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Müller M, Kües U, Budde KB, Gailing O. Applying molecular and genetic methods to trees and their fungal communities. Appl Microbiol Biotechnol 2023; 107:2783-2830. [PMID: 36988668 PMCID: PMC10106355 DOI: 10.1007/s00253-023-12480-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 03/05/2023] [Accepted: 03/07/2023] [Indexed: 03/30/2023]
Abstract
Forests provide invaluable economic, ecological, and social services. At the same time, they are exposed to several threats, such as fragmentation, changing climatic conditions, or increasingly destructive pests and pathogens. Trees, the inherent species of forests, cannot be viewed as isolated organisms. Manifold (micro)organisms are associated with trees playing a pivotal role in forest ecosystems. Of these organisms, fungi may have the greatest impact on the life of trees. A multitude of molecular and genetic methods are now available to investigate tree species and their associated organisms. Due to their smaller genome sizes compared to tree species, whole genomes of different fungi are routinely compared. Such studies have only recently started in forest tree species. Here, we summarize the application of molecular and genetic methods in forest conservation genetics, tree breeding, and association genetics as well as for the investigation of fungal communities and their interrelated ecological functions. These techniques provide valuable insights into the molecular basis of adaptive traits, the impacts of forest management, and changing environmental conditions on tree species and fungal communities and can enhance tree-breeding cycles due to reduced time for field testing. It becomes clear that there are multifaceted interactions among microbial species as well as between these organisms and trees. We demonstrate the versatility of the different approaches based on case studies on trees and fungi. KEY POINTS: • Current knowledge of genetic methods applied to forest trees and associated fungi. • Genomic methods are essential in conservation, breeding, management, and research. • Important role of phytobiomes for trees and their ecosystems.
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Affiliation(s)
- Markus Müller
- Forest Genetics and Forest Tree Breeding, Faculty for Forest Sciences and Forest Ecology, University of Goettingen, Büsgenweg 2, 37077, Göttingen, Germany.
- Center for Integrated Breeding Research (CiBreed), University of Goettingen, 37073, Göttingen, Germany.
| | - Ursula Kües
- Molecular Wood Biotechnology and Technical Mycology, Faculty for Forest Sciences and Forest Ecology, University of Goettingen, Büsgenweg 2, 37077, Göttingen, Germany
- Center for Molecular Biosciences (GZMB), Georg-August-University Göttingen, 37077, Göttingen, Germany
- Center of Sustainable Land Use (CBL), Georg-August-University Göttingen, 37077, Göttingen, Germany
| | - Katharina B Budde
- Forest Genetics and Forest Tree Breeding, Faculty for Forest Sciences and Forest Ecology, University of Goettingen, Büsgenweg 2, 37077, Göttingen, Germany
- Center of Sustainable Land Use (CBL), Georg-August-University Göttingen, 37077, Göttingen, Germany
| | - Oliver Gailing
- Forest Genetics and Forest Tree Breeding, Faculty for Forest Sciences and Forest Ecology, University of Goettingen, Büsgenweg 2, 37077, Göttingen, Germany
- Center for Integrated Breeding Research (CiBreed), University of Goettingen, 37073, Göttingen, Germany
- Center of Sustainable Land Use (CBL), Georg-August-University Göttingen, 37077, Göttingen, Germany
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Coccidioidomycosis in Northern Arizona: an Investigation of the Host, Pathogen, and Environment Using a Disease Triangle Approach. mSphere 2022; 7:e0035222. [PMID: 35972134 PMCID: PMC9599602 DOI: 10.1128/msphere.00352-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Coccidioides immitis and Coccidioides posadasii are the etiological agents of coccidioidomycosis (Valley fever [VF]). Disease manifestation ranges from mild pneumonia to chronic or extrapulmonary infection. If diagnosis is delayed, the risk of severe disease increases. In this report, we investigated the intersection of pathogen, host, and environment for VF cases in Northern Arizona (NAZ), where the risk of acquiring the disease is much lower than in Southern Arizona. We investigated reported cases and assessed pathogen origin by comparing genomes of NAZ clinical isolates to isolates from other regions. Lastly, we surveyed regional soils for presence of Coccidioides. We found that cases of VF increased in NAZ in 2019, and Coccidioides NAZ isolates are assigned to Arizona populations using phylogenetic inference. Importantly, we detected Coccidioides DNA in NAZ soil. Given recent climate modeling of the disease that predicts that cases will continue to increase throughout the region, and the evidence presented in this report, we propose that disease awareness outreach to clinicians throughout the western United States is crucial for improving patient outcomes, and further environmental sampling across the western U.S. is warranted. IMPORTANCE Our work is the first description of the Valley fever disease triangle in Northern Arizona, which addresses the host, the pathogen, and the environmental source in the region. Our data suggest that the prevalence of diagnosed cases rose in 2019 in this region, and some severe cases necessitate hospitalization. We present the first evidence of Coccidioides spp. in Northern Arizona soils, suggesting that the pathogen is maintained in the local environment. Until disease prevention is an achievable option via vaccination, we predict that incidence of Valley fever will rise in the area. Therefore, enhanced awareness of and surveillance for coccidioidomycosis is vital to community health in Northern Arizona.
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Prada-Salcedo LD, Prada-Salcedo JP, Heintz-Buschart A, Buscot F, Goldmann K. Effects of Tree Composition and Soil Depth on Structure and Functionality of Belowground Microbial Communities in Temperate European Forests. Front Microbiol 2022; 13:920618. [PMID: 35910637 PMCID: PMC9328770 DOI: 10.3389/fmicb.2022.920618] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/14/2022] [Indexed: 01/04/2023] Open
Abstract
Depending on their tree species composition, forests recruit different soil microbial communities. Likewise, the vertical nutrient gradient along soil profiles impacts these communities and their activities. In forest soils, bacteria and fungi commonly compete, coexist, and interact, which is challenging for understanding the complex mechanisms behind microbial structuring. Using amplicon sequencing, we analyzed bacterial and fungal diversity in relation to forest composition and soil depth. Moreover, employing random forest models, we identified microbial indicator taxa of forest plots composed of either deciduous or evergreen trees, or their mixtures, as well as of three soil depths. We expected that forest composition and soil depth affect bacterial and fungal diversity and community structure differently. Indeed, relative abundances of microbial communities changed more across soil depths than in relation to forest composition. The microbial Shannon diversity was particularly affected by soil depth and by the proportion of evergreen trees. Our results also reflected that bacterial communities are primarily shaped by soil depth, while fungi were influenced by forest tree species composition. An increasing proportion of evergreen trees did not provoke differences in main bacterial metabolic functions, e.g., carbon fixation, degradation, or photosynthesis. However, significant responses related to specialized bacterial metabolisms were detected. Saprotrophic, arbuscular mycorrhizal, and plant pathogenic fungi were related to the proportion of evergreen trees, particularly in topsoil. Prominent microbial indicator taxa in the deciduous forests were characterized to be r-strategists, whereas K-strategists dominated evergreen plots. Considering simultaneously forest composition and soil depth to unravel differences in microbial communities, metabolic pathways and functional guilds have the potential to enlighten mechanisms that maintain forest soil functionality and provide resistance against disturbances.
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Affiliation(s)
- Luis Daniel Prada-Salcedo
- Department Soil Ecology, Helmholtz-Centre for Environmental Research (UFZ), Halle, Germany
- Department of Biology, University of Leipzig, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (IDiv), Leipzig, Germany
- *Correspondence: Luis Daniel Prada-Salcedo
| | | | - Anna Heintz-Buschart
- Department Soil Ecology, Helmholtz-Centre for Environmental Research (UFZ), Halle, Germany
- German Centre for Integrative Biodiversity Research (IDiv), Leipzig, Germany
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - François Buscot
- Department Soil Ecology, Helmholtz-Centre for Environmental Research (UFZ), Halle, Germany
- German Centre for Integrative Biodiversity Research (IDiv), Leipzig, Germany
| | - Kezia Goldmann
- Department Soil Ecology, Helmholtz-Centre for Environmental Research (UFZ), Halle, Germany
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Rovenolt FH, Tate AT. The Impact of Coinfection Dynamics on Host Competition and Coexistence. Am Nat 2022; 199:91-107. [DOI: 10.1086/717180] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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O'Keeffe KR, Simha A, Mitchell CE. Indirect interactions among co-infecting parasites and a microbial mutualist impact disease progression. Proc Biol Sci 2021; 288:20211313. [PMID: 34375557 DOI: 10.1098/rspb.2021.1313] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Interactions among parasites and other microbes within hosts can impact disease progression, yet study of such interactions has been mostly limited to pairwise combinations of microbes. Given the diversity of microbes within hosts, indirect interactions among more than two microbial species may also impact disease. To test this hypothesis, we performed inoculation experiments that investigated interactions among two fungal parasites, Rhizoctonia solani and Colletotrichum cereale, and a systemic fungal endophyte, Epichloë coenophiala, within the grass, tall fescue (Lolium arundinaceum). Both direct and indirect interactions impacted disease progression. While the endophyte did not directly influence R. solani disease progression or C. cereale symptom development, the endophyte modified the interaction between the two parasites. The magnitude of the facilitative effect of C. cereale on the growth of R. solani tended to be greater when the endophyte was present. Moreover, this interaction modification strongly affected leaf mortality. For plants lacking the endophyte, parasite co-inoculation did not increase leaf mortality compared to single-parasite inoculations. By contrast, for endophyte-infected plants, parasite co-inoculation increased leaf mortality compared to inoculation with R. solani or C. cereale alone by 1.9 or 4.9 times, respectively. Together, these results show that disease progression can be strongly impacted by indirect interactions among microbial symbionts.
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Affiliation(s)
- Kayleigh R O'Keeffe
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Anita Simha
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Biology, Duke University, Durham, NC, USA
| | - Charles E Mitchell
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Environment, Ecology and Energy Program, University of North Carolina, Chapel Hill, NC, USA
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O'Keeffe KR, Halliday FW, Jones CD, Carbone I, Mitchell CE. Parasites, niche modification and the host microbiome: A field survey of multiple parasites. Mol Ecol 2021; 30:2404-2416. [PMID: 33740826 DOI: 10.1111/mec.15892] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 02/04/2021] [Accepted: 03/15/2021] [Indexed: 01/04/2023]
Abstract
Parasites can affect and be affected by the host's microbiome, with consequences for host susceptibility, parasite transmission, and host and parasite fitness. Yet, two aspects of the relationship between parasite infection and host microbiota remain little understood: the nature of the relationship under field conditions, and how the relationship varies among parasites. To overcome these limitations, we performed a field survey of the within-leaf fungal community in a tall fescue population. We investigated how diversity and composition of the fungal microbiome associate with natural infection by fungal parasites with different feeding strategies. A parasite's feeding strategy affects both parasite requirements of the host environment and parasite impacts on the host environment. We hypothesized that parasites that more strongly modify niches available within a host will be associated with greater changes in microbiome diversity and composition. Parasites with a feeding strategy that creates necrotic tissue to extract resources (necrotrophs) may not only have different niche requirements, but also act as particularly strong niche modifiers. Barcoded amplicon sequencing of the fungal ITS region revealed that leaf segments symptomatic of necrotrophs had lower fungal diversity and distinct composition compared to segments that were asymptomatic or symptomatic of other parasites. There were no clear differences in fungal diversity or composition between leaf segments that were asymptomatic and segments symptomatic of other parasite feeding strategies. Our results motivate future experimental work to test how the relationship between the microbiome and parasite infection is impacted by parasite feeding strategy and highlight the potential importance of parasite traits.
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Affiliation(s)
- Kayleigh R O'Keeffe
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Fletcher W Halliday
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Corbin D Jones
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ignazio Carbone
- Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA
| | - Charles E Mitchell
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Environment, Ecology and Energy Program, University of North Carolina, Chapel Hill, NC, USA
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