pH for chitinase activity of both ChiA and ChiADeltasp were 70 degrees C and 4.5-5, respectively. The enzyme maintained 100% activity after 16 h incubation at 70 degrees C, with half-lives of 3 h at 90 degrees C and 45 min at 95 degrees C. Results of activity measurements with chromogenic substrates, thin-layer chromatography, and viscosity measurements demonstrated that the chitinase is an endoacting enzyme releasing chitobiose as a major end product, although it acted as an exochitobiohydrolase with chitin oligomers shorter than five residues. The enzyme was fully inhibited by 5 mM HgCl2, but excess ethylenediamine tetraacetic acid relieved completely the inhibition. The enzyme hydrolyzed 73% deacetylated chitosan, offering an attractive alternative for enzymatic production of chitooligosaccharides at high temperature and low pH. Our results show that the R. marinus chitinase is the most thermostable family 18 chitinase isolated from Bacteria so far.
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de Boer W, Leveau JHJ, Kowalchuk GA, Gunnewiek PJAK, Abeln ECA, Figge MJ, Sjollema K, Janse JD, van Veen JA. Collimonas fungivorans gen. nov., sp. nov., a chitinolytic soil bacterium with the ability to grow on living fungal hyphae. Int J Syst Evol Microbiol 2004; 54:857-864. [PMID: 15143036 DOI: 10.1099/ijs.0.02920-0] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A polyphasic approach was used to describe the phylogenetic position of 22 chitinolytic bacterial isolates that were able to grow at the expense of intact, living hyphae of several soil fungi. These isolates, which were found in slightly acidic dune soils in the Netherlands, were strictly aerobic, Gram-negative rods. Cells grown in liquid cultures were flagellated and possessed pili. A wide range of sugars, alcohols, organic acids and amino acids could be metabolized, whereas several di- and trisaccharides could not be used as substrates. The major cellular fatty acids were C(16 : 0), C(16 : 1)omega7c and C(18 : 1)omega7c. DNA G+C contents were 57-62 mol%. Analysis of nearly full-length 16S rDNA sequences showed that the isolates were related closely to each other (>98.6 % sequence similarity) and could be assigned to the beta-Proteobacteria, family 'Oxalobacteraceae', order 'Burkholderiales'. The most closely related species belonged to the genera Herbaspirillum and Janthinobacterium, exhibiting 95.9-96.7 % (Herbaspirillum species) and 94.3-95.6 % (Janthinobacterium species) 16S rDNA sequence similarity to the isolates. Several physiological and biochemical properties indicated that the isolates could be distinguished clearly from both of these genera. Therefore, it is proposed that the isolates described in this study are representatives of a novel genus, Collimonas gen. nov. Genomic fingerprinting (BOX-PCR), detailed analysis of 16S rDNA patterns and physiological characterization (Biolog) of the isolates revealed the existence of four subclusters. The name Collimonas fungivorans gen. nov., sp. nov. has been given to one subcluster (four isolates) that appears to be in the centre of the novel genus; isolates in the other subclusters have been tentatively named Collimonas sp. The type strain of Collimonas fungivorans gen. nov., sp. nov. is Ter6(T) (=NCCB 100033(T)=LMG 21973(T)).
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Affiliation(s)
- Wietse de Boer
- Netherlands Institute of Ecology, Centre for Terrestrial Ecology, Department of Plant-Microorganism Interactions, NL-6666 ZG Heteren, the Netherlands
| | - Johan H J Leveau
- Netherlands Institute of Ecology, Centre for Terrestrial Ecology, Department of Plant-Microorganism Interactions, NL-6666 ZG Heteren, the Netherlands
| | - George A Kowalchuk
- Netherlands Institute of Ecology, Centre for Terrestrial Ecology, Department of Plant-Microorganism Interactions, NL-6666 ZG Heteren, the Netherlands
| | - Paulien J A Klein Gunnewiek
- Netherlands Institute of Ecology, Centre for Terrestrial Ecology, Department of Plant-Microorganism Interactions, NL-6666 ZG Heteren, the Netherlands
| | - Edwin C A Abeln
- Netherlands Culture Collection of Bacteria, NL-3584 CT Utrecht, the Netherlands
| | - Marian J Figge
- Netherlands Culture Collection of Bacteria, NL-3584 CT Utrecht, the Netherlands
| | - Klaas Sjollema
- Eukaryotic Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, NL-9751 NN Haren, the Netherlands
| | - Jaap D Janse
- Plant Protection Service, Section Bacteriology, NL-6700 HC Wageningen, the Netherlands
| | - Johannes A van Veen
- Netherlands Institute of Ecology, Centre for Terrestrial Ecology, Department of Plant-Microorganism Interactions, NL-6666 ZG Heteren, the Netherlands
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Smits THM, Wick LY, Harms H, Keel C. Characterization of the surface hydrophobicity of filamentous fungi. Environ Microbiol 2003; 5:85-91. [PMID: 12558591 DOI: 10.1046/j.1462-2920.2003.00389.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A method for the quantitative analysis of the hydrophobicity of the mycelial mat of filamentous fungi based on contact angle measurements is presented. It was tested for a range of fungi belonging to the classes of basidiomycetes, ascomycetes and deuteromycetes. The measured contact angles of the mycelial mats ranged between hydrophilic (<30 degrees) for the deuteromycetes Fusarium oxysporum Fo47 GUS1 and Trichoderma harzianum P1[pZEGA1] and hydrophobic (>60 degrees) for the ascomycete Cladosporium sp. DSE48.1b and the basidiomycetes Paxillus involutus WSL 37.7, Hebeloma crustiliniforme WSL 6.2, Suillus bovinus WSL 48.1 and Laccaria bicolor WSL 73.1. For some fungi, variations in the hydrophobicity of the mycelium depending on the growth medium, the physiological state and the exposure to water were distinguished.
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Affiliation(s)
- Theo H M Smits
- ENAC - ISTE - LPE, Swiss Federal Institute of Technology Lausanne (EPFL), Switzerland.
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