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Cecala JM, Vannette RL. Nontarget impacts of neonicotinoids on nectar-inhabiting microbes. Environ Microbiol 2024; 26:e16603. [PMID: 38494634 DOI: 10.1111/1462-2920.16603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 02/23/2024] [Indexed: 03/19/2024]
Abstract
Plant-systemic neonicotinoid (NN) insecticides can exert non-target impacts on organisms like beneficial insects and soil microbes. NNs can affect plant microbiomes, but we know little about their effects on microbial communities that mediate plant-insect interactions, including nectar-inhabiting microbes (NIMs). Here we employed two approaches to assess the impacts of NN exposure on several NIM taxa. First, we assayed the in vitro effects of six NN compounds on NIM growth using plate assays. Second, we inoculated a standardised NIM community into the nectar of NN-treated canola (Brassica napus) and assessed microbial survival and growth after 24 h. With few exceptions, in vitro NN exposure tended to decrease bacterial growth metrics. However, the magnitude of the decrease and the NN concentrations at which effects were observed varied substantially across bacteria. Yeasts showed no consistent in vitro response to NNs. In nectar, we saw no effects of NN treatment on NIM community metrics. Rather, NIM abundance and diversity responded to inherent plant qualities like nectar volume. In conclusion, we found no evidence that NIMs respond to field-relevant NN levels in nectar within 24 h, but our study suggests that context, specifically assay methods, time and plant traits, is important in assaying the effects of NNs on microbial communities.
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Affiliation(s)
- Jacob M Cecala
- Department of Entomology & Nematology, University of California, Davis, California, USA
| | - Rachel L Vannette
- Department of Entomology & Nematology, University of California, Davis, California, USA
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2
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Rering CC, Rudolph AB, Li QB, Read QD, Muñoz PR, Ternest JJ, Hunter CT. A quantitative survey of the blueberry (Vaccinium spp.) culturable nectar microbiome: variation between cultivars, locations, and farm management approaches. FEMS Microbiol Ecol 2024; 100:fiae020. [PMID: 38366934 PMCID: PMC10903978 DOI: 10.1093/femsec/fiae020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 01/25/2024] [Accepted: 02/15/2024] [Indexed: 02/19/2024] Open
Abstract
Microbes in floral nectar can impact both their host plants and floral visitors, yet little is known about the nectar microbiome of most pollinator-dependent crops. In this study, we examined the abundance and composition of the fungi and bacteria inhabiting Vaccinium spp. nectar, as well as nectar volume and sugar concentrations. We compared wild V. myrsinites with two field-grown V. corymbosum cultivars collected from two organic and two conventional farms. Differences in nectar traits and microbiomes were identified between V. corymbosum cultivars but not Vaccinium species. The microbiome of cultivated plants also varied greatly between farms, whereas management regime had only subtle effects, with higher fungal populations detected under organic management. Nectars were hexose-dominant, and high cell densities were correlated with reduced nectar sugar concentrations. Bacteria were more common than fungi in blueberry nectar, although both were frequently detected and co-occurred more often than would be predicted by chance. "Cosmopolitan" blueberry nectar microbes that were isolated in all plants, including Rosenbergiella sp. and Symmetrospora symmetrica, were identified. This study provides the first systematic report of the blueberry nectar microbiome, which may have important implications for pollinator and crop health.
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Affiliation(s)
- Caitlin C Rering
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, 1700 SW 23rd Dr, Gainesville, FL 32608, United States
| | - Arthur B Rudolph
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, 1700 SW 23rd Dr, Gainesville, FL 32608, United States
| | - Qin-Bao Li
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, 1700 SW 23rd Dr, Gainesville, FL 32608, United States
| | - Quentin D Read
- Agricultural Research Service, Southeast Area, United States Department of Agriculture, 840 Oval Drive, Raleigh, NC 27606, United States
| | - Patricio R Muñoz
- Horticultural Sciences Department, University of Florida, 2550 Hull Rd, Gainesville, FL 32611, United States
| | - John J Ternest
- Department of Entomology and Nematology, University of Florida, 1881 Natural Area Dr, Gainesville, FL 32611, United States
| | - Charles T Hunter
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, 1700 SW 23rd Dr, Gainesville, FL 32608, United States
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3
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Rutkowski D, Weston M, Vannette RL. Bees just wanna have fungi: a review of bee associations with nonpathogenic fungi. FEMS Microbiol Ecol 2023; 99:fiad077. [PMID: 37422442 PMCID: PMC10370288 DOI: 10.1093/femsec/fiad077] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/15/2023] [Accepted: 07/06/2023] [Indexed: 07/10/2023] Open
Abstract
Bee-fungus associations are common, and while most studies focus on entomopathogens, emerging evidence suggests that bees associate with a variety of symbiotic fungi that can influence bee behavior and health. Here, we review nonpathogenic fungal taxa associated with different bee species and bee-related habitats. We synthesize results of studies examining fungal effects on bee behavior, development, survival, and fitness. We find that fungal communities differ across habitats, with some groups restricted mostly to flowers (Metschnikowia), while others are present almost exclusively in stored provisions (Zygosaccharomyces). Starmerella yeasts are found in multiple habitats in association with many bee species. Bee species differ widely in the abundance and identity of fungi hosted. Functional studies suggest that yeasts affect bee foraging, development, and pathogen interactions, though few bee and fungal taxa have been examined in this context. Rarely, fungi are obligately beneficial symbionts of bees, whereas most are facultative bee associates with unknown or ecologically contextual effects. Fungicides can reduce fungal abundance and alter fungal communities associated with bees, potentially disrupting bee-fungi associations. We recommend that future study focus on fungi associated with non-honeybee species and examine multiple bee life stages to document fungal composition, abundance, and mechanistic effects on bees.
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Affiliation(s)
- Danielle Rutkowski
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
| | - Makena Weston
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
| | - Rachel L Vannette
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
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4
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Machado C, Cuco AP, Cássio F, Wolinska J, Castro BB. Antiparasitic potential of agrochemical fungicides on a non-target aquatic model (Daphnia × Metschnikowia host-parasite system). THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 833:155296. [PMID: 35429554 DOI: 10.1016/j.scitotenv.2022.155296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 03/29/2022] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
Pesticides are a major anthropogenic threat to the biodiversity of freshwater ecosystems, having the potential to affect non-target aquatic organisms and disrupt the processes in which they intervene. Important knowledge gaps have been recognised concerning the ecological effects of synthetic fungicides on non-target symbiotic aquatic fungi and the ecological processes where they intervene. The goal of this work was to assess the influence of three commonly used fungicides (myclobutanil, metalaxyl and cymoxanil), which differ in their mode of action, on a host (the crustacean Daphnia magna) × parasite (the yeast Metschnikowia bicuspidata) experimental model. Using a set of life history experiments, we evaluated the effect of each fungicide on the outcome of this relationship (disease) and on the fitness of both host and parasite. Contrasting results were observed: (i) cymoxanil and metalaxyl were overall innocuous to host and parasite at the tested concentrations, although host reproduction was occasionally reduced in the simultaneous presence of parasite and fungicide; (ii) on the contrary, myclobutanil displayed a clear antifungal effect, decreasing parasite prevalence and alleviating infection signs in the hosts. This antiparasitic effect of myclobutanil was further investigated with a follow-up experiment that manipulated the timing of application of the fungicide, to understand which stage of parasite development was most susceptible: while myclobutanil did not interfere in the early stages of infection, its antifungal activity was clearly observable at a later stage of the disease (by impairing the production of transmission stages of the parasite). More research is needed to understand the broader consequences of this parasite-clearance effect, especially in face of increasing evidence that parasites are ecologically more important than their cryptic nature might suggest.
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Affiliation(s)
- Cláudia Machado
- CBMA (Centre of Molecular and Environmental Biology) & Department of Biology, School of Sciences, University of Minho, Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), School of Sciences, University of Minho, Braga, Portugal
| | - Ana P Cuco
- CBMA (Centre of Molecular and Environmental Biology) & Department of Biology, School of Sciences, University of Minho, Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), School of Sciences, University of Minho, Braga, Portugal
| | - Fernanda Cássio
- CBMA (Centre of Molecular and Environmental Biology) & Department of Biology, School of Sciences, University of Minho, Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), School of Sciences, University of Minho, Braga, Portugal
| | - Justyna Wolinska
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany; Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität Berlin, Berlin, Germany
| | - Bruno B Castro
- CBMA (Centre of Molecular and Environmental Biology) & Department of Biology, School of Sciences, University of Minho, Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), School of Sciences, University of Minho, Braga, Portugal.
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Kumari A, Kumari S, Prasad GS, Pinnaka AK. Production of Sophorolipid Biosurfactant by Insect Derived Novel Yeast Metschnikowia churdharensis f.a., sp. nov., and Its Antifungal Activity Against Plant and Human Pathogens. Front Microbiol 2021; 12:678668. [PMID: 34149670 PMCID: PMC8212020 DOI: 10.3389/fmicb.2021.678668] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/27/2021] [Indexed: 01/14/2023] Open
Abstract
Biosurfactants are potential biomolecules that have extensive utilization in cosmetics, medicines, bioremediation and processed foods. Yeast produced biosurfactants offer thermal resistance, antioxidant activity, and no risk of pathogenicity, illustrating their promising use in food formulations. The present study is aimed to assess potential of biosurfactant screened from a novel yeast and their inhibition against food spoilage fungi. A novel asexual ascomycetes yeast strain CIG-6AT producing biosurfactant, was isolated from the gut of stingless bee from Churdhar, HP, India. The phylogenetic analysis revealed that the strain CIG-6AT was closely related to Metschnikowia koreensis, showing 94.38% sequence similarity in the D1D2 region for which the name Metschnikowia churdharensis f.a., sp. nov., is proposed. The strain CIG-6AT was able to produce sophorolipid biosurfactant under optimum conditions. Sophorolipid biosurfactant from strain CIG-6AT effectively reduced the surface tension from 72.8 to 35 mN/m. Sophorolipid biosurfactant was characterized using TLC, FTIR, GC-MS and LC-MS techniques and was a mixture of both acidic and lactonic forms. Sophorolipid assessed promising activity against pathogenic fungi viz. Fusarium oxysporum (MTCC 9913), Fusarium solani (MTCC 350), and Colletotrichum gloeosporioides (MTCC 2190). The inhibitory effect of biosurfactant CIG-6AT against F. solani was studied and MIC was 49 μgm/ml, further confirmed through confocal laser scanning microscopy. We illustrated the antifungal activity of sophorolipid biosurfactant from Metschnikowia genus for the first time and suggested a novel antifungal compound against food spoilage and human fungal pathogen.
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Affiliation(s)
- Alka Kumari
- Microbial Type Culture Collection and Gene Bank (MTCC), CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Sumeeta Kumari
- Microbial Type Culture Collection and Gene Bank (MTCC), CSIR-Institute of Microbial Technology, Chandigarh, India
| | - G S Prasad
- Microbial Type Culture Collection and Gene Bank (MTCC), CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Anil Kumar Pinnaka
- Microbial Type Culture Collection and Gene Bank (MTCC), CSIR-Institute of Microbial Technology, Chandigarh, India
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Colda A, Bossaert S, Verreth C, Vanhoutte B, Honnay O, Keulemans W, Lievens B. Inoculation of pear flowers with Metschnikowia reukaufii and Acinetobacter nectaris enhances attraction of honeybees and hoverflies, but does not increase fruit and seed set. PLoS One 2021; 16:e0250203. [PMID: 33886638 PMCID: PMC8061982 DOI: 10.1371/journal.pone.0250203] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/02/2021] [Indexed: 11/28/2022] Open
Abstract
Currently, one of the most important challenges is to provide sufficient and affordable food and energy for a fast-growing world population, alongside preserving natural habitats and maintaining biodiversity. About 35% of the global food production depends on animals for pollination. In recent years, an alarming worldwide decline in pollinators has been reported, putting our food production under additional pressure. Therefore, there is an urgent need to find sustainable ways to ensure this crucial ecosystem service. Recent studies have shown that floral nectar is generally colonized by microorganisms, specifically yeasts and bacteria, which may alter nectar chemistry and enhance attraction of pollinators. In this study, we investigated changes in pollinator foraging behavior and pollination success in European pear (Pyrus communis L.) cultivars 'Regal Red' and 'Sweet Sensation' (red sports of 'Doyenné de Comice') after flower inoculation with the typical nectar-inhabiting microorganisms Metschnikowia reukaufii and Acinetobacter nectaris, and a combination of both. Pollination success was monitored by measuring the number of flower visits, fruit set and seed set in two consecutive years, 2019 and 2020. Results revealed that application of a mixture of M. reukaufii and A. nectaris resulted in significantly higher visitation rates of honeybees and hoverflies. By contrast, no effects on flower visits were found when yeasts and bacteria were applied separately. Fruit set and seed set were not significantly affected by any of the inoculation treatments. The only factors affecting fruit set were initial number of flower clusters on the trees and the year. The absence of treatment effects can most likely be attributed to the fact that pollination was not a limiting factor for fruit set in our experiments. Altogether, our results show that inoculation of flowers with nectar microbes can modify pollinator foraging patterns, but did not lead to increased pollination success under the conditions tested.
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Affiliation(s)
- Agneta Colda
- Division of Crop Biotechnics, Laboratory for Fruit Breeding and Biotechnology, Department of Biosystems, KU Leuven, Leuven, Belgium
| | - Sofie Bossaert
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Department of Microbial and Molecular Systems, Center of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Christel Verreth
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Department of Microbial and Molecular Systems, Center of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Bart Vanhoutte
- Research Center for Fruit Growing, Sint-Truiden, Belgium
| | - Olivier Honnay
- Division of Ecology, Evolution and Biodiversity Conservation, Department of Biology, Plant Conservation and Population Biology, KU Leuven, Leuven, Belgium
| | - Wannes Keulemans
- Division of Crop Biotechnics, Laboratory for Fruit Breeding and Biotechnology, Department of Biosystems, KU Leuven, Leuven, Belgium
| | - Bart Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Department of Microbial and Molecular Systems, Center of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
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7
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Warren ML, Kram KE, Theiss KE. Characterizing the nectar microbiome of the non-native tropical milkweed, Asclepias curassavica, in an urban environment. PLoS One 2020; 15:e0237561. [PMID: 32877468 PMCID: PMC7467256 DOI: 10.1371/journal.pone.0237561] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 07/29/2020] [Indexed: 11/19/2022] Open
Abstract
In increasingly urban landscapes, the loss of native pollen and nectar floral resources is impacting ecologically important pollinators. Increased urbanization has also brought about the rise of urban gardens which introduce new floral resources that may help replace those the pollinators have lost. Recently, studies have shown that the microbial communities of nectar may play an important role in plant-pollinator interactions, but these microbial communities and the floral visitors in urban environments are poorly studied. In this study we characterized the floral visitors and nectar microbial communities of Ascelpias curassavica, a non-native tropical milkweed commonly, in an urban environment. We found that the majority of the floral visitors to A. curassavica were honey bees followed closely by monarch butterflies. We also found that there were several unique visitors to each site, such as ants, wasps, solitary bees, several species of butterflies and moths, Anna’s hummingbird, and the tarantula hawk wasp. Significant differences in the nectar bacterial alpha and beta diversity were found across the urban sites, although we found no significant differences among the fungal communities. We found that the differences in the bacterial communities were more likely due to the environment and floral visitors rather than physiological differences in the plants growing at the gardens. Greater understanding of the impact of urbanization on the nectar microbiome of urban floral resources and consequently their effect on plant-pollinator relationships will help to predict how these relationships will change with urbanization, and how negative impacts can be mitigated through better management of the floral composition in urban gardens.
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Affiliation(s)
- Magdalena L. Warren
- Department of Biology, California State University Dominguez Hills, Carson, California, United States of America
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Karin E. Kram
- Department of Biology, California State University Dominguez Hills, Carson, California, United States of America
| | - Kathryn E. Theiss
- Department of Biology, California State University Dominguez Hills, Carson, California, United States of America
- * E-mail:
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Pimentão AR, Pascoal C, Castro BB, Cássio F. Fungistatic effect of agrochemical and pharmaceutical fungicides on non-target aquatic decomposers does not translate into decreased fungi- or invertebrate-mediated decomposition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 712:135676. [PMID: 31787296 DOI: 10.1016/j.scitotenv.2019.135676] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 11/19/2019] [Accepted: 11/19/2019] [Indexed: 06/10/2023]
Abstract
Leaf litter decomposition is a key ecological process in freshwater ecosystems. Fungi, particularly aquatic hyphomycetes, play a major role in organic matter turnover and constitute a pivotal node in detrital food webs. The extensive use of antifungal formulations, which include agrochemicals and pharmaceuticals, is a threat to biodiversity and may affect non-target microbial and invertebrate decomposer communities. Using a laboratory approach, we assessed the effects of tebuconazole (agrochemical), clotrimazole and terbinafine (pharmaceuticals) on aquatic communities and on the decomposition of plant litter. Alder leaves were colonized by natural microbiota in a clean stream, and then exposed in microcosms to 8 concentrations of each fungicide (10 to 1280 μg L-1). Fungicides led to shifts in species dominance in all tested concentrations, but no effects on leaf decomposition were observed. In addition, tebuconazole and clotrimazole strongly reduced fungal biomass and reproduction, whilst terbinafine stimulated fungal reproduction at lower concentrations but had no measurable effects on fungal biomass. Subsequently, the indirect effects of the fungicides were assessed on the next trophic level (detritivore invertebrates), by evaluating leaf consumption by a specialist (Allogamus sp.) and a generalist (Chironomus riparius) species, when feeding on fungicide-preconditioned leaves. The feeding activity of C. riparius and Allogamus sp. was not affected, and as expected, specialists were more efficient than generalists in exploring leaves as a dietary resource. However, results indicated that these fungicides have direct negative effects on microbial decomposers, and thus may compromise ecosystem functions on the long term.
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Affiliation(s)
- Ana Rita Pimentão
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Cláudia Pascoal
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Bruno B Castro
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Fernanda Cássio
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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9
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Bilska K, Stuper-Szablewska K, Kulik T, Buśko M, Załuski D, Jurczak S, Perkowski J. Changes in Phenylpropanoid and Trichothecene Production by Fusarium culmorum and F. graminearum Sensu Stricto via Exposure to Flavonoids. Toxins (Basel) 2018; 10:toxins10030110. [PMID: 29510600 PMCID: PMC5869398 DOI: 10.3390/toxins10030110] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/02/2018] [Accepted: 03/03/2018] [Indexed: 02/07/2023] Open
Abstract
Flavonoids are a group of hydroxylated polyphenolic compounds widely distributed in the plant kingdom. Biosynthesis of these compounds involves type III PKSs, whose presence has been recently predicted in some fungal species through genome sequencing efforts. In this study, for the first time it was found that Fusaria produce flavonoids on solid YES medium. Naringenin, as the central precursor of all flavonoids, was produced at highest quantities, followed by quercetin, kaempferol, apigenin and luteolin. In plants, flavonoids are involved in the protection of cereals to a wide range of stresses, including host defense against Fusaria. Under in vitro conditions, strains of Fusarium culmorum and F. graminearum sensu stricto were incubated at levels of flavonoids close to amounts produced by cereals in response to fungal infection. The amounts of exogenous naringenin, apigenin, luteolin, kaempferol and quercetin were reduced and converted by fungi to the other flavonoid derivatives. Treatment of fungi with naringenin derivatives led to the inhibition of naringenin production. Correspondingly, the production of fungal-derived phenolic acids decreased in flavonoid treated samples, although this effect appeared to be dependent on the strain, flavonoid molecule and its concentration. Fusaria showed high variability in trichothecene production in response to flavonoids. With emphasis on quercetin, mycotoxin accumulation in the media was significantly decreased by luteolin, kaempferol, naringenin and apigenin. However, in some cases, apigenin led to the increase of mycotoxin content in the media. Gene expression experiments of Tri genes responsible for trichothecene biosynthesis (Tri4, Tri5 and Tri10) proved that the inhibition of mycotoxin production by flavonoids occurred at the transcriptional level. However, the changes in Tri transcript levels were not significant in most apigenin and all kaempferol-treated cultures. In this study, a link was established between antioxidant and antiradical properties of flavonoids and their effects on fungi.
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Affiliation(s)
- Katarzyna Bilska
- Department of Microbiology and Mycology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719 Olsztyn, Poland.
| | - Kinga Stuper-Szablewska
- Department of Chemistry, Poznan University of Life Sciences, Wojska Polskiego 75, 60-637 Poznan, Poland.
| | - Tomasz Kulik
- Department of Microbiology and Mycology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719 Olsztyn, Poland.
| | - Maciej Buśko
- Department of Chemistry, Poznan University of Life Sciences, Wojska Polskiego 75, 60-637 Poznan, Poland.
| | - Dariusz Załuski
- Department of Plant Breeding and Seed Production, University of Warmia and Mazury in Olsztyn, Plac Łódzki 3, 10-727 Olsztyn, Poland.
| | - Sebastian Jurczak
- Department of Microbiology and Mycology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719 Olsztyn, Poland.
| | - Juliusz Perkowski
- Department of Chemistry, Poznan University of Life Sciences, Wojska Polskiego 75, 60-637 Poznan, Poland.
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10
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Kang YM, Choi JE, Komakech R, Park JH, Kim DW, Cho KM, Kang SM, Choi SH, Song KC, Ryu CM, Lee KC, Lee JS. Characterization of a novel yeast species Metschnikowia persimmonesis KCTC 12991BP (KIOM G15050 type strain) isolated from a medicinal plant, Korean persimmon calyx (Diospyros kaki Thumb). AMB Express 2017; 7:199. [PMID: 29127501 PMCID: PMC5681456 DOI: 10.1186/s13568-017-0503-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 11/01/2017] [Indexed: 01/17/2023] Open
Abstract
The yeast strain Metschnikowia persimmonesis Kang and Choi et al., sp. nov. [type strain KIOM_G15050 = Korean Collection for Type Cultures (KCTC) 12991BP] was isolated from the stalk of native persimmon cultivars (Diospyros kaki Thumb) obtained from different regions of South Korea and was characterized phenotypically, genetically, and physiologically. The isolate grew between 4 and 40 °C (optimum temperature: 24–28 °C), pH 3–8 (pH optimum = 6.0), and in 0–4% NaCl solution (with optimal growth in absence of NaCl). It also exhibited strong antibiotic and antimicrobial activities. Morphologically, cells were characterized by the presence of long, needle-shaped ascospores. Based on 18S ribosomal DNA gene sequence analysis, the new species was found to belong to the genus Metschnikowia as a sister clade of Metschnikowia fructicola. We therefore conclude that this yeast isolate from D. kaki is a new member of the genus Metschnikowia and propose the name M. persimmonesis sp. nov. This strain has been deposited in the KCTC for future reference. This discovery provides a basis for future research on M. persimmonesis sp. nov., including its possible contribution to the medicinal properties of the host persimmon plant.
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11
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Schaeffer RN, Vannette RL, Brittain C, Williams NM, Fukami T. Non-target effects of fungicides on nectar-inhabiting fungi of almond flowers. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:79-84. [PMID: 27888579 DOI: 10.1111/1758-2229.12501] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 11/16/2016] [Indexed: 05/27/2023]
Abstract
Nectar mediates interactions between plants and pollinators in natural and agricultural systems. Specialized microorganisms are common nectar inhabitants, and potentially important mediators of plant-pollinator interactions. However, their diversity and role in mediating pollination services in agricultural systems are poorly characterized. Moreover, agrochemicals are commonly applied to minimize crop damage, but may present ecological consequences for non-target organisms. Assessment of ecological risk has tended to focus on beneficial macroorganisms such as pollinators, with less attention paid to microorganisms. Here, using culture-independent methods, we assess the impact of two widely-used fungicides on nectar microbial community structure in the mass-flowering crop almond (Prunus dulcis). We predicted that fungicide application would reduce fungal richness and diversity, whereas competing bacterial richness would increase, benefitting from negative effects on fungi. We found that fungicides reduced fungal richness and diversity in exposed flowers, but did not significantly affect bacterial richness, diversity, or community composition. The relative abundance of Metschnikowia OTUs, nectar specialists that can impact pollination, was reduced by both fungicides. Given growing recognition of the importance of nectar microorganisms as mediators of plant-pollinator mutualisms, future research should consider the impact of management practices on plant-associated microorganisms and consequences for pollination services in agricultural landscapes.
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Affiliation(s)
- Robert N Schaeffer
- Department of Entomology, Washington State University, Pullman, WA, 99164, USA
| | - Rachel L Vannette
- Department of Entomology and Nematology, University of California, Davis, Davis, CA, 95616, USA
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Claire Brittain
- Department of Entomology and Nematology, University of California, Davis, Davis, CA, 95616, USA
| | - Neal M Williams
- Department of Entomology and Nematology, University of California, Davis, Davis, CA, 95616, USA
| | - Tadashi Fukami
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
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Cuco AP, Abrantes N, Gonçalves F, Wolinska J, Castro BB. Interplay between fungicides and parasites: Tebuconazole, but not copper, suppresses infection in a Daphnia-Metschnikowia experimental model. PLoS One 2017; 12:e0172589. [PMID: 28231278 PMCID: PMC5322920 DOI: 10.1371/journal.pone.0172589] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 02/07/2017] [Indexed: 11/23/2022] Open
Abstract
Natural populations are commonly exposed to complex stress scenarios, including anthropogenic contamination and their biological enemies (e.g., parasites). The study of the pollutant-parasite interplay is especially important, given the need for adequate regulations to promote improved ecosystem protection. In this study, a host-parasite model system (Daphnia spp. and the microparasitic yeast Metschnikowia bicuspidata) was used to explore the reciprocal effects of contamination by common agrochemical fungicides (copper sulphate and tebuconazole) and parasite challenge. We conducted 21-day life history experiments with two host clones exposed to copper (0.00, 25.0, 28.8 and 33.1 μg L-1) or tebuconazole (0.00, 154, 192 and 240 μg L-1), in the absence or presence of the parasite. For each contaminant, the experimental design consisted of 2 Daphnia clones × 4 contaminant concentrations × 2 parasite treatments × 20 replicates = 320 experimental units. Copper and tebuconazole decreased Daphnia survival or reproduction, respectively, whilst the parasite strongly reduced host survival. Most importantly, while copper and parasite effects were mostly independent, tebuconazole suppressed infection. In a follow-up experiment, we tested the effect of a lower range of tebuconazole concentrations (0.00, 6.25, 12.5, 25.0, 50.0 and 100 μg L-1) crossed with increasing parasite challenge (2 Daphnia clones × 6 contaminant concentrations × 2 parasite levels × 20 replicates = 480 experimental units). Suppression of infection was confirmed at environmentally relevant concentrations (> 6.25 μg L-1), irrespective of the numbers of parasite challenge. The ecological consequences of such a suppression of infection include interferences in host population dynamics and diversity, as well as community structure and energy flow across the food web, which could upscale to ecosystem level given the important role of parasites.
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Affiliation(s)
- Ana P. Cuco
- Department of Biology, University of Aveiro, Aveiro, Portugal
- Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Aveiro, Portugal
| | - Nelson Abrantes
- Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Aveiro, Portugal
- Department of Environment and Planning, University of Aveiro, Aveiro, Portugal
| | - Fernando Gonçalves
- Department of Biology, University of Aveiro, Aveiro, Portugal
- Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Aveiro, Portugal
| | - Justyna Wolinska
- Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität Berlin, Berlin, Germany
| | - Bruno B. Castro
- Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Aveiro, Portugal
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal
- * E-mail:
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13
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Bartlewicz J, Pozo MI, Honnay O, Lievens B, Jacquemyn H. Effects of agricultural fungicides on microorganisms associated with floral nectar: susceptibility assays and field experiments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:19776-19786. [PMID: 27411538 DOI: 10.1007/s11356-016-7181-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 07/04/2016] [Indexed: 06/06/2023]
Abstract
Pesticides have become an inseparable element of agricultural intensification. While the direct impact of pesticides on non-target organisms, such as pollinators, has recently received much attention, less consideration has been given to the microorganisms that are associated with them. Specialist yeasts and bacteria are known to commonly inhabit floral nectar and change its chemical characteristics in numerous ways, possibly influencing pollinator attraction. In this study, we investigated the in vitro susceptibility of nectar yeasts Metschnikowia gruessi, Metschnikowia reukaufii, and Candida bombi to six widely used agricultural fungicides (prothioconazole, tebuconazole, azoxystrobin, fenamidone, boscalid, and fluopyram). Next, a commercial antifungal mixture containing tebuconazole and trifloxystrobin was applied to natural populations of the plant Linaria vulgaris and the occurrence, abundance, and diversity of nectar-inhabiting yeasts and bacteria was compared between treated and untreated plants. The results showed that prothioconazole and tebuconazole were highly toxic to nectar yeasts, inhibiting their growth at concentrations varying between 0.06 and 0.5 mg/L. Azoxystrobin, fenamidone, boscalid, and fluopyram on the other hand exhibited considerably lower toxicity, inhibiting yeast growth at concentrations between 1 and 32 mg/L or in many cases not inhibiting microbial growth at all. The application of the antifungal mixture in natural plant populations resulted in a significant decrease in the occurrence and abundance of yeasts in individual flowers, but this did not translate into noticeable changes in bacterial incidence and abundance. Yeast and bacterial species richness and distribution did not also differ between treated and untreated plants. We conclude that the application of fungicides may have negative effects on the abundance of nectar yeasts in floral nectar. The consequences of these effects on plant pollination processes in agricultural systems warrant further investigation.
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Affiliation(s)
- Jacek Bartlewicz
- Biology Department, Plant Conservation and Population Biology, KU Leuven, Kasteelpark Arenberg 31, B-3001, Heverlee, Belgium.
| | - María I Pozo
- Biology Department, Plant Conservation and Population Biology, KU Leuven, Kasteelpark Arenberg 31, B-3001, Heverlee, Belgium
| | - Olivier Honnay
- Biology Department, Plant Conservation and Population Biology, KU Leuven, Kasteelpark Arenberg 31, B-3001, Heverlee, Belgium
| | - Bart Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, Fortsesteenweg 30A, B-2860, Sint-Katelijne Waver, Belgium
| | - Hans Jacquemyn
- Biology Department, Plant Conservation and Population Biology, KU Leuven, Kasteelpark Arenberg 31, B-3001, Heverlee, Belgium
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