1
|
Nasif SO, Siddique AB, Siddique AB, Islam MM, Hassan O, Deepo DM, Hossain A. Prospects of endophytic fungi as a natural resource for the sustainability of crop production in the modern era of changing climate. Symbiosis 2022. [DOI: 10.1007/s13199-022-00879-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
2
|
Wen Z, Terhonen E, Asiegbu FO. The dark septate endophyte Phialocephala sphaeroides confers growth fitness benefits and mitigates pathogenic effects of Heterobasidion on Norway spruce. TREE PHYSIOLOGY 2022; 42:891-906. [PMID: 34791486 PMCID: PMC9000907 DOI: 10.1093/treephys/tpab147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 11/09/2021] [Indexed: 05/27/2023]
Abstract
Forest trees frequently interact with a diverse range of microorganisms including dark septate endophytes (DSEs) and fungal pathogens. Plant defense responses to either individual pathogens or endophytes have been widely studied, but very little is known on the effect of coinfection on host defenses. To study the impact of coinfection or tripartite interaction on plant growth and host defenses, Norway spruce (Picea abies (L.) Karst) seedlings were inoculated with a DSE Phialocephala sphaeroides or with a root pathogen Heterobasidion parviporum Niemela & Korhonen or coinfected with both fungi. The results showed that the DSE promoted the root growth of spruce seedlings. Control seedlings without any inoculum were subjected to sequencing and used as a baseline for identification of differentially expressed genes (DEGs). RNA-seq analysis of seedlings inoculated with P. sphaeroides, infected with H. parviporum or coinfected with both fungi resulted in a total of 5269 DEGs. The majority of DEGs were found in P. sphaeroides-inoculated seedlings. Lignin biosynthesis pathways were generally activated during fungal infections. The pattern was distinct with endophyte inoculation. The majority of the genes in the flavonoid biosynthesis pathway were generally suppressed during fungal infections. A specific transcriptional response to P. sphaeroides inoculation was the increased transcripts of genes involved in jasmonic acid biosynthesis, mitogen-activated protein kinases signaling pathway, plant hormone signal transduction and calcium-mediated signaling. This may have potentially contributed to promoting the root growth of seedlings. Although the coinfection suppressed the induction of numerous genes, no negative effect on the growth of the spruce seedlings occurred. We conclude that the subsequent H. parviporum infection triggered reprogramming of host metabolism. Conversely, the endophyte (P. sphaeroides), on the other hand, counteracted the negative effects of H. parviporum on the growth of the spruce seedlings.
Collapse
Affiliation(s)
- Zilan Wen
- Faculty of Agriculture and Forestry, University of Helsinki, Helsinki 00790, Finland
| | - Eeva Terhonen
- Natural Resources Institute Finland (Luke), Helsinki 00790, Finland
| | | |
Collapse
|
3
|
Insights into the beneficial roles of dark septate endophytes in plants under challenging environment: resilience to biotic and abiotic stresses. World J Microbiol Biotechnol 2022; 38:79. [PMID: 35332399 DOI: 10.1007/s11274-022-03264-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 03/09/2022] [Indexed: 12/22/2022]
Abstract
Dark septate endophytes (DSE) exert a plethora of effects in regulating plant growth, signalling and stress tolerance. The advent of metagenomics has led to the identification of various species of DSE to be associated with plant organs. They are known to modulate growth, nutrient uptake, phytohormone biosynthesis and production of active bioconstituents in several plants. The interactions between the DSE and host plants are mostly mutualistic but they can also be neutral or exhibit negative interactions. The DSE has beneficial role in removal/sequestration of toxic heavy metals from various environmental sites. Here, we discuss the beneficial role of DSE in enhancing plant tolerance to heavy metal stress, drought conditions, high salinity and protection from various plant pathogens. Furthermore, the underlying mechanism of stress resilience facilitated by DSE-plant interaction has also been discussed. The article also provides insights to some important future perspectives associated with DSE-mediated phytoremediation and reclamation of polluted land worldwide thus facilitating sustainable agriculture.
Collapse
|
4
|
The Threat of Pests and Pathogens and the Potential for Biological Control in Forest Ecosystems. FORESTS 2021. [DOI: 10.3390/f12111579] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Forests are an essential component of the natural environment, as they support biodiversity, sequester carbon, and play a crucial role in biogeochemical cycles—in addition to producing organic matter that is necessary for the function of terrestrial organisms. Forests today are subject to threats ranging from natural occurrences, such as lightning-ignited fires, storms, and some forms of pollution, to those caused by human beings, such as land-use conversion (deforestation or intensive agriculture). In recent years, threats from pests and pathogens, particularly non-native species, have intensified in forests. The damage, decline, and mortality caused by insects, fungi, pathogens, and combinations of pests can lead to sizable ecological, economic, and social losses. To combat forest pests and pathogens, biocontrol may be an effective alternative to chemical pesticides and fertilizers. This review of forest pests and potential adversaries in the natural world highlights microbial inoculants, as well as research efforts to further develop biological control agents against forest pests and pathogens. Recent studies have shown promising results for the application of microbial inoculants as preventive measures. Other studies suggest that these species have potential as fertilizers.
Collapse
|
5
|
Advances in the Role of Dark Septate Endophytes in the Plant Resistance to Abiotic and Biotic Stresses. J Fungi (Basel) 2021; 7:jof7110939. [PMID: 34829226 PMCID: PMC8622582 DOI: 10.3390/jof7110939] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 02/06/2023] Open
Abstract
Endophytic fungi have been studied in recent decades to understand how they interact with their hosts, the types of relationships they establish, and the potential effects of this interaction. Dark septate endophytes (DSE) are isolated from healthy plants and form melanised structures in the roots, including inter- and intracellular hyphae and microsclerotia, causing low host specificity and covering a wide geographic range. Many studies have revealed beneficial relationships between DSE and their hosts, such as enhanced plant growth, nutrient uptake, and resistance to biotic and abiotic stress. Furthermore, in recent decades, studies have revealed the ability of DSE to mitigate the negative effects of crop diseases, thereby highlighting DSE as potential biocontrol agents of plant diseases (BCAs). Given the importance of these fungi in nature, this article is a review of the role of DSE as BCAs. The findings of increasing numbers of studies on these fungi and their relationships with their plant hosts are also discussed to enable their use as a tool for the integrated management of crop diseases and pests.
Collapse
|
6
|
The Diplodia Tip Blight Pathogen Sphaeropsis sapinea Is the Most Common Fungus in Scots Pines' Mycobiome, Irrespective of Health Status-A Case Study from Germany. J Fungi (Basel) 2021; 7:jof7080607. [PMID: 34436146 PMCID: PMC8396920 DOI: 10.3390/jof7080607] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 11/17/2022] Open
Abstract
The opportunistic pathogen Sphaeropsis sapinea (≡Diplodia sapinea) is one of the most severe pathogens in Scots pine, causing the disease Diplodia tip blight on coniferous tree species. Disease symptoms become visible when trees are weakened by stress. Sphaeropsis sapinea has an endophytic mode in its lifecycle, making it difficult to detect before disease outbreaks. This study aims to record how S. sapinea accumulates in trees of different health status and, simultaneously, monitor seasonal and age-related fluctuations in the mycobiome. We compared the mycobiome of healthy and diseased Scots pines. Twigs were sampled in June and September 2018, and filamentous fungi were isolated. The mycobiome was analyzed by high-throughput sequencing (HTS) of the ITS2 region. A PERMANOVA analysis confirmed that the mycobiome community composition significantly differed between growth years (p < 0.001) and sampling time (p < 0.001) but not between healthy and diseased trees. Sphaeropsis sapinea was the most common endophyte isolated and the second most common in the HTS data. The fungus was highly abundant in symptomless (healthy) trees, presenting in its endophytic mode. Our results highlight the ability of S. sapinea to accumulate unnoticed as an endophyte in healthy trees before the disease breaks out, representing a sudden threat to Scots pines in the future, especially with increasing drought conditions experienced by pines.
Collapse
|
7
|
Stroheker S, Dubach V, Vögtli I, Sieber TN. Investigating Host Preference of Root Endophytes of Three European Tree Species, with a Focus on Members of the Phialocephala fortinii- Acephala applanata Species Complex (PAC). J Fungi (Basel) 2021; 7:jof7040317. [PMID: 33921799 PMCID: PMC8073920 DOI: 10.3390/jof7040317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 10/29/2022] Open
Abstract
Host preference of root endophytes of the three European tree species of Norway spruce (Picea abies), common ash (Fraxinus excelsior), and sycamore maple (Acer pseudoplatanus) were investigated in two forest stands near Zurich, Switzerland. The focus was placed on members of the Phialocephala fortinii s.l. (sensu lato)-Acephala applanata species complex (PAC), as well as other dark septate endopyhtes (DSE). PAC species were identified based on 13 microsatellite loci. Eleven PAC species were found, with Phialocephala helvetica, P. europaea being the most frequent. All but cryptic species 12 (CSP12) preferred Norway spruce as a host. Though very rare in general, CSP12 was most frequently isolated from maple roots. Regarding the abundant PAC species, P. helvetica and P. europaea, the preference of spruce as a host was least pronounced in P. europaea, as it was also often isolated from ash and maple. It is the first record of PAC found on common ash (Fraxinus excelsior). Cadophora orchidicola, a close relative of PAC, has frequently been isolated from ash. Various species of the Nectriaceae (Cylindrocarpon spp.) have often been isolated, particularly from maple roots. By comparison, Pezicula spp. (Cryptosporiopsis spp.) was found to be abundant on all three hosts. Phomopsis phaseoli exhibits a clear preference for spruce.
Collapse
Affiliation(s)
- Sophie Stroheker
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Swiss Forest Protection, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland; (V.D.); (I.V.)
- Correspondence: ; Tel.: +41-447-392-368
| | - Vivanne Dubach
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Swiss Forest Protection, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland; (V.D.); (I.V.)
| | - Irina Vögtli
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Swiss Forest Protection, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland; (V.D.); (I.V.)
| | - Thomas N. Sieber
- ETH Zurich, Institute of Integrative Biology, Forest Pathology and Dendrology, Universitätstrasse 16, 8092 Zurich, Switzerland;
| |
Collapse
|
8
|
Deng X, Song X, Halifu S, Yu W, Song R. Effects of Dark Septate Endophytes Strain A024 on Damping-off Biocontrol, Plant Growth and the Rhizosphere Soil Enviroment of Pinus sylvestris var. mongolica Annual Seedlings. PLANTS (BASEL, SWITZERLAND) 2020; 9:E913. [PMID: 32698328 PMCID: PMC7412355 DOI: 10.3390/plants9070913] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/17/2020] [Accepted: 07/17/2020] [Indexed: 11/16/2022]
Abstract
Dark septate endophytes (DSEs) exert a vital role in promoting plant growth, improving mineral absorption, biological disease control, and enhancing plant stress resistance. The effects of dark septate endophyte strain, Phialocephala bamuru A024 on damping-off biocontrol, plant development, nutrients within the rhizosphere soil, as well as bacterial communities in the annual seedlings of P. sylvestris var. Mongolica were studied. According to our findings, following P. bamuru A024 inoculation, the damping-off disease morbidity decreased significantly compared with control, some physiological indices such as β-1,3-glucanase, chitinase enzyme activity as well as a soluble protein and proline content in P. sylvestris var. mongolica were elevated under R. solani stress. After inoculation with P. bamuru A024, the biomass in seedlings, nutrients in soil, root structure index, together with activities of soil enzymes were remarkably up-regulated relative to control (p < 0.05). As suggested by the results of high-throughput sequencing, the microbial structure in the rhizosphere soil of the P. sylvestris var. mongolica showed significant differences (p < 0.05) after P. bamuru A024 inoculation compared to control treatment and the rhizosphere soil bacterial community structure after DSE A024 inoculation was positively correlated to the main soil nutrition indices.
Collapse
Affiliation(s)
- Xun Deng
- Institute of Forestry Protection, Heilongjiang Academy of Forestry, Harbin 150040, China; (X.D.); (X.S.); (W.Y.)
| | - Xiaoshuang Song
- Institute of Forestry Protection, Heilongjiang Academy of Forestry, Harbin 150040, China; (X.D.); (X.S.); (W.Y.)
| | - Saiyaremu Halifu
- College of Forestry, Northeast Forestry University, Harbin 150040, China;
| | - Wenjing Yu
- Institute of Forestry Protection, Heilongjiang Academy of Forestry, Harbin 150040, China; (X.D.); (X.S.); (W.Y.)
| | - Ruiqing Song
- College of Forestry, Northeast Forestry University, Harbin 150040, China;
| |
Collapse
|
9
|
Landolt M, Stroheker S, Queloz V, Gall A, Sieber TN. Does water availability influence the abundance of species of the Phialocephala fortinii s.l. – Acephala applanata complex (PAC) in roots of pubescent oak (Quercus pubescens) and Scots pine (Pinus sylvestris)? FUNGAL ECOL 2020. [DOI: 10.1016/j.funeco.2019.100904] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
10
|
Tanney J, Seifert K. Mollisiaceae: An overlooked lineage of diverse endophytes. Stud Mycol 2020; 95:293-380. [PMID: 32855742 PMCID: PMC7426276 DOI: 10.1016/j.simyco.2020.02.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 02/15/2020] [Accepted: 02/15/2020] [Indexed: 01/04/2023] Open
Abstract
Mollisia is a taxonomically neglected discomycete genus (Helotiales, Leotiomycetes) of commonly encountered saprotrophs on decaying plant tissues throughout temperate regions. The combination of indistinct morphological characters, more than 700 names in the literature, and lack of reference DNA sequences presents a major challenge when working with Mollisia. Unidentified endophytes, including strains that produced antifungal or antiinsectan secondary metabolites, were isolated from conifer needles in New Brunswick and placed with uncertainty in Phialocephala and Mollisia, necessitating a more comprehensive treatment of these genera. In this study, morphology and multigene phylogenetic analyses were used to explore the taxonomy of Mollisiaceae, including Mollisia, Phialocephala, and related genera, using new field collections, herbarium specimens, and accessioned cultures and sequences. The phylogeny of Mollisiaceae was reconstructed and compared using the nuc internal transcribed spacer rDNA (ITS) barcode and partial sequences of the 28S nuc rDNA (LSU) gene, largest subunit of RNA polymerase II (RPB1), DNA topoisomerase I (TOP1), and the hypothetical protein Lipin/Ned1/Smp2 (LNS2). The results show that endophytism is common throughout the Mollisiaceae lineage in a diverse range of hosts but is infrequently attributed to Mollisia because of a paucity of reference sequences. Generic boundaries within Mollisiaceae are poorly resolved and based on phylogenetic evidence the family included species placed in Acephala, Acidomelania, Barrenia, Bispora, Cheirospora, Cystodendron, Fuscosclera, Hysteronaevia, Loramyces, Mollisia, Neopyrenopeziza, Obtectodiscus, Ombrophila, Patellariopsis, Phialocephala, Pulvinata, Tapesia (=Mollisia), and Trimmatostroma. Taxonomic novelties included the description of five novel Mollisia species and five novel Phialocephala species and the synonymy of Fuscosclera with Phialocephala, Acidomelania with Mollisia, and Loramycetaceae with Mollisiaceae.
Collapse
Affiliation(s)
- J.B. Tanney
- Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, 506 Burnside Road, Victoria, British Columbia, V8Z 1M5, Canada
| | - K.A. Seifert
- Ottawa Research and Development Centre, Biodiversity (Mycology and Microbiology), Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario, K1A 0C6, Canada
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada
| |
Collapse
|
11
|
Yakti W, Kovács GM, Franken P. Differential interaction of the dark septate endophyte Cadophora sp. and fungal pathogens in vitro and in planta. FEMS Microbiol Ecol 2019; 95:fiz164. [PMID: 31609451 PMCID: PMC6864363 DOI: 10.1093/femsec/fiz164] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/05/2019] [Indexed: 12/20/2022] Open
Abstract
Dark septate endophytes (DSEs) present a group of widespread root-colonizing fungi. The role of these endophytes in ecosystems and their interactions with plant pathogens are not well understood. In the current study, we assessed the antagonistic potential of the model DSE Cadophora sp. against the tomato soilborne pathogens Rhizoctonia solani, Pythium aphanidermatum and Verticillium dahliae. To investigate their interactions, we conducted in vitro assays followed by a greenhouse experiments in which tomato plants were inoculated with different combinations of the DSE and pathogens. RNA accumulation of selected tomato pathogenesis-related genes and of Cadophora sp. genes with putative antifungal function was analyzed. Cadophora sp. inhibited the growth of the fungal pathogens in vitro and vice versa; a negative impact of the pathogens on the growth of the DSE was also detected. In roots, however, this mutual negative interaction could not be observed. Expression analyses of plant genes could not explain this differential effect, but among the Cadophora sp. genes analyzed, a gene coding for a chalcone synthase was downregulated in planta. The data indicate that plants can change the interaction between fungi and, therefore, in vitro detected antagonism does not necessarily reflect the situation inside the plant.
Collapse
Affiliation(s)
- Wael Yakti
- Leibniz Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1,14979 Großbeeren, Brandenburg, Germany and Institute of Biology, Plant Physiology Department, Humboldt University of Berlin, Philippstraße 13, 10115 Berlin, Germany
| | - Gábor M Kovács
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Pázmány Péter sétány 1/C, 1117 Budapest, Hungary
- Plant Protection Institute, Centre for Agricultural Research, Budapest 1022, Hungary
| | - Philipp Franken
- Leibniz Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1,14979 Großbeeren, Brandenburg, Germany and Institute of Biology, Plant Physiology Department, Humboldt University of Berlin, Philippstraße 13, 10115 Berlin, Germany
- Erfurt Research Centre for Horticultural Crops, University of Applied Sciences, Kühnhäuser Straße 101, 99090 Erfurt, Thuringia, Germany
| |
Collapse
|
12
|
Berthelot C, Leyval C, Chalot M, Blaudez D. Interactions between dark septate endophytes, ectomycorrhizal fungi and root pathogens in vitro. FEMS Microbiol Lett 2019; 366:5531311. [DOI: 10.1093/femsle/fnz158] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 07/10/2019] [Indexed: 12/22/2022] Open
Abstract
ABSTRACTDark septate endophytes (DSEs) are widely distributed worldwide and can promote plant growth. Therefore, they are considered potentially important plant allies, especially in stressful environments. Previous studies have reported that DSEs cohabit roots with other microorganisms such as ectomycorrhizal (ECM), endophytic and pathogenic fungi/oomycetes. However, interactions between different DSE species have not yet been reported, and studies on the interactions between DSEs and other fungi are scarce. Using a simple and reproducible pairwise growth assay in vitro, we studied the synergistic/antagonistic interactions between eight DSEs, two ECM fungi and three root pathogens. Most of the DSE/DSE outcomes were neutral. Interestingly, we identified several DSE strains acting in synergy with other strains, as well as strains that could potentially act as biocontrol agents. Notably, three metal-tolerant DSE strains, namely, Cadophora sp., Leptodontidium sp. and Phialophora mustea, could decrease the growth of the root phytopathogens Pythium intermedium, Phytophthora citricola and Heterobasidion annosum. The present data are discussed in the general context of the use of fungal consortia as inocula in the tree-based phytomanagement of marginal lands.
Collapse
Affiliation(s)
| | - Corinne Leyval
- Université de Lorraine, CNRS, LIEC, F-54000 Nancy, France
| | - Michel Chalot
- Université de Bourgogne Franche-Comté, UMR CNRS 6249 Laboratoire Chrono-environnement, F-25211 Montbéliard, France
- Université de Lorraine, F-54000 Nancy, France
| | - Damien Blaudez
- Université de Lorraine, CNRS, LIEC, F-54000 Nancy, France
| |
Collapse
|
13
|
Rigerte L, Blumenstein K, Terhonen E. New R-Based Methodology to Optimize the Identification of Root Endophytes against Heterobasidion parviporum. Microorganisms 2019; 7:E102. [PMID: 30959873 PMCID: PMC6517935 DOI: 10.3390/microorganisms7040102] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/02/2019] [Accepted: 04/04/2019] [Indexed: 01/05/2023] Open
Abstract
Many root fungal endophytes inhabiting forest trees have potential impact on the health and disease progression of certain tree species. Hence, the screening of root endophytes for their biocontrol abilities is relevant for their potential to protect their hosts against invaders. The aim of this research is to screen for the potential inhibitory effects of selected conifer root endophytes during interaction, in vitro, with the root rot pathogen, Heterobasidion parviporum. Here, we introduce a guideline that facilitates the use of root fungal endophytes as biocontrol agents. We isolated fungal root endophytes from eight different conifers. These root fungal endophytes were evaluated for their antagonism against the root rot pathogen, H. parviporum, by means of paired-culture antagonism assays. We determined the antagonism of the isolated root fungal endophytes to elucidate potential biocontrol applications. For the analysis, a software package in R was developed. Endophyte candidates with antagonistic potential were identified.
Collapse
Affiliation(s)
- Linda Rigerte
- Forest Pathology Research Group, Büsgen-Institute, Department of Forest Botany and Tree Physiology, Faculty of Forest Sciences and Forest Ecology, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany.
| | | | | |
Collapse
|
14
|
Forest Tree Microbiomes and Associated Fungal Endophytes: Functional Roles and Impact on Forest Health. FORESTS 2019. [DOI: 10.3390/f10010042] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Terrestrial plants including forest trees are generally known to live in close association with microbial organisms. The inherent features of this close association can be commensalism, parasitism or mutualism. The term “microbiota” has been used to describe this ecological community of plant-associated pathogenic, mutualistic, endophytic and commensal microorganisms. Many of these microbiota inhabiting forest trees could have a potential impact on the health of, and disease progression in, forest biomes. Comparatively, studies on forest tree microbiomes and their roles in mutualism and disease lag far behind parallel work on crop and human microbiome projects. Very recently, our understanding of plant and tree microbiomes has been enriched due to novel technological advances using metabarcoding, metagenomics, metatranscriptomics and metaproteomics approaches. In addition, the availability of massive DNA databases (e.g., NCBI (USA), EMBL (Europe), DDBJ (Japan), UNITE (Estonia)) as well as powerful computational and bioinformatics tools has helped to facilitate data mining by researchers across diverse disciplines. Available data demonstrate that plant phyllosphere bacterial communities are dominated by members of only a few phyla (Proteobacteria, Actinobacteria, Bacteroidetes). In bulk forest soil, the dominant fungal group is Basidiomycota, whereas Ascomycota is the most prevalent group within plant tissues. The current challenge, however, is how to harness and link the acquired knowledge on microbiomes for translational forest management. Among tree-associated microorganisms, endophytic fungal biota are attracting a lot of attention for their beneficial health- and growth-promoting effects, and were preferentially discussed in this review.
Collapse
|
15
|
Vallet M, Strittmatter M, Murúa P, Lacoste S, Dupont J, Hubas C, Genta-Jouve G, Gachon CMM, Kim GH, Prado S. Chemically-Mediated Interactions Between Macroalgae, Their Fungal Endophytes, and Protistan Pathogens. Front Microbiol 2018; 9:3161. [PMID: 30627120 PMCID: PMC6309705 DOI: 10.3389/fmicb.2018.03161] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/06/2018] [Indexed: 12/14/2022] Open
Abstract
Filamentous fungi asymptomatically colonize the inner tissues of macroalgae, yet their ecological roles remain largely underexplored. Here, we tested if metabolites produced by fungal endophytes might protect their host against a phylogenetically broad spectrum of protistan pathogens. Accordingly, the cultivable fungal endophytes of four brown algal species were isolated and identified based on LSU and SSU sequencing. The fungal metabolomes were tested for their ability to reduce the infection by protistan pathogens in the algal model Ectocarpus siliculosus. The most active metabolomes effective against the oomycetes Eurychasma dicksonii and Anisolpidium ectocarpii, and the phytomixid Maullinia ectocarpii were further characterized chemically. Several pyrenocines isolated from Phaeosphaeria sp. AN596H efficiently inhibited the infection by all abovementioned pathogens. Strikingly, these compounds also inhibited the infection of nori (Pyropia yezoensis) against its two most devastating oomycete pathogens, Olpidiopsis pyropiae, and Pythium porphyrae. We thus demonstrate that fungal endophytes associated with brown algae produce bioactive metabolites which might confer protection against pathogen infection. These results highlight the potential of metabolites to finely-tune the outcome of molecular interactions between algae, their endophytes, and protistan pathogens. This also provide proof-of-concept toward the applicability of such metabolites in marine aquaculture to control otherwise untreatable diseases.
Collapse
Affiliation(s)
- Marine Vallet
- Muséum National d'Histoire Naturelle, Unité Molécules de Communication et Adaptation des Micro-organismes, UMR 7245, CP 54, Paris, France
| | - Martina Strittmatter
- The Scottish Association for Marine Science, Scottish Marine Institute, Oban, United Kingdom
| | - Pedro Murúa
- The Scottish Association for Marine Science, Scottish Marine Institute, Oban, United Kingdom
| | - Sandrine Lacoste
- Institut Systématique Evolution Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Paris, France
| | - Joëlle Dupont
- Institut Systématique Evolution Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Paris, France
| | - Cedric Hubas
- Unité Biologie des organismes et écosystèmes aquatiques (UMR BOREA), Muséum national d'Histoire Naturelle, Sorbonne Université, Université de Caen Normandie, Université des Antilles, CNRS, IRD; Station Marine de Concarneau, Concarneau, France
| | - Gregory Genta-Jouve
- Muséum National d'Histoire Naturelle, Unité Molécules de Communication et Adaptation des Micro-organismes, UMR 7245, CP 54, Paris, France.,Université Paris Descartes, Laboratoire de Chimie-Toxicologie Analytique et Cellulaire (C-TAC), UMR CNRS 8638, COMETE, Paris, France
| | - Claire M M Gachon
- The Scottish Association for Marine Science, Scottish Marine Institute, Oban, United Kingdom
| | - Gwang Hoon Kim
- Department of Biology, Kongju National University, Kongju, South Korea
| | - Soizic Prado
- Muséum National d'Histoire Naturelle, Unité Molécules de Communication et Adaptation des Micro-organismes, UMR 7245, CP 54, Paris, France
| |
Collapse
|
16
|
Nelson JM, Hauser DA, Hinson R, Shaw AJ. A novel experimental system using the liverwort Marchantia polymorpha and its fungal endophytes reveals diverse and context-dependent effects. THE NEW PHYTOLOGIST 2018; 218:1217-1232. [PMID: 29411387 DOI: 10.1111/nph.15012] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/21/2017] [Indexed: 06/08/2023]
Abstract
Fungal symbioses are ubiquitous in plants, but their effects have mostly been studied in seed plants. This study aimed to assess the diversity of fungal endophyte effects in a bryophyte and identify factors contributing to the variability of outcomes in these interactions. Fungal endophyte cultures and axenic liverwort clones were isolated from wild populations of the liverwort, Marchantia polymorpha. These collections were combined in a gnotobiotic system to test the effects of fungal isolates on the growth rates of hosts under laboratory conditions. Under the experimental conditions, fungi isolated from M. polymorpha ranged from aggressively pathogenic to strongly growth-promoting, but the majority of isolates caused no detectable change in host growth. Growth promotion by selected fungi depended on nutrient concentrations and was inhibited by coinoculation with multiple fungi. The M. polymorpha endophyte system expands the resources for this model liverwort. The experiments presented here demonstrate a wealth of diversity in fungal interactions even in a host reported to lack standard mycorrhizal symbiosis. In addition, they show that some known pathogens of vascular plants live in M. polymorpha and can confer benefits to this nonvascular host. This highlights the importance of studying endophyte effects across the plant tree of life.
Collapse
Affiliation(s)
| | - Duncan A Hauser
- Duke University Department of Biology, Durham, NC, 27708, USA
| | - Rosemary Hinson
- Duke University Department of Biology, Durham, NC, 27708, USA
| | - A Jonathan Shaw
- Duke University Department of Biology, Durham, NC, 27708, USA
| |
Collapse
|
17
|
de Vries S, von Dahlen JK, Schnake A, Ginschel S, Schulz B, Rose LE. Broad-spectrum inhibition of Phytophthora infestans by fungal endophytes. FEMS Microbiol Ecol 2018; 94:4925062. [PMID: 29528408 PMCID: PMC5939626 DOI: 10.1093/femsec/fiy037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/05/2018] [Indexed: 11/12/2022] Open
Abstract
Phytophthora infestans is a devastating pathogen of tomato and potato. It readily overcomes resistance genes and applied agrochemicals and hence even today causes large yield losses. Fungal endophytes provide a largely unexplored avenue of control of Phy. infestans. Not only do endophytes produce a wide array of bioactive metabolites, they may also directly compete with and defeat pathogens in planta. Here, we tested 12 fungal endophytes isolated from different plant species in vitro for their production of metabolites with anti- Phytophthora activity. Four well-performing isolates were evaluated for their ability to suppress nine isolates of Phy. infestans on agar medium and in planta. Two endophytes reliably inhibited all Phy. infestans isolates on agar medium, of which Phoma eupatorii isolate 8082 was the most promising. It nearly abolished infection by Phy. infestans in planta. Our data indicate a role for the production of anti-Phytophthora compounds by the fungus and/or an enhanced plant defense response, as evident by an enhanced anthocyanin production. Here, we present a potential biocontrol agent, which can inhibit a broad-spectrum of Phy. infestans isolates. Such broadly acting inhibition is ideal, because it allows for effective control of genetically diverse isolates and may slow the adaptation of Phy. infestans.
Collapse
Affiliation(s)
- Sophie de Vries
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
- iGRAD-Plant Graduate School, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Janina K von Dahlen
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
| | - Anika Schnake
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
| | - Sarah Ginschel
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
| | - Barbara Schulz
- Institute of Microbiology, Technische Universitaet Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany
| | - Laura E Rose
- Institute of Population Genetics, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
- iGRAD-Plant Graduate School, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
- Ceplas, Cluster of Excellence in Plant Sciences, Heinrich-Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
| |
Collapse
|
18
|
Terhonen E, Kovalchuk A, Zarsav A, Asiegbu FO. Biocontrol Potential of Forest Tree Endophytes. ENDOPHYTES OF FOREST TREES 2018. [DOI: 10.1007/978-3-319-89833-9_13] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
|
19
|
Ibrahim M, Sieber TN, Schlegel M. Communities of fungal endophytes in leaves of Fraxinus ornus are highly diverse. FUNGAL ECOL 2017. [DOI: 10.1016/j.funeco.2017.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
20
|
Schlegel M, Dubach V, von Buol L, Sieber TN. Effects of endophytic fungi on the ash dieback pathogen. FEMS Microbiol Ecol 2016; 92:fiw142. [PMID: 27364360 DOI: 10.1093/femsec/fiw142] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2016] [Indexed: 12/16/2022] Open
Abstract
While Hymenoscyphus fraxineus causes dieback of the European ash (Fraxinus excelsior), flowering ash (F. ornus) appears resistant to the pathogen. To date, contributions of endophytic fungi to host resistance are unknown. The following hypotheses were tested: (i) endophytic fungi enhance the resistance of F. excelsior to the pathogen; (ii) resistance of F. ornus relies on its community of endophytic fungi. Two experiments were performed. (i) The effect of exudates of ash endophytes on the germination rate of H. fraxineus ascospores was studied in vitro Isolates of abundant Fraxinus leaf endophytes, such as Venturia fraxini, Paraconiothyrium sp., Boeremia exigua, Kretzschmaria deusta and Neofabraea alba inhibited ascospore germination. (ii) Ash seedlings inoculated in a climate chamber, with fungi sporulating on the previous year's leaf litter, were exposed to natural infections by the pathogen present in the forest. Non-inoculated seedlings were used as controls. Venturia spp. dominated the inoculated endophyte 'communities'. Subsequent exposure to H. fraxineus led to infection of F. excelsior leaves by the pathogen, but no differences in health status between pre-inoculated and non-inoculated seedlings were detected. Fraxinus ornus leaves experienced a low infection rate, independent of their colonization by endophytic fungi. These results did not support either hypothesis.
Collapse
Affiliation(s)
- Markus Schlegel
- ETH Zurich, Department of Environmental Systems Science, Institute of Integrative Biology, 8092 Zurich, Switzerland
| | - Vivanne Dubach
- ETH Zurich, Department of Environmental Systems Science, Institute of Integrative Biology, 8092 Zurich, Switzerland
| | - Larissa von Buol
- ETH Zurich, Department of Environmental Systems Science, Institute of Integrative Biology, 8092 Zurich, Switzerland
| | - Thomas N Sieber
- ETH Zurich, Department of Environmental Systems Science, Institute of Integrative Biology, 8092 Zurich, Switzerland
| |
Collapse
|
21
|
Hewitt RE, Hollingsworth TN, Stuart Chapin III F, Lee Taylor D. Fire-severity effects on plant-fungal interactions after a novel tundra wildfire disturbance: implications for arctic shrub and tree migration. BMC Ecol 2016; 16:25. [PMID: 27169473 PMCID: PMC4865011 DOI: 10.1186/s12898-016-0075-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 04/05/2016] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Vegetation change in high latitude tundra ecosystems is expected to accelerate due to increased wildfire activity. High-severity fires increase the availability of mineral soil seedbeds, which facilitates recruitment, yet fire also alters soil microbial composition, which could significantly impact seedling establishment. RESULTS We investigated the effects of fire severity on soil biota and associated effects on plant performance for two plant species predicted to expand into Arctic tundra. We inoculated seedlings in a growth chamber experiment with soils collected from the largest tundra fire recorded in the Arctic and used molecular tools to characterize root-associated fungal communities. Seedling biomass was significantly related to the composition of fungal inoculum. Biomass decreased as fire severity increased and the proportion of pathogenic fungi increased. CONCLUSIONS Our results suggest that effects of fire severity on soil biota reduces seedling performance and thus we hypothesize that in certain ecological contexts fire-severity effects on plant-fungal interactions may dampen the expected increases in tree and shrub establishment after tundra fire.
Collapse
Affiliation(s)
- Rebecca E. Hewitt
- />Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775 USA
- />Center for Ecosystem Science and Society, Northern Arizona University, PO Box 5620, Flagstaff, AZ 86011 USA
| | - Teresa N. Hollingsworth
- />US Forest Service, Pacific Northwest Research Station, Boreal Ecology Cooperative Research Unit, Fairbanks, AK 99775 USA
| | - F. Stuart Chapin III
- />Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775 USA
| | - D. Lee Taylor
- />Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775 USA
- />Department of Biology, University of New Mexico, Albuquerque, NM 87131 USA
| |
Collapse
|
22
|
Vohník M, Borovec O, Kolařík M. Communities of Cultivable Root Mycobionts of the Seagrass Posidonia oceanica in the Northwest Mediterranean Sea Are Dominated by a Hitherto Undescribed Pleosporalean Dark Septate Endophyte. MICROBIAL ECOLOGY 2016; 71:442-451. [PMID: 26093964 DOI: 10.1007/s00248-015-0640-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 06/09/2015] [Indexed: 06/04/2023]
Abstract
Seagrasses, a small group of submerged marine macrophytes, were reported to lack mycorrhizae, i.e., the root-fungus symbioses most terrestrial plants use for nutrient uptake. On the other hand, several authors detected fungal endophytes in seagrass leaves, shoots, rhizomes, and roots, and an anatomically and morphologically unique dark septate endophytic (DSE) association has been recently described in the roots of the Mediterranean seagrass Posidonia oceanica. Nevertheless, the global diversity of seagrass mycobionts is not well understood, and it remains unclear what fungus forms the DSE association in P. oceanica roots. We isolated and determined P. oceanica root mycobionts from 11 localities in the northwest Mediterranean Sea with documented presence of the DSE association and compared our results with recent literature. The mycobiont communities were low in diversity (only three species), were dominated by a single yet unreported marine fungal species (ca. 90 % of the total 177 isolates), and lacked common terrestrial and freshwater root mycobionts. Our phylogenetic analysis suggests that the dominating species represents a new monotypic lineage within the recently described Aigialaceae family (Pleosporales, Ascomycota), probably representing a new genus. Most of its examined colonies developed from intracellular microsclerotia occupying host hypodermis and resembling microsclerotia of terrestrial DSE fungi. Biological significance of this hitherto overlooked seagrass root mycobiont remains obscure, but its presence across the NW Mediterranean Sea and apparent root intracellular lifestyle indicate an intriguing symbiotic relationship with the dominant Mediterranean seagrass. Our microscopic observations suggest that it may form the DSE association recently described in P. oceanica roots.
Collapse
Affiliation(s)
- Martin Vohník
- Department of Mycorrhizal Symbioses, Institute of Botany ASCR, Lesní 322, Průhonice, 25243, Czech Republic.
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Viničná 5, Prague, 12843, Czech Republic.
| | - Ondřej Borovec
- Department of Mycorrhizal Symbioses, Institute of Botany ASCR, Lesní 322, Průhonice, 25243, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Viničná 5, Prague, 12843, Czech Republic
| | - Miroslav Kolařík
- Laboratory of Genetics, Physiology and Bioengineering of Fungi, Institute of Microbiology ASCR, Vídeňská 1083, Prague, 14200, Czech Republic
| |
Collapse
|
23
|
Tanney JB, Douglas B, Seifert KA. Sexual and asexual states of some endophytic Phialocephala species of Picea. Mycologia 2016; 108:255-80. [PMID: 26740545 DOI: 10.3852/15-136] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 11/30/2015] [Indexed: 11/10/2022]
Abstract
Unidentified DNA sequences in isolation-based or culture-free studies of conifer endophytes are a persistent problem that requires a field approach to resolve. An investigation of foliar endophytes of Picea glauca, P. mariana, P. rubens and Pinus strobus in eastern Canada, using a combined field, morphological, cultural and DNA sequencing approach, resulted in the frequent isolation of Phialocephala spp. and the first verified discovery of their mollisia-like sexual states in the field. Phialocephala scopiformis and Ph. piceae were the most frequent species isolated as endophytes from healthy conifer needles. Corresponding Mollisia or mollisioid sexual states for Ph. scopiformis, Ph. piceae and several undescribed species in a clade containing Ph. dimorphospora were collected in the sampling area and characterized by analysis of the nuc internal transcribed spacer rDNA (ITS) and gene for the largest subunit of RNA polymerase II (RPB1) loci. Four novel species and one new combination in a clade containing Ph. dimorphospora, the type of Phialocephala, are presented, accompanied by descriptions of apothecia and previously undocumented synanamorphs. An epitype culture and corresponding reference sequences for Phialocephala dimorphospora are proposed. The resulting ITS barcodes linked with robust taxonomic species concepts are an important resource for future research on forest ecosystems and endophytes.
Collapse
Affiliation(s)
- Joey B Tanney
- Biodiversity (Mycology & Botany), Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario, K1A 0C6 Canada
| | - Brian Douglas
- Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, United Kingdom
| | - Keith A Seifert
- Biodiversity (Mycology & Botany), Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario, K1A 0C6 Canada
| |
Collapse
|
24
|
Pautasso M, Schlegel M, Holdenrieder O. Forest health in a changing world. MICROBIAL ECOLOGY 2015; 69:826-842. [PMID: 25502075 DOI: 10.1007/s00248-014-0545-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 11/27/2014] [Indexed: 06/04/2023]
Abstract
Forest pathology, the science of forest health and tree diseases, is operating in a rapidly developing environment. Most importantly, global trade and climate change are increasing the threat to forest ecosystems posed by new diseases. Various studies relevant to forest pathology in a changing world are accumulating, thus making it necessary to provide an update of recent literature. In this contribution, we summarize research at the interface between forest pathology and landscape ecology, biogeography, global change science and research on tree endophytes. Regional outbreaks of tree diseases are requiring interdisciplinary collaboration, e.g. between forest pathologists and landscape ecologists. When tree pathogens are widely distributed, the factors determining their broad-scale distribution can be studied using a biogeographic approach. Global change, the combination of climate and land use change, increased pollution, trade and urbanization, as well as invasive species, will influence the effects of forest disturbances such as wildfires, droughts, storms, diseases and insect outbreaks, thus affecting the health and resilience of forest ecosystems worldwide. Tree endophytes can contribute to biological control of infectious diseases, enhance tolerance to environmental stress or behave as opportunistic weak pathogens potentially competing with more harmful ones. New molecular techniques are available for studying the complete tree endobiome under the influence of global change stressors from the landscape to the intercontinental level. Given that exotic tree diseases have both ecologic and economic consequences, we call for increased interdisciplinary collaboration in the coming decades between forest pathologists and researchers studying endophytes with tree geneticists, evolutionary and landscape ecologists, biogeographers, conservation biologists and global change scientists and outline interdisciplinary research gaps.
Collapse
Affiliation(s)
- Marco Pautasso
- Forest Pathology & Dendrology, Institute of Integrative Biology (IBZ), ETH Zurich, 8092, Zurich, Switzerland,
| | | | | |
Collapse
|
25
|
Lukešová T, Kohout P, Větrovský T, Vohník M. The potential of Dark Septate Endophytes to form root symbioses with ectomycorrhizal and ericoid mycorrhizal middle European forest plants. PLoS One 2015; 10:e0124752. [PMID: 25905493 PMCID: PMC4408093 DOI: 10.1371/journal.pone.0124752] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 03/08/2015] [Indexed: 11/19/2022] Open
Abstract
The unresolved ecophysiological significance of Dark Septate Endophytes (DSE) may be in part due to existence of morphologically indistinguishable cryptic species in the most common Phialocephala fortinii s. l.--Acephala applanata species complex (PAC). We inoculated three middle European forest plants (European blueberry, Norway spruce and silver birch) with 16 strains of eight PAC cryptic species and other DSE and ectomycorrhizal/ericoid mycorrhizal fungi and focused on intraradical structures possibly representing interfaces for plant-fungus nutrient transfer and on host growth response. The PAC species Acephala applanata simultaneously formed structures resembling ericoid mycorrhiza (ErM) and DSE microsclerotia in blueberry. A. macrosclerotiorum, a close relative to PAC, formed ectomycorrhizae with spruce but not with birch, and structures resembling ErM in blueberry. Phialocephala glacialis, another close relative to PAC, formed structures resembling ErM in blueberry. In blueberry, six PAC strains significantly decreased dry shoot biomass compared to ErM control. In birch, one A. macrosclerotiorum strain increased root biomass and the other shoot biomass in comparison with non-inoculated control. The dual mycorrhizal ability of A. macrosclerotiorum suggested that it may form mycorrhizal links between Ericaceae and Pinaceae. However, we were unable to detect this species in Ericaceae roots growing in a forest with presence of A. macrosclerotiorum ectomycorrhizae. Nevertheless, the diversity of Ericaceae mycobionts was high (380 OTUs) with individual sites often dominated by hitherto unreported helotialean and chaetothyrialean/verrucarialean species; in contrast, typical ErM fungi were either absent or low in abundance. Some DSE apparently have a potential to form mycorrhizae with typical middle European forest plants. However, except A. applanata, the tested representatives of all hitherto described PAC cryptic species formed typical DSE colonization without specific structures necessary for mycorrhizal nutrient transport. A. macrosclerotiorum forms ectomycorrhiza with conifers but not with broadleaves and probably does not form common mycorrhizal networks between conifers with Ericaceae.
Collapse
Affiliation(s)
- Tereza Lukešová
- Department of Plant Experimental Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
- Department of Mycorrhizal Symbioses, Institute of Botany ASCR, Průhonice, Czech Republic
| | - Petr Kohout
- Department of Plant Experimental Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
- Department of Mycorrhizal Symbioses, Institute of Botany ASCR, Průhonice, Czech Republic
- Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia
| | - Tomáš Větrovský
- Laboratory of Environmental Microbiology, Institute of Microbiology ASCR, Prague, Czech Republic
| | - Martin Vohník
- Department of Plant Experimental Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
- Department of Mycorrhizal Symbioses, Institute of Botany ASCR, Průhonice, Czech Republic
| |
Collapse
|
26
|
Mandyam KG, Jumpponen A. Mutualism-parasitism paradigm synthesized from results of root-endophyte models. Front Microbiol 2015; 5:776. [PMID: 25628615 PMCID: PMC4290590 DOI: 10.3389/fmicb.2014.00776] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 12/17/2014] [Indexed: 01/01/2023] Open
Abstract
Plant tissues host a variety of fungi. One important group is the dark septate endophytes (DSEs) that colonize plant roots and form characteristic intracellular structures - melanized hyphae and microsclerotia. The DSE associations are common and frequently observed in various biomes and plant taxa. Reviews suggest that the proportion of plant species colonized by DSE equal that colonized by AM and microscopic studies show that the proportion of the root system colonized by fungi DSE can equal, or even exceed, the colonization by AM fungi. Despite the high frequency and suspected ecological importance, the effects of DSE colonization on plant growth and performance have remained unclear. Here, we draw from over a decade of experimentation with the obscure DSE symbiosis and synthesize across large bodies of published and unpublished data from Arabidopsis thaliana and Allium porrum model systems as well as from experiments that use native plants to better resolve the host responses to DSE colonization. The data indicate similar distribution of host responses in model and native plant studies, validating the use of model plants for tractable dissection of DSE symbioses. The available data also permit empirical testing of the environmental modulation of host responses to DSE colonization and refining the "mutualism-parasitism-continuum" paradigm for DSE symbioses. These data highlight the context dependency of the DSE symbioses: not only plant species but also ecotypes vary in their responses to populations of conspecific DSE fungi - environmental conditions further shift the host responses similar to those predicted based on the mutualism-parasitism-continuum paradigm. The model systems provide several established avenues of inquiry that permit more detailed molecular and functional dissection of fungal endophyte symbioses, identifying thus likely mechanisms that may underlie the observed host responses to endophyte colonization.
Collapse
Affiliation(s)
| | - Ari Jumpponen
- Division of Biology, Ecological Genomics Institute, Kansas State UniversityManhattan, KS, USA
| |
Collapse
|
27
|
Control of pathogenic PAC strains by non-pathogenic PAC strains in planta does not correlate with higher competitiveness of non-pathogenic PAC strains ex planta. Mycol Prog 2014. [DOI: 10.1007/s11557-014-0986-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
28
|
Reininger V, Sieber TN. Mitigation of antagonistic effects on plant growth due to root co-colonization by dark septate endophytes and ectomycorrhiza. ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:892-898. [PMID: 24249297 DOI: 10.1111/1758-2229.12091] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 07/30/2013] [Indexed: 06/02/2023]
Abstract
Dark septate endophytes (DSE) are very common root colonizers of woody plant species. Ascomycetes of the Phialocephala fortinii s.l.-Acephala applanata species complex (PAC) are the main representatives of DSE fungi in forest ecosystems. PAC and mycorrhizal fungi share the same habitat, but interactions among PAC, mycorrhizal fungi and plants are poorly understood. We compared the effects of single and dual inoculation of Norway spruce seedlings with PAC and the ectomycorrhizal (ECM) fungus Hebeloma crustuliniforme on host growth, degree of mycorrhization and density of endophytic PAC biomass. Single colonization by H. crustuliniforme or PAC significantly reduced plant biomass. Dual colonization reduced or neutralized plant growth depression caused by single fungal colonization. The degree of mycorrhization was independent on PAC colonization, and mycorrhization significantly reduced endophytic PAC biomass. Plant biomass of dually colonized plants positively correlated with PAC biomass. These results demonstrate the ability of dual inoculation of PAC and H. crustuliniforme to neutralize plant growth depression caused by single fungal inoculation. Our explanations of enhanced plant growth in dually inoculated plants are the inhibition of PAC during root colonization by the ECM mantle and ECM-mediated access to plant growth-promoting nutrients resulting from the mineralization of the potting medium by PAC.
Collapse
Affiliation(s)
- Vanessa Reininger
- Institute of Integrative Biology, ETH Zürich, Zürich, 8092, Switzerland; Department of Biology, Algoma University, Sault Ste. Marie, ON, P6A 2G4, Canada
| | | |
Collapse
|
29
|
Tellenbach C, Sumarah MW, Grünig CR, Miller JD. Inhibition of Phytophthora species by secondary metabolites produced by the dark septate endophyte Phialocephala europaea. FUNGAL ECOL 2013. [DOI: 10.1016/j.funeco.2012.10.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|