Working with Mycorrhizas in Forestry and Agriculture

Crop Production/Industries,

Tree diversity and species identity effects on soil fungi, protists and animals are context dependent

Plant species richness and the presence of certain influential species (sampling effect) drive the stability and functionality of ecosystems as well as primary production and biomass of consumers. However, little is known about these floristic effects on richness and community composition of soil biota in forest habitats owing to methodological constraints. We developed a DNA metabarcoding approach to identify the major eukaryote groups directly from soil with roughly species-level resolution. Using this method, we examined the effects of tree diversity and individual tree species on soil microbial biomass and taxonomic richness of soil biota in two experimental study systems in Finland and Estonia and accounted for edaphic variables and spatial autocorrelation. Our analyses revealed that the effects of tree diversity and individual species on soil biota are largely context dependent. Multiple regression and structural equation modelling suggested that biomass, soil pH, nutrients and tree species directly affect richness of different taxonomic groups. The community composition of most soil organisms was strongly correlated due to similar response to environmental predictors rather than causal relationships. On a local scale, soil resources and tree species have stronger effect on diversity of soil biota than tree species richness per se

Chemical elements in Ascomycetes and Basidiomycetes - The reference mushrooms as instruments for investigating bioindication and biodiversity

Fungi in the wild are among the principal agents in biogeochemical cycles; those cycles of matter and energy that enable ecosystems to work. By investigating the biodiversity of Italian fungal species and concentration levels of chemical elements in them, it may be possible to use these fungi as biological indicators for the quality of forest, woodland and semi-natural environments. The database of this EUR Report record the dry-material concentrations of 35 chemical elements, including heavy metals, in over 9,000 samples of higher mushrooms (Ascomycetes and Basidiomycetes). These samples represent approximately 200 genera and a thousand species. As the database has attained statistical stability it has been possible to define the concept of a “reference mushroom”. The use of a “reference mushroom” may benefit – perhaps only as a methodological approach – various fields of mycological and environmental research; from biodiversity and bioindication, through taxonomy right up to health and sanitation issues. The sheer volume of the collected data may prove to be useful as a comparison for data collected in the future; such results would also allow a better and more exhaustive interpretation of the effects of environmental protection laws that have been in place over the years to reduce or remedy current climate change phenomena and the environmental damage caused by human activity. Studies pertaining to the frequency of occurrence and the ecology of the various fungal species found on Italian soil have tended to link the reference habitats used to European classification guidelines (Natura 2000, CORINE Land Cover, CORINE Biotopes and EUNIS). Thereby the foundations have been laid for the use of mushrooms as biological indicators for the measurement of soil and ecosystem quality.JRC.DDG.H.5-Rural, water and ecosystem resource

Fungal endophytes enhance growth and production of natural products in Echinacea purpurea (Moench.)

Echinacea purpurea is a native herbaceous perennial with substantial economic value for its medicinal and ornamental qualities. Arbuscular mycorrhizae are symbiotic fungi that form relationships with plant roots and are known to enhance growth in the host. Mycorrhizae and other fungal endophytes often affect stress resistance and secondary metabolism in the host, as well as the ecology of other endophytes in the plant. A newly emerging paradigm in sustainable biotechnique is the targeted use of fungal endophytes to enhance growth and secondary metabolism in crops. Many of the therapeutic compounds in E. purpurea could be affected by fungal colonization. In this research the effects of inoculation of Echinacea purpurea with two classes of fungal endophytes: the arbuscular mycorrhizal fungi Glomus intraradices and Gigaspora margarita and the entomopathogenic endophyte Beauveria bassiana were evaluated . Endophyte colonization and impacts on plant growth and phytochemistry were tested in multiple greenhouse experiments. Arbuscular mycorrhizae and B. bassiana effectively colonized E. purpurea with some significant interactive effects. Consistent, substantial, and significant increases in all growth parameters were observed in mycorrhizal plants; mycorrhizal plants produced up to four times the biomass of controls in 12 weeks. Broad spectrum changes in fertilization were necessary to produce mycorrhizal and nonmycorrhizal samples of equal size, and severely nutrient-limited mycorrhizal E. purpurea seedlings maintained growth rates comparable to well fertilized samples. Treatment with B. bassiana had minor and inconsistent effects on some plant growth parameters, and there were significant interactive effects with arbuscular mycorrhizae. Phytochemical concentrations in all metabolite classes tested responded significantly to inoculation with both classes of fungal endophytes. Changes were observed in various pigments, caffeic acid derivatives, alkylamides, and terpenes. Many of the affected compounds have important roles in metabolism or have bioactive value as natural products. When considered from a net production perspective (concentration X dry weight), compared to controls, plants inoculated with endophytes produced as much as 30 times the content of some compounds in 12 weeks. This work effectively demonstrates that fungal endophytes can enhance the bioactivity of plant tissues and the production of natural products in E. purpurea

The hidden side of interaction: microbes and roots get together to improve plant resilience

Plants have evolved various belowground traits to adapt to the changing environments, and root-associated soil microbes play a crucial role in the response, adaptation, and resilience to adverse environmental conditions. This comprehensive review explores the diverse interactions between plants and soil microbes, focusing on the role of root-associated microbiota, with a particular emphasis on arbuscular mycorrhizal fungi, in plant responses to diverse environmental conditions. How plant genotype, root traits, and growth environments influence these interactions, and consequently plant resilience and productivity, are discussed. Recent advances in root phenotyping, including traditional and machine learning-based methods are also presented as an innovative tool to study and characterize root-microbe interactions. Overall, these studies highlight the importance of considering the hidden side of the interactions between roots and microbes to improve plant nutrition and protection in the context of sustainable agriculture in the face of climate change

Factors affecting growth of the arbuscular mycorrhizal fungal mycelium

Arbuscular mycorrhizal relationsliips link plant root systems and zygomycetous fungi from the family Glomales in a symbiotic association which provides a carbon source to the fungus and benefits to the plant in terms of nutrient and water acquisition, and disease resistance. Root system colonisation is characterised by the formation of intracellular hyphae and internal fungal structures, the arbuscles and vesicles. Colonisation occurs after root penetration by fimgal hyphae originating from either spores or extra-radical hyphae. Tire extra-radical hyphae, which form the fungal mycelium in the soil and have a primary role in host plant nutrition, are a largely neglected feature of the symbiosis due to the difficulties involved in their study.In the present work, methodologies were developed to allow in vitro studies of extra-radical hyphae and thus circumvent problems associated with the inaccessibility and opacity of the soil environment. Root pieces colonised by the arbuscular mycorrhizal (AM) fungus Glomus etunicatum Becker & Gerdemann (S329, INVAM, USA) were inoculated onto dialysis membrane overlying transparent high purity agarose gel. This restricted the hyphae to a two-dimensional growth form which facilitated observation using microscopy and image analysis techniques, and enabled morphological measurements to be taken without the added complexity of three dimensional growth.The two major influences 011 AM fimgal growth are those of soil and of plant origin. The present work studied the effects of plant related factors on AM fungal hyphae. Host and non-host plant factors, and derivatives of these, were found to influence hyphal growth as characterised both by length measurements and morphological parameters. Host root exudates reduced hyphal growth, apparently as a result of changes in the overall distribution of hyphae within the mycelium, as measured by fractal dimension (FD). Non-host exudates and plant flavonoid compounds also decreased hyphal growth, but this result could not be attributed to changes in either branching or mycelial organisation. Root extracts of host and non­host plants did not significantly affect hyphal length, but did affect mycelial morphology. Although host root extracts appeared to have no effect 011 branching, they did alter hyphal distribution within the mycelium, as evidenced by an increase in FD. Non-host root extracts increased both branching and FD. Colonised host plant root extracts increased both hyp ha I length and branching, but had 110 significant effect on hyphal distribution within the mycelium.Results are discussed in the context of previous work earned out on germ tube hyphae of AM fungi from spore inoculum. Observations of extra-radical hyphae showed differential responses when compared with germ tube hyphae more commonly studied by previous authors. This indicates that different phases of the fungal life cycle respond in different ways to similar environmental influences

Patterns and Drivers of Wiregrass Gap Longleaf Pine (Pinus palustris Mill.) Woodland Succession as Part of Restoration Efforts

Longleaf Pine (Pinus palustris) communities are widespread throughout the Southeastern United States with a dominant understory vegetation of wiregrass (Aristida spp.) in most of its range. A small area in central South Carolina that is naturally free of wiregrass is called the “Wiregrass Gap”. Here, the understory vegetation is dominated by bluestems grasses (Andropogon spp. and Schizachyrium spp.) which drive the disturbance regime of frequent low-intensity fire. The successful establishment of these grasses is key for longleaf pine woodland restoration efforts in this region, but few resources detail the ecological drivers at play that enable successful restoration in these longleaf pine woodlands. I investigated these drivers of succession through the lens of slash manipulation treatments that resulted from a restoration harvest. Exposed duff and mineral soil had a favorable effect on the herbaceous response but also benefitted the regeneration of many loblolly pine seedlings. This complicates restoration efforts. An abundance of woody material was suspected as a suppressant of establishing vegetation. In addition, I investigated how early successional plants can contribute to the restoration process. By quickly establishing in soil devoid of arbuscular mycorrhizal fungi that are vital for plant growth, early successional plants can enhance the arbuscular mycorrhizal inoculum in the soil and successfully preconditioning it for the benefit of later successional plants as they colonize the site. The restoration of Wiregrass Gap longleaf pine communities is thus adaptable to different induced and ecological drivers that together can result in successful woodland restoration

Ponderosa pine ecosystems restoration and conservation: Steps toward stewardship

This volume is divided into three sections: (1) Ecological, Biological, and Physical Science; (2) Social and Cultural; and (3) Economics and Utilization. Effective ecological restoration requires a combination of science and management. The authors of the first section exemplified this integration in the course of addressing a broad range of topics, from detailed microsite and small-scale changes in fungal, plant, and animal communities, up through landscape, regional, and subcontinental scales. Although the themes were diverse, papers were linked by underscoring the relationship between restorative management actions and ecological effects. Social sciences play a key role in ecosystem restoration because collaboration, development of common goals, and political and economic feasibility are essential for success. The authors of the second section focused on public attitudes, partnerships, and the relationship between social and ecological factors. In the third section, the economics and utilization of products from forest restoration were compared in several Western locations. Both the markets for these products and the range of utilization opportunitiesfrom small-diameter logs to energy creationwill surely evolve rapidly as society moves to address the fire hazards and other problems caused by stressed and weakened ecosystems. The turn of the century is an appropriate point to capture dramatic changes in perspective: consider how attitudes toward Western forests have evolved between 1900 and 2000. The papers in this volume chronicle adaptive research that continues to deepen our understanding of restoration in ecosystems and social systems