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Gossner MM, Perret-Gentil A, Britt E, Queloz V, Glauser G, Ladd T, Roe AD, Cleary M, Liziniewicz M, Nielsen LR, Ghosh SK, Bonello P, Eisenring M. A glimmer of hope - ash genotypes with increased resistance to ash dieback pathogen show cross-resistance to emerald ash borer. THE NEW PHYTOLOGIST 2023; 240:1219-1232. [PMID: 37345294 DOI: 10.1111/nph.19068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 05/18/2023] [Indexed: 06/23/2023]
Abstract
Plants rely on cross-resistance traits to defend against multiple, phylogenetically distinct enemies. These traits are often the result of long co-evolutionary histories. Biological invasions can force naïve plants to cope with novel, coincident pests, and pathogens. For example, European ash (Fraxinus excelsior) is substantially threatened by the emerald ash borer (EAB), Agrilus planipennis, a wood-boring beetle, and the ash dieback (ADB) pathogen, Hymenoscyphus fraxineus. Yet, plant cross-resistance traits against novel enemies are poorly explored and it is unknown whether naïve ash trees can defend against novel enemy complexes via cross-resistance mechanisms. To gain mechanistic insights, we quantified EAB performance on grafted replicates of ash genotypes varying in ADB resistance and characterized ash phloem chemistry with targeted and untargeted metabolomics. Emerald ash borer performed better on ADB-susceptible than on ADB-resistant genotypes. Moreover, changes in EAB performance aligned with differences in phloem chemical profiles between ADB-susceptible and ADB-resistant genotypes. We show that intraspecific variation in phloem chemistry in European ash can confer increased cross-resistance to invasive antagonists from different taxonomic kingdoms. Our study suggests that promotion of ADB-resistant ash genotypes may simultaneously help to control the ADB disease and reduce EAB-caused ash losses, which may be critical for the long-term stability of this keystone tree species.
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Affiliation(s)
- Martin M Gossner
- Forest Health & Biotic Interactions, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), 8903, Birmensdorf, Switzerland
- Institute of Terrestrial Ecosystems, ETH Zürich, 8092, Zurich, Switzerland
| | - Anouchka Perret-Gentil
- Forest Health & Biotic Interactions, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), 8903, Birmensdorf, Switzerland
| | - Elisabeth Britt
- Forest Health & Biotic Interactions, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), 8903, Birmensdorf, Switzerland
| | - Valentin Queloz
- Forest Health & Biotic Interactions, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), 8903, Birmensdorf, Switzerland
| | - Gaétan Glauser
- Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, 2000, Neuchâtel, Switzerland
| | - Tim Ladd
- Great Lakes Forestry Centre, Canadian Forest Service, Natural Resources Canada, ON P6A 2E5, Sault Ste. Marie, ON, Canada
| | - Amanda D Roe
- Great Lakes Forestry Centre, Canadian Forest Service, Natural Resources Canada, ON P6A 2E5, Sault Ste. Marie, ON, Canada
| | - Michelle Cleary
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, SE-234 22, Alnarp, Sweden
| | | | - Lene R Nielsen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, 1958, Frederiksberg C, Denmark
| | - Soumya K Ghosh
- Department of Plant Pathology, The Ohio State University, Columbus, 43210, OH, USA
| | - Pierluigi Bonello
- Department of Plant Pathology, The Ohio State University, Columbus, 43210, OH, USA
| | - Michael Eisenring
- Forest Health & Biotic Interactions, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), 8903, Birmensdorf, Switzerland
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Williams GM, Ginzel MD, Ma Z, Adams DC, Campbell F, Lovett GM, Pildain MB, Raffa KF, Gandhi KJK, Santini A, Sniezko RA, Wingfield MJ, Bonello P. The Global Forest Health Crisis: A Public-Good Social Dilemma in Need of International Collective Action. ANNUAL REVIEW OF PHYTOPATHOLOGY 2023; 61:377-401. [PMID: 37253697 DOI: 10.1146/annurev-phyto-021722-024626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Society is confronted by interconnected threats to ecological sustainability. Among these is the devastation of forests by destructive non-native pathogens and insects introduced through global trade, leading to the loss of critical ecosystem services and a global forest health crisis. We argue that the forest health crisis is a public-good social dilemma and propose a response framework that incorporates principles of collective action. This framework enables scientists to better engage policymakers and empowers the public to advocate for proactive biosecurity and forest health management. Collective action in forest health features broadly inclusive stakeholder engagement to build trust and set goals; accountability for destructive pest introductions; pooled support for weakest-link partners; and inclusion of intrinsic and nonmarket values of forest ecosystems in risk assessment. We provide short-term and longer-term measures that incorporate the above principles to shift the societal and ecological forest health paradigm to a more resilient state.
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Affiliation(s)
- Geoffrey M Williams
- International Programs, US Forest Service, US Department of Agriculture, Lansing, Michigan, USA;
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana, USA
| | - Matthew D Ginzel
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana, USA
- Department of Entomology, Purdue University, West Lafayette, Indiana, USA
| | - Zhao Ma
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana, USA
| | - Damian C Adams
- Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Faith Campbell
- Center for Invasive Species Prevention, Bethesda, Maryland, USA
| | - Gary M Lovett
- Cary Institute of Ecosystem Studies, Millbrook, New York, USA
| | - María Belén Pildain
- Centro de Investigación y Extensión Forestal Andino Patagónico, Consejo Nacional de Investigaciones Científicas y Técnicas, Esquel, Chubut, Argentina
| | - Kenneth F Raffa
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kamal J K Gandhi
- D. B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| | - Alberto Santini
- Institute for Sustainable Plant Protection, National Research Council, Sesto Fiorentino, Italy
| | - Richard A Sniezko
- Dorena Genetic Resource Center, US Forest Service, US Department of Agriculture, Cottage Grove, Oregon, USA
| | - Michael J Wingfield
- Forestry and Agricultural Biotechnology Institute, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Pierluigi Bonello
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, USA;
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3
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Seeley MM, Martin RE, Giardina C, Luiz B, Francisco K, Cook Z, Hughes MA, Asner GP. Leaf spectroscopy of resistance to Ceratocystis wilt of 'Ōhi'a. PLoS One 2023; 18:e0287144. [PMID: 37352315 PMCID: PMC10289452 DOI: 10.1371/journal.pone.0287144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 05/31/2023] [Indexed: 06/25/2023] Open
Abstract
Plant pathogens are increasingly compromising forest health, with impacts to the ecological, economic, and cultural goods and services these global forests provide. One response to these threats is the identification of disease resistance in host trees, which with conventional methods can take years or even decades to achieve. Remote sensing methods have accelerated host resistance identification in agricultural crops and for a select few forest tree species, but applications are rare. Ceratocystis wilt of 'ōhi'a, caused by the fungal pathogen Ceratocystis lukuohia has been killing large numbers of the native Hawaiian tree, Metrosideros polymorpha or 'Ōhi'a, Hawaii's most common native tree and a biocultural keystone species. Here, we assessed whether resistance to C. lukuohia is detectable in leaf-level reflectance spectra (400-2500 nm) and used chemometric conversion equations to understand changes in leaf chemical traits of the plants as indicators of wilt symptom progression. We collected leaf reflectance data prior to artificially inoculating 2-3-year-old M. polymorpha clones with C. lukuohia. Plants were rated 3x a week for foliar wilt symptom development and leaf spectra data collected at 2 to 4-day intervals for 120 days following inoculation. We applied principal component analysis (PCA) to the pre-inoculation spectra, with plants grouped according to site of origin and subtaxon, and two-way analysis of variance to assess whether each principal component separated individuals based on their disease severity ratings. We identified seven leaf traits that changed in susceptible plants following inoculation (tannins, chlorophyll a+b, NSC, total C, leaf water, phenols, and cellulose) and leaf chemistries that differed between resistant and early-stage susceptible plants, most notably chlorophyll a+b and cellulose. Further, disease resistance was found to be detectable in the reflectance data, indicating that remote sensing work could expedite Ceratocystis wilt of 'ōhi'a resistance screenings.
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Affiliation(s)
- Megan M. Seeley
- Center for Global Discovery and Conservation Science, Arizona State University, Hilo, Hawaiʻi, United States of America
- School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, Arizona, United States of America
| | - Roberta E. Martin
- Center for Global Discovery and Conservation Science, Arizona State University, Hilo, Hawaiʻi, United States of America
- School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, Arizona, United States of America
| | - Christian Giardina
- Institute of Pacific Islands Forestry, Pacific Southwest Research Station, USDA Forest Service, Hilo, Hawaiʻi, United States of America
| | - Blaine Luiz
- Akaka Foundation for Tropical Forests, Hilo, Hawaiʻi, United States of America
| | - Kainana Francisco
- Institute of Pacific Islands Forestry, Pacific Southwest Research Station, USDA Forest Service, Hilo, Hawaiʻi, United States of America
| | - Zachary Cook
- Institute of Pacific Islands Forestry, Pacific Southwest Research Station, USDA Forest Service, Hilo, Hawaiʻi, United States of America
| | - Marc A. Hughes
- Institute of Pacific Islands Forestry, Pacific Southwest Research Station, USDA Forest Service, Hilo, Hawaiʻi, United States of America
| | - Gregory P. Asner
- Center for Global Discovery and Conservation Science, Arizona State University, Hilo, Hawaiʻi, United States of America
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Nielsen LR, Nagy NE, Piqueras S, Kosawang C, Thygesen LG, Hietala AM. Host−Pathogen Interactions in Leaf Petioles of Common Ash and Manchurian Ash Infected with Hymenoscyphus fraxineus. Microorganisms 2022; 10:microorganisms10020375. [PMID: 35208829 PMCID: PMC8875166 DOI: 10.3390/microorganisms10020375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 02/04/2023] Open
Abstract
Some common ash trees (Fraxinus excelsior) show tolerance towards shoot dieback caused by the invasive ascomycete Hymenoscyphus fraxineus. Leaf petioles are considered to serve as a pathogen colonization route to the shoots. We compared four common ash clones with variation in disease tolerance, and included the native host, Manchurian ash (Fraxinus mandshurica), as a reference. Tissue colonization, following rachis inoculation by H. fraxineus, was monitored by histochemical observations and a quantitative polymerase chain reaction (qPCR) assay specific to H. fraxineus. Axial spread of the pathogen towards the petiole base occurred primarily within the phloem and parenchyma, tissues rich in starch in healthy petioles. In inoculated petioles, a high content of phenolics surrounded the hyphae, presumably a host defense response. There was a relationship between field performance and susceptibility to leaf infection in three of the four studied common ash clones, i.e., good field performance was associated with a low petiole colonization level and vice versa. Low susceptibility to leaf infection may counteract leaf-to-shoot spread of the pathogen in common ash, but the limited number of clones studied warrants caution and a larger study. The Manchurian ash clone had the highest petiole colonization level, which may suggest that this native host has evolved additional mechanisms to avoid shoot infection.
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Affiliation(s)
- Lene R. Nielsen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, 1958 Frederiksberg, Denmark; (S.P.); (C.K.); (L.G.T.)
- Correspondence:
| | - Nina E. Nagy
- Division of Biotechnology and Plant Health, Norwegian Institute of Bioeconomy Research (NIBIO), 1431 Ås, Norway;
| | - Sara Piqueras
- Department of Geosciences and Natural Resource Management, University of Copenhagen, 1958 Frederiksberg, Denmark; (S.P.); (C.K.); (L.G.T.)
| | - Chatchai Kosawang
- Department of Geosciences and Natural Resource Management, University of Copenhagen, 1958 Frederiksberg, Denmark; (S.P.); (C.K.); (L.G.T.)
| | - Lisbeth G. Thygesen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, 1958 Frederiksberg, Denmark; (S.P.); (C.K.); (L.G.T.)
| | - Ari M. Hietala
- Norwegian Institute of Bioeconomy Research (NIBIO), 7734 Steinkjer, Norway;
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Hebda A, Liszka A, Zgłobicki P, Nawrot-Chorabik K, Lyczakowski JJ. Transformation of European Ash ( Fraxinus excelsior L.) Callus as a Starting Point for Understanding the Molecular Basis of Ash Dieback. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112524. [PMID: 34834887 PMCID: PMC8622397 DOI: 10.3390/plants10112524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 06/13/2023]
Abstract
The population of European ash (Fraxinus excelsior L.) is currently facing the risk of collapse, mainly due to ash dieback, a disease caused by a pathogenic fungus, Hymenoscyphus fraxineus. To facilitate studies into the molecular basis of ash dieback and design breeding strategies for a generation of resistant trees, it is necessary to develop tools enabling the study of gene function in F. excelsior. Despite this, a method for the genetic engineering of F. excelsior is still missing. Here, we report the first successful genetic transformation of F. excelsior callus and a selection process enabling the formation of stable transgenic callus lines. The protocol relies on the use of Agrobacterium tumefaciens to transform callus tissue derived from embryos of F. excelsior. In our experiments, we used the β-glucuronidase (GUS) reporter system to demonstrate the transformation of callus cells and performed RT-PCR experiments to confirm the stable expression of the transgene. Since ash dieback threatens the long-term stability of many native F. excelsior populations, we hope that the transformation techniques described in this manuscript will facilitate rapid progress in uncovering the molecular basis of the disease and the validation of gene targets previously proposed to be linked to the resistance of trees to H. fraxineus pathogenicity.
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Affiliation(s)
- Anna Hebda
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland; (A.H.); (A.L.); (P.Z.)
| | - Aleksandra Liszka
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland; (A.H.); (A.L.); (P.Z.)
| | - Piotr Zgłobicki
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland; (A.H.); (A.L.); (P.Z.)
| | - Katarzyna Nawrot-Chorabik
- Department of Forest Ecosystems Protection, Faculty of Forestry, University of Agriculture in Krakow, 29-Listopada Ave. 46, 31-425 Krakow, Poland;
| | - Jan J. Lyczakowski
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland; (A.H.); (A.L.); (P.Z.)
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6
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Sidda JD, Song L, Parker JL, Studholme DJ, Sambles C, Grant M. Diversity of secoiridoid glycosides in leaves of UK and Danish ash provide new insight for ash dieback management. Sci Rep 2020; 10:19566. [PMID: 33177633 PMCID: PMC7658974 DOI: 10.1038/s41598-020-76140-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 10/14/2020] [Indexed: 12/23/2022] Open
Abstract
Secoiridoid glycosides are anti-feeding deterrents of the Oleaceae family recently highlighted as potential biomarkers in Danish ash trees to differentiate between those tolerant and susceptible to the fungal disease ash dieback. With the knowledge that emerald ash borer has recently entered Europe from Russia, and that extensive selection trials are ongoing in Europe for ash dieback tolerant European ash (Fraxinus excelsior), we undertook comprehensive screening of secoiridoid glycosides in leaf extracts of trees tolerant and susceptible to ash dieback sampled from sites in the UK and Denmark. Here we report an unexpected diversity of secoiridoid glycosides in UK trees and higher levels of secoiridoid glycosides in the UK sample group. While it is unlikely that secoiridoid glycosides generally can serve as reliable markers for ash dieback susceptibility, there are differences between tolerant and susceptible groups for specific secoiridoids. We predict that the high levels-and structural diversity-of secoiridoids present in the UK group may provide a robust reservoir of anti-feeding deterrents to mitigate future herbivore threats such as the Emerald ash borer.
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Affiliation(s)
- John D Sidda
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
| | - Lijiang Song
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Jack L Parker
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | | | | | - Murray Grant
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
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7
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Nemesio-Gorriz M, Menezes RC, Paetz C, Hammerbacher A, Steenackers M, Schamp K, Höfte M, Svatoš A, Gershenzon J, Douglas GC. Canditate metabolites for ash dieback tolerance in Fraxinus excelsior. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6074-6083. [PMID: 32598444 DOI: 10.1093/jxb/eraa306] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
Ash dieback, a forest epidemic caused by the invasive fungus Hymenoscyphus fraxineus, threatens ash trees throughout Europe. Within Fraxinus excelsior populations, a small proportion of genotypes show a low susceptibility to the pathogen. We compared the metabolomes from a cohort of low-susceptibility ash genotypes with a cohort of high-susceptibility ash genotypes. This revealed two significantly different chemotypes. A total of 64 candidate metabolites associated with reduced or increased susceptibility in the chemical families secoiridoids, coumarins, flavonoids, phenylethanoids, and lignans. Increased levels of two coumarins, fraxetin and esculetin, were strongly associated with reduced susceptibility to ash dieback. Both coumarins inhibited the growth of H. fraxineus in vitro when supplied at physiological concentrations, thereby validating their role as markers for low susceptibility to ash dieback. Similarly, fungal growth inhibition was observed when the methanolic bark extract of low-susceptibility ash genotypes was supplied. Our findings indicate the presence of constitutive chemical defense barriers against ash dieback in ash.
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Affiliation(s)
| | - Riya C Menezes
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | | | - Almuth Hammerbacher
- Max Planck Institute for Chemical Ecology, Jena, Germany
- Department of Zoology and Entomology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | | | - Kurt Schamp
- Research Institute for Nature and Forest (INBO), Geraardsbergen, Belgium
| | - Monica Höfte
- Department of Crop Protection, Faculty of Agricultural and Applied Biological Sciences, Ghent University, Ghent, Belgium
| | - Aleš Svatoš
- Max Planck Institute for Chemical Ecology, Jena, Germany
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8
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Sahraei SE, Cleary M, Stenlid J, Brandström Durling M, Elfstrand M. Transcriptional responses in developing lesions of European common ash (Fraxinus excelsior) reveal genes responding to infection by Hymenoscyphus fraxineus. BMC PLANT BIOLOGY 2020; 20:455. [PMID: 33023496 PMCID: PMC7541206 DOI: 10.1186/s12870-020-02656-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND With the expanding ash dieback epidemic that has spread across the European continent, an improved functional understanding of the disease development in afflicted hosts is needed. The study investigated whether differences in necrosis extension between common ash (Fraxinus excelsior) trees with different levels of susceptibility to the fungus Hymenoscyphus fraxineus are associated with, and can be explained by, the differences in gene expression patterns. We inoculated seemingly healthy branches of each of two resistant and susceptible ash genotypes with H. fraxineus grown in a common garden. RESULTS Ten months after the inoculation, the length of necrosis on the resistant genotypes were shorter than on the susceptible genotypes. RNA sequencing of bark samples collected at the border of necrotic lesions and from healthy tissues distal to the lesion revealed relatively limited differences in gene expression patterns between susceptible and resistant genotypes. At the necrosis front, only 138 transcripts were differentially expressed between the genotype categories while 1082 were differentially expressed in distal, non-symptomatic tissues. Among these differentially expressed genes, several genes in the mevalonate (MVA) and iridoid pathways were found to be co-regulated, possibly indicating increased fluxes through these pathways in response to H. fraxineus. Comparison of transcriptional responses of symptomatic and non-symptomatic ash in a controlled greenhouse experiment revealed a relatively small set of genes that were differentially and concordantly expressed in both studies. This gene-set included the rate-limiting enzyme in the MVA pathway and a number of transcription factors. Furthermore, several of the concordantly expressed candidate genes show significant similarity to genes encoding players in the abscisic acid- or Jasmonate-signalling pathways. CONCLUSIONS A set of candidate genes, concordantly expressed between field and greenhouse experiments, was identified. The candidates are associated with hormone signalling and specialized metabolite biosynthesis pathways indicating the involvement of these pathways in the response of the host to infection by H. fraxineus.
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Affiliation(s)
- Shadi Eshghi Sahraei
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Michelle Cleary
- Southern Swedish Forest Research Center, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Jan Stenlid
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Mikael Brandström Durling
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Malin Elfstrand
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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9
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The Relationship between Fungal Diversity and Invasibility of a Foliar Niche-The Case of Ash Dieback. J Fungi (Basel) 2020; 6:jof6030150. [PMID: 32858843 PMCID: PMC7558441 DOI: 10.3390/jof6030150] [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] [Received: 07/24/2020] [Revised: 08/19/2020] [Accepted: 08/24/2020] [Indexed: 12/30/2022] Open
Abstract
European ash (Fraxinus excelsior) is threatened by the invasive ascomycete Hymenoscyphus fraxineus originating from Asia. Ash leaf tissues serve as a route for shoot infection but also as a sporulation substrate for this pathogen. Knowledge of the leaf niche partitioning by indigenous fungi and H. fraxineus is needed to understand the fungal community receptiveness to the invasion. We subjected DNA extracted from unwashed and washed leaflets of healthy and diseased European ash to PacBio sequencing of the fungal ITS1-5.8S-ITS2 rDNA region. Leaflets from co-inhabiting rowan trees (Sorbus aucuparia) served as a reference. The overlap in leaflet mycobiomes between ash and rowan was remarkably high, but unlike in rowan, in ash leaflets the sequence read proportion, and the qPCR-based DNA amount estimates of H. fraxineus increased vigorously towards autumn, concomitant with a significant decline in overall fungal richness. The niche of ash and rowan leaves was dominated by epiphytic propagules (Vishniacozyma yeasts, the dimorphic fungus Aureobasidion pullulans and the dematiaceous hyphomycete Cladosporium ramotenellum and H. fraxineus), and endophytic thalli of biotrophs (Phyllactinia and Taphrina species), the indigenous necrotroph Venturia fraxini and H. fraxineus. Mycobiome comparison between healthy and symptomatic European ash leaflets revealed no significant differences in relative abundance of H. fraxineus, but A. pullulans was more prevalent in symptomatic trees. The impacts of host specificity, spatiotemporal niche partitioning, species carbon utilization profiles and life cycle traits are discussed to understand the ecological success of H. fraxineus in Europe. Further, the inherent limitations of different experimental approaches in the profiling of foliicolous fungi are addressed.
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10
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Halecker S, Wennrich JP, Rodrigo S, Andrée N, Rabsch L, Baschien C, Steinert M, Stadler M, Surup F, Schulz B. Fungal endophytes for biocontrol of ash dieback: The antagonistic potential of Hypoxylon rubiginosum. FUNGAL ECOL 2020. [DOI: 10.1016/j.funeco.2020.100918] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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11
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Mukrimin M, Conrad AO, Kovalchuk A, Julkunen-Tiitto R, Bonello P, Asiegbu FO. Fourier-transform infrared (FT-IR) spectroscopy analysis discriminates asymptomatic and symptomatic Norway spruce trees. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 289:110247. [PMID: 31623795 DOI: 10.1016/j.plantsci.2019.110247] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/28/2019] [Accepted: 08/30/2019] [Indexed: 05/27/2023]
Abstract
Conifer trees, including Norway spruce, are threatened by fungi of the Heterobasidion annosum species complex, which severely affect timber quality and cause economic losses to forest owners. The timely detection of infected trees is complicated, as the pathogen resides within the heartwood and sapwood of infected trees. The presence of the disease and the extent of the wood decay often becomes evident only after tree felling. Fourier-transform infrared (FT-IR) spectroscopy is a potential method for non-destructive sample analysis that may be useful for identifying infected trees in this pathosystem. We performed FT-IR analysis of 18 phloem, 18 xylem, and 18 needle samples from asymptomatic and symptomatic Norway spruce trees. FT-IR spectra from 1066 - 912 cm-1 could be used to distinguish phloem, xylem, and needle tissue extracts. FT-IR spectra collected from xylem and needle extracts could also be used to discriminate between asymptomatic and symptomatic trees using spectral bands from 1657 - 994 cm-1 and 1104 - 994 cm-1, respectively. A partial least squares regression model predicted the concentration of condensed tannins, a defense-related compound, in phloem of asymptomatic and symptomatic trees. This work is the first to show that FT-IR spectroscopy can be used for the identification of Norway spruce trees naturally infected with Heterobasidion spp.
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Affiliation(s)
- Mukrimin Mukrimin
- Department of Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, P.O. Box 27, 00014, Helsinki, Finland; Department of Forestry, Faculty of Forestry, Hasanuddin University, Jln. Perintis Kemerdekaan Km. 10, 90245, Makassar, Indonesia
| | - Anna O Conrad
- Department of Plant Pathology, The Ohio State University, 2021 Coffey Road, Columbus, OH, 43210, USA
| | - Andriy Kovalchuk
- Department of Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, P.O. Box 27, 00014, Helsinki, Finland
| | - Riitta Julkunen-Tiitto
- Department of Environmental and Biological Sciences, Joensuu Campus, University of Eastern Finland (UEF), P.O. Box 111, FI-80101, Joensuu, Finland
| | - Pierluigi Bonello
- Department of Plant Pathology, The Ohio State University, 2021 Coffey Road, Columbus, OH, 43210, USA
| | - Fred O Asiegbu
- Department of Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, P.O. Box 27, 00014, Helsinki, Finland.
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