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Clark KR, Goldberg Oppenheimer P. Vibrational spectroscopic profiling of biomolecular interactions between oak powdery mildew and oak leaves. SOFT MATTER 2024; 20:959-970. [PMID: 38189096 PMCID: PMC10828924 DOI: 10.1039/d3sm01392h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/02/2024] [Indexed: 01/09/2024]
Abstract
Oak powdery mildew, caused by the biotrophic fungus Erysiphe alphitoides, is a prevalent disease affecting oak trees, such as English oak (Quercus robur). While mature oak populations are generally less susceptible to this disease, it can endanger young oak seedlings and new leaves on mature trees. Although disruptions of photosynthate and carbohydrate translocation have been observed, accurately detecting and understanding the specific biomolecular interactions between the fungus and the leaves of oak trees is currently lacking. Herein, via hybrid Raman spectroscopy combined with an advanced artificial neural network algorithm, the underpinning biomolecular interactions between biological soft matter, i.e., Quercus robur leaves and Erysiphe alphitoides, are investigated and profiled, generating a spectral library and shedding light on the changes induced by fungal infection and the tree's defence response. The adaxial surfaces of oak leaves are categorised based on either the presence or absence of Erysiphe alphitoides mildew and further distinguishing between covered or not covered infected leaf tissues, yielding three disease classes including healthy controls, non-mildew covered and mildew-covered. By analysing spectral changes between each disease category per tissue type, we identified important biomolecular interactions including disruption of chlorophyll in the non-vein and venule tissues, pathogen-induced degradation of cellulose and pectin and tree-initiated lignification of cell walls in response, amongst others, in lateral vein and mid-vein tissues. Via our developed computational algorithm, the underlying biomolecular differences between classes were identified and allowed accurate and rapid classification of disease with high accuracy of 69.6% for non-vein, 73.5% for venule, 82.1% for lateral vein and 85.6% for mid-vein tissues. Interfacial wetting differences between non-mildew covered and mildew-covered tissue were further analysed on the surfaces of non-vein and venule tissue. The overall results demonstrated the ability of Raman spectroscopy, combined with advanced AI, to act as a powerful and specific tool to probe foliar interactions between forest pathogens and host trees with the simultaneous potential to probe and catalogue molecular interactions between biological soft matter, paving the way for exploring similar relations in broader forest tree-pathogen systems.
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Affiliation(s)
- Kieran R Clark
- School of Chemical Engineering, Advanced Nanomaterials Structures and Applications Laboratories, College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
- Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Pola Goldberg Oppenheimer
- School of Chemical Engineering, Advanced Nanomaterials Structures and Applications Laboratories, College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
- Healthcare Technologies Institute, Institute of Translational Medicine, Mindelsohn Way, Birmingham, B15 2TH, UK
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Relationships between the Pathogen Erysiphe alphitoides, the Phytophagous Mite Schizotetranychus garmani (Acari: Tetranychidae) and the Predatory Mite Euseius finlandicus (Acari: Phytoseiidae) in Oak. INSECTS 2021; 12:insects12110981. [PMID: 34821782 PMCID: PMC8620041 DOI: 10.3390/insects12110981] [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: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 11/17/2022]
Abstract
Simple Summary Knowledge about the relationships between plant pathogens, arthropods, and their natural enemies is scarce. We studied the relationships between the plant fungal pathogen, Erysiphe alphitoides, the phytophagous mite Schizotetranychus garmani, and the predatory mite Euseius finlandicus in leaves of pedunculate oak. In June, July and August 2016, in 30 trees located in three forests near Belgrade, Serbia, the presence of E. alphitoides, S. garmani and E. finlandicus was assessed. The occurrence of E. alphitoides was high where the population of S. garmani was high. However, the presence of the leaf pathogen E. alphitoides was not related to the amount of the predatory mite E. finlandicus. The relationships between powdery mildew and the two mite species were stable across time and space, and the presence of one mite was not influenced by the presence of the other mite. Abstract Food webs on forest trees include plant pathogens, arthropods, and their natural enemies. To increase the understanding of the impact of a plant pathogen on herbivore-natural enemy interactions, we studied the powdery mildew fungus Erysiphe alphitoides, the phytophagous mite Schizotetranychus garmani, and the predatory and mycophagous mite Euseius finlandicus in pedunculate oak (Quercus robur) leaves. In June, July and August of 2016, we assessed the severity of powdery mildew, mite population density and adult female mite size in 30 trees in three forests near Belgrade, Serbia. In August, the infection severity of E. alphitoides related positively to the population density of S. garmani and negatively to the body size of S. garmani females. Throughout the vegetative season, the infection severity of E. alphitoides related positively to the population density of E. finlandicus but not to its body size. The effect of E. alphitoides on the population density and adult size of S. garmani was not mediated by the population density of E. finlandicus, and vice versa. Interactions were consistent in all forests and varied with the summer month. Our findings indicate that E. alphitoides can influence the average body size and population densities of prey and predatory mites studied, irrespective of predator-prey relationships.
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Pathogen infection influences the relationship between spring and autumn phenology at the seedling and leaf level. Oecologia 2021; 197:447-457. [PMID: 34553245 DOI: 10.1007/s00442-021-05044-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 09/14/2021] [Indexed: 01/08/2023]
Abstract
Seasonal life history events are often interdependent, but we know relatively little about how the relationship between different events is influenced by the abiotic and biotic environment. Such knowledge is important for predicting the immediate and evolutionary phenological response of populations to changing conditions. We manipulated germination timing and shade in a multi-factorial experiment to investigate the relationship between spring and autumn phenology in seedlings of the pedunculate oak, Quercus robur, and whether this relationship was mediated by natural colonization of leaves by specialist fungal pathogens (i.e., the oak powdery mildew complex). Each week delay in germination corresponded to about 2 days delay in autumn leaf senescence, and heavily shaded seedlings senesced 5-8 days later than seedlings in light shade or full sun. Within seedlings, leaves on primary-growth shoots senesced later than those on secondary-growth shoots in some treatments. Path analyses demonstrated that germination timing and shade affected autumn phenology both directly and indirectly via pathogen load, though the specific pattern differed among and within seedlings. Pathogen load increased with later germination and greater shade. Greater pathogen load was in turn associated with later senescence for seedlings, but with earlier senescence for individual leaves. Our findings show that relationships between seasonal events can be partly mediated by the biotic environment and suggest that these relationships may differ between the plant and leaf level. The influence of biotic interactions on phenological correlations across scales has implications for understanding phenotypic variation in phenology and for predicting how populations will respond to climatic perturbation.
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Bradshaw M, Braun U, Elliott M, Kruse J, Liu SY, Guan G, Tobin P. A global genetic analysis of herbarium specimens reveals the invasion dynamics of an introduced plant pathogen. Fungal Biol 2021; 125:585-595. [PMID: 34281652 DOI: 10.1016/j.funbio.2021.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 03/14/2021] [Accepted: 03/16/2021] [Indexed: 10/21/2022]
Abstract
The introduction, spread, and impact of fungal plant pathogens is a critical concern in ecological systems. In this study, we were motivated by the rather sudden appearance of Acermacrophyllum heavily infected with powdery mildew. We used morphological and genetic analyses to confirm the pathogen causing the epidemic was Sawadaea bicornis. In subsequent field studies, this pathogen was found in several locations in western North America, and in greenhouse studies, A. macrophyllum was found to be significantly more susceptible to S. bicornis than nine other Acer species tested. A genetic analysis of 178 specimens of powdery mildew from freshly collected and old herbarium specimens from 15 countries revealed seven different haplotypes. The high diversity of haplotypes found in Europe coupled with sequence results from a specimen from 1864 provides evidence that S. bicornis has a European origin. Furthermore, sequence data from a specimen from 1938 in Canada show that the pathogen has been present in North America for at least 82 years revealing a considerable lag time between the introduction and current epidemic. This study used old herbarium specimens to genetically hypothesize the origin, the native host, and the invasion time of a detrimental fungal plant pathogen.
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Affiliation(s)
- Michael Bradshaw
- University of Washington, School of Environmental and Forest Sciences, Seattle, WA, 98195, USA.
| | - Uwe Braun
- Martin Luther University, Institute of Biology, Geobotany Division and Botanical Garden, Herbarium, Neuwerk 21, 06099 Halle (Saale), Germany.
| | | | - Julia Kruse
- Pfalzmuseum für Naturkunde, Hermann-Schäfer-Straße 17, 67098, Bad Dürkheim, Germany.
| | - Shu-Yan Liu
- Laboratory of Plant Pathology, College of Plant Protection, Jilin Agricultural University, Changchun, 130118, Jilin Province, PR China.
| | - Guanxiu Guan
- Laboratory of Plant Pathology, College of Plant Protection, Jilin Agricultural University, Changchun, 130118, Jilin Province, PR China.
| | - Patrick Tobin
- University of Washington, School of Environmental and Forest Sciences, Seattle, WA, 98195, USA.
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van Dijk LJA, Ehrlén J, Tack AJM. The timing and asymmetry of plant-pathogen-insect interactions. Proc Biol Sci 2020; 287:20201303. [PMID: 32962544 PMCID: PMC7542815 DOI: 10.1098/rspb.2020.1303] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Insects and pathogens frequently exploit the same host plant and can potentially impact each other's performance. However, studies on plant–pathogen–insect interactions have mainly focused on a fixed temporal setting or on a single interaction partner. In this study, we assessed the impact of time of attacker arrival on the outcome and symmetry of interactions between aphids (Tuberculatus annulatus), powdery mildew (Erysiphe alphitoides), and caterpillars (Phalera bucephala) feeding on pedunculate oak, Quercus robur, and explored how single versus multiple attackers affect oak performance. We used a multifactorial greenhouse experiment in which oak seedlings were infected with either zero, one, two, or three attackers, with the order of attacker arrival differing among treatments. The performances of all involved organisms were monitored throughout the experiment. Overall, attackers had a weak and inconsistent impact on plant performance. Interactions between attackers, when present, were asymmetric. For example, aphids performed worse, but powdery mildew performed better, when co-occurring. Order of arrival strongly affected the outcome of interactions, and early attackers modified the strength and direction of interactions between later-arriving attackers. Our study shows that interactions between plant attackers can be asymmetric, time-dependent, and species specific. This is likely to shape the ecology and evolution of plant–pathogen–insect interactions.
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Affiliation(s)
- Laura J A van Dijk
- Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91 Stockholm, Sweden
| | - Johan Ehrlén
- Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91 Stockholm, Sweden
| | - Ayco J M Tack
- Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91 Stockholm, Sweden
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Leroy T, Plomion C, Kremer A. Oak symbolism in the light of genomics. THE NEW PHYTOLOGIST 2020; 226:1012-1017. [PMID: 31183874 PMCID: PMC7166128 DOI: 10.1111/nph.15987] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 05/31/2019] [Indexed: 05/09/2023]
Abstract
Throughout the Northern Hemisphere, human societies, political systems, and religions have appropriated oaks in symbolic representations. In this review, we explore the possible associations between recent genetic and genomic findings and the symbolic representations of oaks. We first consider the ways in which evolutionary history during the Holocene has tightened links between humans and oaks in Europe, and how this may have led to symbolic representations. We then show how recent findings concerning the structure and evolution of the oak genome have provided additional knowledge about symbolic representations, such as longevity, cohesiveness, and robustness.
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Affiliation(s)
- Thibault Leroy
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Place Eugène Bataillon, 34095 Montpellier, France
- BIOGECO, INRA, Université de Bordeaux, 69 Route d'Arcachon, 33612 Cestas, France
- correspondence:
| | - Christophe Plomion
- BIOGECO, INRA, Université de Bordeaux, 69 Route d'Arcachon, 33612 Cestas, France
| | - Antoine Kremer
- BIOGECO, INRA, Université de Bordeaux, 69 Route d'Arcachon, 33612 Cestas, France
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Field E, Schönrogge K, Barsoum N, Hector A, Gibbs M. Individual tree traits shape insect and disease damage on oak in a climate-matching tree diversity experiment. Ecol Evol 2019; 9:8524-8540. [PMID: 31410259 PMCID: PMC6686283 DOI: 10.1002/ece3.5357] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 05/04/2019] [Indexed: 11/09/2022] Open
Abstract
Diversifying planted forests by increasing genetic and species diversity is often promoted as a method to improve forest resilience to climate change and reduce pest and pathogen damage. In this study, we used a young tree diversity experiment replicated at two sites in the UK to study the impacts of tree diversity and tree provenance (geographic origin) on the oak (Quercus robur) insect herbivore community and a specialist biotrophic pathogen, oak powdery mildew. Local UK, French, and Italian provenances were planted in monocultures, provenance mixtures, and species mixes, allowing us to test whether: (a) local and nonlocal provenances differ in their insect herbivore and pathogen communities, and (b) admixing trees leads to associational effects on insect herbivore and pathogen damage. Tree diversity had variable impacts on foliar organisms across sites and years, suggesting that diversity effects can be highly dependent on environmental context. Provenance identity impacted upon both herbivores and powdery mildew, but we did not find consistent support for the local adaptation hypothesis for any group of organisms studied. Independent of provenance, we found tree vigor traits (shoot length, tree height) and tree apparency (the height of focal trees relative to their surroundings) were consistent positive predictors of powdery mildew and insect herbivory. Synthesis. Our results have implications for understanding the complex interplay between tree identity and diversity in determining pest damage, and show that tree traits, partially influenced by tree genotype, can be important drivers of tree pest and pathogen loads.
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Affiliation(s)
- Elsa Field
- Department of Plant SciencesUniversity of OxfordOxfordUK
| | | | | | - Andrew Hector
- Department of Plant SciencesUniversity of OxfordOxfordUK
| | - Melanie Gibbs
- Centre for Ecology & HydrologyCrowmarsh GiffordWallingfordUK
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Kiss L, Kovács GM, Bóka K, Bohár G, Bohárné KV, Németh MZ, Takamatsu S, Shin HD, Hayova V, Nischwitz C, Seier MK, Evans HC, Cannon PF, Ash GJ, Shivas RG, Müller-Schärer H. Deciphering the biology of Cryptophyllachora eurasiatica gen. et sp. nov., an often cryptic pathogen of an allergenic weed, Ambrosia artemisiifolia. Sci Rep 2018; 8:10806. [PMID: 30018297 PMCID: PMC6050288 DOI: 10.1038/s41598-018-29102-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/26/2018] [Indexed: 01/05/2023] Open
Abstract
A little known, unculturable ascomycete, referred to as Phyllachora ambrosiae, can destroy the inflorescences of Ambrosia artemisiifolia, an invasive agricultural weed and producer of highly allergenic pollen. The fungus often remains undetectable in ragweed populations. This work was conducted to understand its origin and pathogenesis, a prerequisite to consider its potential as a biocontrol agent. The methods used included light and transmission electron microscopy, nrDNA sequencing, phylogenetic analyses, artificial inoculations, and the examination of old herbarium and recent field specimens from Hungary, Korea, Ukraine and USA. The Eurasian and the North American specimens of this fungus were to represent two distinct, although closely related lineages that were only distantly related to other lineages within the Ascomycota. Consequently, we describe a new genus that includes Cryptophyllachora eurasiatica gen. et sp. nov. and C. ambrosiae comb. nov., respectively. The pathogenesis of C. eurasiatica was shown in A. artemisiifolia. No evidence was found for either seed-borne transmission or systemic infection. Two hypotheses were developed to explain the interaction between C. eurasiatica and A. artemisiifolia: (i) as yet undetected seed-borne transmissions and latent, systemic infections; or (ii) alternative hosts.
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Affiliation(s)
- Levente Kiss
- University of Southern Queensland, Centre for Crop Health, Toowoomba, Qld, 4350, Australia.
- Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences (MTA-ATK), Budapest, H-1525, Hungary.
| | - Gábor M Kovács
- Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences (MTA-ATK), Budapest, H-1525, Hungary
- Eötvös Loránd University, Institute of Biology, Department of Plant Anatomy, Budapest, H-1117, Hungary
| | - Károly Bóka
- Eötvös Loránd University, Institute of Biology, Department of Plant Anatomy, Budapest, H-1117, Hungary
| | - Gyula Bohár
- Biovéd 2005 Ltd., Kemenestaródfa, H-9923, Hungary
| | | | - Márk Z Németh
- Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences (MTA-ATK), Budapest, H-1525, Hungary
| | - Susumu Takamatsu
- Mie University, Graduate School of Bioresources, Tsu, 514-8507, Japan
| | - Hyeon-Dong Shin
- Korea University, Division of Environmental Science and Ecological Engineering, Seoul, 02841, Korea
| | - Vera Hayova
- National Academy of Sciences of Ukraine, M.G. Kholodny Institute of Botany, Kyiv, 01004, Ukraine
| | | | | | - Harry C Evans
- CABI Europe-UK, Egham, Surrey, TW20 9TY, United Kingdom
| | - Paul F Cannon
- Royal Botanic Gardens, Jodrell Laboratory, Mycology Section, Kew, TW9 3AB, United Kingdom
| | - Gavin James Ash
- University of Southern Queensland, Centre for Crop Health, Toowoomba, Qld, 4350, Australia
| | - Roger G Shivas
- University of Southern Queensland, Centre for Crop Health, Toowoomba, Qld, 4350, Australia
| | - Heinz Müller-Schärer
- University of Fribourg, Department of Biology/Ecology & Evolution, Fribourg, CH-1700, Switzerland
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Dillen M, Smit C, Buyse M, Höfte M, De Clercq P, Verheyen K. Stronger diversity effects with increased environmental stress: A study of multitrophic interactions between oak, powdery mildew and ladybirds. PLoS One 2017; 12:e0176104. [PMID: 28419174 PMCID: PMC5395233 DOI: 10.1371/journal.pone.0176104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 04/05/2017] [Indexed: 11/19/2022] Open
Abstract
Recent research has suggested that increasing neighbourhood tree species diversity may mitigate the impact of pests or pathogens by supporting the activities of their natural enemies and/or reducing the density of available hosts. In this study, we attempted to assess these mechanisms in a multitrophic study system of young oak (Quercus), oak powdery mildew (PM, caused by Erysiphe spp.) and a mycophagous ladybird (Psyllobora vigintiduopunctata). We assessed ladybird mycophagy on oak PM in function of different neighbourhood tree species compositions. We also evaluated whether these species interactions were modulated by environmental conditions as suggested by the Stress Gradient Hypothesis. We adopted a complementary approach of a field experiment where we monitored oak saplings subjected to a reduced rainfall gradient in a young planted forest consisting of different tree species mixtures, as well as a lab experiment where we independently evaluated the effect of different watering treatments on PM infections and ladybird mycophagy. In the field experiment, we found effects of neighbourhood tree species richness on ladybird mycophagy becoming more positive as the target trees received less water. This effect was only found as weather conditions grew drier. In the lab experiment, we found a preference of ladybirds to graze on infected leaves from trees that received less water. We discuss potential mechanisms that might explain this preference, such as emissions of volatile leaf chemicals. Our results are in line with the expectations of the Natural Enemies Hypothesis and support the hypothesis that biodiversity effects become stronger with increased environmental stress.
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Affiliation(s)
- Mathias Dillen
- Conservation Ecology group, Groningen Institute for Evolutionary Sciences (GELIFES), University of Groningen, Groningen, the Netherlands
- Forest & Nature Lab, Department of Forest and Water Management, Ghent University, Gontrode, Belgium
| | - Christian Smit
- Conservation Ecology group, Groningen Institute for Evolutionary Sciences (GELIFES), University of Groningen, Groningen, the Netherlands
| | - Martijn Buyse
- Forest & Nature Lab, Department of Forest and Water Management, Ghent University, Gontrode, Belgium
| | - Monica Höfte
- Laboratory of Phytopathology, Department of Crop Protection, Ghent University, Ghent, Belgium
| | - Patrick De Clercq
- Laboratory of Agrozoology, Department of Crop Protection, Ghent University,Ghent, Belgium
| | - Kris Verheyen
- Forest & Nature Lab, Department of Forest and Water Management, Ghent University, Gontrode, Belgium
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