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Ruedenauer FA. Strategies of flowering plants to avoid pollen collection by undesirable flower visitors. A commentary on 'High toxin concentration in pollen may deter collection by bees in butterfly-pollinated Rhododendron molle'. ANNALS OF BOTANY 2024:mcae088. [PMID: 38902985 DOI: 10.1093/aob/mcae088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Affiliation(s)
- Fabian A Ruedenauer
- Plant-Insect-Interactions, Research Department Life Science Systems, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
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2
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Bernauer OM, Jain A, de Bivort B, Holbrook NM, Myers SS, Ziska LH, Crall JD. Elevated atmospheric CO 2 has small, species-specific effects on pollen chemistry and plant growth across flowering plant species. Sci Rep 2024; 14:13760. [PMID: 38877021 PMCID: PMC11178917 DOI: 10.1038/s41598-024-63967-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 06/04/2024] [Indexed: 06/16/2024] Open
Abstract
Elevated atmospheric carbon dioxide (eCO2) can affect plant growth and physiology, which can, in turn, impact herbivorous insects, including by altering pollen or plant tissue nutrition. Previous research suggests that eCO2 can reduce pollen nutrition in some species, but it is unknown whether this effect is consistent across flowering plant species. We experimentally quantified the effects of eCO2 across multiple flowering plant species on plant growth in 9 species and pollen chemistry (%N an estimate for protein content and nutrition in 12 species; secondary chemistry in 5 species) in greenhouses. For pollen nutrition, only buckwheat significantly responded to eCO2, with %N increasing in eCO2; CO2 treatment did not affect pollen amino acid composition but altered secondary metabolites in buckwheat and sunflower. Plant growth under eCO2 exhibited two trends across species: plant height was taller in 44% of species and flower number was affected for 63% of species (3 species with fewer and 2 species with more flowers). The remaining growth metrics (leaf number, above-ground biomass, flower size, and flowering initiation) showed divergent, species-specific responses, if any. Our results indicate that future eCO2 is unlikely to uniformly change pollen chemistry or plant growth across flowering species but may have the potential to alter ecological interactions, or have particularly important effects on specialized pollinators.
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Affiliation(s)
- Olivia M Bernauer
- Department of Entomology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI, 53706, USA.
| | - Anupreksha Jain
- Department of Entomology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI, 53706, USA
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA
| | - Benjamin de Bivort
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA
| | - Samuel S Myers
- Bloomberg School of Public Health, Johns Hopkins University, 615 N Wolfe St, Baltimore, MD, 21205, USA
| | - Lewis H Ziska
- Mailman School of Public Health, Columbia University, 722 W. 168Th Street, New York, NY, 10032, USA
| | - James D Crall
- Department of Entomology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI, 53706, USA
- Department of Organismic and Evolutionary Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA
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3
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Rivest S, Lee ST, Cook D, Forrest JRK. Consequences of pollen defense compounds for pollinators and antagonists in a pollen-rewarding plant. Ecology 2024; 105:e4306. [PMID: 38590050 DOI: 10.1002/ecy.4306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 01/09/2024] [Accepted: 02/19/2024] [Indexed: 04/10/2024]
Abstract
Plants produce an array of defensive compounds with toxic or deterrent effects on insect herbivores. Pollen can contain relatively high concentrations of such defense compounds, but the causes and consequences of this enigmatic phenomenon remain mostly unknown. These compounds could potentially protect pollen against antagonists but could also reduce flower attractiveness to pollinators. We combined field observations of the pollen-rewarding Lupinus argenteus with chemical analysis and laboratory assays to test three hypotheses for the presence of pollen defense compounds: (1) these compounds are the result of spillover from adjacent tissues, (2) they protect against pollen thieves, and (3) they act as antimicrobial compounds. We also tested whether pollen defense compounds affect pollinator behavior. We found a positive relationship between alkaloid concentrations in pollen and petals, supporting the idea that pollen defense compounds partly originate from spillover. However, pollen and petals exhibited quantitatively (but not qualitatively) distinct alkaloid profiles, suggesting that plants can adjust pollen alkaloid composition independently from that of adjacent tissues. We found no relationship between pollen alkaloid concentration and the abundance of pollen thieves in Lupinus flowers. However, pollen alkaloids were negatively associated with bacterial abundance. Finally, plants with more alkaloids in their pollen received more pollinator visits, but these visits were shorter, resulting in no change in the overall number of flowers visited. We propose that pollen defense compounds are partly the result of spillover from other tissues, while they also play an antimicrobial role. The absence of negative effects of these compounds on pollinator visitation likely allows their maintenance in pollen at relatively high concentrations. Taken together, our results suggest that pollen alkaloids affect and are mediated by the interplay of multiple interactions.
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Affiliation(s)
- Sébastien Rivest
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
- Rocky Mountain Biological Laboratory, Crested Butte, Colorado, USA
| | - Stephen T Lee
- USDA ARS Poisonous Plant Research Laboratory, Logan, Utah, USA
| | - Daniel Cook
- USDA ARS Poisonous Plant Research Laboratory, Logan, Utah, USA
| | - Jessica R K Forrest
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
- Rocky Mountain Biological Laboratory, Crested Butte, Colorado, USA
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Feng HH, Lv XW, Yang XC, Huang SQ. High toxin concentration in pollen may deter collection by bees in butterfly-pollinated Rhododendron molle. ANNALS OF BOTANY 2024:mcae047. [PMID: 38507570 DOI: 10.1093/aob/mcae047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Indexed: 03/22/2024]
Abstract
BACKGROUNDS AND AIMS The hypothesis that plants evolve features that protect accessible pollen from consumption by flower visitors remains poorly understood. METHODS To explore potential chemical defenses against pollen consumption, we examined the pollinator assemblage, foraging behaviour, visitation frequency and pollen transfer efficiency in Rhododendron molle, a highly toxic shrub containing Rhodojaponin III. Nutrient (protein and lipid) and toxic components in pollen and other tissues were measured. KEY RESULTS Overall in the five populations, floral visits by butterflies and bumblebees were relatively more frequent than visits by honeybees. All foraged for nectar but not pollen. Butterflies did not differ from bumblebees in the amount of pollen removed per visit, but deposited more pollen per visit. Pollination experiments indicated that R. molle was self-compatible, but both fruit and seed production were pollen limited. Our analysis indicated that the pollen was not protein-poor and had a higher concentration of the toxic compound Rhodojaponin III than petals and leaves, which compound was undetectable in nectar. CONCLUSION Pollen toxicity in Rhododendron flowers may discourage pollen robbers (bees) from taking the freely accessible pollen grains, while the toxin-free nectar rewards effective pollinators, promoting pollen transfer. This preliminary study supports the hypothesis that chemical defense in pollen would be likely to evolve in species without physical protection from pollinivores.
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Affiliation(s)
- Hui-Hui Feng
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
- Department of Ecology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiao-Wen Lv
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | - Xiao-Chen Yang
- College of Biology and Environmental Sciences, Jishou University, Jishou 416000, Hunan Province, China
| | - Shuang-Quan Huang
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
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5
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Rivest S, Muralidhar M, Forrest JRK. Pollen chemical and mechanical defences restrict host-plant use by bees. Proc Biol Sci 2024; 291:20232298. [PMID: 38471551 PMCID: PMC10932708 DOI: 10.1098/rspb.2023.2298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/31/2024] [Indexed: 03/14/2024] Open
Abstract
Plants produce an array of chemical and mechanical defences that provide protection against many herbivores and pathogens. Putatively defensive compounds and structures can even occur in floral rewards: for example, the pollen of some plant taxa contains toxic compounds or possesses conspicuous spines. Yet little is known about whether pollen defences restrict host-plant use by bees. In other words, do bees, like other insect herbivores, tolerate the defences of their specific host plants while being harmed by non-host defences? To answer this question, we compared the effects of a chemical defence from Lupinus (Fabaceae) pollen and a putative mechanical defence (pollen spines) from Asteraceae pollen on larval survival of nine bee species in the tribe Osmiini (Megachilidae) varying in their pollen-host use. We found that both types of pollen defences reduce larval survival rate in some bee species. These detrimental effects were, however, mediated by host-plant associations, with bees being more tolerant of the pollen defences of their hosts, relative to the defences of plant taxa exploited by other species. This pattern strongly suggests that bees are adapted to the pollen defences of their hosts, and that host-plant use by bees is constrained by their ability to tolerate such defences.
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Affiliation(s)
- Sébastien Rivest
- Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5
- Rocky Mountain Biological Laboratory, Crested Butte, CO 81224, USA
| | | | - Jessica R. K. Forrest
- Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5
- Rocky Mountain Biological Laboratory, Crested Butte, CO 81224, USA
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6
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Scanlan JL, Robin C. Phylogenomics of the Ecdysteroid Kinase-like (EcKL) Gene Family in Insects Highlights Roles in Both Steroid Hormone Metabolism and Detoxification. Genome Biol Evol 2024; 16:evae019. [PMID: 38291829 PMCID: PMC10859841 DOI: 10.1093/gbe/evae019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 11/21/2023] [Accepted: 01/23/2024] [Indexed: 02/01/2024] Open
Abstract
The evolutionary dynamics of large gene families can offer important insights into the functions of their individual members. While the ecdysteroid kinase-like (EcKL) gene family has previously been linked to the metabolism of both steroid molting hormones and xenobiotic toxins, the functions of nearly all EcKL genes are unknown, and there is little information on their evolution across all insects. Here, we perform comprehensive phylogenetic analyses on a manually annotated set of EcKL genes from 140 insect genomes, revealing the gene family is comprised of at least 13 subfamilies that differ in retention and stability. Our results show the only two genes known to encode ecdysteroid kinases belong to different subfamilies and therefore ecdysteroid metabolism functions must be spread throughout the EcKL family. We provide comparative phylogenomic evidence that EcKLs are involved in detoxification across insects, with positive associations between family size and dietary chemical complexity, and we also find similar evidence for the cytochrome P450 and glutathione S-transferase gene families. Unexpectedly, we find that the size of the clade containing a known ecdysteroid kinase is positively associated with host plant taxonomic diversity in Lepidoptera, possibly suggesting multiple functional shifts between hormone and xenobiotic metabolism. Our evolutionary analyses provide hypotheses of function and a robust framework for future experimental studies of the EcKL gene family. They also open promising new avenues for exploring the genomic basis of dietary adaptation in insects, including the classically studied coevolution of butterflies with their host plants.
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Affiliation(s)
- Jack L Scanlan
- School of BioSciences, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Charles Robin
- School of BioSciences, The University of Melbourne, Melbourne, VIC 3010, Australia
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Sasidharan R, Brokate L, Eilers EJ, Müller C. Chemodiversity in flowers of Tanacetum vulgare has consequences on a florivorous beetle. PLANT BIOLOGY (STUTTGART, GERMANY) 2023; 25:1071-1082. [PMID: 37703504 DOI: 10.1111/plb.13576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/18/2023] [Indexed: 09/15/2023]
Abstract
The chemical composition of plant individuals can vary, leading to high intraspecific chemodiversity. Diversity of floral chemistry may impact the responses of flower-feeding insects. Tanacetum vulgare plants vary significantly in their leaf terpenoid composition, forming distinct chemotypes. We investigated the composition of terpenoids and nutrients of flower heads and pollen in plants belonging to three chemotypes - dominated either by β-thujone (BThu), artemisia ketone (Keto) or a mixture of (Z)-myroxide, santolina triene, and artemisyl acetate (Myrox) - using different analytical platforms. We tested the effects of these differences on preferences, weight gain and performance of adults of the shining flower beetle, Olibrus aeneus. The terpenoid composition and diversity of flower heads and pollen significantly differed among individuals belonging to the above chemotypes, while total concentrations of pollen terpenoids, sugars, amino acids, and lipids did not differ. Beetles preferred BThu over the Myrox chemotype in both olfactory and contact choice assays, while the Keto chemotype was marginally repellent according to olfactory assays. The beetles gained the least weight within 48 h and their initial mortality was highest when feeding exclusively on floral tissues of the Myrox chemotype. Short-term weight gain and long-term performance were highest when feeding on the BThu chemotype. In conclusion, the beetles showed chemotype-specific responses towards different T. vulgare chemotypes, which may be attributed to the terpenoid composition in flower heads and pollen rather than to differences in nutrient profiles. Both richness and overall diversity are important factors when determining chemodiversity of individual plants and their consequences on interacting insects.
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Affiliation(s)
- R Sasidharan
- Department of Chemical Ecology, Bielefeld University, Bielefeld, Germany
| | - L Brokate
- Department of Chemical Ecology, Bielefeld University, Bielefeld, Germany
| | - E J Eilers
- Department of Chemical Ecology, Bielefeld University, Bielefeld, Germany
- CTL GmbH Bielefeld, Bielefeld, Germany
| | - C Müller
- Department of Chemical Ecology, Bielefeld University, Bielefeld, Germany
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8
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Sasidharan R, Junker RR, Eilers EJ, Müller C. Floral volatiles evoke partially similar responses in both florivores and pollinators and are correlated with non-volatile reward chemicals. ANNALS OF BOTANY 2023; 132:1-14. [PMID: 37220889 PMCID: PMC10550281 DOI: 10.1093/aob/mcad064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 05/19/2023] [Indexed: 05/25/2023]
Abstract
BACKGROUND Plants often use floral displays to attract mutualists and prevent antagonist attacks. Chemical displays detectable from a distance include attractive or repellent floral volatile organic compounds (FVOCs). Locally, visitors perceive contact chemicals including nutrients but also deterrent or toxic constituents of pollen and nectar. The FVOC and pollen chemical composition can vary intra- and interspecifically. For certain pollinator and florivore species, responses to these compounds are studied in specific plant systems, yet we lack a synthesis of general patterns comparing these two groups and insights into potential correlations between FVOC and pollen chemodiversity. SCOPE We reviewed how FVOCs and non-volatile floral chemical displays, i.e. pollen nutrients and toxins, vary in composition and affect the detection by and behaviour of insect visitors. Moreover, we used meta-analyses to evaluate the detection of and responses to FVOCs by pollinators vs. florivores within the same plant genera. We also tested whether the chemodiversity of FVOCs, pollen nutrients and toxins is correlated, hence mutually informative. KEY RESULTS According to available data, florivores could detect more FVOCs than pollinators. Frequently tested FVOCs were often reported as pollinator-attractive and florivore-repellent. Among FVOCs tested on both visitor groups, there was a higher number of attractive than repellent compounds. FVOC and pollen toxin richness were negatively correlated, indicating trade-offs, whereas a marginal positive correlation between the amount of pollen protein and toxin richness was observed. CONCLUSIONS Plants face critical trade-offs, because floral chemicals mediate similar information to both mutualists and antagonists, particularly through attractive FVOCs, with fewer repellent FVOCs. Furthermore, florivores might detect more FVOCs, whose richness is correlated with the chemical richness of rewards. Chemodiversity of FVOCs is potentially informative of reward traits. To gain a better understanding of the ecological processes shaping floral chemical displays, more research is needed on floral antagonists of diverse plant species and on the role of floral chemodiversity in visitor responses.
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Affiliation(s)
- Rohit Sasidharan
- Department of Chemical Ecology, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Robert R Junker
- Department of Biology, Evolutionary Ecology of Plants, University of Marburg, Karl-von-Frisch-Straße 8, 35043 Marburg, Germany
- Department of Environment and Biodiversity, University of Salzburg, Kapitalgasse 4-6, 5020 Salzburg, Austria
| | - Elisabeth J Eilers
- Department of Chemical Ecology, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
- CTL GmbH Bielefeld, Krackser Straße 12, 33659 Bielefeld, Germany
| | - Caroline Müller
- Department of Chemical Ecology, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
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9
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Leponiemi M, Freitak D, Moreno-Torres M, Pferschy-Wenzig EM, Becker-Scarpitta A, Tiusanen M, Vesterinen EJ, Wirta H. Honeybees' foraging choices for nectar and pollen revealed by DNA metabarcoding. Sci Rep 2023; 13:14753. [PMID: 37679501 PMCID: PMC10484984 DOI: 10.1038/s41598-023-42102-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 09/05/2023] [Indexed: 09/09/2023] Open
Abstract
Honeybees are the most widespread managed pollinators of our food crops, and a crucial part of their well-being is a suitable diet. Yet, we do not know how they choose flowers to collect nectar or pollen from. Here we studied forty-three honeybee colonies in six apiaries over a summer, identifying the floral origins of honey and hive-stored pollen samples by DNA-metabarcoding. We recorded the available flowering plants and analyzed the specialized metabolites in honey. Overall, we find that honeybees use mostly the same plants for both nectar and pollen, yet per colony less than half of the plant genera are used for both nectar and pollen at a time. Across samples, on average fewer plant genera were used for pollen, but the composition was more variable among samples, suggesting higher selectivity for pollen sources. Of the available flowering plants, honeybees used only a fraction for either nectar or pollen foraging. The time of summer guided the plant choices the most, and the location impacted both the plants selected and the specialized metabolite composition in honey. Thus, honeybees are selective for both nectar and pollen, implicating a need of a wide variety of floral resources to choose an optimal diet from.
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Affiliation(s)
- Matti Leponiemi
- Institute of Biology, Karl-Franzen University of Graz, Universitätsplatz 2, 8010, Graz, Austria
| | - Dalial Freitak
- Institute of Biology, Karl-Franzen University of Graz, Universitätsplatz 2, 8010, Graz, Austria
| | - Miguel Moreno-Torres
- Institute of Environmental Systems Science, Karl-Franzens-Universität Graz, Merangasse 18/I, 8010, Graz, Austria
| | - Eva-Maria Pferschy-Wenzig
- Institute of Pharmaceutical Sciences, Pharmacognosy, University of Graz, Beethovenstraße 8, Graz, Austria
| | | | - Mikko Tiusanen
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zürich, Switzerland
- Department of Agricultural Sciences, University of Helsinki, Latokartanonkaari 5, P.O. Box 27, 00014, Helsinki, Finland
| | - Eero J Vesterinen
- Department of Biology, University of Turku, Vesilinnantie 5, Turku, Finland
| | - Helena Wirta
- Department of Agricultural Sciences, University of Helsinki, Latokartanonkaari 5, P.O. Box 27, 00014, Helsinki, Finland.
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Rutkowski D, Weston M, Vannette RL. Bees just wanna have fungi: a review of bee associations with nonpathogenic fungi. FEMS Microbiol Ecol 2023; 99:fiad077. [PMID: 37422442 PMCID: PMC10370288 DOI: 10.1093/femsec/fiad077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/15/2023] [Accepted: 07/06/2023] [Indexed: 07/10/2023] Open
Abstract
Bee-fungus associations are common, and while most studies focus on entomopathogens, emerging evidence suggests that bees associate with a variety of symbiotic fungi that can influence bee behavior and health. Here, we review nonpathogenic fungal taxa associated with different bee species and bee-related habitats. We synthesize results of studies examining fungal effects on bee behavior, development, survival, and fitness. We find that fungal communities differ across habitats, with some groups restricted mostly to flowers (Metschnikowia), while others are present almost exclusively in stored provisions (Zygosaccharomyces). Starmerella yeasts are found in multiple habitats in association with many bee species. Bee species differ widely in the abundance and identity of fungi hosted. Functional studies suggest that yeasts affect bee foraging, development, and pathogen interactions, though few bee and fungal taxa have been examined in this context. Rarely, fungi are obligately beneficial symbionts of bees, whereas most are facultative bee associates with unknown or ecologically contextual effects. Fungicides can reduce fungal abundance and alter fungal communities associated with bees, potentially disrupting bee-fungi associations. We recommend that future study focus on fungi associated with non-honeybee species and examine multiple bee life stages to document fungal composition, abundance, and mechanistic effects on bees.
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Affiliation(s)
- Danielle Rutkowski
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
| | - Makena Weston
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
| | - Rachel L Vannette
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
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Shapter FM, Granados-Soler JL, Stewart AJ, Bertin FR, Allavena R. Equine Crofton Weed ( Ageratina spp.) Pneumotoxicity: What Do We Know and What Do We Need to Know? Animals (Basel) 2023; 13:2082. [PMID: 37443880 DOI: 10.3390/ani13132082] [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: 06/01/2023] [Revised: 06/16/2023] [Accepted: 06/19/2023] [Indexed: 07/15/2023] Open
Abstract
Crofton weed (Ageratina adenophora) is a global and highly invasive weed, with ingestion causing severe respiratory disease in horses, leading to irreversible and untreatable pulmonary fibrosis and oedema. While reports of equine pneumotoxicity remain common in Australia and New Zealand, equine pneumotoxicity may be underdiagnosed in other countries where Crofton weed is endemic but poorly differentiated. The pathogenesis of Crofton weed toxicity following ingestion has been well described in a number of different animal models, including rodents, rabbits, and goats. However, induced toxicity is organ-selective across different animal species, and these vastly differ from the pathogenesis described in horses, both clinically and after experimental exposure. Sources of variation may include species-specific susceptibility to different toxins present in the plant, different mechanistic processes of toxicity, and species differences in toxin biotransformation and bioactivation across different organs. Considering disease severity and Crofton weed's invasiveness globally, assessing published toxicological and exposure data is necessary to advance research, identify specific toxins for horses, and possible prophylactic and therapeutic strategies. This review presents an overview of the available literature on equine toxicity, parallels between toxicity in horses and other animal species, and important aspects to be included in the future research agenda.
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Affiliation(s)
- Frances Marie Shapter
- School of Veterinary Science, University of Queensland Gatton, 5391 Warrego Highway, Gatton, QLD 4343, Australia
| | - José Luis Granados-Soler
- School of Veterinary Science, University of Queensland Gatton, 5391 Warrego Highway, Gatton, QLD 4343, Australia
| | - Allison J Stewart
- School of Veterinary Science, University of Queensland Gatton, 5391 Warrego Highway, Gatton, QLD 4343, Australia
| | - Francois Rene Bertin
- School of Veterinary Science, University of Queensland Gatton, 5391 Warrego Highway, Gatton, QLD 4343, Australia
| | - Rachel Allavena
- School of Veterinary Science, University of Queensland Gatton, 5391 Warrego Highway, Gatton, QLD 4343, Australia
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12
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Bellec L, Cortesero AM, Marnet N, Faure S, Hervé MR. Age-specific allocation of glucosinolates within plant reproductive tissues. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 331:111690. [PMID: 36965631 DOI: 10.1016/j.plantsci.2023.111690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 06/18/2023]
Abstract
The Optimal Defense Theory (ODT) predicts that the distribution of defenses within a plant should mirror the value and vulnerability of each tissue. Although the ODT has received much experimental support, very few studies have examined defense allocation among reproductive tissues and none assessed simultaneously how these defenses evolve with age. We quantified glucosinolates in perianths, anthers and pistils at different bud maturity stages (i.e., intermediate flower buds, old flower buds and flowers) of undamaged and mechanically damaged plants of an annual brassicaceous species. The youngest leaf was used as a reference for vegetative organs, since it is predicted to be one of the most defended. In line with ODT predictions, reproductive tissues were more defended than vegetative tissues constitutively, and within the former, pistils and anthers more defended than perianths. No change in the overall defense level was found between bud maturity stages, but a significant temporal shift was observed between pistils and anthers. Contrary to ODT predictions, mechanical damage did not induce systemic defenses in leaves but only in pistils. Our results show that defense allocation in plant reproductive tissues occurs at fine spatial and temporal scales, extending the application framework of the ODT. They also demonstrate interactions between space and time in fine-scale defense allocation.
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Affiliation(s)
- Laura Bellec
- IGEPP, INRAE, Institut Agro, Univ Rennes, 35000 Rennes, France; Innolea, 6 Chemin de Panedautes, 31700 Mondonville, France.
| | | | | | | | - Maxime R Hervé
- IGEPP, INRAE, Institut Agro, Univ Rennes, 35000 Rennes, France
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13
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Fattorini R, Egan PA, Rosindell J, Farrell IW, Stevenson PC. Grayanotoxin I variation across tissues and species of Rhododendron suggest pollinator-herbivore defence trade-offs. PHYTOCHEMISTRY 2023; 212:113707. [PMID: 37149121 DOI: 10.1016/j.phytochem.2023.113707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/25/2023] [Accepted: 05/03/2023] [Indexed: 05/08/2023]
Abstract
Grayanotoxin I (GTX I) is a major toxin in leaves of Rhododendron species, where it provides a defence against insect and vertebrate herbivores. Surprisingly, it is also present in R. ponticum nectar, and this can hold important implications for plant-pollinator mutualisms. However, knowledge of GTX I distributions across the genus Rhododendron and in different plant materials is currently limited, despite the important ecological function of this toxin. Here we characterise GTX I expression in the leaves, petals, and nectar of seven Rhododendron species. Our results indicated interspecific variation in GTX I concentration across all species. GTX I concentrations were consistently higher in leaves compared to petals and nectar. Our findings provide preliminary evidence for phenotypic correlation between GTX I concentrations in defensive tissues (leaves and petals) and floral rewards (nectar), suggesting that Rhododendron species may commonly experience functional trade-offs between herbivore defence and pollinator attraction.
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Affiliation(s)
- Róisín Fattorini
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire, SL5 7PY, UK; Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK.
| | - Paul A Egan
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, PO Box 102, Alnarp 23053, Sweden
| | - James Rosindell
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire, SL5 7PY, UK
| | - Iain W Farrell
- Royal Botanic Gardens, Kew Green, Kew, Richmond, Surrey, TW9 3AE UK
| | - Philip C Stevenson
- Royal Botanic Gardens, Kew Green, Kew, Richmond, Surrey, TW9 3AE UK; Natural Resources Institute, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, UK
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14
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Heiling JM, Irwin RE, Morris WF. Conflicting constraints on male mating success shape reward size in pollen-rewarding plants. AMERICAN JOURNAL OF BOTANY 2023:e16158. [PMID: 37040609 DOI: 10.1002/ajb2.16158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 06/19/2023]
Abstract
PREMISE Pollen-rewarding plants face two conflicting constraints: They must prevent consumptive emasculation while remaining attractive to pollen-collecting visitors. Small pollen packages (the quantity of pollen available in a single visit) may discourage visitors from grooming (reducing consumptive loss) but may also decrease a plant's attractiveness to pollen-collecting visitors. What package size best balances these two constraints? METHODS We modeled the joint effects of pollinators' grooming behaviors and package size preferences on the optimal package size (i.e., the size that maximizes pollen donation). We then used this model to examine Darwin's conjecture that selection should favor increased pollen production in pollen-rewarding plants. RESULTS When package size preferences are weak, minimizing package size reduces grooming losses and should be favored (as in previous theoretical studies). Stronger preferences select for larger packages despite the associated increase to grooming loss because loss associated with nonremoval of smaller packages is even greater. Total pollen donation increases with production (as Darwin suggested). However, if floral visitation declines or packages size preference increases with overall pollen availability, the fraction of pollen donated may decline as per-plant pollen production increases. Hence, increasing production may result in diminishing returns. CONCLUSIONS Pollen-rewarding plants can balance conflicting constraints on pollen donation by producing intermediate-sized pollen packages. Strictly pollen-rewarding plants may have responded to past selection to produce more pollen in total, but diminishing returns may limit the strength of that selection.
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Affiliation(s)
- Jacob M Heiling
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, USA
- Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC, USA
| | - Rebecca E Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, USA
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15
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Fetters AM, Ashman TL. The pollen virome: A review of pollen-associated viruses and consequences for plants and their interactions with pollinators. AMERICAN JOURNAL OF BOTANY 2023:e16144. [PMID: 36924316 DOI: 10.1002/ajb2.16144] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 06/18/2023]
Abstract
The movement of pollen grains from anthers to stigmas, often by insect pollinator vectors, is essential for plant reproduction. However, pollen is also a unique vehicle for viral spread. Pollen-associated plant viruses reside on the outside or inside of pollen grains, infect susceptible individuals through vertical or horizontal infection pathways, and can decrease plant fitness. These viruses are transferred with pollen between plants by pollinator vectors as they forage for floral resources; thus, pollen-associated viral spread is mediated by floral and pollen grain phenotypes and pollinator traits, much like pollination. Most of what is currently known about pollen-associated viruses was discovered through infection and transmission experiments in controlled settings, usually involving one virus and one plant species of agricultural or horticultural interest. In this review, we first provide an updated, comprehensive list of the recognized pollen-associated viruses. Then, we summarize virus, plant, pollinator vector, and landscape traits that can affect pollen-associated virus transmission, infection, and distribution. Next, we highlight the consequences of plant-pollinator-virus interactions that emerge in complex communities of co-flowering plants and pollinator vectors, such as pollen-associated virus spread between plant species and viral jumps from plant to pollinator hosts. We conclude by emphasizing the need for collaborative research that bridges pollen biology, virology, and pollination biology.
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Affiliation(s)
- Andrea M Fetters
- Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Avenue, Pittsburgh, PA, 15260, USA
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, 318 W. 12th Avenue, Columbus, OH, 43210, USA
| | - Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Avenue, Pittsburgh, PA, 15260, USA
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16
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Abstract
Stingless bees form perennial colonies of honey-making insects. The >600 species of stingless bees, mainly Neotropical, live throughout tropical latitudes. Foragers influence floral biology, plant reproduction, microbe dispersal, and diverse ecosystem functions. As tropical forest residents since the upper Cretaceous, they have had a long evolutionary history without competition from honey bees. Most stingless bees are smaller than any Apis species and recruit nest mates to resources, while their defense strategies exclude stinging behavior but incorporate biting. Stingless bees have diversified ecologically; excel in nesting site selection and mutualisms with plants, arthropods, and microbes; and display opportunism, including co-opting plant defenses. As their biology becomes better known, applications to human endeavors are imposing selective pressures from exploitation and approaches to conservation that entail colony extraction from wildlands. Although some meliponines can adjust to new conditions, their populations shall require tropical diversity for survival and reproduction.
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Affiliation(s)
- David W Roubik
- Smithsonian Tropical Research Institute, Balboa, Republic of Panamá;
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17
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Hao K, Xu Q, Huang SQ. Pollen-feeding behavior of diverse insects on Geranium delavayi, a flower with large, accessible pollen grains. AMERICAN JOURNAL OF BOTANY 2023; 110:e16113. [PMID: 36462154 DOI: 10.1002/ajb2.16113] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
PREMISE Why have pollen grains evolved to be exceptionally large in some species? Pollen-feeding hypothesis suggests that if the proportion of pollen amounts for feeding is reduced in a flower, the low allocation to pollen number would allow pollen grains to be larger. METHODS To examine whether species with large pollen grains experience low pollen consumption, the behavior of insects feeding on nectar and pollen was observed and pollen transfer efficiency was estimated for four visitor types in Geranium delavayi. To see whether bees actively collected pollen, the numbers of grains in pollen baskets and on the body were compared. Both nutritional value (total protein and lipid) and chemical defense (phenolic metabolites) in pollen against pollen feeders were measured. RESULTS Bumblebees and honeybees foraged for nectar, rarely groomed pollen into corbiculae, and had >5× higher pollen transfer efficiency than smaller solitary bees and flies, which were pollen eaters that removed more pollen but deposited less. Pollen grains were characterized by low protein and high lipid content with a low protein-lipid ratio, an unfavorable combination for bumblebees. Three secondary metabolites were significantly higher in pollen grains (7.77 mg/g) than in petals (1.08 mg/g) or in nectar (0.44 mg/g), suggesting stronger chemical defense in pollen. CONCLUSIONS Our results indicated that large bees took nectar but little of the nutritionally poor and highly toxic pollen. These data support one prediction of the pollen-feeding hypothesis, that species with few and large pollen grains would also have low pollen-consumption rates.
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Affiliation(s)
- Kai Hao
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Qi Xu
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Shuang-Quan Huang
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
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18
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Mancini E, Sabatelli S, Hu Y, Frasca S, Di Giulio A, Audisio P, Brown CD, Russell JA, Trizzino M. Uncovering Active Bacterial Symbionts in Three Species of Pollen-feeding Beetles (Nitidulidae: Meligethinae). MICROBIAL ECOLOGY 2023; 85:335-339. [PMID: 35059821 DOI: 10.1007/s00248-022-01964-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Microbial symbionts enable many phytophagous insects to specialize on plant-based diets through a range of metabolic services. Pollen comprises one-plant tissue consumed by such herbivores. While rich in lipids and proteins, its nutrient content is often imbalanced and difficult-to-access due to a digestibly recalcitrant cell wall. Pollen quality can be further degraded by harmful allelochemicals. To identify microbes that may aid in palynivory, we performed cDNA-based 16S rRNA metabarcoding on three related pollen beetles (Nitidulidae: Meligethinae) exhibiting different dietary breadths: Brassicogethes aeneus, B. matronalis, and Meligethes atratus. Nine bacterial symbionts (i.e., 97% OTUs) exhibited high metabolic activity during active feeding. Subsequent PCR surveys revealed varying prevalence of those from three Rickettsialles genera-Lariskella, Rickettsia, and Wolbachia-within beetle populations. Our findings lay the groundwork for future studies on the influence of phylogeny and diet on palynivorous insect microbiomes, and roles of symbionts in the use of challenging diets.
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Affiliation(s)
- Emiliano Mancini
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Viale dell'Università 32, 00185, Rome, Italy.
| | - Simone Sabatelli
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Viale dell'Università 32, 00185, Rome, Italy
| | - Yi Hu
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA, 19104, USA
- State Key Laboratory of Earth Surface Process and Resource Ecology and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Sara Frasca
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Viale dell'Università 32, 00185, Rome, Italy
| | - Andrea Di Giulio
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146, Rome, Italy
| | - Paolo Audisio
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Viale dell'Università 32, 00185, Rome, Italy
| | - Christopher D Brown
- Department of Genetics, University of Pennsylvania, 538B 415, Curie Blvd, Philadelphia, PA, 19103, USA
| | - Jacob A Russell
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA, 19104, USA
| | - Marco Trizzino
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 S 10TH street, Philadelphia, PA, 19107, USA
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19
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Echium vulgare and Echium plantagineum: A Comparative Study to Evaluate Their Inclusion in Mediterranean Urban Green Roofs. SUSTAINABILITY 2022. [DOI: 10.3390/su14159581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Green roofs (GRs) are proposed to offset against numerous environmental and socio-economic concerns associated with climate change and urban sprawl. In Mediterranean urban areas, to protect and conserve biodiversity through GRs, the use of native plant species from arid environments and with shallow roots is generally recommended. In north Europe, Echium vulgare L. is widely used on GRs for its tolerance to abiotic stresses and its attractiveness for bees; unfortunately, since this species requires cold winters to induce flowering and warm wet summers for vegetative growths, its adaptability to Mediterranean GRs has been questioned. The current study is based on the hypothesis that Echium plantagineum L. can adapt better to the Mediterranean environment than E. vulgare and offer blooms to pollinators, thus providing the important urban ecosystem service (UES) of protecting entomofauna biodiversity. To compare the adaptability of E. plantagineum vs. E. vulgare, both Echium species were grown and studied on the extensive GR installed at ENEA Casaccia Research Center, in the north of Rome, Lazio, Italy. The comparative analysis of the GR performance of the two species was based on several plant-related traits, including seed morphology, rosette stage, inflorescence, flower and root-related traits, and their biological life cycle, most of them showing significant differences (for example, rosette area was 1.42-fold major in E. plantagineum than in E. vulgare). The information provided in this manuscript will be useful to update the herbarium records for conservation biology. A dramatic water stress was purposely applied in the GR before the end of the hot summer season, and while E. plantagineum faced with success the imposed dehydration (88.4% vegetation cover), E. vulgare did not (7.5% vegetation cover), presumably because of its biennial life cycle which did not allow it to complete seed maturation (only 46.9% percentage mature seeds in E. vulgare respect to 89.5% in E. plantagineum). In summary, as the main result, this work shows that in Mediterranean areas, the inclusion of E. plantagineum in seed mixes for flower meadow GRs could represent a valuable alternative to E. vulgare in temperate areas, providing a safeguard for pollinators and allowing water and energy saving.
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20
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Palmer-Young EC, Schwarz RS, Chen Y, Evans JD. Can floral nectars reduce transmission of Leishmania? PLoS Negl Trop Dis 2022; 16:e0010373. [PMID: 35551517 PMCID: PMC9098005 DOI: 10.1371/journal.pntd.0010373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 03/29/2022] [Indexed: 11/19/2022] Open
Abstract
Background Insect-vectored Leishmania are responsible for loss of more disability-adjusted life years than any parasite besides malaria. Elucidation of the environmental factors that affect parasite transmission by vectors is essential to develop sustainable methods of parasite control that do not have off-target effects on beneficial insects or environmental health. Many phytochemicals that inhibit growth of sand fly-vectored Leishmania—which have been exhaustively studied in the search for phytochemical-based drugs—are abundant in nectars, which provide sugar-based meals to infected sand flies. Principle findings In a quantitative meta-analysis, we compare inhibitory phytochemical concentrations for Leishmania to concentrations present in floral nectar and pollen. We show that nectar concentrations of several flowering plant species exceed those that inhibit growth of Leishmania cell cultures, suggesting an unexplored, landscape ecology-based approach to reduce Leishmania transmission. Significance If nectar compounds are as effective against parasites in the sand fly gut as predicted from experiments in vitro, strategic planting of antiparasitic phytochemical-rich floral resources or phytochemically enriched baits could reduce Leishmania loads in vectors. Such interventions could provide an environmentally friendly complement to existing means of disease control. Leishmania parasites infect over a million people each year—including over 200,000 infections with deadly visceral leishmaniasis—resulting in a greater health burden than any human parasite besides malaria. Leishmania infections of humans are transmitted by blood-feeding sand flies, which also consume floral nectar. Nectar contains many chemicals that inhibit Leishmania growth and are candidate treatments for infection of humans. However, these same compounds could also reduce infection in nectar-consuming sand flies. By combining existing data on the chemistry of nectar and sensitivity of Leishmania to plant compounds, we show that some floral nectars contain sufficient chemical concentrations to inhibit growth of insect-stage Leishmania. Our results suggest that consumption of these nectars could reduce parasite loads in sand flies and transmission of parasites to new human hosts. In contrast to insecticide-based methods of sand fly control, incorporation of antiparasitic nectar sources into landscapes and domestic settings could benefit public health without threatening beneficial insects. These findings suggest an unexplored, landscape-based approach to reduce transmission of a major neglected tropical disease worldwide.
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Affiliation(s)
- Evan C. Palmer-Young
- USDA-ARS Bee Research Laboratory, Beltsville, Maryland, United States of America
- * E-mail: ,
| | - Ryan S. Schwarz
- Department of Biology, Fort Lewis College, Durango, Colorado, United States of America
| | - Yanping Chen
- USDA-ARS Bee Research Laboratory, Beltsville, Maryland, United States of America
| | - Jay D. Evans
- USDA-ARS Bee Research Laboratory, Beltsville, Maryland, United States of America
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21
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Bellec L, Seimandi‐Corda G, Menacer K, Trabalon M, Ollivier J, Lunel C, Faure S, Cortesero A, Hervé M. Factors driving the within‐plant patterns of resource exploitation in a herbivore. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Laura Bellec
- IGEPP‐UMR 1349, INRAE, Institut Agro, Univ Rennes 1, 35000 Rennes France
- Innolea, 6 Chemin de Panedautes, 31700 Mondonville France
| | - Gaëtan Seimandi‐Corda
- IGEPP‐UMR 1349, INRAE, Institut Agro, Univ Rennes 1, 35000 Rennes France
- Biointeractions and Crop protections, Rothamsted Research Harpenden
| | - Kathleen Menacer
- IGEPP‐UMR 1349, INRAE, Institut Agro, Univ Rennes 1, 35000 Rennes France
| | - Marie Trabalon
- EthoS‐UMR 6552, CNRS, Univ Rennes 1, 35000 Rennes France
| | - Jérôme Ollivier
- IGEPP‐UMR 1349, INRAE, Institut Agro, Univ Rennes 1, 35000 Rennes France
- ISCR, CNRS, 35000 Rennes France
| | - Christophe Lunel
- IGEPP‐UMR 1349, INRAE, Institut Agro, Univ Rennes 1, 35000 Rennes France
| | | | | | - Maxime Hervé
- IGEPP‐UMR 1349, INRAE, Institut Agro, Univ Rennes 1, 35000 Rennes France
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22
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Fitch G, Figueroa LL, Koch H, Stevenson PC, Adler LS. Understanding effects of floral products on bee parasites: Mechanisms, synergism, and ecological complexity. Int J Parasitol Parasites Wildl 2022; 17:244-256. [PMID: 35299588 PMCID: PMC8920997 DOI: 10.1016/j.ijppaw.2022.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 12/27/2022]
Abstract
Floral nectar and pollen commonly contain diverse secondary metabolites. While these compounds are classically thought to play a role in plant defense, recent research indicates that they may also reduce disease in pollinators. Given that parasites have been implicated in ongoing bee declines, this discovery has spurred interest in the potential for 'medicinal' floral products to aid in pollinator conservation efforts. We review the evidence for antiparasitic effects of floral products on bee diseases, emphasizing the importance of investigating the mechanism underlying antiparasitic effects, including direct or host-mediated effects. We discuss the high specificity of antiparasitic effects of even very similar compounds, and highlight the need to consider how nonadditive effects of multiple compounds, and the post-ingestion transformation of metabolites, mediate the disease-reducing capacity of floral products. While the bulk of research on antiparasitic effects of floral products on bee parasites has been conducted in the lab, we review evidence for the impact of such effects in the field, and highlight areas for future research at the floral product-bee disease interface. Such research has great potential both to enhance our understanding of the role of parasites in shaping plant-bee interactions, and the role of plants in determining bee-parasite dynamics. This understanding may in turn reveal new avenues for pollinator conservation.
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Affiliation(s)
- Gordon Fitch
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
- Corresponding author.
| | - Laura L. Figueroa
- Department of Entomology, Cornell University, Ithaca, NY, 14853, USA
- Department of Environmental Conservation, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Hauke Koch
- Royal Botanic Gardens, Kew Green, Kew, Richmond, Surrey, TW9 3AE, UK
| | - Philip C. Stevenson
- Royal Botanic Gardens, Kew Green, Kew, Richmond, Surrey, TW9 3AE, UK
- Natural Resources Institute, University of Greenwich, Kent, ME4 4TB, UK
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
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23
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Gekière A, Semay I, Gérard M, Michez D, Gerbaux P, Vanderplanck M. Poison or Potion: Effects of Sunflower Phenolamides on Bumble Bees and Their Gut Parasite. BIOLOGY 2022; 11:biology11040545. [PMID: 35453744 PMCID: PMC9030180 DOI: 10.3390/biology11040545] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 11/29/2022]
Abstract
Simple Summary Bee declines have been reported worldwide, partly due to parasite spread induced by human activities. However, bees may forage on specific floral resources to face parasite infection. Such natural resources are comparable to ‘natural pharmacies’ and may be favoured in bee conservation strategies. Consumption of sunflower pollen, despite being detrimental for larval development, has been recently shown to reduce the load of a widespread bumble bee gut parasite in the common eastern bumble bee. Although the underlying mechanisms remain unknown, it has been suggested that sunflower phenolamides—a family of molecules found in most flowering plants—may be responsible for such a reduction in parasite load. Here, we tested the impacts of sunflower phenolamides on healthy and infected buff-tailed bumble bees. Expectedly, sunflower pollen had harmful consequences on bumble bee development but surprisingly, it did not alter parasite load. By contrast, sunflower phenolamides had milder effects on bumble bee development but unexpectedly increased parasite load. Phenolamide effects may stem from the physiological stress they induced or the gut microbial community alteration they may have triggered. Since biological models and experimental framework differ greatly in related studies tackling plant–bee–parasite interplays, we challenged the definition of medicinal effects and questioned the way to assess them in controlled conditions. Abstract Specific floral resources may help bees to face environmental challenges such as parasite infection, as recently shown for sunflower pollen. Whereas this pollen diet is known to be unsuitable for the larval development of bumble bees, it has been shown to reduce the load of a trypanosomatid parasite (Crithidia bombi) in the bumble bee gut. Recent studies suggested it could be due to phenolamides, a group of compounds commonly found in flowering plants. We, therefore, decided to assess separately the impacts of sunflower pollen and its phenolamides on a bumble bee and its gut parasite. We fed Crithidia-infected and -uninfected microcolonies of Bombus terrestris either with a diet of willow pollen (control), a diet of sunflower pollen (natural diet) or a diet of willow pollen supplemented with sunflower phenolamides (supplemented diet). We measured several parameters at both microcolony (i.e., food collection, parasite load, brood development and stress responses) and individual (i.e., fat body content and phenotypic variation) levels. As expected, the natural diet had detrimental effects on bumble bees but surprisingly, we did not observe any reduction in parasite load, probably because of bee species-specific outcomes. The supplemented diet also induced detrimental effects but by contrast to our a priori hypothesis, it led to an increase in parasite load in infected microcolonies. We hypothesised that it could be due to physiological distress or gut microbiota alteration induced by phenolamide bioactivities. We further challenged the definition of medicinal effects and questioned the way to assess them in controlled conditions, underlining the necessity to clearly define the experimental framework in this research field.
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Affiliation(s)
- Antoine Gekière
- Laboratoire de Zoologie, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium;
- Correspondence: (A.G.); (M.V.); Tel.: +32-65373436 (A.G.)
| | - Irène Semay
- Organic Synthesis and Mass Spectrometry Laboratory, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium; (I.S.); (P.G.)
| | - Maxence Gérard
- Insect Lab., Division of Functional Morphology, Department of Zoology, Stockholm University, 11418 Stockholm, Sweden;
| | - Denis Michez
- Laboratoire de Zoologie, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium;
| | - Pascal Gerbaux
- Organic Synthesis and Mass Spectrometry Laboratory, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium; (I.S.); (P.G.)
| | - Maryse Vanderplanck
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, 34293 Montpellier, France
- Correspondence: (A.G.); (M.V.); Tel.: +32-65373436 (A.G.)
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24
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Palmer-Young EC, Schwarz RS, Chen Y, Evans JD. Punch in the gut: Parasite tolerance of phytochemicals reflects host diet. Environ Microbiol 2022; 24:1805-1817. [PMID: 35315572 DOI: 10.1111/1462-2920.15981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 03/18/2022] [Accepted: 03/20/2022] [Indexed: 11/30/2022]
Abstract
Gut parasites of plant-eating insects are exposed to antimicrobial phytochemicals that can reduce infection. Trypanosomatid gut parasites infect insects of diverse nutritional ecologies as well as mammals and plants, raising the question of how host diet-associated phytochemicals shape parasite evolution and host specificity. To test the hypothesis that phytochemical tolerance of trypanosomatids reflects the chemical ecology of their hosts, we compared related parasites from honey bees and mosquitoes-hosts that differ in phytochemical consumption-and contrasted our results with previous studies on phylogenetically related, human-parasitic Leishmania. We identified one bacterial and ten plant-derived substances with known antileishmanial activity that also inhibited honey bee parasites associated with colony collapse. Bee parasites exhibited greater tolerance of chrysin-a flavonoid found in nectar, pollen, and plant resin-derived propolis. In contrast, mosquito parasites were more tolerant of cinnamic acid-a product of lignin decomposition present in woody debris-rich larval habitats. Parasites from both hosts tolerated many compounds that inhibit Leishmania, hinting at possible trade-offs between phytochemical tolerance and mammalian infection. Our results implicate the phytochemistry of host diets as a potential driver of insect-trypanosomatid associations, and identify compounds that could be incorporated into colony diets or floral landscapes to ameliorate infection in bees. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Ryan S Schwarz
- Department of Biology, Fort Lewis College, Durango, CO, USA
| | | | - Jay D Evans
- USDA-ARS Bee Research Lab, Beltsville, MD, USA
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Darshani P, Sen Sarma S, Srivastava AK, Baishya R, Kumar D. Anti-viral triterpenes: a review. PHYTOCHEMISTRY REVIEWS : PROCEEDINGS OF THE PHYTOCHEMICAL SOCIETY OF EUROPE 2022; 21:1761-1842. [PMID: 35283698 PMCID: PMC8896976 DOI: 10.1007/s11101-022-09808-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/27/2022] [Indexed: 05/07/2023]
Abstract
Triterpenes are naturally occurring derivatives biosynthesized following the isoprene rule of Ruzicka. The triterpenes have been reported to possess a wide range of therapeutic applications including anti-viral properties. In this review, the recent studies (2010-2020) concerning the anti-viral activities of triterpenes have been summarized. The structure activity relationship studies have been described as well as brief biosynthesis of these triterpenes is discussed.
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Affiliation(s)
- Priya Darshani
- Organic and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja SC Mullick Road, Jadavpur, Kolkata, India
| | - Shreya Sen Sarma
- Organic and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja SC Mullick Road, Jadavpur, Kolkata, India
| | - Amit K. Srivastava
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, 4, Raja SC Mullick Road, Jadavpur, Kolkata, India
| | - Rinku Baishya
- Natural Product Chemistry Group, CSIR-North East Institute of Science and Technology (NEIST), NH-37, Pulibor, Jorhat, Assam India
| | - Deepak Kumar
- Organic and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja SC Mullick Road, Jadavpur, Kolkata, India
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Sydenham MAK, Venter ZS, Reitan T, Rasmussen C, Skrindo AB, Skoog DIJ, Hanevik K, Hegland SJ, Dupont YL, Nielsen A, Chipperfield J, Rusch GM. MetaComNet: A random forest‐based framework for making spatial predictions of plant–pollinator interactions. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13762] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Trond Reitan
- Department of Biosciences Centre for Ecological and Evolutionary Synthesis (CEES) University of Oslo Oslo Norway
| | | | | | - Daniel I. J. Skoog
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences Ås Norway
| | - Kaj‐Andreas Hanevik
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences Ås Norway
| | - Stein Joar Hegland
- Department of Environmental Sciences Western University of Applied Sciences Sogndal Norway
| | - Yoko L. Dupont
- Department of Ecoscience Aarhus University Rønde Denmark
| | - Anders Nielsen
- Department of Biosciences Centre for Ecological and Evolutionary Synthesis (CEES) University of Oslo Oslo Norway
- Department of Landscape and Biodiversity Norwegian Institute of Bioeconomy Research (NIBIO) Ås Norway
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Pollen Feeding Reduces Predation of Northern Corn Rootworm Eggs (Coleoptera: Chrysomelidae, Diabrotica barberi) by a Soil-Dwelling Mite (Acari: Laelapidae: Stratiolaelaps scimitus). INSECTS 2021; 12:insects12110979. [PMID: 34821780 PMCID: PMC8619414 DOI: 10.3390/insects12110979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/22/2021] [Accepted: 10/26/2021] [Indexed: 11/17/2022]
Abstract
Simple Summary Flowering plants are used to enhance pest control by predators and parasitoids, but insect herbivores can also use floral resources. We documented the species of adult rootworm beetles on key plants, and found that northern corn rootworm (NCR) adults were commonly associated with sunflower inflorescences while western corn rootworm adults were most abundant in corn and on squash blossoms. Consumption of sunflower and corn pollen by NCR adults did not impact predation of their eggs by an omnivorous mite, but a predatory soil-dwelling mite ate pest eggs less frequently and took longer to feed on eggs when NCR adults had fed on sunflower pollen. While increasing plant diversity can benefit natural enemies and pest control within agroecosystems, it is important to consider how floral resources alter dietary preferences of biocontrol agents. Abstract Landscape diversification with flowering plants can benefit pollinators and natural enemies, although insect pests can also use floral resources for nutrition and chemoprotection. Corn rootworms (Coleoptera: Chrysomelidae, Diabrotica spp.) are major pests of corn (Zea mays L.), and while subterranean larvae primarily feed on corn roots, adult rootworms commonly consume floral resources from other plant species. We quantified the species, density, and sex of adult corn Diabroticite rootworm beetles on wild and cultivated sunflower, corn, and squash, quantified pollen within the bodies of adult northern corn rootworms [NCR, D. barberi (Smith & Lawrence)], and investigated how consumption of sunflower and corn pollen by NCR adults impacted predation of their eggs by two soil-dwelling mites with different feeding specialization. NCR were the most common Diabroticite species on sunflower inflorescences and western corn rootworm (WCR, D. v. virgifera LeConte) were more abundant in corn and squash blossoms. Pollen feeding by NCR adults did not impact egg predation by omnivorous Tyrophagus putrescentiae (Schrank) (Acari: Sarcoptiformes, Acaridae), but predatory Stratiolaelaps scimitus (Womersley) (Acari: Mesostigmata, Laelapidae) ate eggs less frequently and took longer to feed on eggs from NCR females that had fed on sunflower pollen. This research suggests pollen feeding by adult NCR can impact predation of their eggs. While increasing plant diversity can benefit natural enemies and pest control within agroecosystems, it is important to consider how floral resources alter dietary preferences of biocontrol agents.
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Dorchin A, Shafir A, Neumann FH, Langgut D, Vereecken NJ, Mayrose I. Bee flowers drive macroevolutionary diversification in long-horned bees. Proc Biol Sci 2021; 288:20210533. [PMID: 34547912 PMCID: PMC8515878 DOI: 10.1098/rspb.2021.0533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The role of plant–pollinator interactions in the rapid radiation of the angiosperms have long fascinated evolutionary biologists. Studies have brought evidence for pollinator-driven diversification of various plant lineages, particularly plants with specialized flowers and concealed rewards. By contrast, little is known about how this crucial interaction has shaped macroevolutionary patterns of floral visitors. In particular, there is currently no empirical evidence that floral host association has increased diversification in bees, the most prominent group of floral visitors that essentially rely on angiosperm pollen. In this study, we examine how floral host preference influenced diversification in eucerine bees (Apidae, Eucerini), which exhibit large variations in their floral associations. We combine quantitative pollen analyses with a recently proposed phylogenetic hypothesis, and use a state speciation and extinction probabilistic approach. Using this framework, we provide the first evidence that multiple evolutionary transitions from host plants with accessible pollen to restricted pollen from ‘bee-flowers’ have significantly increased the diversification of a bee clade. We suggest that exploiting host plants with restricted pollen has allowed the exploitation of a new ecological niche for eucerine bees and contributed both to their colonization of vast regions of the world and their rapid diversification.
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Affiliation(s)
- Achik Dorchin
- The National Natural History Collections, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel
| | - Anat Shafir
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, The Edmond J. Safra Center for Bioinformatics, Tel Aviv University, Tel Aviv 69978, Israel
| | - Frank H Neumann
- Evolutionary Studies Institute, University of the Witwatersrand, Braamfontein 2050, Johannesburg, South Africa
| | - Dafna Langgut
- Department of Archaeology and Ancient Near Eastern Cultures, and The Steinhardt Museum of Natural History, Tel Aviv University, Israel
| | | | - Itay Mayrose
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, The Edmond J. Safra Center for Bioinformatics, Tel Aviv University, Tel Aviv 69978, Israel
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29
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Sculfort O, Gérard M, Gekière A, Nonclercq D, Gerbaux P, Duez P, Vanderplanck M. Specialized Metabolites in Floral Resources: Effects and Detection in Buff-Tailed Bumblebees. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.669352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The selection of appropriate food resources by bees is a critical aspect for the maintenance of their populations, especially in the current context of global change and pollinator decline. Wild bees have a sophisticated ability to forage selectively on specific resources, and can assess the quality of pollen using contact chemosensory perception (taste). While numerous studies have investigated the detection of pollen macronutrients in bees and their impact on bee health and reproductive success, only a few studies have described the gustatory responses of bees toward specialized metabolites. In addition, these studies mostly focused on the response to nectar and neglected pollen, which is the main food resource for both bee imagines and larvae. Whether bees have the ability to detect specialized toxic metabolites in pollen and then rapidly adapt their foraging behavior to avoid them is very little studied. In this study, we tested whether pollen specialized metabolites affect bumblebees at both the micro-colony and individual levels (i.e., bioassays using supplemented pollen), and whether foragers detect these specialized metabolites and potentially display an avoidance behavior (i.e., preference tests using supplemented syrup). Bumblebees were fed with either amygdalin-, scopolamine- or sinigrin-supplemented pollen diets in ratios that mimic 50%, 100%, and 200% of naturally occurring concentrations. We found no effect of these specialized metabolites on resource collection, reproductive success and stress response at the micro-colony level. At the individual level, bumblebees fed on 50%-amygdalin or 50%-scopolamine diets displayed the highest scores for damage to their digestive systems. Interestingly, during the preference tests, the solution with 50%-scopolamine displayed a phagostimulatory activity, whereas solution with 50%-amygdalin had a deterrent effect and could trigger an active avoidance behavior in bumblebees, with a faster proboscis retraction. Our results suggest that regulation of toxin intake is not as well-established and effective as the regulation of nutrient intake in bees. Bees are therefore not equally adapted to all specialized pollen metabolites that they can come into contact with.
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van der Kooi CJ, Vallejo-Marín M, Leonhardt SD. Mutualisms and (A)symmetry in Plant-Pollinator Interactions. Curr Biol 2021; 31:R91-R99. [PMID: 33497641 DOI: 10.1016/j.cub.2020.11.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The majority of flowering plants relies on animal pollinators for sexual reproduction and many animal pollinators rely on floral resources. However, interests of plants and pollinators are often not the same, resulting in an asymmetric relationship that ranges from mutualistic to parasitic interactions. Our understanding of the processes that underlie this asymmetry remains fragmentary. In this Review, we bring together evidence from evolutionary biology, plant chemistry, biomechanics, sensory ecology and behaviour to illustrate that the degree of symmetry often depends on the perspective taken. We also highlight variation in (a)symmetry within and between plant and pollinator species as well as between geographic locations. Through taking different perspectives from the plant and pollinator sides we provide new ground for studies on the maintenance and evolution of animal pollination and on the (a)symmetry in plant-pollinator interactions.
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Affiliation(s)
- Casper J van der Kooi
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands.
| | | | - Sara D Leonhardt
- Department of Ecology and Ecosystem Management, Technical University of Munich, Freising, Germany
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31
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Didaras NA, Kafantaris I, Dimitriou TG, Mitsagga C, Karatasou K, Giavasis I, Stagos D, Amoutzias GD, Hatjina F, Mossialos D. Biological Properties of Bee Bread Collected from Apiaries Located across Greece. Antibiotics (Basel) 2021; 10:antibiotics10050555. [PMID: 34068740 PMCID: PMC8151309 DOI: 10.3390/antibiotics10050555] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/07/2021] [Accepted: 05/08/2021] [Indexed: 01/18/2023] Open
Abstract
Bee bread is the only fermented product of the beehive. It constitutes the main source of proteins, lipids, vitamins, and macro- and microelements in honeybee nutrition and it exerts antioxidant and antimicrobial properties, though research on these aspects has been limited so far. In this study 18 samples of Greek bee bread, two of which were monofloral, were collected during different seasons from diverse locations such as Crete and Mount Athos and were tested for their bioactivity. Samples were analyzed for their antibacterial properties, antioxidant activity, total phenolic content (TPC), and total flavonoid content (TFC). The antimicrobial activity of each sample was tested against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Salmonella typhimurium. Our data demonstrate that all samples exert inhibitory and most of them bactericidal activity against at least two pathogens. Furthermore, all samples exert significant antioxidant activity, where the monofloral Castanea Sativa sample demonstrated superior antioxidant activity. Nevertheless, the antioxidant and antimicrobial activity were not strongly correlated. Furthermore, machine learning methods demonstrated that the palynological composition of the samples is a good predictor of their TPC and ABTS activity. This is the first study that focuses on the biological properties of Greek bee bread and demonstrates that bee bread can be considered a functional food and a possible source of novel antimicrobial compounds.
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Affiliation(s)
- Nikos Asoutis Didaras
- Laboratory of Microbial Biotechnology, Molecular Bacteriology, Virology, Department of Biochemistry & Biotechnology, School of Health Sciences, University of Thessaly, 41500 Larissa, Greece; (N.A.D.); (I.K.); (T.G.D.)
| | - Ioannis Kafantaris
- Laboratory of Microbial Biotechnology, Molecular Bacteriology, Virology, Department of Biochemistry & Biotechnology, School of Health Sciences, University of Thessaly, 41500 Larissa, Greece; (N.A.D.); (I.K.); (T.G.D.)
| | - Tilemachos G. Dimitriou
- Laboratory of Microbial Biotechnology, Molecular Bacteriology, Virology, Department of Biochemistry & Biotechnology, School of Health Sciences, University of Thessaly, 41500 Larissa, Greece; (N.A.D.); (I.K.); (T.G.D.)
| | - Chrysanthi Mitsagga
- Laboratory of Food Microbiology and Biotechnology, Department of Food Science and Nutrition, University of Thessaly, 43100 Karditsa, Greece; (C.M.); (I.G.)
| | - Katerina Karatasou
- Apicultural Centre of Larissa, Federation of Greek Beekeepers Associations, 41222 Larissa, Greece;
| | - Ioannis Giavasis
- Laboratory of Food Microbiology and Biotechnology, Department of Food Science and Nutrition, University of Thessaly, 43100 Karditsa, Greece; (C.M.); (I.G.)
| | - Dimitris Stagos
- Laboratory of Animal Physiology, Department of Biochemistry & Biotechnology, School of Health Sciences, University of Thessaly, 41500 Larissa, Greece;
| | - Grigoris D. Amoutzias
- Bioinformatics Laboratory, Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, 41500 Larissa, Greece;
| | - Fani Hatjina
- Department of Apiculture, Institute of Animal Science, Hellenic Agricultural Organisation DEMETER, 63200 Nea Moudania, Greece;
| | - Dimitris Mossialos
- Laboratory of Microbial Biotechnology, Molecular Bacteriology, Virology, Department of Biochemistry & Biotechnology, School of Health Sciences, University of Thessaly, 41500 Larissa, Greece; (N.A.D.); (I.K.); (T.G.D.)
- Correspondence: ; Tel.: +30-241-056-5270
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32
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Zu P, Koch H, Schwery O, Pironon S, Phillips C, Ondo I, Farrell IW, Nes WD, Moore E, Wright GA, Farman DI, Stevenson PC. Pollen sterols are associated with phylogeny and environment but not with pollinator guilds. THE NEW PHYTOLOGIST 2021; 230:1169-1184. [PMID: 33484583 PMCID: PMC8653887 DOI: 10.1111/nph.17227] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/14/2021] [Indexed: 06/01/2023]
Abstract
Phytosterols are primary plant metabolites that have fundamental structural and regulatory functions. They are also essential nutrients for phytophagous insects, including pollinators, that cannot synthesize sterols. Despite the well-described composition and diversity in vegetative plant tissues, few studies have examined phytosterol diversity in pollen. We quantified 25 pollen phytosterols in 122 plant species (105 genera, 51 families) to determine their composition and diversity across plant taxa. We searched literature and databases for plant phylogeny, environmental conditions, and pollinator guilds of the species to examine the relationships with pollen sterols. 24-methylenecholesterol, sitosterol and isofucosterol were the most common and abundant pollen sterols. We found phylogenetic clustering of twelve individual sterols, total sterol content and sterol diversity, and of sterol groupings that reflect their underlying biosynthesis pathway (C-24 alkylation, ring B desaturation). Plants originating in tropical-like climates (higher mean annual temperature, lower temperature seasonality, higher precipitation in wettest quarter) were more likely to record higher pollen sterol content. However, pollen sterol composition and content showed no clear relationship with pollinator guilds. Our study is the first to show that pollen sterol diversity is phylogenetically clustered and that pollen sterol content may adapt to environmental conditions.
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Affiliation(s)
- Pengjuan Zu
- Royal Botanic GardensKew, Natural Capital and Plant Health DepartmentRichmondSurreyTW9 3ABUK
- Department Fish Ecology and EvolutionSwiss Federal Institute of Aquatic Science and TechnologySeestrasse 79KastanienbaumCH‐6047Switzerland
| | - Hauke Koch
- Royal Botanic GardensKew, Natural Capital and Plant Health DepartmentRichmondSurreyTW9 3ABUK
| | - Orlando Schwery
- New Mexico Consortium4200 W. Jemez Rd, Suite 301Los AlamosNM87544USA
| | - Samuel Pironon
- Royal Botanic GardensKew, Biodiversity Informatics and Spatial Analysis DepartmentRichmondSurreyTW9 3ABUK
| | - Charlotte Phillips
- Royal Botanic GardensKew, Biodiversity Informatics and Spatial Analysis DepartmentRichmondSurreyTW9 3ABUK
- Royal Botanic GardensKew, Conservation Science DepartmentWakehurst PlaceArdinglyWest SussexRH17 6TNUK
| | - Ian Ondo
- Royal Botanic GardensKew, Biodiversity Informatics and Spatial Analysis DepartmentRichmondSurreyTW9 3ABUK
| | - Iain W. Farrell
- Royal Botanic GardensKew, Natural Capital and Plant Health DepartmentRichmondSurreyTW9 3ABUK
| | - W. David Nes
- Department of Chemistry & BiochemistryTexas Tech UniversityLubbockTX79424USA
| | - Elynor Moore
- Department of ZoologyUniversity of Oxford11a Mansfield RoadOxfordOX1 3SZUK
| | | | - Dudley I. Farman
- Natural Resources InstituteUniversity of GreenwichChatham, KentME4 4TBUK
| | - Philip C. Stevenson
- Royal Botanic GardensKew, Natural Capital and Plant Health DepartmentRichmondSurreyTW9 3ABUK
- Natural Resources InstituteUniversity of GreenwichChatham, KentME4 4TBUK
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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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Crone MK, Grozinger CM. Pollen protein and lipid content influence resilience to insecticides in honey bees ( Apis mellifera). J Exp Biol 2021; 224:jeb.242040. [PMID: 33758024 DOI: 10.1242/jeb.242040] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/17/2021] [Indexed: 12/19/2022]
Abstract
In honey bees (Apis mellifera), there is growing evidence that the impacts of multiple stressors can be mitigated by quality nutrition. Pollen, which is the primary source of protein and lipids in bees diets, is particularly critical for generating more resilient phenotypes. Here, we evaluate the relationship between pollen protein-to-lipid ratios (P:Ls) and honey bee insecticide resilience. We hypothesized that pollen diets richer in lipids would lead to increased survival in bees exposed to insecticides, as pollen-derived lipids have previously been shown to improve bee resilience to pathogens and parasites. Furthermore, lipid metabolic processes are altered in bees exposed to insecticides.We fed age-matched bees pollen diets of different P:Ls by altering a base pollen by either adding protein (casein powder) or lipids (canola oil) and simulating chronic insecticide exposure by feeding bees an organophosphate (Chlorpyrifos). We also tested pollen diets of naturally different P:Ls to determine if results are consistent. Linear regression analysis revealed that mean survival time for altered diets was best explained by protein concentration (p =0.04 , adjusted R2 =0.92), and that mean survival time for natural diets was best explained by P:L ratio (p =0.008 , adjusted R2 =0.93). Our results indicate that higher ratios of dietary protein to lipid has a negative effect on bee physiology when combined with insecticide exposure, while lower ratios have a positive effect. These results suggest that protein and lipid intake differentially influence insecticide response in bees, laying the groundwork for future studies of metabolic processes and development of improved diets.
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Affiliation(s)
- Makaylee K Crone
- Intercollege Graduate Program in Ecology, Center for Pollinator Research, Huck Institutes of the Life Sciences, Pennsylvania State University, USA
| | - Christina M Grozinger
- Department of Entomology, Center for Pollinator Research, Huck Institutes of the Life Sciences, Pennsylvania State University, USA
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Abstract
Mobile apps play an important role in COVID-19 tracing and tracking, with different countries taking different approaches. Our study focuses on 17 government owned COVID-19 Contact Tracing Apps (CTAs) and analyze them using a proposed COVIDTAS framework. User satisfaction is not directly related to the COVIDTAS score or the interaction between users and the app developers. To increase adoption of CTAs, government leadership must offer assurance to its citizens that their identify will be concealed and emphasize the benefits of CTAs as it relates to shared public health. While no country has topped the list on all three major factors (COVIDTAS Score, User Reviews, and User Ratings), the CTA from India seems to have above average performance on all three factors.
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Eilers EJ, Kleine S, Eckert S, Waldherr S, Müller C. Flower Production, Headspace Volatiles, Pollen Nutrients, and Florivory in Tanacetum vulgare Chemotypes. FRONTIERS IN PLANT SCIENCE 2021; 11:611877. [PMID: 33552105 PMCID: PMC7855176 DOI: 10.3389/fpls.2020.611877] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/23/2020] [Indexed: 06/01/2023]
Abstract
Floral volatiles and reward traits are major drivers for the behavior of mutualistic as well as antagonistic flower visitors, i.e., pollinators and florivores. These floral traits differ tremendously between species, but intraspecific differences and their consequences on organism interactions remain largely unknown. Floral volatile compounds, such as terpenoids, function as cues to advertise rewards to pollinators, but should at the same time also repel florivores. The reward composition, e.g., protein and lipid contents in pollen, differs between individuals of distinct plant families. Whether the nutritional value of rewards within the same plant species is linked to their chemotypes, which differ in their pattern of specialized metabolites, has yet not been investigated. In the present study, we compared Tanacetum vulgare plants of five terpenoid chemotypes with regard to flower production, floral headspace volatiles, pollen macronutrient and terpenoid content, and floral attractiveness to florivorous beetles. Our analyses revealed remarkable differences between the chemotypes in the amount and diameter of flower heads, duration of bloom period, and pollen nutritional quality. The floral headspace composition of pollen-producing mature flowers, but not of premature flowers, was correlated to that of pollen and leaves in the same plant individual. For two chemotypes, florivorous beetles discriminated between the scent of mature and premature flower heads and preferred the latter. In semi-field experiments, the abundance of florivorous beetles and flower tissue miners differed between T. vulgare chemotypes. Moreover, the scent environment affected the choice and beetles were more abundant in homogenous plots composed of one single chemotype than in plots with different neighboring chemotypes. In conclusion, flower production, floral metabolic composition and pollen quality varied to a remarkable extend within the species T. vulgare, and the attractiveness of floral scent differed also intra-individually with floral ontogeny. We found evidence for a trade-off between pollen lipid content and pollen amount on a per-plant-level. Our study highlights that chemotypes which are more susceptible to florivory are less attacked when they grow in the neighborhood of other chemotypes and thus gain a benefit from high overall chemodiversity.
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Affiliation(s)
| | - Sandra Kleine
- Chemical Ecology, Bielefeld University, Bielefeld, Germany
| | - Silvia Eckert
- Chemical Ecology, Bielefeld University, Bielefeld, Germany
- Biodiversity Research/Systematic Botany, University of Potsdam, Potsdam, Germany
| | - Simon Waldherr
- Chemical Ecology, Bielefeld University, Bielefeld, Germany
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Pijnakker J, Vangansbeke D, Duarte M, Moerkens R, Wäckers FL. Predators and Parasitoids-in-First: From Inundative Releases to Preventative Biological Control in Greenhouse Crops. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2020. [DOI: 10.3389/fsufs.2020.595630] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Repeated mass introductions of natural enemies have been widely used as a biological control strategy in greenhouse systems when the resident population of natural enemies is insufficient to suppress the pests. As an alternative strategy, supporting the establishment and population development of beneficials can be more effective and economical. The preventative establishment of predators and parasitoids, before the arrival of pests, has become a key element to the success of biological control programs. This “Predators and parasitoids-in-first” strategy is used both in Inoculative Biological Control (IBC), and in Conservation Biological Control (CBC). Here, we provide an overview of tools used to boost resident populations of biocontrol agents.
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Contribution of Extensive Farming Practices to the Supply of Floral Resources for Pollinators. INSECTS 2020; 11:insects11110818. [PMID: 33233506 PMCID: PMC7699504 DOI: 10.3390/insects11110818] [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: 11/05/2020] [Revised: 11/13/2020] [Accepted: 11/17/2020] [Indexed: 11/17/2022]
Abstract
Simple Summary One of the causes of pollinator decline is the decreased availability of flower resources, that constitute their nutritional requirements. In particular, the intensification of agricultural practices has led to a loss of flower resources. For many years, as part of the Common Agricultural Policy and the efforts to preserve biodiversity, several Agri-Environmental Schemes (AESs) and extensive farming practices have been promoted in Europe. To assess the relative contribution of extensive farming practices such as hedgerows, organic crops and extensive grasslands, we compared pairs of agricultural landscapes in Belgium. We recorded the densities of the insect-pollinated plant species per biotope and per month, the abundance and diversity of the main visiting insects. In April, hedgerows and forest edges constituted the main nectar resources. In May, most of the nectar resources were produced by grasslands and mass-flowering crops. In June, extensive grasslands and organic crops contributed to nectar resources, contrarily to intensive agricultural elements. Extensive and diverse agricultural practices should therefore be encouraged to provide less fluctuating nectar resources on a landscape scale. Abstract Intensification of agricultural practices leads to a loss of floral resources and drives pollinator decline. Extensive agricultural practices are encouraged in Europe and contribute to the preservation of biodiversity. We compared three agricultural landscapes without extensive farming practices with three adjacent landscapes containing organic crops and extensively managed grasslands in Belgium. Nectar resource availability and plant–pollinator interactions were monitored from April to June. Flower density per plant species and plant–pollinator interactions were recorded in different landscape elements. In April, the main nectar resources were provided by linear elements such as hedgerows and forest edges. Nectar production peaked in May, driven by intensive grasslands and mass-flowering crops. Occurrence of extensive grasslands and organic crops significantly alleviated the nectar resource gap observed in June. Our results underscore the importance of maintaining landscape heterogeneity for continuous flower resources and highlight the specific role of extensive grasslands and organic crops in June.
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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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McAulay MK, Killingsworth SZ, Forrest JRK. Understanding pollen specialization in mason bees: a case study of six species. Oecologia 2020; 195:559-574. [PMID: 33106935 DOI: 10.1007/s00442-020-04786-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 10/10/2020] [Indexed: 10/23/2022]
Abstract
Many bee species are dietary specialists and restrict their pollen foraging to a subset of the available flowers. However, the reasons for specialization-and the reasons certain plant taxa support numerous specialists-are often unclear. Many bees specialize on the plant family Asteraceae, despite evidence its pollen is a poor food for non-specialists. Here, we studied six mason bee (Osmia) species, including three Asteraceae specialists, to test whether observed pollen-usage patterns reflect larval nutritional requirements, to investigate what aspects of Asteraceae pollen make it unsuitable for non-specialists, and to understand how Asteraceae specialists tolerate their seemingly low-quality diet. We reared larval bees on host and nonhost pollen and found that Asteraceae specialists could develop on nonhost provisions, but that other bees could not survive on Asteraceae provisions. These effects did not seem related to nutritional deficiencies, since Asteraceae provisions were not amino acid deficient, and we found no consistent differences in digestive efficiency among pollen types. However, Asteraceae specialists completed more foraging flights per larva, generally collected relatively larger provisions, and produced more frass (waste) than the other species, suggesting quantitative compensation for low food quality. Toxins, deficiencies in unmeasured nutrients, or aspects of pollen grain structure might explain poor survival of non-specialists on Asteraceae provisions. Our results suggest that floral host selection by specialist bees is not related to optimizing larval nutrition. We recommend further investigation of host-selection behaviour in adult bees and of pollen digestion in larvae to better understand the evolution of bee-flower associations.
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Affiliation(s)
- Megan K McAulay
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada. .,Rocky Mountain Biological Laboratory, Crested Butte, CO, 81224, USA.
| | | | - Jessica R K Forrest
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada.,Rocky Mountain Biological Laboratory, Crested Butte, CO, 81224, USA
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Aguirre LA, Davis JK, Stevenson PC, Adler LS. Herbivory and Time Since Flowering Shape Floral Rewards and Pollinator-Pathogen Interactions. J Chem Ecol 2020; 46:978-986. [PMID: 32876829 DOI: 10.1007/s10886-020-01213-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/07/2020] [Accepted: 08/24/2020] [Indexed: 10/23/2022]
Abstract
Herbivory can induce chemical changes throughout plant tissues including flowers, which could affect pollinator-pathogen interactions. Pollen is highly defended compared to nectar, but no study has examined whether herbivory affects pollen chemistry. We assessed the effects of leaf herbivory on nectar and pollen alkaloids in Nicotiana tabacum, and how herbivory-induced changes in nectar and pollen affect pollinator-pathogen interactions. We damaged leaves of Nicotiana tabacum using the specialist herbivore Manduca sexta and compared nicotine and anabasine concentrations in nectar and pollen. We then pooled nectar and pollen by collection periods (within and after one month of flowering), fed them in separate experiments to bumble bees (Bombus impatiens) infected with the gut pathogen Crithidia bombi, and assessed infections after seven days. We did not detect alkaloids in nectar, and leaf damage did not alter the effect of nectar on Crithidia counts. In pollen, herbivory induced higher concentrations of anabasine but not nicotine, and alkaloid concentrations rose and then fell as a function of days since flowering. Bees fed pollen from damaged plants had Crithidia counts 15 times higher than bees fed pollen from undamaged plants, but only when pollen was collected after one month of flowering, indicating that both damage and time since flowering affected interaction outcomes. Within undamaged treatments, bees fed late-collected pollen had Crithidia counts 10 times lower than bees fed early-collected pollen, also indicating the importance of time since flowering. Our results emphasize the role of herbivores in shaping pollen chemistry, with consequences for interactions between pollinators and their pathogens.
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Affiliation(s)
- Luis A Aguirre
- Department of Biology, University of Massachusetts, Amherst, MA, 01003, USA.
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA, 01003, USA.
| | - Julie K Davis
- Department of Entomology, Cornell University, Ithaca, NY, 14850, USA
| | - Philip C Stevenson
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Surrey, TW9 3AB, UK
- Natural Resources Institute, University of Greenwich, Chatham, Kent, ME4 4TB, UK
| | - Lynn S Adler
- Department of Biology, University of Massachusetts, Amherst, MA, 01003, USA
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Ritmejerytė E, Boughton BA, Bayly MJ, Miller RE. Unique and highly specific cyanogenic glycoside localization in stigmatic cells and pollen in the genus Lomatia (Proteaceae). ANNALS OF BOTANY 2020; 126:387-400. [PMID: 32157299 PMCID: PMC7424758 DOI: 10.1093/aob/mcaa038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 03/06/2020] [Indexed: 05/12/2023]
Abstract
BACKGROUND AND AIMS Floral chemical defence strategies remain understudied despite the significance of flowers to plant fitness, and the fact that many flowers contain secondary metabolites that confer resistance to herbivores. Optimal defence and apparency theories predict that the most apparent plant parts and/or those most important to fitness should be most defended. To test whether within-flower distributions of chemical defence are consistent with these theories we used cyanogenic glycosides (CNglycs), which are constitutive defence metabolites that deter herbivores by releasing hydrogen cyanide upon hydrolysis. METHODS We used cyanogenic florets of the genus Lomatia to investigate at what scale there may be strategic allocation of CNglycs in flowers, what their localization reveals about function, and whether levels of floral CNglycs differ between eight congeneric species across a climatic gradient. Within-flower distributions of CNglycs during development were quantified, CNglycs were identified and their localization was visualized in cryosectioned florets using matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI). KEY RESULTS Florets of all congeneric species studied were cyanogenic, and concentrations differed between species. Within florets there was substantial variation in CNglyc concentrations, with extremely high concentrations (up to 14.6 mg CN g-1 d. wt) in pollen and loose, specialized surface cells on the pollen presenter, among the highest concentrations reported in plant tissues. Two tyrosine-derived CNglycs, the monoglycoside dhurrin and diglycoside proteacin, were identified. MALDI-MSI revealed their varying ratios in different floral tissues; proteacin was primarily localized to anthers and ovules, and dhurrin to specialized cells on the pollen presenter. The mix of transient specialized cells and pollen of L. fraxinifolia was ~11 % dhurrin and ~1.1 % proteacin by mass. CONCLUSIONS Tissue-specific distributions of two CNglycs and substantial variation in their concentrations within florets suggests their allocation is under strong selection. Localized, high CNglyc concentrations in transient cells challenge the predictions of defence theories, and highlight the importance of fine-scale metabolite visualization, and the need for further investigation into the ecological and metabolic roles of CNglycs in floral tissues.
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Affiliation(s)
- Edita Ritmejerytė
- School of Ecosystem and Forest Sciences, The University of Melbourne, Richmond, Victoria, Australia
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Berin A Boughton
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
- Metabolomics Australia, School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Michael J Bayly
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Rebecca E Miller
- School of Ecosystem and Forest Sciences, The University of Melbourne, Richmond, Victoria, Australia
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Trunz V, Lucchetti MA, Bénon D, Dorchin A, Desurmont GA, Kast C, Rasmann S, Glauser G, Praz CJ. To bee or not to bee: The ‘raison d'être’ of toxic secondary compounds in the pollen of Boraginaceae. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13581] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vincent Trunz
- Institute of Biology University of Neuchatel Neuchatel Switzerland
| | - Matteo A. Lucchetti
- Institute of Biology University of Neuchatel Neuchatel Switzerland
- Agroscope Swiss Bee Research Centre Bern Switzerland
| | - Dimitri Bénon
- Institute of Biology University of Neuchatel Neuchatel Switzerland
| | - Achik Dorchin
- The Steinhardt Museum of Natural History Tel Aviv University Tel Aviv Israel
| | | | | | - Sergio Rasmann
- Institute of Biology University of Neuchatel Neuchatel Switzerland
| | - Gaétan Glauser
- Neuchatel Platform of Analytical Chemistry University of Neuchatel Neuchâtel Switzerland
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