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Biosynthesis of 2-Heptanone, a Volatile Organic Compound with a Protective Role against Honey Bee Pathogens, by Hive Associated Bacteria. Microorganisms 2021; 9:microorganisms9112218. [PMID: 34835345 PMCID: PMC8624620 DOI: 10.3390/microorganisms9112218] [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: 10/01/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 11/18/2022] Open
Abstract
Beehives are populated by bacterial species with a protective role against honey bee pathogens thanks to the production of bioactive metabolites. These compounds are largely unexploited despite their high potential interest for pest management. This study evaluated the capability of bacterial species associated with honey bees to produce 2-heptanone, a volatile organic compound with anesthetic properties of the parasitic mite Varroa destructor. The production of this compound was quantified by SPME-GC-MS in a culture filtrate of nine bacterial strains isolated from the surface of honey bees, and the biosynthetic potential was evaluated in bacterial species associated with apiaries by searching for protein homologs putatively involved in its biosynthesis by using biocomputational tools. The findings pointed out that 2-heptanone was produced by Acetobacteraceae bacterium, Bacillus thuringiensis and Apilactobacillus kunkeei isolates in concentrations between 1.5 and 2.6 ng/mL and that its production was strain-specific. Putative methylketone synthase homologs were found in Bacillus, Gilliamella, Acetobacteraceae, Bartonella and Lactobacillaceae, and the protein sequence results were distributed in nine Sequence Similarity Network (SSN) clusters. These preliminary results support the hypothesis that 2-heptanone may act as a mediator of microbial relationships in hives and provide contributions to assess the role and biosynthetic potential of 2-heptanone in apiaries.
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52
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Crowley B, Russell A. Plant biology: Nectar bacteria grow by germinating and bursting pollen. Curr Biol 2021; 31:R1120-R1122. [PMID: 34637711 DOI: 10.1016/j.cub.2021.08.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Microbial residents of floral nectar must survive in a carbohydrate-rich yet seemingly nitrogen-poor environment. A new study shows that Acinetobacter spp., common nectar-inhabiting bacteria, differentially induce the pollen commonly found in nectar to germinate and burst, releasing nutrients for microbial growth.
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Affiliation(s)
- Bailey Crowley
- Department of Biology, Utah State University, Logan, UT 84322, USA
| | - Avery Russell
- Department of Biology, Missouri State University, Springfield, MO 65897, USA.
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53
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O'Brien AM, Ginnan NA, Rebolleda-Gómez M, Wagner MR. Microbial effects on plant phenology and fitness. AMERICAN JOURNAL OF BOTANY 2021; 108:1824-1837. [PMID: 34655479 DOI: 10.1002/ajb2.1743] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 07/07/2021] [Indexed: 06/13/2023]
Abstract
Plant development and the timing of developmental events (phenology) are tightly coupled with plant fitness. A variety of internal and external factors determine the timing and fitness consequences of these life-history transitions. Microbes interact with plants throughout their life history and impact host phenology. This review summarizes current mechanistic and theoretical knowledge surrounding microbe-driven changes in plant phenology. Overall, there are examples of microbes impacting every phenological transition. While most studies have focused on flowering time, microbial effects remain important for host survival and fitness across all phenological phases. Microbe-mediated changes in nutrient acquisition and phytohormone signaling can release plants from stressful conditions and alter plant stress responses inducing shifts in developmental events. The frequency and direction of phenological effects appear to be partly determined by the lifestyle and the underlying nature of a plant-microbe interaction (i.e., mutualistic or pathogenic), in addition to the taxonomic group of the microbe (fungi vs. bacteria). Finally, we highlight biases, gaps in knowledge, and future directions. This biotic source of plasticity for plant adaptation will serve an important role in sustaining plant biodiversity and managing agriculture under the pressures of climate change.
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Affiliation(s)
- Anna M O'Brien
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Nichole A Ginnan
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA
| | - María Rebolleda-Gómez
- Department of Ecology and Evolutionary Biology, University of California-Irvine, Irvine, CA, USA
| | - Maggie R Wagner
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA
- Kansas Biological Survey and Center for Ecological Research, University of Kansas, Lawrence, KS, USA
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54
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Zea mays Volatiles that Influence Oviposition and Feeding Behaviors of Spodoptera frugiperda. J Chem Ecol 2021; 47:799-809. [PMID: 34347233 DOI: 10.1007/s10886-021-01302-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/22/2021] [Accepted: 07/25/2021] [Indexed: 10/20/2022]
Abstract
Fall armyworm (Spodoptera frugiperda) is a major global pest of many crops, including maize (Zea mays). This insect is known to use host plant-derived volatile organic compounds to locate suitable hosts during both its adult and larval stages, yet the function of individual compounds remains mostly enigmatic. In this study, we use a combination of volatile profiling, electrophysiological assays, pair-wise choice behavioral assays, and chemical supplementation treatments to identify and assess specific compounds from maize that influence S. frugiperda host location. Our findings reveal that methyl salicylate and (E)-alpha-bergamotene are oviposition attractants for adult moths but do not impact larval behavior. While geranyl acetate can act as an oviposition attractant or repellent depending on the host volatile context and (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) is an oviposition deterrent. These compounds can also be attractive to the larvae when applied to specific maize inbreds. These data show that S. frugiperda uses different plant volatile cues for host location in its adult and larval stage and that the background volatile context that specific volatiles are perceived in, alters their impact as behavioral cues.
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55
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Christensen SM, Munkres I, Vannette RL. Nectar bacteria stimulate pollen germination and bursting to enhance microbial fitness. Curr Biol 2021; 31:4373-4380.e6. [PMID: 34324834 DOI: 10.1016/j.cub.2021.07.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/27/2021] [Accepted: 07/08/2021] [Indexed: 12/27/2022]
Abstract
Many organisms consume pollen, yet mechanisms of its digestion remain a fundamental enigma in pollination biology,1-3 as pollen is protected by a recalcitrant outer shell.4-8 Pollen is commonly found in floral nectar,9,10 as are nectar microbes, which are nearly ubiquitous among flowers.11-13 Nectar specialist bacteria, like Acinetobacter, can reach high densities (up to 109 cells/mL), despite the fact that floral nectar is nitrogen poor.14-17 Here, we show evidence that the genus Acinetobacter, prevalent nectar- and bee-associated bacteria,12,18-20 can induce pollen germination and bursting, gain access to protoplasm nutrients, and thereby grow to higher densities. Although induced germination had been suggested as a potential method in macroscopic pollen consumers,2,21-23 and fungal inhibition of pollen germination has been shown,24-27 direct biological induction of germination has not been empirically documented outside of plants.28-32Acinetobacter pollinis SCC47719 induced over 5× greater pollen germination and 20× greater pollen bursting than that of uninoculated pollen by 45 min. When provided with germinable pollen, A. pollinis stimulates protein release and grows to nearly twice the density compared to growth with ungerminable pollen, indicating that stimulation of germination benefits bacterial fitness. In contrast, a common nectar-inhabiting yeast (Metschnikowia)33 neither induced nor benefited from pollen germination. We conclude that Acinetobacter both specifically causes and benefits from inducing pollen germination and bursting. Further study of microbe-pollen interactions may inform many aspects of pollination ecology, including floral microbial ecology,34,35 pollinator nutrient acquisition from pollen,2,3,21,36 and cues of pollen germination for plant reproduction.37-39.
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Affiliation(s)
- Shawn M Christensen
- Department of Entomology and Nematology, University of California Davis, Davis, CA, USA.
| | - Ivan Munkres
- Department of Entomology and Nematology, University of California Davis, Davis, CA, USA
| | - Rachel L Vannette
- Department of Entomology and Nematology, University of California Davis, Davis, CA, USA
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56
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Junker RR, Eisenhauer N, Schmidt A, Türke M. Invertebrate decline reduces bacterial diversity associated with leaves and flowers. FEMS Microbiol Ecol 2021; 97:6307018. [PMID: 34151344 DOI: 10.1093/femsec/fiab088] [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: 04/27/2021] [Accepted: 06/17/2021] [Indexed: 11/14/2022] Open
Abstract
Defaunation including invertebrate decline is one of the major consequences of anthropogenic alterations of the environment. Despite recent reports of ubiquitous invertebrate decline, the ecosystem consequences have been rarely documented. We exposed standardized plant communities grown in the iDiv Ecotron to different levels of invertebrate numbers and biomass and tracked effects on the diversity and composition of bacterial communities associated with flowers and leaves of Scorzoneroides autumnalis and Trifolium pratense using next-generation 16S rRNA gene amplicon sequencing. Our data indicate that invertebrate decline reduces bacterial richness and β-diversity and alters community composition. These effects may result from direct effects of invertebrates that may serve as dispersal agents of bacteria; or from indirect effects where animal-induced changes in the plant's phenotype shape the niches plants provide for bacterial colonizers. Because bacteria are usually not dispersal limited and because species sorting, i.e. niche-based processes, has been shown to be a dominant process in bacterial community assembly, indirect effects may be more likely. Given that a healthy microbiome is of fundamental importance for the well-being of plants, animals (including humans) and ecosystems, a loss of bacterial diversity may be a dramatic yet previously unknown consequence of current invertebrate decline.
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Affiliation(s)
- Robert R Junker
- Evolutionary Ecology of Plants, Department of Biology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35043 Marburg, Germany.,Department of Biosciences, University Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria
| | - Nico Eisenhauer
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstr. 4, 04103 Leipzig, Germany.,Institute of Biology, Leipzig University, Puschstr. 4, 04103 Leipzig, Germany
| | - Anja Schmidt
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstr. 4, 04103 Leipzig, Germany.,Institute of Biology, Leipzig University, Puschstr. 4, 04103 Leipzig, Germany.,Helmholtz Centre for Environmental Research - UFZ, Department of Community Ecology, Theodor-Lieser-Str. 4, 06120 Halle, Germany
| | - Manfred Türke
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstr. 4, 04103 Leipzig, Germany.,Institute of Biology, Leipzig University, Puschstr. 4, 04103 Leipzig, Germany
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57
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Rering CC, Rudolph AB, Beck JJ. Pollen and yeast change nectar aroma and nutritional content alone and together, but honey bee foraging reflects only the avoidance of yeast. Environ Microbiol 2021; 23:4141-4150. [PMID: 33876542 DOI: 10.1111/1462-2920.15528] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 04/12/2021] [Indexed: 11/28/2022]
Abstract
Floral nectar often contains pollen and microorganisms, which may change nectar's chemical composition, and in turn impact pollinator affinity. However, their individual and combined effects remain understudied. Here, we examined the impacts of the nectar specialist yeast, Metschnikowia reukaufii, and the addition of sunflower (Hellianthus annus) pollen. Pollen grains remained intact, yet still increased yeast growth and amino acid concentrations in nectar, whereas yeast depleted amino acids. Pollen, but not yeast, changed nectar sugar concentrations by converting sucrose to its monomers. Both pollen and yeast contributed emissions from nectar, though yeast volatiles were more abundant than pollen volatiles. Yeast volatile emission was positively correlated with pollen concentration and cell density, and yeast depleted a subset of pollen-derived volatiles. Honey bees avoided foraging on yeast-inoculated nectar and foraged equally among uninoculated nectars regardless of pollen content, underscoring the importance of microbial metabolites in mediating pollinator foraging.
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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, Gainesville, FL, 32608, USA
| | - Arthur B Rudolph
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, Gainesville, FL, 32608, USA
| | - John J Beck
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, Gainesville, FL, 32608, USA
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58
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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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59
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Francis JS, Tatarko AR, Richman SK, Vaudo AD, Leonard AS. Microbes and pollinator behavior in the floral marketplace. CURRENT OPINION IN INSECT SCIENCE 2021; 44:16-22. [PMID: 33075580 DOI: 10.1016/j.cois.2020.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
Pollinator foraging decisions shape microbial dispersal, and microbes change floral phenotypes in ways perceivable by pollinators. Yet, the role microbes play in the cognitive ecology of pollination is relatively unexplored. Reviewing recent literature on floral microbial ecology and pollinator behavior, we advocate for further integration between these two fields. Insights into pollinator learning, memory, and decision-making can help explain their responses to microbially-altered floral phenotypes. Specifically, considering how pollinators forage for multiple nutrients, cope with uncertainty, structure foraging bouts, and move through their environment could inform predictions about microbial dispersal within plant communities. We highlight how behavior connects microbial changes in floral phenotype to downstream effects on both microbial dispersal and plant fitness.
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Affiliation(s)
- Jacob S Francis
- Ecology, Evolution and Conservation Biology Graduate Program, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, United States
| | - Anna R Tatarko
- Ecology, Evolution and Conservation Biology Graduate Program, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, United States
| | - Sarah K Richman
- Department of Biology, MS-314, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, United States
| | - Anthony D Vaudo
- Department of Biology, MS-314, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, United States
| | - Anne S Leonard
- Department of Biology, MS-314, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, United States.
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60
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Crowley-Gall A, Rering CC, Rudolph AB, Vannette RL, Beck JJ. Volatile microbial semiochemicals and insect perception at flowers. CURRENT OPINION IN INSECT SCIENCE 2021; 44:23-34. [PMID: 33096275 DOI: 10.1016/j.cois.2020.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/06/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
Many plant-associated microbial communities produce volatile signals that influence insect responses, yet the impact of floral microorganisms has received less attention than other plant microbiomes. Floral microorganisms alter plant and floral odors by adding their own emissions or modifying plant volatiles. These contextual and microbe species-specific changes in floral signaling are detectable by insects and can modify their behavior. Opportunities for future work in floral systems include identifying specific microbial semiochemicals that underlie insect behavioral responses and examining if insect species vary in their responses to microbial volatiles. Examining if documented patterns are consistent across diverse plant-microbe-insect interactions and in realistic plant-based studies will improve our understanding of how microbes mediate pollination interactions in complex system.
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Affiliation(s)
- Amber Crowley-Gall
- Department of Entomology and Nematology, University of California Davis, 43 Briggs Hall, Davis, CA 95616, USA.
| | - Caitlin C Rering
- Chemistry Research Unit, Center for Medical, Agricultural, and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, Gainesville, FL 32608, USA
| | - Arthur B Rudolph
- Chemistry Research Unit, Center for Medical, Agricultural, and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, Gainesville, FL 32608, USA
| | - Rachel L Vannette
- Department of Entomology and Nematology, University of California Davis, 43 Briggs Hall, Davis, CA 95616, USA
| | - John J Beck
- Chemistry Research Unit, Center for Medical, Agricultural, and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, Gainesville, FL 32608, USA
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61
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Adler LS, Irwin RE, McArt SH, Vannette RL. Floral traits affecting the transmission of beneficial and pathogenic pollinator-associated microbes. CURRENT OPINION IN INSECT SCIENCE 2021; 44:1-7. [PMID: 32866657 PMCID: PMC7914268 DOI: 10.1016/j.cois.2020.08.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 05/22/2023]
Abstract
Flowers provide resources for pollinators, and can also be transmission venues for beneficial or pathogenic pollinator-associated microbes. Floral traits could mediate transmission similarly for beneficial and pathogenic microbes, although some beneficial microbes can grow in flowers while pathogenic microbes may only survive until acquired by a new host. In spite of conceptual similarities, research on beneficial and pathogenic pollinator-associated microbes has progressed mostly independently. Recent advances demonstrate that floral traits are associated with transmission of beneficial and pathogenic microbes, with consequences for pollinator populations and communities. However, there is a near-absence of experimental manipulations of floral traits to determine causal effects on transmission, and a need to understand how floral, microbe and host traits interact to mediate transmission.
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Affiliation(s)
- Lynn S Adler
- Department of Biology, University of Massachusetts, 221 Morrill Science Center, 611 N. Pleasant St., Amherst MA 01002 USA.
| | - Rebecca E Irwin
- Department of Applied Ecology, North Carolina State University, 127 David Clark Labs, 100 Eugene Brooks Ave., Raleigh, NC 27695 USA
| | - Scott H McArt
- Department of Entomology, Cornell University, 4132 Comstock Hall, 129 Garden Ave., Ithaca, NY 14853 USA
| | - Rachel L Vannette
- Department of Entomology and Nematology, University of California, 43 Briggs Hall, Davis CA 95616 USA
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62
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Jacquemyn H, Pozo MI, Álvarez-Pérez S, Lievens B, Fukami T. Yeast-nectar interactions: metacommunities and effects on pollinators. CURRENT OPINION IN INSECT SCIENCE 2021; 44:35-40. [PMID: 33065340 DOI: 10.1016/j.cois.2020.09.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/21/2020] [Accepted: 09/29/2020] [Indexed: 06/11/2023]
Abstract
About 90% of all flowering plant species are pollinated by animals. Animals are attracted to flowers because they often provide food in the form of nectar and pollen. While floral nectar is assumed to be initially sterile, it commonly becomes colonized by yeasts after animals have visited the flowers. Although yeast communities in floral nectar appear simple, community assembly depends on a complex interaction between multiple factors. Yeast colonization has a significant effect on the scent of floral nectar, foraging behavior of insects and nectar consumption. Consumption of nectar colonized by yeasts has been shown to improve bee fitness, but effects largely depended on yeast species. Altogether, these results indicate that dispersal, colonization history and nectar chemistry strongly interact and have pronounced effects on yeast metacommunities and, as a result, on bee foraging behavior and fitness. Future research directions to better understand the dynamics of plant-microbe-pollinator interactions are discussed.
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Affiliation(s)
- Hans Jacquemyn
- Laboratory of Plant Conservation and Population Biology, Biology Department, KU Leuven, B-3001 Leuven, Belgium
| | - María I Pozo
- Laboratory of Plant Conservation and Population Biology, Biology Department, KU Leuven, B-3001 Leuven, Belgium
| | - Sergio Álvarez-Pérez
- Department of Animal Health, Complutense University of Madrid, 28040 Madrid, Spain
| | - Bart Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems, KU Leuven, B-3001 Leuven, Belgium.
| | - Tadashi Fukami
- Department of Biology, Stanford University, 94305 Stanford, CA, USA
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63
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Schmitt A, Roy R, Carter CJ. Nectar antimicrobial compounds and their potential effects on pollinators. CURRENT OPINION IN INSECT SCIENCE 2021; 44:55-63. [PMID: 33771735 DOI: 10.1016/j.cois.2021.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/24/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
Nectar is a sugary, aqueous solution that plants offer as a reward to animal mutualists for visitation. Since nectars are so nutrient-rich, they often harbor significant microbial communities, which can be pathogenic, benign, or even sometimes beneficial to plant fitness. Through recent advances, it is now clear that these microbes alter nectar chemistry, which in turn influences mutualist behavior (e.g. pollinator visitation). To counteract unwanted microbial growth, nectars often contain antimicrobial compounds, especially in the form of proteins, specialized (secondary) metabolites, and metals. This review covers our current understanding of nectar antimicrobials, as well as their interplay with both microbes and insect visitors.
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Affiliation(s)
- Anthony Schmitt
- Department of Plant & Microbial Biology, University of Minnesota, 1479 Gortner Ave, St. Paul, MN 55108, USA
| | - Rahul Roy
- Biology Department, St. Catherine University, 2004 Randolph Ave, St. Paul, MN 55105, USA
| | - Clay J Carter
- Department of Plant & Microbial Biology, University of Minnesota, 1479 Gortner Ave, St. Paul, MN 55108, USA.
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64
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Keller A, McFrederick QS, Dharampal P, Steffan S, Danforth BN, Leonhardt SD. (More than) Hitchhikers through the network: the shared microbiome of bees and flowers. CURRENT OPINION IN INSECT SCIENCE 2021; 44:8-15. [PMID: 32992041 DOI: 10.1016/j.cois.2020.09.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/04/2020] [Accepted: 09/16/2020] [Indexed: 05/11/2023]
Abstract
Growing evidence reveals strong overlap between microbiomes of flowers and bees, suggesting that flowers are hubs of microbial transmission. Whether floral transmission is the main driver of bee microbiome assembly, and whether functional importance of florally sourced microbes shapes bee foraging decisions are intriguing questions that remain unanswered. We suggest that interaction network properties, such as nestedness, connectedness, and modularity, as well as specialization patterns can predict potential transmission routes of microbes between hosts. Yet microbial filtering by plant and bee hosts determines realized microbial niches. Functionally, shared floral microbes can provide benefits for bees by enhancing nutritional quality, detoxification, and disintegration of pollen. Flower microbes can also alter the attractiveness of floral resources. Together, these mechanisms may affect the structure of the flower-bee interaction network.
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Affiliation(s)
- Alexander Keller
- Department of Bioinformatics, Biocenter, University of Würzburg, 97074, Würzburg, Germany; Center for Computational and Theoretical Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany.
| | - Quinn S McFrederick
- Department of Entomology, University of California, Riverside, Riverside, CA 92501, USA
| | - Prarthana Dharampal
- Department of Entomology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Shawn Steffan
- Department of Entomology, University of Wisconsin-Madison, Madison, WI 53706, USA; USDA-ARS, Vegetable Crops Research Unit, Madison, Wisconsin, USA
| | - Bryan N Danforth
- Department of Entomology, Cornell University, Ithaca, NY 14850, USA
| | - Sara D Leonhardt
- Department of Life Science Systems, School of Life Sciences, Technical University of Munich, 85354 Freising, Germany
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Pileggi MT, Chase JR, Shu R, Teng L, Jeong KC, Kaufman PE, Wong ACN. Prevalence of Field-Collected House Flies and Stable Flies With Bacteria Displaying Cefotaxime and Multidrug Resistance. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:921-928. [PMID: 33210705 DOI: 10.1093/jme/tjaa241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Indexed: 06/11/2023]
Abstract
Antibiotic use in livestock accounts for 80% of total antibiotic use in the United States and has been described as the driver for resistance evolution and spread. As clinical infections with multidrug-resistant pathogens are rapidly rising, there remains a missing link between agricultural antibiotic use and its impact on human health. In this study, two species of filth flies from a livestock operation were collected over the course of 11 mo: house flies Musca domestica (L.) (Diptera: Muscidae), representing a generalist feeder, and stable flies Stomoxys calcitrans (L.) (Diptera: Muscidae), representing a specialist (blood) feeder. The prevalence of flies carrying cefotaxime-resistant (CTX-R) bacteria in whole bodies and dissected guts were assayed by culturing on antibiotic-selective media, with distinct colonies identified by Sanger sequencing. Of the 149 flies processed, including 81 house flies and 68 stable flies, 18 isolates of 12 unique bacterial species resistant to high-level cefotaxime were recovered. These isolates also showed resistance to multiple classes of antibiotics. The CTX-R isolates were predominantly recovered from female flies, which bore at least two resistant bacterial species. The majority of resistant bacteria were isolated from the guts encompassing both enteric pathogens and commensals, sharing no overlap between the two fly species. Together, we conclude that house flies and stable flies in the field could harbor multidrug-resistant bacteria. The fly gut may serve as a reservoir for the acquisition and dissemination of resistance genes.
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Affiliation(s)
- Matthew T Pileggi
- Entomology and Nematology Department, University of Florida, Gainesville, FL
| | - John R Chase
- Entomology and Nematology Department, University of Florida, Gainesville, FL
| | - Runhang Shu
- Entomology and Nematology Department, University of Florida, Gainesville, FL
| | - Lin Teng
- Emerging Pathogens Institute, University of Florida, Gainesville, FL
- Department of Animal Sciences, University of Florida, Gainesville, FL
| | - Kwangcheol C Jeong
- Emerging Pathogens Institute, University of Florida, Gainesville, FL
- Department of Animal Sciences, University of Florida, Gainesville, FL
| | - Phillip E Kaufman
- Entomology and Nematology Department, University of Florida, Gainesville, FL
| | - Adam C N Wong
- Entomology and Nematology Department, University of Florida, Gainesville, FL
- Genetics Institute, University of Florida, Gainesville, FL
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66
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Evolutionary and Ecological Considerations on Nectar-Mediated Tripartite Interactions in Angiosperms and Their Relevance in the Mediterranean Basin. PLANTS 2021; 10:plants10030507. [PMID: 33803275 PMCID: PMC7999006 DOI: 10.3390/plants10030507] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/22/2021] [Accepted: 03/03/2021] [Indexed: 11/16/2022]
Abstract
The Mediterranean basin hosts a high diversity of plants and bees, and it is considered one of the world's biodiversity hotspots. Insect pollination, i.e., pollen transfer from male reproductive structures to conspecific female ones, was classically thought to be a mutualistic relationship that links these two groups of organisms, giving rise to an admirable and complex network of interactions. Although nectar is often involved in mediating these interactions, relatively little is known about modifications in its chemical traits during the evolution of plants. Here, we examine how the current sucrose-dominated floral nectar of most Mediterranean plants could have arisen in the course of evolution of angiosperms. The transition from hexose-rich to sucrose-rich nectar secretion was probably triggered by increasing temperature and aridity during the Cretaceous period, when most angiosperms were radiating. This transition may have opened new ecological niches for new groups of insects that were co-diversifying with angiosperms and for specific nectar-dwelling yeasts that originated later (i.e., Metschnikowiaceae). Our hypothesis embeds recent discoveries in nectar biology, such as the involvement of nectar microbiota and nectar secondary metabolites in shaping interactions with pollinators, and it suggests a complex, multifaceted ecological and evolutionary scenario that we are just beginning to discover.
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67
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Zemenick AT, Vanette RL, Rosenheim JA. Linked networks reveal dual roles of insect dispersal and species sorting for bacterial communities in flowers. OIKOS 2021. [DOI: 10.1111/oik.06818] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Ash T. Zemenick
- Dept of Entomology and Nematology, Univ. of California, Davis Davis CA USA
- Dept of Plant Biology, Michigan State Univ. East Lansing MI USA
| | - Rachel L. Vanette
- Dept of Entomology and Nematology, Univ. of California, Davis Davis CA USA
| | - Jay A. Rosenheim
- Dept of Entomology and Nematology, Univ. of California, Davis Davis CA USA
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68
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Peach DAH, Carroll C, Meraj S, Gomes S, Galloway E, Balcita A, Coatsworth H, Young N, Uriel Y, Gries R, Lowenberger C, Moore M, Gries G. Nectar-dwelling microbes of common tansy are attractive to its mosquito pollinator, Culex pipiens L. BMC Ecol Evol 2021; 21:29. [PMID: 33593286 PMCID: PMC7885224 DOI: 10.1186/s12862-021-01761-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/08/2021] [Indexed: 11/14/2022] Open
Abstract
Background There is widespread interkingdom signalling between insects and microbes. For example, microbes found in floral nectar may modify its nutritional composition and produce odorants that alter the floral odor bouquet which may attract insect pollinators. Mosquitoes consume nectar and can pollinate flowers. We identified microbes isolated from nectar of common tansy, Tanacetum vulgare, elucidated the microbial odorants, and tested their ability to attract the common house mosquito, Culex pipiens. Results We collected 19 microbial isolates from T. vulgare nectar, representing at least 12 different taxa which we identified with 16S or 26S rDNA sequencing as well as by biochemical and physiological tests. Three microorganisms (Lachancea thermotolerans, Micrococcus lactis, Micrococcus luteus) were grown on culture medium and tested in bioassays. Only the yeast L. thermotolerans grown on nectar, malt extract agar, or in synthetic nectar broth significantly attracted Cx. pipiens females. The odorant profile produced by L. thermotolerans varied with the nutritional composition of the culture medium. All three microbes grown separately, but presented concurrently, attracted fewer Cx. pipiens females than L. thermotolerans by itself. Conclusions Floral nectar of T. vulgare contains various microbes whose odorants contribute to the odor profile of inflorescences. In addition, L. thermotolerans produced odorants that attract Cx. pipiens females. As the odor profile of L. thermotolerans varied with the composition of the culture medium, we hypothesize that microbe odorants inform nectar-foraging mosquitoes about the availability of certain macro-nutrients which, in turn, affect foraging decisions by mosquitoes.
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Affiliation(s)
- D A H Peach
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada. .,The University of British Columbia, 2329 West Mall, Vancouver, BC, Canada.
| | - C Carroll
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada
| | - S Meraj
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada
| | - S Gomes
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada
| | - E Galloway
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada
| | - A Balcita
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada.,University of Saskatchewan, 129-72 Campus Drive, Saskatoon, SK, Canada
| | - H Coatsworth
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada.,Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, Gainesville, FL, USA
| | - N Young
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada
| | - Y Uriel
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada
| | - R Gries
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada
| | - C Lowenberger
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada
| | - M Moore
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada
| | - G Gries
- Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada
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69
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Pozo MI, Mariën T, van Kemenade G, Wäckers F, Jacquemyn H. Effects of pollen and nectar inoculation by yeasts, bacteria or both on bumblebee colony development. Oecologia 2021; 195:689-703. [PMID: 33582870 DOI: 10.1007/s00442-021-04872-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/03/2021] [Indexed: 11/28/2022]
Abstract
It is increasingly recognized that gut microbiota have a major effect on the physiology, biology, ecology and evolution of their animal hosts. Because in social insects, the gut microbiota is acquired through the diet and by contact with nest provisions, it can be hypothesized that regular supplementation of microorganisms to the diet will have an impact on the fitness of the consumer and on the development of the whole colony. To test this hypothesis, we investigated how supplementation of bacteria, yeasts, and combinations of the two to either pollen or nectar affected colony development in the social bumblebee Bombus terrestris. Three yeasts and three bacterial species that live at the flower-insect interface were used in the experiments and the development of bumblebee colonies was monitored over a period of 10 weeks. The results showed that administration of microbes via pollen had a stronger positive impact on colony development than when provided via sugar water. Supplementation of bacteria led, in general, to a faster egg laying, higher brood size and increased production of workers during the first weeks, whereas yeasts or a combination of yeasts and bacteria had less impact on colony development. However, the results differed between microbial species, with Wickerhamiella bombiphila and Rosenbergiella nectarea showing the strongest increase in colony development. Torulaspora delbrueckii induced early male production, which is likely a fitness cost. We conclude that the tested bacteria-yeast consortia did not result in better colony development than the interacting species alone.
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Affiliation(s)
- María I Pozo
- Biology Department, Plant Conservation and Population Biology, KU Leuven, 3001, Heverlee, Belgium.
| | - Toon Mariën
- Biology Department, Plant Conservation and Population Biology, KU Leuven, 3001, Heverlee, Belgium
| | - Gaby van Kemenade
- Biology Department, Plant Conservation and Population Biology, KU Leuven, 3001, Heverlee, Belgium.,Biobest Group, Research and Development, 2260, Westerlo, Belgium
| | - Felix Wäckers
- Biobest Group, Research and Development, 2260, Westerlo, Belgium
| | - Hans Jacquemyn
- Biology Department, Plant Conservation and Population Biology, KU Leuven, 3001, Heverlee, Belgium
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70
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Goelen T, Vuts J, Sobhy IS, Wäckers F, Caulfield JC, Birkett MA, Rediers H, Jacquemyn H, Lievens B. Identification and application of bacterial volatiles to attract a generalist aphid parasitoid: from laboratory to greenhouse assays. PEST MANAGEMENT SCIENCE 2021; 77:930-938. [PMID: 32975888 DOI: 10.1002/ps.6102] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/25/2020] [Accepted: 09/25/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Recent studies have shown that microorganisms emit volatile compounds that affect insect behaviour. However, it remains largely unclear whether microbes can be exploited as a source of attractants to improve biological control of insect pests. In this study, we used a combination of coupled gas chromatography-electroantennography (GC-EAG) and Y-tube olfactometer bioassays to identify attractive compounds in the volatile extracts of three bacterial strains that are associated with the habitat of the generalist aphid parasitoid Aphidius colemani, and to create mixtures of synthetic compounds to find attractive blends for A. colemani. Subsequently, the most attractive blend was evaluated in two-choice cage experiments under greenhouse conditions. RESULTS GC-EAG analysis revealed 20 compounds that were linked to behaviourally attractive bacterial strains. A mixture of two EAG-active compounds, styrene and benzaldehyde applied at a respective dose of 1 μg and 10 ng, was more attractive than the single compounds or the culture medium of the bacteria in Y-tube olfactometer bioassays. Application of this synthetic mixture under greenhouse conditions resulted in significant attraction of the parasitoids, and outperformed application of the bacterial culture medium. CONCLUSION Compounds isolated from bacterial blends were capable of attracting parasitoids both in laboratory and greenhouse assays, indicating that microbial cultures are an effective source of insect attractants. This opens new opportunities to attract and retain natural enemies of pest species and to enhance biological pest control.
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Affiliation(s)
- Tim Goelen
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Centre of Microbial and Plant Genetics (CMPG), Department of Microbial and Molecular Systems (M2S), Leuven, Belgium
| | - József Vuts
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, UK
| | - Islam S Sobhy
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Centre of Microbial and Plant Genetics (CMPG), Department of Microbial and Molecular Systems (M2S), Leuven, Belgium
- Department of Plant Protection, Faculty of Agriculture, Suez Canal University, Ismailia, Egypt
| | - Felix Wäckers
- Biobest, Westerlo, Belgium
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - John C Caulfield
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, UK
| | - Michael A Birkett
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, UK
| | - Hans Rediers
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Centre of Microbial and Plant Genetics (CMPG), Department of Microbial and Molecular Systems (M2S), Leuven, Belgium
| | - Hans Jacquemyn
- Laboratory of Plant Conservation and Population Biology, Biology Department, KU Leuven, Leuven, Belgium
| | - Bart Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Centre of Microbial and Plant Genetics (CMPG), Department of Microbial and Molecular Systems (M2S), Leuven, Belgium
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71
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Hayes RA, Rebolleda‐Gómez M, Butela K, Cabo LF, Cullen N, Kaufmann N, O'Neill S, Ashman T. Spatially explicit depiction of a floral epiphytic bacterial community reveals role for environmental filtering within petals. Microbiologyopen 2021; 10:e1158. [PMID: 33650801 PMCID: PMC7859501 DOI: 10.1002/mbo3.1158] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 01/04/2023] Open
Abstract
The microbiome of flowers (anthosphere) is an understudied compartment of the plant microbiome. Within the flower, petals represent a heterogeneous environment for microbes in terms of resources and environmental stress. Yet, little is known of drivers of structure and function of the epiphytic microbial community at the within-petal scale. We characterized the petal microbiome in two co-flowering plants that differ in the pattern of ultraviolet (UV) absorption along their petals. Bacterial communities were similar between plant hosts, with only rare phylogenetically distant species contributing to differences. The epiphyte community was highly culturable (75% of families) lending confidence in the spatially explicit isolation and characterization of bacteria. In one host, petals were heterogeneous in UV absorption along their length, and in these, there was a negative relationship between growth rate and position on the petal, as well as lower UV tolerance in strains isolated from the UV-absorbing base than from UV reflecting tip. A similar pattern was not seen in microbes isolated from a second host whose petals had uniform patterning along their length. Across strains, the variation in carbon usage and chemical tolerance followed common phylogenetic patterns. This work highlights the value of petals for spatially explicit explorations of bacteria of the anthosphere.
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Affiliation(s)
- Rebecca A. Hayes
- Department of Biological SciencesUniversity of PittsburghPittsburghPAUSA
| | - Maria Rebolleda‐Gómez
- Department of Biological SciencesUniversity of PittsburghPittsburghPAUSA
- Department of Ecology and Evolutionary BiologyYale UniversityNew HavenCTUSA
| | - Kristen Butela
- Department of Biological SciencesUniversity of PittsburghPittsburghPAUSA
| | - Leah F. Cabo
- Department of Biological SciencesUniversity of PittsburghPittsburghPAUSA
| | - Nevin Cullen
- Department of Biological SciencesUniversity of PittsburghPittsburghPAUSA
| | - Nancy Kaufmann
- Department of Biological SciencesUniversity of PittsburghPittsburghPAUSA
| | - Steffani O'Neill
- Department of Biological SciencesUniversity of PittsburghPittsburghPAUSA
| | - Tia‐Lynn Ashman
- Department of Biological SciencesUniversity of PittsburghPittsburghPAUSA
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72
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Sharaby Y, Rodríguez-Martínez S, Lalzar M, Halpern M, Izhaki I. Geographic partitioning or environmental selection: What governs the global distribution of bacterial communities inhabiting floral nectar? THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 749:142305. [PMID: 33370885 DOI: 10.1016/j.scitotenv.2020.142305] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/07/2020] [Accepted: 09/07/2020] [Indexed: 06/12/2023]
Abstract
Floral nectar harbors microbial communities which have significant impacts on its chemistry, volatiles, nutritional contents, and attractiveness for pollinators. Yet, fundamental knowledge regarding the structure and composition of nectar-associated microbiomes remains largely unknown. Especially elusive are the environmental factors and spatial effects that shape nectar-inhabiting microbial communities. The aim of this study was to explore and analyze the role of geographical and environmental factors affecting the composition and global distribution of floral nectar microbiota. We explored and compared the structure of bacterial communities inhabiting the floral nectar of the widely spread and invasive tobacco tree (Nicotiana glauca) in six continents: South and North America, Australia, Europe, Africa, and Asia, using 16S rRNA gene sequencing. Environmental abiotic data for each sampled plant was obtained from the Worldclim database and applied for inferring the effects of environmental conditions on bacterial community structure and diversity. Most abundant in the nectar were the Proteobacteria, Firmicutes, and Actinobacteria phyla, with Acinetobacter and Rosenbergiella (Proteobacteria) being the dominant bacterial genera that contributed most to the dissimilarities between sites. Acinetobacter and Rosenbergiella abundances were negatively correlated and significantly higher in the Mediterranean regions (Greece, Israel, and the Canary Islands) compared to Argentina and Australia. Temperature, site-elevation, rainfall, and density of vegetation were found to have significant effects on the structure and diversity of these bacterial communities in the nectar. Vegetation density was positively correlated with microbial diversity, while increased temperatures and elevation reduced the diversity and evenness of bacterial communities. Mantel's test showed that the similarity between the bacterial communities' composition significantly decreased as distances between them increased. We conclude that both geographical distance and local environmental abiotic conditions affect and shape the composition and diversity of nectar inhabiting bacterial communities.
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Affiliation(s)
- Yehonatan Sharaby
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel
| | - Sarah Rodríguez-Martínez
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel
| | - Maya Lalzar
- Bioinformatics Service Unit, University of Haifa, Haifa 3498838, Israel
| | - Malka Halpern
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel; Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Tivon, Israel.
| | - Ido Izhaki
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel
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73
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Rering CC, Gaffke AM, Rudolph AB, Beck JJ, Alborn HT. A Comparison of Collection Methods for Microbial Volatiles. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2020. [DOI: 10.3389/fsufs.2020.598967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recently, there has been an increase in the number of reports that highlight the role of microbes and their volatile metabolites in interactions with plants and insects, including interactions which may benefit agricultural production. Accurate and reproducible volatile collection is crucial to investigations of chemical-mediated communication between organisms. Accordingly, accurate detection of volatiles emitted from microbe-inoculated media is a research priority. Though numerous classes of volatile organic compounds are emitted from plants, insects, and microbes, emissions from microbes typically contain polar compounds of high volatility. Therefore, commonly used plant or insect volatile collection techniques may not provide an accurate representation of microbe-specific volatile profiles. Here, we present and compare the volatile data derived via three solventless collection techniques: direct headspace injection, solid-phase microextraction (SPME), and active sampling with a sorptive matrix blend specifically designed to prevent collection filter breakthrough of VOCs (solid-phase extraction, SPE). These methods were applied to a synthetic floral nectar media containing a nectar-inhabiting yeast, Metschnikowia reukaufii, and sunflower (Helianthus annus) pollen. The yeast contributed alcohols, ketones, and esters, and the pollen provided terpenoids. Direct headspace injections were not effective, and the resultant chromatography was poor despite the use of on-column cryofocusing. SPME and SPE detected a similar number of volatiles, but with varying relative abundances. SPE collected a greater abundance of microbial volatiles than SPME, a difference driven by high ethanol capture in SPE. Both SPE and SPME are appropriate for analysis of microbial volatiles, though the sorbent type and amount, and other collection parameters should be further evaluated for each studied system.
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74
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Vannette RL. The Floral Microbiome: Plant, Pollinator, and Microbial Perspectives. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2020. [DOI: 10.1146/annurev-ecolsys-011720-013401] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Flowers at times host abundant and specialized communities of bacteria and fungi that influence floral phenotypes and interactions with pollinators. Ecological processes drive variation in microbial abundance and composition at multiple scales, including among plant species, among flower tissues, and among flowers on the same plant. Variation in microbial effects on floral phenotype suggests that microbial metabolites could cue the presence or quality of rewards for pollinators, but most plants are unlikely to rely on microbes for pollinator attraction or reproduction. From a microbial perspective, flowers offer opportunities to disperse between habitats, but microbial species differ in requirements for and benefits received from such dispersal. The extent to which floral microbes shape the evolution of floral traits, influence fitness of floral visitors, and respond to anthropogenic change is unclear. A deeper understanding of these phenomena could illuminate the ecological and evolutionary importance of floral microbiomes and their role in the conservation of plant–pollinator interactions.
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Affiliation(s)
- Rachel L. Vannette
- Department of Entomology and Nematology, University of California, Davis, California 95616, USA
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75
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Geldert C, Abdo Z, Stewart JE, H S A. Dietary supplementation with phytochemicals improves diversity and abundance of honey bee gut microbiota. J Appl Microbiol 2020; 130:1705-1720. [PMID: 33058297 DOI: 10.1111/jam.14897] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/21/2020] [Accepted: 10/10/2020] [Indexed: 12/20/2022]
Abstract
AIM Determine the impact of beneficial phytochemicals on diversity and abundance of the gut microbiome in the honey bee (Apis mellifera). METHODS AND RESULTS Eight-day-old honey bee workers were fed 25 ppm of phytochemical (caffeine, gallic acid, p-coumaric acid or kaempferol) in 20% sucrose. Guts of bees collected at 3 and 6 days were excised and subjected to next-generation sequencing for bacterial 16S and fungal ITS regions. Although phytochemical supplementation fostered gut microbial diversity and abundance, the patterns differed between phytochemicals and there was a temporal stabilization of the bacterial community. While bacterial and fungal communities responded differently, all phytochemical treatments displayed increased abundance of the most represented bacterial genera, Snodgrassella sp. and Lactobacillus sp. CONCLUSIONS Phytochemical supplementation improves gut microbial diversity and abundance, reiterating the need for diverse habitats that provide bees with access to pollen and nectar rich in these micronutrients. Diverse gut microbiota can provide a strong line of defense for bees against biotic stressors while improving worker bee lifespan. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first report on the impact of phytochemical supplementation on gut microbiota in honey bees and these findings have implications for strategic hive management through standardization of effective phytochemical and probiotic feed supplements.
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Affiliation(s)
- C Geldert
- College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Z Abdo
- College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - J E Stewart
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, USA
| | - Arathi H S
- USDA/ARS, WRRC Invasive Species and Pollinator Health Research Unit, Davis, CA, USA
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77
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Intraspecific Variation in Nectar Chemistry and Its Implications for Insect Visitors: The Case of the Medicinal Plant, Polemonium Caeruleum L. PLANTS 2020; 9:plants9101297. [PMID: 33019586 PMCID: PMC7600102 DOI: 10.3390/plants9101297] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 11/17/2022]
Abstract
Floral nectar, being a primary reward for insect visitors, is a key factor in shaping plant–pollinator interactions. However, little is known about the variability in nectar traits, which could potentially affect pollinators and the reproduction of the species. We investigated intraspecific variation in nectar traits in 14 populations of a Red-listed plant, Polemonium caeruleum. Populations varied in terms of the proportion of self-compatible and self-incompatible individuals, and insect communities visiting flowers. Using HPLC, we determined the nectar sugar and amino acid (AA) composition and concentration. We also recorded some basic habitat parameters, which could influence nectar chemistry. In seven selected populations, we investigated the taxonomic composition of the insects visiting flowers. Our observations revealed significant intraspecific variability in nectar chemistry in P. caeruleum. Nectar production was male-biased, with male-phase flowers secreting sucrose- and AA-rich nectar. An analysis revealed that variability in P. caeruleum nectar may be slightly shaped by environmental factors. The studied nectar characters, especially sugars, had little effect on insects visiting flowers. We argue that variation in nectar traits in this generalist plant is a matter of random genetic drift or “adaptive wandering” rather than directional specialization and adaptation in the most effective and abundant group of pollinators.
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78
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Rering CC, Franco JG, Yeater KM, Mallinger RE. Drought stress alters floral volatiles and reduces floral rewards, pollinator activity, and seed set in a global plant. Ecosphere 2020. [DOI: 10.1002/ecs2.3254] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Caitlin C. Rering
- Center for Medical, Agricultural and Veterinary Entomology USDA‐Agricultural Research Service 1700 SW 23rd Drive Gainesville Florida32608USA
| | - Jose G. Franco
- Northern Great Plains Research Laboratory USDA‐Agricultural Research Service 1701 10th Avenue SW Mandan North Dakota58554USA
- Dale Bumpers Small Farms Research Center USDA‐Agricultural Research Service 6883 South State Highway 23 Booneville Arkansas72927USA
| | - Kathleen M. Yeater
- Plains Area, Office of the Director USDA‐Agricultural Research Service 2150 Centre Avenue, Building D, Suite 300 Fort Collins Colorado80526USA
| | - Rachel E. Mallinger
- Department of Entomology and Nematology University of Florida 1881 Natural Areas Drive Gainesville Florida32611USA
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Laraba I, McCormick SP, Vaughan MM, Proctor RH, Busman M, Appell M, O'Donnell K, Felker FC, Catherine Aime M, Wurdack KJ. Pseudoflowers produced by Fusarium xyrophilum on yellow-eyed grass (Xyris spp.) in Guyana: A novel floral mimicry system? Fungal Genet Biol 2020; 144:103466. [PMID: 32956810 DOI: 10.1016/j.fgb.2020.103466] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 12/18/2022]
Abstract
Pseudoflower formation is arguably the rarest outcome of a plant-fungus interaction. Here we report on a novel putative floral mimicry system in which the pseudoflowers are composed entirely of fungal tissues in contrast to modified leaves documented in previous mimicry systems. Pseudoflowers on two perennial Xyris species (yellow-eyed grass, X. setigera and X. surinamensis) collected from savannas in Guyana were produced by Fusarium xyrophilum, a novel Fusarium species. These pseudoflowers mimic Xyris flowers in gross morphology and are ultraviolet reflective. Axenic cultures of F. xyrophilum produced two pigments that had fluorescence emission maxima in light ranges that trichromatic insects are sensitive to and volatiles known to attract insect pollinators. One of the volatiles emitted by F. xyrophilum cultures (i.e., 2-ethylhexanol) was also detected in the head space of X. laxifolia var. iridifolia flowers, a perennial species native to the New World. Results of microscopic and PCR analyses, combined with examination of gross morphology of the pseudoflowers, provide evidence that the fungus had established a systemic infection in both Xyris species, sterilized them and formed fungal pseudoflowers containing both mating type idiomorphs. Fusarium xyrophilum cultures also produced the auxin indole-3-acetic acid (IAA) and the cytokinin isopentenyl adenosine (iPR). Field observations revealed that pseudoflowers and Xyris flowers were both visited by bees. Together, the results suggest that F. xyrophilum pseudoflowers are a novel floral mimicry system that attracts insect pollinators, via visual and olfactory cues, into vectoring its conidia, which might facilitate outcrossing of this putatively heterothallic fungus and infection of previously uninfected plants.
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Affiliation(s)
- Imane Laraba
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA.
| | - Susan P McCormick
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Martha M Vaughan
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Robert H Proctor
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Mark Busman
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Michael Appell
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Kerry O'Donnell
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Frederick C Felker
- Functional Food Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - M Catherine Aime
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907-2054, USA
| | - Kenneth J Wurdack
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-2012, USA
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80
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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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81
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From Diverse Origins to Specific Targets: Role of Microorganisms in Indirect Pest Biological Control. INSECTS 2020; 11:insects11080533. [PMID: 32823898 PMCID: PMC7469166 DOI: 10.3390/insects11080533] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 01/29/2023]
Abstract
Integrated pest management (IPM) is today a widely accepted pest management strategy to select and use the most efficient control tactics and at the same time reduce over-dependence on chemical insecticides and their potentially negative environmental effects. One of the main pillars of IPM is biological control. While biological control programs of pest insects commonly rely on natural enemies such as predatory insects, parasitoids and microbial pathogens, there is increasing evidence that plant, soil and insect microbiomes can also be exploited to enhance plant defense against herbivores. In this mini-review, we illustrate how microorganisms from diverse origins can contribute to plant fitness, functional traits and indirect defense responses against pest insects, and therefore be indirectly used to improve biological pest control practices. Microorganisms in the rhizosphere, phyllosphere and endosphere have not only been shown to enhance plant growth and plant strength, but also promote plant defense against herbivores both above- and belowground by providing feeding deterrence or antibiosis. Also, herbivore associated molecular patterns may be induced by microorganisms that come from oral phytophagous insect secretions and elicit plant-specific responses to herbivore attacks. Furthermore, microorganisms that inhabit floral nectar and insect honeydew produce volatile organic compounds that attract beneficial insects like natural enemies, thereby providing indirect pest control. Given the multiple benefits of microorganisms to plants, we argue that future IPMs should consider and exploit the whole range of possibilities that microorganisms offer to enhance plant defense and increase attraction, fecundity and performance of natural enemies.
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82
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Goelen T, Sobhy IS, Vanderaa C, Wäckers F, Rediers H, Wenseleers T, Jacquemyn H, Lievens B. Bacterial phylogeny predicts volatile organic compound composition and olfactory response of an aphid parasitoid. OIKOS 2020. [DOI: 10.1111/oik.07301] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tim Goelen
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Dept of Microbial and Molecular Systems, KU Leuven BE‐3001 Leuven Belgium
| | - Islam S. Sobhy
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Dept of Microbial and Molecular Systems, KU Leuven BE‐3001 Leuven Belgium
- Dept of Plant Protection, Faculty of Agriculture, Suez Canal Univ. Ismailia Egypt
| | - Christophe Vanderaa
- Laboratory of Socio‐Ecology & Social Evolution, Biology Dept, KU Leuven Leuven Belgium
| | - Felix Wäckers
- Biobest, Westerlo, Belgium, and: Lancaster Environment Centre, Lancaster Univ. Lancaster UK
| | - Hans Rediers
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Dept of Microbial and Molecular Systems, KU Leuven BE‐3001 Leuven Belgium
| | - Tom Wenseleers
- Laboratory of Socio‐Ecology & Social Evolution, Biology Dept, KU Leuven Leuven Belgium
| | - Hans Jacquemyn
- Laboratory of Plant Conservation and Population Biology, Biology Dept, KU Leuven Leuven Belgium
| | - Bart Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Dept of Microbial and Molecular Systems, KU Leuven BE‐3001 Leuven Belgium
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83
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Sprayberry JDH. Compounds without borders: A mechanism for quantifying complex odors and responses to scent-pollution in bumblebees. PLoS Comput Biol 2020; 16:e1007765. [PMID: 32320390 PMCID: PMC7197864 DOI: 10.1371/journal.pcbi.1007765] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 05/04/2020] [Accepted: 03/02/2020] [Indexed: 11/21/2022] Open
Abstract
Bumblebees are critical pollinators whose populations have been experiencing troubling declines over the past several decades. Successful foraging improves colony fitness, thus understanding how anthropogenic influences modulate foraging behavior may aid conservation efforts. Odor pollution can have negative impacts on bumble- and honey-bees foraging behavior. However, given the vast array of potential scent contaminants, individually testing pollutants is an ineffective approach. The ability to quantitatively measure how much scent-pollution of a floral-odor bumblebees can tolerate would represent a paradigm shift in odor-pollution studies. Current statistical methods for analyzing complex odors have poor predictive power because statistically-derived odor-spaces are rewritten when new odors are added. This study presents an alternative method of analyzing complex odor blends based on the encoding properties of insect olfactory systems. This “Compounds Without Borders” (CWB) method vectorizes odors in a multidimensional space representing relevant functional group and carbon characteristics of their component odorants. A single vector can be built for any scent, which allows the angular distance between any two odors to be calculated–including a learned odor and its polluted counterpart. Data presented here indicate that CWB-angles are capable of both describing and predicting bumblebee odor-discrimination behavior: odor pairs with angular distances in the 20–29° range appear to be generalized, while odor pairs over 30 degrees are differentiated. The neurophysiological properties underlying CWB-vectorization of odors are not unique to bumblebees; CWB-angle analysis of a small sample of published odor-data supports the idea that this method may have broader applications.
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Affiliation(s)
- Jordanna D H Sprayberry
- Departments of Biology & Neuroscience, Muhlenberg College, Allentown, Pennsylvania, United States of America
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84
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Laviad-Shitrit S, Izhaki I, Whitman WB, Shapiro N, Woyke T, Kyrpides NC, Halpern M. Draft genome of Rosenbergiella nectarea strain 8N4 T provides insights into the potential role of this species in its plant host. PeerJ 2020; 8:e8822. [PMID: 32292647 PMCID: PMC7144588 DOI: 10.7717/peerj.8822] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/28/2020] [Indexed: 11/20/2022] Open
Abstract
Background Rosenbergiella nectarea strain 8N4T, the type species of the genus Rosenbergiella, was isolated from Amygdalus communis (almond) floral nectar. Other strains of this species were isolated from the floral nectar of Citrus paradisi (grapefruit), Nicotiana glauca (tobacco tree) and from Asphodelus aestivus. R. nectarea strain 8N4T is a Gram-negative, oxidase-negative, facultatively anaerobic bacterium in the family Enterobacteriaceae. Results Here we describe features of this organism, together with its genome sequence and annotation. The DNA GC content is 47.38%, the assembly size is 3,294,717 bp, and the total number of genes are 3,346. The genome discloses the possible role that this species may play in the plant. The genome contains both virulence genes, like pectin lyase and hemolysin, that may harm plant cells and genes that are predicted to produce volatile compounds that may impact the visitation rates by nectar consumers, such as pollinators and nectar thieves. Conclusions The genome of R. nectarea strain 8N4T reveals a mutualistic interaction with the plant host and a possible effect on plant pollination and fitness.
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Affiliation(s)
- Sivan Laviad-Shitrit
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Ido Izhaki
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | | | - Nicole Shapiro
- Department of Energy Joint Genome Institute, DOE Joint Genome Institute, Berkeley, CA, USA
| | - Tanja Woyke
- Department of Energy Joint Genome Institute, DOE Joint Genome Institute, Berkeley, CA, USA
| | - Nikos C Kyrpides
- Department of Energy Joint Genome Institute, DOE Joint Genome Institute, Berkeley, CA, USA
| | - Malka Halpern
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Kiryat Tivon, Israel
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85
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Microbial Co-Occurrence in Floral Nectar Affects Metabolites and Attractiveness to a Generalist Pollinator. J Chem Ecol 2020; 46:659-667. [PMID: 32246258 DOI: 10.1007/s10886-020-01169-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/27/2020] [Accepted: 03/06/2020] [Indexed: 12/25/2022]
Abstract
Microbial metabolism can shape cues important for animal attraction in service-resource mutualisms. Resources are frequently colonized by microbial communities, but experimental assessment of animal-microbial interactions often focus on microbial monocultures. Such an approach likely fails to predict effects of microbial assemblages, as microbe-microbe interactions may affect in a non-additive manner microbial metabolism and resulting chemosensory cues. Here, we compared effects of microbial mono- and cocultures on growth of constituent microbes, volatile metabolite production, sugar catabolism, and effects on pollinator foraging across two nectar environments that differed in sugar concentration. Growth in co-culture decreased the abundance of the yeast Metschnikowia reukaufii, but not the bacterium Asaia astilbes. Volatile emissions differed significantly between microbial treatments and with nectar concentration, while sugar concentration was relatively similar among mono- and cocultures. Coculture volatile emission closely resembled an additive combination of monoculture volatiles. Despite differences in microbial growth and chemosensory cues, honey bee feeding did not differ between microbial monocultures and assemblages. Taken together, our results suggest that in some cases, chemical and ecological effects of microbial assemblages are largely predictable from those of component species, but caution that more work is necessary to predict under what circumstances non-additive effects are important.
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86
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Rivest S, Forrest JRK. Defence compounds in pollen: why do they occur and how do they affect the ecology and evolution of bees? THE NEW PHYTOLOGIST 2020; 225:1053-1064. [PMID: 31569278 DOI: 10.1111/nph.16230] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/25/2019] [Indexed: 05/23/2023]
Abstract
Pollen plays two important roles in angiosperm reproduction, serving as a vehicle for the plant's male gametes, but also, in many species, as a lure for pollen-feeding animals. Despite being an important food source for many pollinators, pollen often contains compounds with known deterrent or toxic properties, as documented in a growing number of studies. Here we review these studies and discuss the role of pollen defensive compounds in the coevolutionary relationship between plants and bees, the preeminent consumers of pollen. Next, we evaluate three hypotheses that may explain the existence of defensive compounds in pollen. The pleiotropy hypothesis, which proposes that defensive compounds in pollen merely reflect physiological spillover from other plant tissues, is contradicted by evidence from several species. Although plants may experience selection to defend pollen against poor-quality pollinators, we also find only partial support for the protection-against-pollen-collection-hypothesis. Finally, pollen defences might protect pollen from colonisation by antagonistic microorganisms (antimicrobial hypothesis), although data to evaluate this idea are scarce. Further research on the effects of pollen defensive compounds on pollinators, pollen thieves, and pollen-colonising microbes will be needed to understand why many plants have chemically defended pollen, and the consequences of those defences for pollen consumers.
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Affiliation(s)
- Sébastien Rivest
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada
| | - Jessica R K Forrest
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada
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87
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Morris MM, Frixione NJ, Burkert AC, Dinsdale EA, Vannette RL. Microbial abundance, composition, and function in nectar are shaped by flower visitor identity. FEMS Microbiol Ecol 2020; 96:5700281. [DOI: 10.1093/femsec/fiaa003] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 01/08/2020] [Indexed: 11/12/2022] Open
Abstract
ABSTRACT
Microbial dispersal is essential for establishment in new habitats, but the role of vector identity is poorly understood in community assembly and function. Here, we compared microbial assembly and function in floral nectar visited by legitimate pollinators (hummingbirds) and nectar robbers (carpenter bees). We assessed effects of visitation on the abundance and composition of culturable bacteria and fungi and their taxonomy and function using shotgun metagenomics and nectar chemistry. We also compared metagenome-assembled genomes (MAGs) of Acinetobacter, a common and highly abundant nectar bacterium, among visitor treatments. Visitation increased microbial abundance, but robbing resulted in 10× higher microbial abundance than pollination. Microbial communities differed among visitor treatments: robbed flowers were characterized by predominant nectar specialists within Acetobacteraceae and Metschnikowiaceae, with a concurrent loss of rare taxa, and these resulting communities harbored genes relating to osmotic stress, saccharide metabolism and specialized transporters. Gene differences were mirrored in function: robbed nectar contained a higher percentage of monosaccharides. Draft genomes of Acinetobacter revealed distinct amino acid and saccharide utilization pathways in strains isolated from robbed versus pollinated flowers. Our results suggest an unrecognized cost of nectar robbing for pollination and distinct effects of visitor type on interactions between plants and pollinators. Overall, these results suggest vector identity is an underappreciated factor structuring microbial community assembly and function.
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Affiliation(s)
- Megan M Morris
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Natalie J Frixione
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Alexander C Burkert
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
| | | | - Rachel L Vannette
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
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88
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Goelen T, Sobhy IS, Vanderaa C, Boer JG, Delvigne F, Francis F, Wäckers F, Rediers H, Verstrepen KJ, Wenseleers T, Jacquemyn H, Lievens B. Volatiles of bacteria associated with parasitoid habitats elicit distinct olfactory responses in an aphid parasitoid and its hyperparasitoid. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13503] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tim Goelen
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM) Department of Microbial and Molecular Systems KU Leuven Leuven Belgium
| | - Islam S. Sobhy
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM) Department of Microbial and Molecular Systems KU Leuven Leuven Belgium
- Department of Plant Protection Faculty of Agriculture Suez Canal University Ismailia Egypt
| | - Christophe Vanderaa
- Laboratory of Socio‐Ecology & Social Evolution Biology Department KU Leuven Leuven Belgium
| | - Jetske G. Boer
- Department of Terrestrial Ecology Netherlands Institute of Ecology (NIOO‐KNAW) Wageningen The Netherlands
| | - Frank Delvigne
- Microbial Processes and Interactions (MiPI) TERRA Université de Liège‐Gembloux Agro‐Bio Tech Gembloux Belgium
| | - Frédéric Francis
- Functional & Evolutionary Entomology TERRA Université de Liège‐Gembloux Agro‐Bio Tech Gembloux Belgium
| | - Felix Wäckers
- Biobest Westerlo Belgium
- Lancaster Environment Centre Lancaster University Lancaster UK
| | - Hans Rediers
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM) Department of Microbial and Molecular Systems KU Leuven Leuven Belgium
| | - Kevin J. Verstrepen
- Lab for Systems Biology VIB Center for Microbiology & Centre of Microbial and Plant Genetics (CMPG) Lab for Genetics and Genomics Department of Microbial and Molecular Systems KU Leuven Leuven Belgium
| | - Tom Wenseleers
- Laboratory of Socio‐Ecology & Social Evolution Biology Department KU Leuven Leuven Belgium
| | - Hans Jacquemyn
- Laboratory of Plant Conservation and Population Biology Biology Department KU Leuven Leuven Belgium
| | - Bart Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM) Department of Microbial and Molecular Systems KU Leuven Leuven Belgium
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89
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Klaps J, Lievens B, Álvarez-Pérez S. Towards a better understanding of the role of nectar-inhabiting yeasts in plant-animal interactions. Fungal Biol Biotechnol 2020; 7:1. [PMID: 31921433 PMCID: PMC6947986 DOI: 10.1186/s40694-019-0091-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 12/26/2019] [Indexed: 11/29/2022] Open
Abstract
Flowers offer a wide variety of substrates suitable for fungal growth. However, the mycological study of flowers has only recently begun to be systematically addressed from an ecological point of view. Most research on the topic carried out during the last decade has focused on studying the prevalence and diversity of flower-inhabiting yeasts, describing new species retrieved from floral parts and animal pollinators, and the use of select nectar yeasts as model systems to test ecological hypotheses. In this primer article, we summarize the current state of the art in floral nectar mycology and provide an overview of some research areas that, in our view, still require further attention, such as the influence of fungal volatile organic compounds on the foraging behavior of pollinators and other floral visitors, the analysis of the direct and indirect effects of nectar-inhabiting fungi on the fitness of plants and animals, and the nature and consequences of fungal-bacterial interactions taking place within flowers.
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Affiliation(s)
- Joon Klaps
- Department of Microbial and Molecular Systems (M2S), Laboratory for Process Microbial Ecology and Bioinspirational Management (PME & BIM), KU Leuven, Willem De Croylaan 46, Leuven, 3001 Belgium
| | - Bart Lievens
- Department of Microbial and Molecular Systems (M2S), Laboratory for Process Microbial Ecology and Bioinspirational Management (PME & BIM), KU Leuven, Willem De Croylaan 46, Leuven, 3001 Belgium
| | - Sergio Álvarez-Pérez
- Department of Microbial and Molecular Systems (M2S), Laboratory for Process Microbial Ecology and Bioinspirational Management (PME & BIM), KU Leuven, Willem De Croylaan 46, Leuven, 3001 Belgium
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90
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Diversity of Floral Glands and Their Secretions in Pollinator Attraction. REFERENCE SERIES IN PHYTOCHEMISTRY 2020. [DOI: 10.1007/978-3-319-96397-6_48] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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91
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Mbaluto CM, Ayelo PM, Duffy AG, Erdei AL, Tallon AK, Xia S, Caballero-Vidal G, Spitaler U, Szelényi MO, Duarte GA, Walker WB, Becher PG. Insect chemical ecology: chemically mediated interactions and novel applications in agriculture. ARTHROPOD-PLANT INTERACTIONS 2020; 14:671-684. [PMID: 33193908 PMCID: PMC7650581 DOI: 10.1007/s11829-020-09791-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 10/16/2020] [Indexed: 05/19/2023]
Abstract
Insect chemical ecology (ICE) evolved as a discipline concerned with plant-insect interactions, and also with a strong focus on intraspecific pheromone-mediated communication. Progress in this field has rendered a more complete picture of how insects exploit chemical information in their surroundings in order to survive and navigate their world successfully. Simultaneously, this progress has prompted new research questions about the evolution of insect chemosensation and related ecological adaptations, molecular mechanisms that mediate commonly observed behaviors, and the consequences of chemically mediated interactions in different ecosystems. Themed meetings, workshops, and summer schools are ideal platforms for discussing scientific advancements as well as identifying gaps and challenges within the discipline. From the 11th to the 22nd of June 2018, the 11th annual PhD course in ICE was held at the Swedish University of Agricultural Sciences (SLU) Alnarp, Sweden. The course was made up of 35 student participants from 22 nationalities (Fig. 1a) as well as 32 lecturers. Lectures and laboratory demonstrations were supported by literature seminars, and four broad research areas were covered: (1) multitrophic interactions and plant defenses, (2) chemical communication focusing on odor sensing, processing, and behavior, (3) disease vectors, and (4) applied aspects of basic ICE research in agriculture. This particular article contains a summary and brief synthesis of these main emergent themes and discussions from the ICE 2018 course. In addition, we also provide suggestions on teaching the next generation of ICE scientists, especially during unprecedented global situations.
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Affiliation(s)
- Crispus M. Mbaluto
- Molecular Interaction Ecology, German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Pusch straße 4, 04103 Leipzig, Germany
- Institute of Biodiversity, Friedrich-Schiller-Universität Jena, Dornburger Str. 159, 07743 Jena, Germany
| | - Pascal M. Ayelo
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772-00100, Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Hatfield, Private Bag X20, Pretoria, 0028 South Africa
| | - Alexandra G. Duffy
- Evolutionary Ecology Laboratories, Department of Biology, Brigham Young University, 4102 Life Science Building, Provo, UT 84602 USA
| | - Anna L. Erdei
- Zoology Department, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó str. 15, Budapest, 1022 Hungary
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, P.O. Box 102, 23053 Alnarp, Sweden
| | - Anaїs K. Tallon
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, P.O. Box 102, 23053 Alnarp, Sweden
| | - Siyang Xia
- Department of Ecology and Evolutionary Biology, Yale University, 21 Sachem Street, New Haven, CT 06511 USA
| | - Gabriela Caballero-Vidal
- INRAE, Institute of Ecology and Environmental Sciences of Paris, CNRS, IRD, UPEC, Sorbonne Université, Université Paris Diderot, Route de Saint-Cyr, 78026 Versailles Cedex, France
| | - Urban Spitaler
- Institute of Plant Health, Laimburg Research Centre, Laimburg 6, 3904 Ora, South Tyrol Italy
- Department of Crop Sciences, Institute of Plant Protection, University of Natural Resources and Life Sciences (BOKU), Gregor-Mendel-Straße 33, 1180 Vienna, Austria
| | - Magdolna O. Szelényi
- Zoology Department, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó str. 15, Budapest, 1022 Hungary
| | - Gonçalo A. Duarte
- LEAF-Linking Landscape, Environment, Agriculture and Food Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisbon, Portugal
| | - William B. Walker
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, P.O. Box 102, 23053 Alnarp, Sweden
| | - Paul G. Becher
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, P.O. Box 102, 23053 Alnarp, Sweden
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92
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Tyc O, Putra R, Gols R, Harvey JA, Garbeva P. The ecological role of bacterial seed endophytes associated with wild cabbage in the United Kingdom. Microbiologyopen 2020; 9:e00954. [PMID: 31721471 PMCID: PMC6957406 DOI: 10.1002/mbo3.954] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 12/03/2022] Open
Abstract
Endophytic bacteria are known for their ability in promoting plant growth and defense against biotic and abiotic stress. However, very little is known about the microbial endophytes living in the spermosphere. Here, we isolated bacteria from the seeds of five different populations of wild cabbage (Brassica oleracea L) that grow within 15 km of each other along the Dorset coast in the UK. The seeds of each plant population contained a unique microbiome. Sequencing of the 16S rRNA genes revealed that these bacteria belong to three different phyla (Actinobacteria, Firmicutes, and Proteobacteria). Isolated endophytic bacteria were grown in monocultures or mixtures and the effects of bacterial volatile organic compounds (VOCs) on the growth and development on B. oleracea and on resistance against a insect herbivore was evaluated. Our results reveal that the VOCs emitted by the endophytic bacteria had a profound effect on plant development but only a minor effect on resistance against an herbivore of B. oleracea. Plants exposed to bacterial VOCs showed faster seed germination and seedling development. Furthermore, seed endophytic bacteria exhibited activity via volatiles against the plant pathogen F. culmorum. Hence, our results illustrate the ecological importance of the bacterial seed microbiome for host plant health and development.
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Affiliation(s)
- Olaf Tyc
- Department of Microbial EcologyNetherlands Institute of Ecology (NIOO‐KNAW)WageningenThe Netherlands
- Department of Internal Medicine IGoethe UniversityUniversity Hospital FrankfurtFrankfurtGermany
| | - Rocky Putra
- Department of Microbial EcologyNetherlands Institute of Ecology (NIOO‐KNAW)WageningenThe Netherlands
- Laboratory of EntomologyWageningen UniversityWageningenThe Netherlands
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithAustralia
| | - Rieta Gols
- Laboratory of EntomologyWageningen UniversityWageningenThe Netherlands
| | - Jeffrey A. Harvey
- Department of Terrestrial EcologyNetherlands Institute of EcologyWageningenThe Netherlands
- Department of Ecological SciencesSection Animal EcologyVU University AmsterdamAmsterdamThe Netherlands
| | - Paolina Garbeva
- Department of Microbial EcologyNetherlands Institute of Ecology (NIOO‐KNAW)WageningenThe Netherlands
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93
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von Arx M, Moore A, Davidowitz G, Arnold AE. Diversity and distribution of microbial communities in floral nectar of two night-blooming plants of the Sonoran Desert. PLoS One 2019; 14:e0225309. [PMID: 31830071 PMCID: PMC6907802 DOI: 10.1371/journal.pone.0225309] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 11/01/2019] [Indexed: 12/03/2022] Open
Abstract
Nectar-inhabiting microbes are increasingly appreciated as important components of plant-pollinator interactions. We quantified the incidence, abundance, diversity, and composition of bacterial and fungal communities in floral nectar of two night-blooming plants of the Sonoran Desert over the course of a flowering season: Datura wrightii (Solanaceae), which is pollinated by hawkmoths, and Agave palmeri (Agavaceae), which is pollinated by bats but visited by hawkmoths that forage for nectar. We examined the relevance of growing environment (greenhouse vs. field), time (before and after anthesis), season (from early to late in the flowering season), and flower visitors (excluded via mesh sleeves or allowed to visit flowers naturally) in shaping microbial assemblages in nectar. We isolated and identified bacteria and fungi from >300 nectar samples to estimate richness and taxonomic composition. Our results show that microbes were common in D. wrightii and A. palmeri nectar in the greenhouse but more so in field environments, both before and especially after anthesis. Bacteria were isolated more frequently than fungi. The abundance of microbes in nectar of D. wrightii peaked near the middle of the flowering season. Microbes generally were more abundant as time for floral visitation increased. The composition of bacterial and especially fungal communities differed significantly between nectars of D. wrightii and A. palmeri, opening the door to future studies examining their functional roles in shaping nectar chemistry, attractiveness, and pollinator specialization.
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Affiliation(s)
- Martin von Arx
- Department of Entomology, The University of Arizona, Tucson, AZ, United States of America
| | - Autumn Moore
- Department of Entomology, The University of Arizona, Tucson, AZ, United States of America
| | - Goggy Davidowitz
- Department of Entomology, The University of Arizona, Tucson, AZ, United States of America
| | - A. Elizabeth Arnold
- School of Plant Sciences and Department of Ecology and Evolutionary Biology, The University of Arizona, Tucson, AZ, United States of America
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94
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Calcagnile M, Tredici SM, Talà A, Alifano P. Bacterial Semiochemicals and Transkingdom Interactions with Insects and Plants. INSECTS 2019; 10:E441. [PMID: 31817999 PMCID: PMC6955855 DOI: 10.3390/insects10120441] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/02/2019] [Accepted: 12/05/2019] [Indexed: 01/08/2023]
Abstract
A peculiar feature of all living beings is their capability to communicate. With the discovery of the quorum sensing phenomenon in bioluminescent bacteria in the late 1960s, it became clear that intraspecies and interspecies communications and social behaviors also occur in simple microorganisms such as bacteria. However, at that time, it was difficult to imagine how such small organisms-invisible to the naked eye-could influence the behavior and wellbeing of the larger, more complex and visible organisms they colonize. Now that we know this information, the challenge is to identify the myriad of bacterial chemical signals and communication networks that regulate the life of what can be defined, in a whole, as a meta-organism. In this review, we described the transkingdom crosstalk between bacteria, insects, and plants from an ecological perspective, providing some paradigmatic examples. Second, we reviewed what is known about the genetic and biochemical bases of the bacterial chemical communication with other organisms and how explore the semiochemical potential of a bacterium can be explored. Finally, we illustrated how bacterial semiochemicals managing the transkingdom communication may be exploited from a biotechnological point of view.
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Affiliation(s)
| | | | | | - Pietro Alifano
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Prov.le Lecce-Monteroni, 73100 Lecce, Italy; (M.C.); (S.M.T.); (A.T.)
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95
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Bouwmeester H, Schuurink RC, Bleeker PM, Schiestl F. The role of volatiles in plant communication. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 100:892-907. [PMID: 31410886 PMCID: PMC6899487 DOI: 10.1111/tpj.14496] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 05/31/2019] [Accepted: 06/17/2019] [Indexed: 05/08/2023]
Abstract
Volatiles mediate the interaction of plants with pollinators, herbivores and their natural enemies, other plants and micro-organisms. With increasing knowledge about these interactions the underlying mechanisms turn out to be increasingly complex. The mechanisms of biosynthesis and perception of volatiles are slowly being uncovered. The increasing scientific knowledge can be used to design and apply volatile-based agricultural strategies.
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Affiliation(s)
- Harro Bouwmeester
- University of AmsterdamSwammerdam Institute for Life SciencesGreen Life Science research clusterScience Park 9041098 XHAmsterdamThe Netherlands
| | - Robert C. Schuurink
- University of AmsterdamSwammerdam Institute for Life SciencesGreen Life Science research clusterScience Park 9041098 XHAmsterdamThe Netherlands
| | - Petra M. Bleeker
- University of AmsterdamSwammerdam Institute for Life SciencesGreen Life Science research clusterScience Park 9041098 XHAmsterdamThe Netherlands
| | - Florian Schiestl
- Department of Systematic and Evolutionary BotanyUniversity of ZürichZollikerstrasse 107CH‐8008ZürichSwitzerland
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96
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Liu H, Macdonald CA, Cook J, Anderson IC, Singh BK. An Ecological Loop: Host Microbiomes across Multitrophic Interactions. Trends Ecol Evol 2019; 34:1118-1130. [DOI: 10.1016/j.tree.2019.07.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 07/12/2019] [Accepted: 07/22/2019] [Indexed: 10/26/2022]
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97
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Pozo MI, Kemenade G, Oystaeyen A, Aledón‐Catalá T, Benavente A, Van den Ende W, Wäckers F, Jacquemyn H. The impact of yeast presence in nectar on bumble bee behavior and fitness. ECOL MONOGR 2019. [DOI: 10.1002/ecm.1393] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- María I. Pozo
- KU Leuven Biology Department Plant Population and Conservation Biology B‐3001 Heverlee Belgium
- Biobest Group, Research and Development B‐2260 Westerlo Belgium
| | - Gaby Kemenade
- KU Leuven Biology Department Plant Population and Conservation Biology B‐3001 Heverlee Belgium
- Biobest Group, Research and Development B‐2260 Westerlo Belgium
| | | | - Tomás Aledón‐Catalá
- KU Leuven Biology Department Plant Population and Conservation Biology B‐3001 Heverlee Belgium
- Biobest Group, Research and Development B‐2260 Westerlo Belgium
| | | | - Wim Van den Ende
- KU Leuven Biology Department Molecular Plant Biology B‐3001 Heverlee Belgium
| | - Felix Wäckers
- Biobest Group, Research and Development B‐2260 Westerlo Belgium
| | - Hans Jacquemyn
- KU Leuven Biology Department Plant Population and Conservation Biology B‐3001 Heverlee Belgium
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98
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Domingos-Melo A, Milet-Pinheiro P, Navarro DMDAF, Lopes AV, Machado IC. It's raining fragrant nectar in the Caatinga: evidence of nectar olfactory signaling in bat-pollinated flowers. Ecology 2019; 101:e02914. [PMID: 31612468 DOI: 10.1002/ecy.2914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 08/30/2019] [Accepted: 09/11/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Arthur Domingos-Melo
- Departamento de Botânica, Centro de Biociências, Universidade Federal de Pernambuco, Recife, Pernambuco, 50670-901, Brazil
| | - Paulo Milet-Pinheiro
- Departamento de Botânica, Centro de Biociências, Universidade Federal de Pernambuco, Recife, Pernambuco, 50670-901, Brazil.,Universidade de Pernambuco, Campus de Petrolina, Rodovia BR 203, Km 2, s/n - Vila Eduardo, Petrolina, Pernambuco, 56328-903, Brazil
| | | | - Ariadna Valentina Lopes
- Departamento de Botânica, Centro de Biociências, Universidade Federal de Pernambuco, Recife, Pernambuco, 50670-901, Brazil
| | - Isabel Cristina Machado
- Departamento de Botânica, Centro de Biociências, Universidade Federal de Pernambuco, Recife, Pernambuco, 50670-901, Brazil
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99
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Rebolleda-Gómez M, Forrester NJ, Russell AL, Wei N, Fetters AM, Stephens JD, Ashman TL. Gazing into the anthosphere: considering how microbes influence floral evolution. THE NEW PHYTOLOGIST 2019; 224:1012-1020. [PMID: 31442301 DOI: 10.1111/nph.16137] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 08/13/2019] [Indexed: 06/10/2023]
Abstract
The flower is the hallmark of angiosperms and its evolution is key to their diversification. As knowledge of ecological interactions between flowers and their microbial communities (the anthosphere) expands, it becomes increasingly important to consider the evolutionary impacts of these associations and their potential eco-evolutionary dynamics. In this Viewpoint we synthesize current knowledge of the anthosphere within a multilevel selection framework and illustrate the potential for the extended floral phenotype (the phenotype expressed from the genes of the plant and its associated flower microbes) to evolve. We argue that flower microbes are an important, but understudied, axis of variation that shape floral trait evolution and angiosperm reproductive ecology. We highlight knowledge gaps and discuss approaches that are critical for gaining a deeper understanding of the role microbes play in mediating plant reproduction, ecology, and evolution.
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Affiliation(s)
- María Rebolleda-Gómez
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA
| | - Nicole J Forrester
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Avery L Russell
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Na Wei
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Andrea M Fetters
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Jessica D Stephens
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
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100
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Yeast Volatomes Differentially Affect Larval Feeding in an Insect Herbivore. Appl Environ Microbiol 2019; 85:AEM.01761-19. [PMID: 31444202 PMCID: PMC6803314 DOI: 10.1128/aem.01761-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 08/18/2019] [Indexed: 01/25/2023] Open
Abstract
Yeasts interface insect herbivores with their food plants. Communication depends on volatile metabolites, and decoding this chemical dialogue is key to understanding the ecology of insect-yeast interactions. This study explores the volatomes of eight yeast species which have been isolated from foliage, from flowers or fruit, and from plant-feeding insects. These yeasts each release a rich bouquet of volatile metabolites, including a suite of known insect attractants from plant and floral scent. This overlap underlines the phylogenetic dimension of insect-yeast associations, which according to the fossil record long predate the appearance of flowering plants. Volatome composition is characteristic for each species, aligns with yeast taxonomy, and is further reflected by a differential behavioral response of cotton leafworm larvae, which naturally feed on foliage of a wide spectrum of broad-leaved plants. Larval discrimination may establish and maintain associations with yeasts and is also a substrate for designing sustainable insect management techniques. Yeasts form mutualistic interactions with insects. Hallmarks of this interaction include provision of essential nutrients, while insects facilitate yeast dispersal and growth on plant substrates. A phylogenetically ancient chemical dialogue coordinates this interaction, where the vocabulary, the volatile chemicals that mediate the insect response, remains largely unknown. Here, we used gas chromatography-mass spectrometry, followed by hierarchical cluster and orthogonal partial least-squares discriminant analyses, to profile the volatomes of six Metschnikowia spp., Cryptococcus nemorosus, and brewer’s yeast (Saccharomyces cerevisiae). The yeasts, which are all found in association with insects feeding on foliage or fruit, emit characteristic, species-specific volatile blends that reflect the phylogenetic context. Species specificity of these volatome profiles aligned with differential feeding of cotton leafworm (Spodoptera littoralis) larvae on these yeasts. Bioactivity correlates with yeast ecology; phylloplane species elicited a stronger response than fruit yeasts, and larval discrimination may provide a mechanism for establishment of insect-yeast associations. The yeast volatomes contained a suite of insect attractants known from plant and especially floral headspace, including (Z)-hexenyl acetate, ethyl (2E,4Z)-deca-2,4-dienoate (pear ester), (3E)-4,8-dimethylnona-1,3,7-triene (DMNT), linalool, α-terpineol, β-myrcene, or (E,E)-α-farnesene. A wide overlap of yeast and plant volatiles, notably floral scents, further emphasizes the prominent role of yeasts in plant-microbe-insect relationships, including pollination. The knowledge of insect-yeast interactions can be readily brought to practical application, as live yeasts or yeast metabolites mediating insect attraction provide an ample toolbox for the development of sustainable insect management. IMPORTANCE Yeasts interface insect herbivores with their food plants. Communication depends on volatile metabolites, and decoding this chemical dialogue is key to understanding the ecology of insect-yeast interactions. This study explores the volatomes of eight yeast species which have been isolated from foliage, from flowers or fruit, and from plant-feeding insects. These yeasts each release a rich bouquet of volatile metabolites, including a suite of known insect attractants from plant and floral scent. This overlap underlines the phylogenetic dimension of insect-yeast associations, which according to the fossil record long predate the appearance of flowering plants. Volatome composition is characteristic for each species, aligns with yeast taxonomy, and is further reflected by a differential behavioral response of cotton leafworm larvae, which naturally feed on foliage of a wide spectrum of broad-leaved plants. Larval discrimination may establish and maintain associations with yeasts and is also a substrate for designing sustainable insect management techniques.
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