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Rodriguez-Algaba J, Villegas D, Cantero-Martínez C, Patpour M, Berlin A, Hovmøller MS, Jin Y, Justesen AF. Recombination in the wheat stem rust pathogen mediated by an indigenous barberry species in Spain. Front Plant Sci 2024; 14:1322406. [PMID: 38293628 PMCID: PMC10825791 DOI: 10.3389/fpls.2023.1322406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/22/2023] [Indexed: 02/01/2024]
Abstract
The comeback of wheat stem rust in Europe, caused by Puccinia graminis f. sp. tritici, and the prevalence of the alternate (sexual) host in local areas have recently regained attention as a potential threat to European wheat production. The aim of this study was to investigate a potential epidemiological link between the aecia found on an indigenous barberry species and stem rust infections on nearby cereals and grasses. Aecial infections collected from Berberis vulgaris subsp. seroi were inoculated on a panel of susceptible genotypes of major cereal crop species. In total, 67 stem rust progeny isolates were recovered from wheat (51), barley (7), and rye (9), but none from oat, indicating the potential of barberry derived isolates to infect multiple cereals. Molecular genotyping of the progeny isolates and 20 cereal and grass stem rust samples collected at the same locations and year, revealed a clear genetic relatedness between the progeny isolated from barberry and the stem rust infections found on nearby cereal and grass hosts. Analysis of Molecular Variance indicated that variation between the stem rust populations accounted for only 1%. A Principal Components Analysis using the 62 detected multilocus genotypes also demonstrated a low degree of genetic variation among isolates belonging to the two stem rust populations. Lastly, pairwise comparisons based on fixation index (Fst), Nei's genetic distances and number of effective migrants (Nm) revealed low genetic differentiation and high genetic exchange between the two populations. Our results demonstrated a direct epidemiological link and functionality of an indigenous barberry species as the sexual host of P. graminis in Spain, a factor that should be considered when designing future strategies to prevent stem rust in Europe and beyond.
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Affiliation(s)
- Julian Rodriguez-Algaba
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Slagelse, Denmark
| | - Dolors Villegas
- Sustainable Field Crops, IRTA, Institute of Agrifood Research and Technology, Lleida, Spain
| | | | - Mehran Patpour
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Slagelse, Denmark
| | - Anna Berlin
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Mogens S. Hovmøller
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Slagelse, Denmark
| | - Yue Jin
- USDA-ARS Cereal Disease Laboratory, University of Minnesota, St Paul, MN, United States
| | - Annemarie F. Justesen
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Slagelse, Denmark
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2
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Rodriguez-Algaba J, Hovmøller MS, Schulz P, Hansen JG, Lezáun JA, Joaquim J, Randazzo B, Czembor P, Zemeca L, Slikova S, Hanzalová A, Holdgate S, Wilderspin S, Mascher F, Suffert F, Leconte M, Flath K, Justesen AF. Stem rust on barberry species in Europe: Host specificities and genetic diversity. Front Genet 2022; 13:988031. [PMID: 36246643 PMCID: PMC9554944 DOI: 10.3389/fgene.2022.988031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
The increased emergence of cereal stem rust in southern and western Europe, caused by the pathogen Puccinia graminis, and the prevalence of alternate (sexual) host, Berberis species, have regained attention as the sexual host may serve as source of novel pathogen variability that may pose a threat to cereal supply. The main objective of the present study was to investigate the functional role of Berberis species in the current epidemiological situation of cereal stem rust in Europe. Surveys in 11 European countries were carried out from 2018 to 2020, where aecial infections from five barberry species were collected. Phylogenetic analysis of 121 single aecial clusters of diverse origin using the elongation factor 1-α gene indicated the presence of different special forms (aka formae speciales) of P. graminis adapted to different cereal and grass species. Inoculation studies using aecial clusters from Spain, United Kingdom, and Switzerland resulted in 533 stem rust isolates sampled from wheat, barley, rye, and oat, which confirmed the presence of multiple special forms of P. graminis. Microsatellite marker analysis of a subset of 192 sexually-derived isolates recovered on wheat, barley and rye from the three populations confirmed the generation of novel genetic diversity revealed by the detection of 135 multilocus genotypes. Discriminant analysis of principal components resulted in four genetic clusters, which grouped at both local and country level. Here, we demonstrated that a variety of Berberis species may serve as functional alternate hosts for cereal stem rust fungi and highlights the increased risks that the sexual cycle may pose to cereal production in Europe, which calls for new initiatives within rust surveillance, epidemiological research and resistance breeding.
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Affiliation(s)
- Julian Rodriguez-Algaba
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Slagelse, Denmark
- *Correspondence: Julian Rodriguez-Algaba,
| | - Mogens S. Hovmøller
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Slagelse, Denmark
| | - Philipp Schulz
- Federal Research Centre for Cultivated Plants, Julius Kühn-Institut, Institute for Plant Protection in Field Crops and Grassland, Kleinmachnow, Germany
| | - Jens G. Hansen
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Slagelse, Denmark
| | - Juan Antonio Lezáun
- INTIA, Institute for Agrifood Technology and Infrastructures of Navarra, Villava, Navarra, Spain
| | - Jessica Joaquim
- Agroscope, Crop Plant Breeding and Genetic Ressources, Nyon, Switzerland
| | | | - Paweł Czembor
- Plant Breeding and Acclimatization Institute-National Research Institute, Radzików, Poland
| | - Liga Zemeca
- Institute of Plant Protection Research “Agrihorts”, Latvia University of Life Sciences and Technologies, Jelgava, Latvia
| | | | - Alena Hanzalová
- Crop Research Institute, Department of Genetics and Plant Breeding Methods, Prague, Czech Republic
| | - Sarah Holdgate
- National Institute of Agricultural Botany (NIAB), Cambridge, United Kingdom
| | - Sarah Wilderspin
- National Institute of Agricultural Botany (NIAB), Cambridge, United Kingdom
| | - Fabio Mascher
- Agroscope, Crop Plant Breeding and Genetic Ressources, Nyon, Switzerland
| | - Frederic Suffert
- INRAE (French National Institute for Agriculture Food and Environment), Université Paris-Saclay, Thiverval-Grignon, France
| | - Marc Leconte
- INRAE (French National Institute for Agriculture Food and Environment), Université Paris-Saclay, Thiverval-Grignon, France
| | - Kerstin Flath
- Federal Research Centre for Cultivated Plants, Julius Kühn-Institut, Institute for Plant Protection in Field Crops and Grassland, Kleinmachnow, Germany
| | - Annemarie F. Justesen
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Slagelse, Denmark
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Chen W, Zhang Z, Ma X, Zhang G, Yao Q, Kang Z, Zhao J. Phenotyping and Genotyping Analyses Reveal the Spread of Puccinia striiformis f. sp. tritici Aeciospores From Susceptible Barberry to Wheat in Qinghai of China. Front Plant Sci 2021; 12:764304. [PMID: 34975948 PMCID: PMC8719489 DOI: 10.3389/fpls.2021.764304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 11/22/2021] [Indexed: 05/26/2023]
Abstract
Puccinia striiformis f. sp. tritici Eriks., the cause of wheat yellow or stripe rust on wheat, undergoes sexual reproduction on barberry, but it is unclear if barberry plays any role in stripe rust epidemics under natural conditions. P. striiformis f. sp. tritici was isolated from its alternate host barberry (Berberis spp.) and primary host wheat in the vicinity of barberry by inoculation of aeciospores and urediniospores on Mingxian 169 cultivar in Qinghai province of China in 2018. The P. striiformis f. sp. tritici isolates from barberry and wheat were characterized to virulence patterns by inoculation on 24 differentials bearing Yr gene under control conditions and analyzed using 12 polymorphic simple sequence repeat (SSR) markers. The occurrence frequency of P. striiformis f. sp. tritici on barberry was 1.87% by inoculation aecia, collected from barberry on Mingxian 169 of wheat. A close virulence relationship was presented between P. striiformis f. sp. tritici isolates from both barberry and wheat based on virulence simple matching coefficient and principal coordinates analysis (PCoA). Additionally, the same genetic ancestry, based on structure analysis by STRUCTURE program and genetic relationship analyses using discriminant analysis of principal components and PCoA, was shared between P. striiformis f. sp. tritici isolates from barberry and those from wheat. Together, all the results indicated that the role of barberry in providing aeciospores as an inoculum source causing wheat stripe rust epidemic in Qinghai in spring is of considerable importance.
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Affiliation(s)
- Wen Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
- Guizhou Academy of Agricultural Sciences, Institute of Plant Protection, Guiyang, China
| | - ZeDong Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Xinyao Ma
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Gensheng Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Qiang Yao
- Academy of Agricultural and Forestry Sciences, Qinghai University, Xining, China
| | - Zhensheng Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Jie Zhao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
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4
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Rangel LI, Hamilton O, de Jonge R, Bolton MD. Fungal social influencers: secondary metabolites as a platform for shaping the plant-associated community. Plant J 2021; 108:632-645. [PMID: 34510609 DOI: 10.1111/tpj.15490] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
Fungal secondary metabolites (FSMs) are capable of manipulating plant community dynamics by inhibiting or facilitating the establishment of co-habitating organisms. Although production of FSMs is not crucial for survival of the producer, their absence can indirectly impair growth and/or niche competition of these fungi on the plant. The presence of FSMs with no obvious consequence on the fitness of the producer leaves questions regarding ecological impact. This review investigates how fungi employ FSMs as a platform to mediate fungal-fungal, fungal-bacterial and fungal-animal interactions associated with the plant community. We discuss how the biological function of FSMs may indirectly benefit the producer by altering the dynamics of surrounding organisms. We introduce several instances where FSMs influence antagonistic- or alliance-driven interactions. Part of our aim is to decipher the meaning of the FSM 'language' as it is widely noted to impact the surrounding community. Here, we highlight the contribution of FSMs to plant-associated interaction networks that affect the host either broadly or in ways that may have previously been unclear.
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Affiliation(s)
- Lorena I Rangel
- Northern Crop Science Laboratory, US Dept. Agriculture, Fargo, ND, USA
| | - Olivia Hamilton
- Northern Crop Science Laboratory, US Dept. Agriculture, Fargo, ND, USA
- Department of Plant Pathology, North Dakota State University, Fargo, ND, USA
| | - Ronnie de Jonge
- Department of Plant-Microbe Interactions, Utrecht University, Utrecht, The Netherlands
| | - Melvin D Bolton
- Northern Crop Science Laboratory, US Dept. Agriculture, Fargo, ND, USA
- Department of Plant Pathology, North Dakota State University, Fargo, ND, USA
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5
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Laraba I, McCormick SP, Vaughan MM, Proctor RH, Busman M, Appell M, O'Donnell K, Felker FC, Catherine Aime M, Wurdack KJ. Pseudoflowers produced by Fusarium xyrophilum on yellow-eyed grass (Xyris spp.) in Guyana: A novel floral mimicry system? Fungal Genet Biol 2020; 144:103466. [PMID: 32956810 DOI: 10.1016/j.fgb.2020.103466] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 12/18/2022]
Abstract
Pseudoflower formation is arguably the rarest outcome of a plant-fungus interaction. Here we report on a novel putative floral mimicry system in which the pseudoflowers are composed entirely of fungal tissues in contrast to modified leaves documented in previous mimicry systems. Pseudoflowers on two perennial Xyris species (yellow-eyed grass, X. setigera and X. surinamensis) collected from savannas in Guyana were produced by Fusarium xyrophilum, a novel Fusarium species. These pseudoflowers mimic Xyris flowers in gross morphology and are ultraviolet reflective. Axenic cultures of F. xyrophilum produced two pigments that had fluorescence emission maxima in light ranges that trichromatic insects are sensitive to and volatiles known to attract insect pollinators. One of the volatiles emitted by F. xyrophilum cultures (i.e., 2-ethylhexanol) was also detected in the head space of X. laxifolia var. iridifolia flowers, a perennial species native to the New World. Results of microscopic and PCR analyses, combined with examination of gross morphology of the pseudoflowers, provide evidence that the fungus had established a systemic infection in both Xyris species, sterilized them and formed fungal pseudoflowers containing both mating type idiomorphs. Fusarium xyrophilum cultures also produced the auxin indole-3-acetic acid (IAA) and the cytokinin isopentenyl adenosine (iPR). Field observations revealed that pseudoflowers and Xyris flowers were both visited by bees. Together, the results suggest that F. xyrophilum pseudoflowers are a novel floral mimicry system that attracts insect pollinators, via visual and olfactory cues, into vectoring its conidia, which might facilitate outcrossing of this putatively heterothallic fungus and infection of previously uninfected plants.
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Affiliation(s)
- Imane Laraba
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA.
| | - Susan P McCormick
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Martha M Vaughan
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Robert H Proctor
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Mark Busman
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Michael Appell
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Kerry O'Donnell
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - Frederick C Felker
- Functional Food Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, IL 61604-3999, USA
| | - M Catherine Aime
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907-2054, USA
| | - Kenneth J Wurdack
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-2012, USA
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6
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Capador H, Samils B, Kaitera J, Olson Å. Genetic evidence for sexual reproduction and multiple infections of Norway spruce cones by the rust fungus Thekopsora areolata. Ecol Evol 2020; 10:7389-7403. [PMID: 32760536 PMCID: PMC7391340 DOI: 10.1002/ece3.6466] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 11/06/2022] Open
Abstract
Rust fungi are obligate parasites, of plants, with complex and in many cases poorly known life cycles which may include host alteration and up to five spore types with haploid, diploid, and dikaryotic nuclear stages. This study supports that Thekopasora areolata, the causal agent of cherry-spruce rust in Norway spruce, is a macrocyclic heteroecious fungus with all five spore stages which uses two host plants Prunus padus and Picea abies to complete its life cycle. High genotypic diversity without population structure was found, which suggests predominantly sexual reproduction, random mating and a high gene flow within and between the populations in Fennoscandia. There was no evidence for an autoecious life cycle resulting from aeciospore infection of pistillate cones that would explain the previously reported rust epidemics without the alternate host. However, within cones and scales identical multilocus genotypes were repeatedly sampled which can be explained by vegetative growth of the fertilized mycelia or repeated mating of mycelium by spermatia of the same genotype. The high genotypic diversity within cones and haplotype inference show that each pistillate cone is infected by several basidiospores. This study provides genetic evidence for high gene flow, sexual reproduction, and multiple infections of Norway spruce cone by the rust fungus T. areolata which expands the general understanding of the biology of rust fungi.
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Affiliation(s)
- Hernán Capador
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
| | - Berit Samils
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
| | - Juha Kaitera
- Natural Resources Institute FinlandUniversity of OuluOuluFinland
| | - Åke Olson
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
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Noman A, Aqeel M, Qasim M, Haider I, Lou Y. Plant-insect-microbe interaction: A love triangle between enemies in ecosystem. Sci Total Environ 2020; 699:134181. [PMID: 31520944 DOI: 10.1016/j.scitotenv.2019.134181] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/28/2019] [Accepted: 08/28/2019] [Indexed: 05/20/2023]
Abstract
In natural ecosystems, plants interact with biotic components such as microbes, insects, animals and other plants as well. Generally, researchers have focused on each interaction separately, which condenses the significance of the interaction. This limited presentation of the facts masks the collective role of constantly interacting organisms in complex communities disturbing not only plant responses but also the response of organisms for each other in natural ecological settings. Beneficial microorganisms interact with insect herbivores, their predators and pollinators in a bidirectional way through the plant. Fascinatingly, insects employ diverse tactics to protect themselves from parasites or predators. Influences of microbial and insects attack on plants can bring changes in info-chemical frameworks and play a role in the food chain also. After insect herbivory and microbial pathogenesis, plants exhibit intense morpho-physiological and chemical reprogramming that leads to repellence/attraction of attacking organism or its natural enemy. The characterization of such interactions in different ecosystems is receiving due consideration, and underlying molecular and physiological mechanisms must be the point of concentration to unveil the evolution of multifaceted multitrophic interactions. Therefore, we have focused this phenomenon in a more realistic setting by integrating ecology and physiology to portray these multidimensional interfaces. We have shown, in this article, physiological trajectories in plant-microbe and insect relationship and their ecological relevance in nature. We focus and discuss microbial pathogenesis in plants, induced defense and the corresponding behavior of herbivore insects and vice-versa. It is hoped that this review will stimulate interest and zeal in microbes mediated plant-insect interactions along with their ecological consequences and encourage scientists to accept the challenges in this field.
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Affiliation(s)
- Ali Noman
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China; Department of Botany, Government College University, Faisalabad 38040, Pakistan.
| | - Muhammad Aqeel
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, PR China
| | - Muhammad Qasim
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China
| | - Ijaz Haider
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China; Department of Entomology, University of Agriculture, Faisalabad 38040, Pakistan
| | - Yonggen Lou
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China.
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8
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Laraba I, Kim HS, Proctor RH, Busman M, O'Donnell K, Felker FC, Aime MC, Koch RA, Wurdack KJ. Fusarium xyrophilum, sp. nov., a member of the Fusarium fujikuroi species complex recovered from pseudoflowers on yellow-eyed grass ( Xyris spp.) from Guyana. Mycologia 2019; 112:39-51. [PMID: 31825746 DOI: 10.1080/00275514.2019.1668991] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We report on the discovery and characterization of a novel Fusarium species that produced yellow-orange pseudoflowers on Xyris spp. (yellow-eyed grass; Xyridaceae) growing in the savannas of the Pakaraima Mountains of western Guyana. The petaloid fungal structures produced on infected plants mimic host flowers in gross morphology. Molecular phylogenetic analyses of full-length RPB1 (RNA polymerase largest subunit), RPB2 (RNA polymerase second largest subunit), and TEF1 (elongation factor 1-α) DNA sequences mined from genome sequences resolved the fungus, described herein as F. xyrophilum, sp. nov., as sister to F. pseudocircinatum within the African clade of the F. fujikuroi species complex. Results of a polymerase chain reaction (PCR) assay for mating type idiomorph revealed that single-conidial isolates of F. xyrophilum had only one of the MAT idiomorphs (MAT1-1 or MAT1-2), which suggests that the fungus may have a heterothallic sexual reproductive mode. BLASTn searches of whole-genome sequence of three strains of F. xyrophilum indicated that it has the genetic potential to produce secondary metabolites, including phytohormones, pigments, and mycotoxins. However, a polyketide-derived pigment, 8-O-methylbostrycoidin, was the only metabolite detected in cracked maize kernel cultures. When grown on carnation leaf agar, F. xyrophilum is phenotypically distinct from other described Fusarium species in that it produces aseptate microconidia on erect indeterminate synnemata that are up to 2 mm tall and it does not produce multiseptate macroconidia.
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Affiliation(s)
- Imane Laraba
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, Illinois 61604-3999
| | - Hye-Seon Kim
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, Illinois 61604-3999
| | - Robert H Proctor
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, Illinois 61604-3999
| | - Mark Busman
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, Illinois 61604-3999
| | - Kerry O'Donnell
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, Illinois 61604-3999
| | - Frederick C Felker
- Functional Food Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, Illinois 61604-3999
| | - M Catherine Aime
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054
| | - Rachel A Koch
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054
| | - Kenneth J Wurdack
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-2012
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9
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Hammerbacher A, Coutinho TA, Gershenzon J. Roles of plant volatiles in defence against microbial pathogens and microbial exploitation of volatiles. Plant Cell Environ 2019; 42:2827-2843. [PMID: 31222757 DOI: 10.1111/pce.13602] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 05/22/2023]
Abstract
Plants emit a large variety of volatile organic compounds during infection by pathogenic microbes, including terpenes, aromatics, nitrogen-containing compounds, and fatty acid derivatives, as well as the volatile plant hormones, methyl jasmonate, and methyl salicylate. Given the general antimicrobial activity of plant volatiles and the timing of emission following infection, these compounds have often been assumed to function in defence against pathogens without much solid evidence. In this review, we critically evaluate current knowledge on the toxicity of volatiles to fungi, bacteria, and viruses and their role in plant resistance as well as how they act to induce systemic resistance in uninfected parts of the plant and in neighbouring plants. We also discuss how microbes can detoxify plant volatiles and exploit them as nutrients, attractants for insect vectors, and inducers of volatile emissions, which stimulate immune responses that make plants more susceptible to infection. Although much more is known about plant volatile-herbivore interactions, knowledge of volatile-microbe interactions is growing and it may eventually be possible to harness plant volatiles to reduce disease in agriculture and forestry. Future research in this field can be facilitated by making use of the analytical and molecular tools generated by the prolific research on plant-herbivore interactions.
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Affiliation(s)
- Almuth Hammerbacher
- Department of Zoology and Entomology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, 0002, South Africa
| | - Teresa A Coutinho
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, Centre for Microbial Ecology and Genetics, University of Pretoria, Pretoria, 0002, South Africa
| | - Jonathan Gershenzon
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Jena, 07745, Germany
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10
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Cellini A, Giacomuzzi V, Donati I, Farneti B, Rodriguez-Estrada MT, Savioli S, Angeli S, Spinelli F. Pathogen-induced changes in floral scent may increase honeybee-mediated dispersal of Erwinia amylovora. ISME J 2019; 13:847-859. [PMID: 30504898 PMCID: PMC6461938 DOI: 10.1038/s41396-018-0319-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 10/31/2018] [Accepted: 11/06/2018] [Indexed: 11/09/2022]
Abstract
Honeybees are well recognised for their key role in plant reproduction as pollinators. On the other hand, their activity may vector some pathogens, such as the bacterium Erwinia amylovora, the causative agent of fire blight disease in pomaceous plants. In this research, we evaluated whether honeybees are able to discriminate between healthy and E. amylovora-infected flowers, thus altering the dispersal of the pathogen. For this reason, honeybees were previously trained to forage either on inoculated or healthy (control) apple flower. After the training, the two honeybee groups were equally exposed to inoculated and control flowering apple plants. To assess their preference, three independent methods were used: (1) direct count of visiting bees per time frame; (2) incidence on apple flowers of a marker bacterium (Pantoea agglomerans, strain P10c) carried by foragers; (3) quantification of E. amylovora populations in the collected pollen loads, proportional to the number of visits to infected flowers. The results show that both honeybee groups preferred control flowers over inoculated ones. The characterisation of volatile compounds released by flowers revealed a different emission of several bioactive compounds, providing an explanation for honeybee preference. As an unexpected ecological consequence, the influence of infection on floral scent increasing the visit rate on healthy flowers may promote a secondary bacterial spread.
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Affiliation(s)
- Antonio Cellini
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, viale G. Fanin 44, Bologna, 40127, Italy
| | - Valentino Giacomuzzi
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, Bolzano, 39100, Italy
| | - Irene Donati
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, viale G. Fanin 44, Bologna, 40127, Italy
| | - Brian Farneti
- Department of Genomics and Biology of Fruit Crops, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, S. Michele all'Adige (TN), 38010, Italy
| | - Maria T Rodriguez-Estrada
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, viale G. Fanin 44, Bologna, 40127, Italy
| | - Stefano Savioli
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, viale G. Fanin 44, Bologna, 40127, Italy
| | - Sergio Angeli
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, Bolzano, 39100, Italy
| | - Francesco Spinelli
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, viale G. Fanin 44, Bologna, 40127, Italy.
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11
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Rosati L, Romano VA, Cerone L, Fascetti S, Potenza G, Bazzato E, Cillo D, Mecca M, Racioppi R, D'Auria M, Farris E. Pollination features and floral volatiles of Gymnospermium scipetarum (Berberidaceae). J Plant Res 2019; 132:49-56. [PMID: 30456735 DOI: 10.1007/s10265-018-1073-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 10/23/2018] [Indexed: 06/09/2023]
Abstract
The discovery of few isolated populations of Gymnospermium scipetarum (since now considered as an amphi-Adriatic endemic) in the S-Apennines prompted to investigate, also for conservation purposes, some aspects of its reproductive biology. We aim: (1) to determine if insects play an important role in pollination; (2) to describe the pollinator community; (3) to detect floral scent composition. Experiments of insect exclusion were carried out in the field using 24 flowering individuals: one raceme was capped whereas the nearest one was used as control to ascertain differences in seed set. Pollinator community was detected during the blooming phase of two consecutive flowering seasons by visual observation; insect identification was made at the highest possible taxonomic resolution with the help of digital photographs. In order to determine the chemical composition of the volatiles, we used SPME sampling of cultivated plants. Mann-Whitney U test reveals significant differences for treatment in mean seed set with very low values for capped flowers, thus clearly indicating as insects are crucial for successful pollination. During the 42 h of observations we detected 326 visitors belonging to only three guilds: 79% were Diptera, 20% Hymenoptera and 1% Coleoptera. We identified overall 36 floral organic compounds with only two compounds common to the other studied Berberidaceae. Ambrox was never identified before in the floral scents of any angiosperm. The presence in the scent of several aldehydes and one ketone (benzophenone) could be related to the detected dominance of muscoid flies as pollinators. Floral morphology and composition of the pollinators community indicate a generalist pollination behaviour probably related to its phenology and habitat preference. The possibility of being pollinated also by muscoid flies can be considered an advantage for the reproductive fitness of the species, since these Diptera are abundant in the mountain pastures surrounding the forest habitat of Gymnospermium.
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Affiliation(s)
- Leonardo Rosati
- Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università della Basilicata, Via Ateneo Lucano, 10, 85100, Potenza, Italy.
| | - Vito Antonio Romano
- Dipartimento di Scienze, Università della Basilicata, Via Ateneo Lucano, 10, 85100, Potenza, Italy
| | - Luca Cerone
- Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università della Basilicata, Via Ateneo Lucano, 10, 85100, Potenza, Italy
| | - Simonetta Fascetti
- Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università della Basilicata, Via Ateneo Lucano, 10, 85100, Potenza, Italy
| | - Giovanna Potenza
- Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università della Basilicata, Via Ateneo Lucano, 10, 85100, Potenza, Italy
| | - Erika Bazzato
- Dipartimento di Scienze della Vita e dell'Ambiente, Università degli Studi di Cagliari, Viale S. Ignazio, 13, 09123, Cagliari, Italy
| | | | - Marisabel Mecca
- Dipartimento di Scienze, Università della Basilicata, Via Ateneo Lucano, 10, 85100, Potenza, Italy
| | - Rocco Racioppi
- Dipartimento di Scienze, Università della Basilicata, Via Ateneo Lucano, 10, 85100, Potenza, Italy
| | - Maurizio D'Auria
- Dipartimento di Scienze, Università della Basilicata, Via Ateneo Lucano, 10, 85100, Potenza, Italy
| | - Emmanuele Farris
- Dipartimento di Chimica e Farmacia, Università di Sassari, Via Piandanna, 4, 07100, Sassari, Italy
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12
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Zhang X, Ji Y, Zhang Y, Liu F, Chen H, Liu J, Handberg ES, Chagovets VV, Chingin K. Molecular analysis of semen-like odor emitted by chestnut flowers using neutral desorption extractive atmospheric pressure chemical ionization mass spectrometry. Anal Bioanal Chem 2018; 411:4103-4112. [DOI: 10.1007/s00216-018-1487-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 10/12/2018] [Accepted: 11/07/2018] [Indexed: 11/28/2022]
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13
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Zhang X, Chingin K, Zhong D, Luo L, Frankevich V, Chen H. Deciphering the chemical origin of the semen-like floral scents in three angiosperm plants. Phytochemistry 2018; 145:137-145. [PMID: 29127940 DOI: 10.1016/j.phytochem.2017.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 10/27/2017] [Accepted: 11/01/2017] [Indexed: 06/07/2023]
Abstract
The chemical origin and biological role of distinct semen-like odor occasionally found in some flowers are very curious but remain scarcely studied. Here, we used direct ambient corona discharge ionization mass spectrometry (MS) to study the volatile chemical composition behind the semen-like odor emitted by the fresh flowers of Photinia serrulata, Castanopsis sclerophylla and Stemona japonica without any chemical pretreatment. Chemical identification was performed using high-resolution MS analysis in combination with tandem MS analysis and whenever possible was confirmed by the analysis of standard reference compounds. A total of 19 compounds, mostly belonging to nitrogenous volatiles, were identified in P. serrulata, C. sclerophylla, and S. japonica flowers, 1-pyrroline, 1-piperideine, 2-pyrrolidone, and phenethylamine being common in all the three studied species. Several lines of evidence indicate that the major component responsible for the semen-like odor is most likely 1-pyrroline. 1-Pyrroline is most probably formed via the oxidative deamination of putrescine, as indicated by the observation of signal from 4-amino-butanal intermediate. Flower visitation observations suggest that the released volatiles serve to attract dipterans, including Syrphidae, Calliphoridae, and Muscidae. On the analytical side, the comparison of our results to earlier studies also indicate that compared to the traditional GC-MS approach the direct corona discharge ionization mass spectrometry provides more sensitive detection of VOCs with high proton affinity, in particular volatile amines, and therefore can be used to complement traditional GC-MS approach for the highest chemical coverage of VOC analysis.
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Affiliation(s)
- Xiaoping Zhang
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang, 330013, PR China
| | - Konstantin Chingin
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang, 330013, PR China.
| | - Dacai Zhong
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang, 330013, PR China
| | - Liping Luo
- School of Life Sciences, Nanchang University, Nanchang, 330031, PR China
| | - Vladimir Frankevich
- Department of System Biology in Reproduction, Federal State Budget Institution "Research Center for Obstetrics, Gynecology and Perinatology", Moscow, 117997, Russia
| | - Huanwen Chen
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang, 330013, PR China
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14
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Hamedi A, Moheimani SM, Sakhteman A, Etemadfard H, Moein M. An Overview on Indications and Chemical Composition of Aromatic Waters (Hydrosols) as Functional Beverages in Persian Nutrition Culture and Folk Medicine for Hyperlipidemia and Cardiovascular Conditions. J Evid Based Complementary Altern Med 2017; 22:544-561. [PMID: 29228785 PMCID: PMC5871258 DOI: 10.1177/2156587216686460] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 12/04/2016] [Indexed: 02/05/2023] Open
Abstract
Hydrosol beverages in Persian nutrition culture and ethnomedicine are the side products of essential oil industry that are used as delicious drinks or safe remedies. To investigate indications and chemical composition of hydrosol beverages for hyperlipidemia and cardiovascular conditions, Fars province was selected as the field of study. Ethnomedical data were gathered by questionnaires. The constituents of hydrosols were extracted with liquid/liquid extraction and analyzed by gas chromatography-mass spectrometry. Statistical analysis were used to cluster their constituents and find the relevance of their composition. A literature survey was also performed on plants used to prepare them. Thymol was the major or second major component of these beverages, except for wormwood and olive leaf hydrosols. Based on clustering methods, although some similarities could be found, composition of barberry, will fumitory, dill, and aloe hydrosols have more differences than others. These studies may help in developing some functional beverages or new therapeutics.
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Affiliation(s)
- Azadeh Hamedi
- Medicinal Plants Processing Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Seyed Mahmoud Moheimani
- Student Research Committee, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Amirhossein Sakhteman
- Medicinal Plants Processing Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hamed Etemadfard
- Medicinal Plants Processing Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mahmoodreza Moein
- Medicinal Plants Processing Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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15
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Rodriguez-Algaba J, Sørensen CK, Labouriau R, Justesen AF, Hovmøller MS. Genetic diversity within and among aecia of the wheat rust fungus Puccinia striiformis on the alternate host Berberis vulgaris. Fungal Biol 2017; 121:541-549. [PMID: 28606349 DOI: 10.1016/j.funbio.2017.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/10/2017] [Indexed: 10/19/2022]
Abstract
An isolate of the fungus Puccinia striiformis, causing yellow (stripe) rust on cereals and grasses, was selfed on the alternate (sexual) host, Berberis vulgaris. This enabled us to investigate genetic variability of progeny isolates within and among aecia. Nine aecial clusters each consisting of an aecium (single aecial cup) and nine clusters containing multiple aecial cups were selected from 18 B. vulgaris leaves. Aeciospores from each cluster were inoculated on susceptible wheat seedlings and 64 progeny isolates were recovered. Molecular genotyping using 37 simple sequence repeat markers confirmed the parental origin of all progeny isolates. Thirteen molecular markers, which were heterozygous in the parental isolate, were used to analyse genetic diversity within and among aecial cups. The 64 progeny isolates resulted in 22 unique recombinant multilocus genotypes and none of them were resampled in different aecial clusters. Isolates derived from a single cup were always of the same genotype whereas isolates originating from clusters containing up to nine aecial cups revealed one to three genotypes per cluster. These results implied that each aecium was the result of a successful fertilization in a corresponding pycnium and that an aecium consisted of genetically identical aeciospores probably multiplied via repetitive mitotic divisions. Furthermore, the results suggested that aecia within a cluster were the result of independent fertilization events often involving genetically different pycniospores. The application of molecular markers represented a major advance in comparison to previous studies depending on phenotypic responses on host plants. The study allowed significant conclusions about fundamental aspects of the biology and genetics of an important cereal rust fungus.
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Affiliation(s)
- Julian Rodriguez-Algaba
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Forsøgsvej 1, 4200 Slagelse, Denmark.
| | - Chris K Sørensen
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Forsøgsvej 1, 4200 Slagelse, Denmark
| | - Rodrigo Labouriau
- Department of Mathematics, Faculty of Science and Technology, Aarhus University, Ny Munkegade 118, 8000 Aarhus, Denmark
| | - Annemarie F Justesen
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Forsøgsvej 1, 4200 Slagelse, Denmark
| | - Mogens S Hovmøller
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Forsøgsvej 1, 4200 Slagelse, Denmark
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16
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McArt SH, Miles TD, Rodriguez-Saona C, Schilder A, Adler LS, Grieshop MJ. Floral Scent Mimicry and Vector-Pathogen Associations in a Pseudoflower-Inducing Plant Pathogen System. PLoS One 2016; 11:e0165761. [PMID: 27851747 PMCID: PMC5113062 DOI: 10.1371/journal.pone.0165761] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 10/17/2016] [Indexed: 01/29/2023] Open
Abstract
Several fungal plant pathogens induce 'pseudoflowers' on their hosts to facilitate insect-mediated transmission of gametes and spores. When spores must be transmitted to host flowers to complete the fungal life cycle, we predict that pseudoflowers should evolve traits that mimic flowers and attract the most effective vectors in the flower-visiting community. We quantified insect visitation to flowers, healthy leaves and leaves infected with Monilinia vaccinii-corymbosi (Mvc), the causative agent of mummy berry disease of blueberry. We developed a nested PCR assay for detecting Mvc spores on bees, flies and other potential insect vectors. We also collected volatiles from blueberry flowers, healthy leaves and leaves infected with Mvc, and experimentally manipulated specific pathogen-induced volatiles to assess attractiveness to potential vectors. Bees and flies accounted for the majority of contacts with flowers, leaves infected with Mvc and healthy leaves. Flowers were contacted most often, while there was no difference between bee or fly contacts with healthy and infected leaves. While bees contacted flowers more often than flies, flies contacted infected leaves more often than bees. Bees were more likely to have Mvc spores on their bodies than flies, suggesting that bees may be more effective vectors than flies for transmitting Mvc spores to flowers. Leaves infected with Mvc had volatile profiles distinct from healthy leaves but similar to flowers. Two volatiles produced by flowers and infected leaves, cinnamyl alcohol and cinnamic aldehyde, were attractive to bees, while no volatiles manipulated were attractive to flies or any other insects. These results suggest that Mvc infection of leaves induces mimicry of floral volatiles, and that transmission occurs primarily via bees, which had the highest likelihood of carrying Mvc spores and visited flowers most frequently.
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Affiliation(s)
- Scott H. McArt
- Department of Entomology, Cornell University, Ithaca, New York, 14853, United States of America
| | - Timothy D. Miles
- School of Natural Sciences, California State University–Monterey Bay, Seaside, California, 93955, United States of America
| | - Cesar Rodriguez-Saona
- Department of Entomology, Philip E. Marucci Center, Rutgers University, Chatsworth, New Jersey, 08019, United States of America
| | - Annemiek Schilder
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, 01003, United States of America
| | - Matthew J. Grieshop
- Department of Entomology, Michigan State University, East Lansing, Michigan, 48824, United States of America
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17
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Shuttleworth A. Smells like debauchery: The chemical composition of semen-like, sweat-like and faintly foetid floral odours in Xysmalobium (Apocynaceae: Asclepiadoideae). BIOCHEM SYST ECOL 2016; 66:63-75. [DOI: 10.1016/j.bse.2016.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18
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Wang Z, Zhao J, Chen X, Peng Y, Ji J, Zhao S, Lv Y, Huang L, Kang Z. Virulence Variations of Puccinia striiformis f. sp. tritici Isolates Collected from Berberis spp. in China. Plant Dis 2016; 100:131-138. [PMID: 30688563 DOI: 10.1094/pdis-12-14-1296-re] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The stripe rust pathogen Puccinia striiformis f. sp. tritici frequently causes significant yield losses in China, due to rapid development of new races that overcome resistance in wheat cultivars. Indirect evidence suggests that sexual reproduction occurs in the P. striiformis f. sp. tritici population in China but direct evidence was still lacking. In this study, a large-scale survey of barberry (Berberis spp.) was conducted in Gansu, Shaanxi, Tibet, and Xinjiang provinces in western China. In total, 9,297 single-aecial (SA) samples were used to inoculate a susceptible wheat cultivar to identify samples of P. striiformis f. sp. tritici. Sixteen of the SA samples were identified as P. striiformis f. sp. tritici. When tested on the wheat differentials for identifying P. striiformis f. sp. tritici races, 15 of the 16 SA samples had different virulence patterns, indicating that they were sexually produced through barberry. From the 16 SA samples, 118 single-uredinium (SU) isolates were obtained, from which 88 virulence patterns were identified when tested on 17 Yr single-gene lines. The virulence patterns had relatively narrow virulence spectra, ranging from 0 to 9, with a mean of four virulences per SU isolates. Of the 17 Yr genes, no virulences were detected for Yr5, Yr10, and Yr15; virulences to YrTr1, Yr24, and Yr27 were extremely low (<3%); those to YrSP, Yr9, Yr28, and Yr2 were low (13.6 to 28.0%); those to Yr7, Yr17, Yr8, and YrExp2 were moderate (33.1 to 48.3%); and those to Yr6, Yr44, and Yr25 were high (52.5 to 72.9%). This study provides direct evidence that natural sexual reproduction occurs in the P. striiformis f. sp. tritici population in China, but the frequency appears to be very low. The sexual reproduction on alternate host plants can generate a great virulence diversity, which may have contributed to the high variation in the P. striiformis f. sp. tritici population in China.
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Affiliation(s)
- Zhiyan Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, P. R. China
| | - Jie Zhao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, P. R. China
| | - Xianming Chen
- United States Department of Agriculture-Agricultural Research Service, Wheat Genetics, Quality, Physiology, and Disease Research Unit and Department of Plant Pathology, Washington State University, Pullman 99164-6430
| | - Yuelin Peng
- Department of Plant Sciences, Agricultural and Animal Husbandry College of Tibet University, Linzhi, Tibet 86000, P. R. China
| | - Jingjing Ji
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University
| | - Shilei Zhao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University
| | - Yanjie Lv
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University
| | - Lili Huang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University
| | - Zhensheng Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University
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19
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McArt SH, Koch H, Irwin RE, Adler LS. Arranging the bouquet of disease: floral traits and the transmission of plant and animal pathogens. Ecol Lett 2014; 17:624-36. [PMID: 24528408 DOI: 10.1111/ele.12257] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 01/17/2014] [Indexed: 10/25/2022]
Abstract
Several floral microbes are known to be pathogenic to plants or floral visitors such as pollinators. Despite the ecological and economic importance of pathogens deposited in flowers, we often lack a basic understanding of how floral traits influence disease transmission. Here, we provide the first systematic review regarding how floral traits attract vectors (for plant pathogens) or hosts (for animal pathogens), mediate disease establishment and evolve under complex interactions with plant mutualists that can be vectors for microbial antagonists. Attraction of floral visitors is influenced by numerous phenological, morphological and chemical traits, and several plant pathogens manipulate floral traits to attract vectors. There is rapidly growing interest in how floral secondary compounds and antimicrobial enzymes influence disease establishment in plant hosts. Similarly, new research suggests that consumption of floral secondary compounds can reduce pathogen loads in animal pollinators. Given recent concerns about pollinator declines caused in part by pathogens, the role of floral traits in mediating pathogen transmission is a key area for further research. We conclude by discussing important implications of floral transmission of pathogens for agriculture, conservation and human health, suggesting promising avenues for future research in both basic and applied biology.
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Affiliation(s)
- Scott H McArt
- Department of Biology, University of Massachusetts-Amherst, Amherst, MA, 01003, USA
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20
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Abstract
Rust fungi are important components of ecological communities and in ecosystem function. Their unique life strategies as biotrophic pathogens with complicated life cycles could make them vulnerable to global environmental change. While there are gaps in our knowledge, especially in natural plant–rust systems, this review of the exposure of rust fungi to global change parameters revealed that some host–rust relationships would decline under predicted environmental change scenarios, whereas others would either remain unchanged or become more prevalent. Notably, some graminicolous rusts are negatively affected by higher temperatures and increased concentrations of atmospheric CO2. An increase of atmospheric O3 appears to favour rust diseases on trees but not those on grasses. Combined effects of CO2 and O3 are intermediary. The most important global drivers for the geographical and host plant range expansion and prevalence of rusts, however, are global plant trade, host plant genetic homogenization and the regular occurrence of conducive environmental conditions, especially the availability of moisture. However, while rusts thrive in high-humidity environments, they can also survive in desert habitats, and as a group their environmental tolerance is large, with no conclusive change in their overall prevalence predictable to date.
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Abstract
Barberry (Berberis spp.) hosts the aecial stage of several rust species, including Puccinia graminis, which causes stem rust on grasses and cereals. The aecial stage of this pathogen has received less attention because it is not as economically important compared with the uredinial and telial stages. The main objective of this study was to identify and describe the rust species that were found on Berberis spp. collected in different parts of Sweden. A morphological study, including spore measurements and aecia descriptions, was conducted, as well as DNA sequence analyses (using the internal transcribed spacer region and the EF1-α gene). Based on spore and aecia morphology as well as the genetic analyses, three different taxa could be distinguished on barberry: P. graminis f. sp. avenae, P. graminis f. sp. tritci/secalis, and P. arrhenatheri. The genetic analysis revealed little or no differentiation between P. graminis f. sp. tritici and P. graminis f. sp. secalis and, thus, this group of samples was denominated P. graminis f. sp. tritici/secalis. Aecial morphology may be used to differentiate between different taxa. In particular, examination of aecial cross-sections may be used to distinguish between P. graminis f. sp. avenae and P. graminis f. sp. tritici/secalis. A clear differentiation in the mode of growth on barberry was also found; P. arrhenatheri always appeared systemic whereas P. graminis always appeared localized.
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Affiliation(s)
- A Berlin
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - J Kyaschenko
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - A F Justesen
- Department of Agroecology, Plant Pathology and Entomology, Aarhus University, 4200, Slagelse, Denmark
| | - J Yuen
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
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Morath SU, Hung R, Bennett JW. Fungal volatile organic compounds: A review with emphasis on their biotechnological potential. FUNGAL BIOL REV 2012; 26:73-83. [DOI: 10.1016/j.fbr.2012.07.001] [Citation(s) in RCA: 295] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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23
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Tabata J, De Moraes CM, Mescher MC. Olfactory cues from plants infected by powdery mildew guide foraging by a mycophagous ladybird beetle. PLoS One 2011; 6:e23799. [PMID: 21876772 PMCID: PMC3158101 DOI: 10.1371/journal.pone.0023799] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 07/25/2011] [Indexed: 11/19/2022] Open
Abstract
Powdery mildews (Erysiphales) are economically important plant pathogens that attack many agricultural crops. Conventional management strategies involving fungicide application face challenges, including the evolution of resistance and concerns over impacts on non-target organisms, that call for investigation of more sustainable alternatives. Mycophagous ladybird beetles (Coleoptera: Coccinellidae) feed on powdery mildew and have considerable potential as biological control agents; however, the foraging ecology and behavior of these beetles is not well understood. Here we document the olfactory cues presented by squash plants (Cucurbita moschata) infected by powdery mildew (Podosphaera sp.) and the behavioral responses of twenty-spotted ladybird beetles (Psyllobora vigintimaculata) to these cues. Volatile analyses through gas chromatography revealed a number of volatile compounds characteristic of infected plants, including 3-octanol and its analogues 1-octen-3-ol and 3-octanone. These compounds are typical "moldy" odorants previously reported in volatiles collected from other fungi. In addition, infected plants exhibited elevated emissions of several compounds also observed in collections from healthy leaves, including linalool and benzyl alcohol, which are reported to have anti-fungal properties. In Y-tube choice assays, P. vigintimaculata beetles displayed a significant preference for the odors of infected plants compared to those of healthy plants. Moreover, beetles exhibited strong attraction to one individual compound, 1-octen-3-ol, which was the most abundant of the characteristic fungal compounds identified. These results enhance our understanding of the olfactory cues that guide foraging by mycophagous insects and may facilitate the development of integrated disease-management strategies informed by an understanding of underlying ecological mechanisms.
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Affiliation(s)
- Jun Tabata
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Biodiversity Division, National Institute for Agro-Environmental Sciences, Tsukuba, Ibaraki Prefecture, Japan
| | - Consuelo M. De Moraes
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Mark C. Mescher
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
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Vereecken NJ, McNeil JN. Cheaters and liars: chemical mimicry at its finestThe present review is one in the special series of reviews on animal-plant interactions.In memory of Jan Tengö (1939–2010), who made exceptional contributions to our understanding of the chemical ecology of solitary bees, including chemical mimicry. CAN J ZOOL 2010. [DOI: 10.1139/z10-040] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chemical mimicry is an essential part of certain interspecific interactions, where the outcome for both species may depend on the degree to which the original signals are mimicked. In this review, we discuss a number of specific cases relating to pollination and obtaining nutrient resources that we believe exemplify recent advances in our understanding of chemical mimicry. Subsequently, we suggest avenues for future ecological and chemical research that should allow us to gain further insight into the evolution of chemical mimicry.
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Affiliation(s)
- N. J. Vereecken
- Evolutionary Biology and Ecology, Free University of Brussels/Université Libre de Bruxelles, avenue FD Roosevelt 50 CP 160/12, B-1050 Brussels, Belgium
- Department of Biology, The University of Western Ontario, London ON N6A 5B7, Canada
- Institute of Systematic Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
| | - J. N. McNeil
- Evolutionary Biology and Ecology, Free University of Brussels/Université Libre de Bruxelles, avenue FD Roosevelt 50 CP 160/12, B-1050 Brussels, Belgium
- Department of Biology, The University of Western Ontario, London ON N6A 5B7, Canada
- Institute of Systematic Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
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25
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Dötterl S, Jürgens A, Wolfe L, Biere A. Disease status and population origin effects on floral scent:: potential consequences for oviposition and fruit predation in a complex interaction between a plant, fungus, and noctuid moth. J Chem Ecol 2009; 35:307-19. [PMID: 19241105 DOI: 10.1007/s10886-009-9601-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 01/20/2009] [Accepted: 02/02/2009] [Indexed: 10/21/2022]
Abstract
In the Silene latifolia-Hadena bicruris nursery pollination system, the Hadena moth is both pollinator and seed predator of its host plant. Floral scent, which differs among S. latifolia individuals and populations, is important for adult Hadena to locate its host. However, the success of moth larvae is strongly reduced if hosts are infected by the anther smut fungus Microbotryum violaceum, a pathogen that is transmitted by flower visitors. There were no qualitative differences between the scent of flowers from healthy and diseased plants. In addition, electroantennographic measurements showed that Hadena responded to the same subset of 19 compounds in samples collected from healthy and diseased plants. However, there were significant quantitative differences in scent profiles. Flowers from diseased plants emitted both a lower absolute amount of floral scent and had a different scent pattern, mainly due to their lower absolute amount of lilac aldehyde, whereas their amount of (E)-beta-ocimene was similar to that in healthy flowers. Dual choice behavioral wind tunnel tests using differently scented flowers confirmed that moths respond to both qualitative and quantitative aspects of floral scent, suggesting that they could use differences in floral scent between healthy and infected plants to discriminate against diseased plants. Population mean fruit predation rates significantly increased with population mean levels of the emission rates of lilac aldehyde per flower, indicating that selection on floral scent compounds may not only be driven by effects on pollinator attraction but also by effects on fruit predation. However, variation in mean emission rates of scent compounds per flower generally could not explain the higher fruit predation in populations originating from the introduced North American range compared to populations native to Europe.
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26
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Feldman TS, O'Brien HE, Arnold AE. Moths that vector a plant pathogen also transport endophytic fungi and mycoparasitic antagonists. Microb Ecol 2008; 56:742-750. [PMID: 18491176 DOI: 10.1007/s00248-008-9393-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 03/29/2008] [Accepted: 04/05/2008] [Indexed: 05/26/2023]
Abstract
Claviceps paspali, a common fungal pathogen of Paspalum grasses, attracts moth vectors by producing sugary exudates in the grass florets it infects. These exudates also support mycoparasitic Fusarium species that may negatively influence C. paspali fitness. We examined the potential for moths on which C. paspali depends to also transmit mycoparasitic Fusarium and fungal endophytes, which inhabit asymptomatic plant tissue and may influence host susceptibility to pathogens. We quantified infections by C. paspali, Fusarium spp., and endophytic fungi associated with Paspalum spp. at focal sites in the southeastern USA and used data from the nuclear internal transcribed spacer (ITS rDNA) to compare communities of plant-associated and moth-borne fungi. ITS sequences of moth-borne fungi were identical to reference sequences of mycoparasitic Fusarium heterosporum and to three distinct endophytic fungi isolated from Paspalum species. Our results demonstrate an unexpected overlap of fungal communities between disparate locations and among plant species and plant tissues, and suggest an unexpected role of moths, which vector a plant pathogen, to transmit other guilds of fungi. In turn, the potential for insects to transmit plant pathogens as well as mycoparasites and endophytic fungi suggests complex interactions underlying a commonly observed grass-pathogen system.
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Affiliation(s)
- Tracy S Feldman
- Biology Department, Duke University, Box 90338, Durham, NC 27708-0338, USA.
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27
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Steinebrunner F, Twele R, Francke W, Leuchtmann A, Schiestl FP. Role of odour compounds in the attraction of gamete vectors in endophytic Epichloë fungi. New Phytol 2008; 178:401-411. [PMID: 18194147 DOI: 10.1111/j.1469-8137.2007.02347.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Grass-infecting Epichloë endophytes (Ascomycota, Calvicipitaceae) depend on Botanophila flies for gamete transfer, while fly larvae feed and develop on the fertilized fungal fruiting structures. Flies are known to be attracted by volatile signals, but the exact mechanisms of chemical communication and the degree of specialization are unknown. Headspace samples collected from five different Epichloë species were analysed with respect to physiologically active substances using Botanophila flies. In field bioassays using synthetic compounds, their attractiveness and the specificity of the Epichloë-Botanophila attraction were investigated. The identification of a new natural product, methyl (Z)-3-methyldodec-2-enoate, attracting Botanophila flies is reported here, and chokol K is confirmed as an attractive compound. Different blends of the two compounds attracted Botanophila flies under field conditions, but the three fly taxa present at the study site showed no preference for specific blends of volatiles. Chemical communication in the Epichloë-Botanophila system relies on a few specific compounds, known as a communication system with 'private channels'. Although ratios of emitted compounds vary in different Epichloë species, this seems not to lead to specialized attraction of Botanophila flies. Low selective pressure for specialization may have maintained a more generalist interaction between fungi and flies.
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Affiliation(s)
- Fabrizio Steinebrunner
- Plant Ecological Genetics, Institute of Integrative Biology (IBZ), ETH Zürich, CH-8092 Zürich, Switzerland
| | - Robert Twele
- Department of Organic Chemistry, University of Hamburg, D-20146 Hamburg, Germany
| | - Wittko Francke
- Department of Organic Chemistry, University of Hamburg, D-20146 Hamburg, Germany
| | - Adrian Leuchtmann
- Plant Ecological Genetics, Institute of Integrative Biology (IBZ), ETH Zürich, CH-8092 Zürich, Switzerland
| | - Florian P Schiestl
- Institute of Systematic Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
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Hossaert-McKey M, McKey D, Dormont L. Fungal sex as a private matter: odour signals in a specialized pollination-like insect-fungus mutualism. New Phytol 2008; 178:225-227. [PMID: 18371002 DOI: 10.1111/j.1469-8137.2008.02428.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Martine Hossaert-McKey
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR CNRS 5175, 1919 route de Mende, F-34293 Montpellier Cedex 5, France (*Author for correspondence: tel +33 4 67 61 32 30; fax +33 4 67 41 21 38; email )
| | - Doyle McKey
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR CNRS 5175, 1919 route de Mende, F-34293 Montpellier Cedex 5, France (*Author for correspondence: tel +33 4 67 61 32 30; fax +33 4 67 41 21 38; email )
| | - Laurent Dormont
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR CNRS 5175, 1919 route de Mende, F-34293 Montpellier Cedex 5, France (*Author for correspondence: tel +33 4 67 61 32 30; fax +33 4 67 41 21 38; email )
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29
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Schiestl FP, Steinebrunner F, Schulz C, von Reuss S, Francke W, Weymuth C, Leuchtmann A. Evolution of 'pollinator'- attracting signals in fungi. Biol Lett 2006; 2:401-4. [PMID: 17148414 PMCID: PMC1686216 DOI: 10.1098/rsbl.2006.0479] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Accepted: 03/23/2006] [Indexed: 11/12/2022] Open
Abstract
Fungi produce a plethora of secondary metabolites yet their biological significance is often little understood. Some compounds show well-known antibiotic properties, others may serve as volatile signals for the attraction of insects that act as vectors of spores or gametes. Our investigations in an outcrossing, self-incompatible fungus show that a fungus-produced volatile compound with fungitoxic activities is also responsible for the attraction of specific insects that transfer gametes. We argue that insect attraction using this compound is likely to have evolved from its primary function of defence--as has been suggested for floral scent in the angiosperms. We, thus, propose that similar yet convergent evolutionary pathways have lead to interspecific communication signals in both fungi and plants.
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Affiliation(s)
- Florian P Schiestl
- Plant Ecological Genetics, Institute of Integrative Biology, ETH Zürich, Universitätsstrasse 16, 8092 Zürich, Switzerland.
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Abstract
Mimicry is the close resemblance of one living organism (the mimic) to another (the model), leading to misidentification by a third organism (the operator). Similar to other organism groups, certain species of plant-parasitic fungi are known to engage in mimetic relationships, thereby increasing their fitness. In some cases, fungal infection can lead to the formation of flower mimics (pseudo flowers) that attract insect pollinators via visual and/or olfactory cues; these insects then either transmit fungal gametes to accomplish outcrossing (e.g. in some heterothallic rust fungi belonging to the genera Puccinia and Uromyces) or vector infectious spores to healthy plants, thereby spreading disease (e.g. in the anther smut fungus Microbotryum violaceum and the mummy berry pathogen Monilinia vaccinii-corymbosi). In what is termed aggressive mimicry, some specialized plant-parasitic fungi are able to mimic host structures or host molecules to gain access to resources. An example is M. vaccinii-corymbosi, whose conidia and germ tubes, respectively, mimic host pollen grains and pollen tubes anatomically and physiologically, allowing the pathogen to gain entry into the host's ovary via stigma and style. We review these and other examples of mimicry by plant-parasitic fungi and some of the mechanisms, signals, and evolutionary implications.
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Affiliation(s)
- Henry K Ngugi
- Department of Plant Pathology, University of Georgia, Athens, GA, USA.
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31
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Abstract
Some flowering plants mimic the scent and appearance of mushroom fruiting bodies. Fungi may also mimic flowers. In addition, infection of plants by certain fungi can direct the plant to develop nonfunctional floral-like structures that nonetheless primarily serve the reproductive advantage of the fungus. These various mimicries may serve to attract insects that in turn spread fungal spores or plant pollen, thus facilitating sexual reproduction of the cryptic organism.
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Affiliation(s)
- Roman Kaiser
- Givaudan Schweiz AG, Fragrance Research, Ueberlandstrasse 138, CH-8600 Dubendorf, Switzerland.
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Abstract
The concept of plant venereal disease is examined from definitional, operational and axiomatic viewpoints. The transmission of many plant pathogens occurs during the flowering phase and is effected either by pollinators or by wind dispersal of spores from inflorescences. Attraction of insects by pseudo-flowers or sugary secretions also serves to spread many diseases. Given the diversity of processes involved, a simple all-encompassing parallel with animal venereal diseases is not possible. Operationally establishing the routes of disease transmission, as well as quantifying the relative magnitudes of these different routes, remains critical for understanding disease dynamics and controlling spread in agricultural contexts. From an axiomatic viewpoint, sexually transmitted diseases are characterized by frequency-dependent transmission, transmission in the adult stage, and by virulence effects involving sterility rather than mortality. These characteristics serve to differentiate the dynamics and evolution of sexually transmitted diseases from that of other diseases and are features that are also shared by many pollinator-transmitted diseases. However, the majority of plant diseases that involve the reproductive structures show a rich biology that defies easy categorization. The experimental convenience of plants and their pathogens is likely to play an important role in understanding the evolution of disease traits, irrespective of what descriptive terms are applied to the natural history of the transmission process.
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Affiliation(s)
- Janis Antonovics
- Biology Department, University of Virginia, Charlottesville, Virginia 22904, USA.
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Abstract
Parasites and pathogens are hypothesized to change host growth, reproduction and/or behaviour to increase their own transmission. However, studies which clearly demonstrate that parasites or pathogens are directly responsible for changes in hosts are lacking. We previously found that infection by the systemic fungus Epichloë glyceriae was associated with greater clonal growth by its host, Glyceria striata. Whether greater clonal growth resulted directly from pathogen infection or indirectly from increased likelihood of infection for host genotypes with greater clonal growth could not be determined because only naturally infected and uninfected plants were used. In this study, we decoupled infection and host genotype to evaluate the role of pathogen infection on host development and clonal growth. We found that total biomass production did not differ for clones of the same genotype, but infected clones allocated more biomass to clonal growth. Disinfected clones had more tillers and a greater proportion of their biomass in the mother ramet. Infected clones produced fewer tillers but significantly more and longer stolons than disinfected clones. These results support the hypothesis that pathogen infection directly alters host development. Parasite alteration of clonal growth patterns might be advantageous to the persistence and spread of host plants in some ecological conditions.
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Affiliation(s)
- Jean J Pan
- Department of Biology, Indiana University, Bloomington, IN 47405, USA.
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Guidot A, Johannesson H, Dahlberg A, Stenlid J. Parental tracking in the postfire wood decay ascomycete Daldinia loculata using highly variable nuclear gene loci. Mol Ecol 2003; 12:1717-30. [PMID: 12803626 DOI: 10.1046/j.1365-294x.2003.01858.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The origin of the male and female gametes involved in fertilization events within a local population of the postfire wood decay ascomycete Daldinia loculata was investigated by genotyping the mycelia growing in the wood and the sexual ascospores, using three highly variable nuclear gene loci. The study was conducted in a geographically isolated burned forest site in southern Sweden. An intensive sampling was performed by collecting stromata containing ascospores and wood samples containing mycelia. In total, from 32 mapped burned birches, cultures of 22 haploid genets from decayed wood and six ascospores from each of 19 stromata were isolated and analysed. In 80% of the investigated burned branches, only one genet was found. From the analysis of the ascospore genotypes, we detected 30 fertilization events and 60% of them were the result of mating between conidia (clonal propagules) acting as male gametes and the genets in the branches representing the female gametes. The male parents producing the conidia were detected within the same local population as the female parents in 27% of the fertilization events and originated either from the same branch or from different trees located at 0.5-36 m away from the female parents. In 33% of the fertilization events, conidia originated from three male parents that were not found within the local population sampled. These parents could be anywhere inside or outside the sampled area. For the remaining fertilization events, we could not rule out the ascospores or the conidia as fertilizing propagules. No strong evidence for fertilization by recombinant propagules (ascospores) was detected in this study. The pyrophilous insect species associated with conidia of D. loculata are suggested to be essential vectors for the realization of the sexual cycle of this fungal species. By feeding on the conidia and flying between nearby trees inhabiting wood decay mycelia, these insects allow the transfer of conidia and therefore the opposite mating types to meet within a localized burned forest site.
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Affiliation(s)
- A Guidot
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, PO Box 7026, S-750 07 Uppsala, Sweden.
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