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Specificity of plant-microbe interactions in the tree mycorrhizosphere biome and consequences for soil C cycling.

Churchland C, Grayston SJ - Front Microbiol (2014)

Bottom Line: Mycorrhizal morphology affects not only spatial distribution of C in forests, but also differences in the longevity of these diverse structures may have important consequences for C sequestration in soil.Through new genomic techniques we are beginning to understand the mechanisms involved in the specificity and selection of ectomycorrhizal associations though much less is known about arbuscular mycorrhizal associations.The enormity of the mycorrhizosphere biome in forests and its potential to sequester substantial C belowground highlights the vital importance of increasing our knowledge of the dynamics of the different mycorrhizal functional groups in diverse forests.

View Article: PubMed Central - PubMed

Affiliation: Belowground Ecosystem Group, Department of Forest and Conservation Sciences, University of British Columbia Vancouver, BC, Canada.

ABSTRACT
Mycorrhizal associations are ubiquitous and form a substantial component of the microbial biomass in forest ecosystems and fluxes of C to these belowground organisms account for a substantial portion of carbon assimilated by forest vegetation. Climate change has been predicted to alter belowground plant-allocated C which may cause compositional shifts in soil microbial communities, and it has been hypothesized that this community change will influence C mitigation in forest ecosystems. Some 10,000 species of ectomycorrhizal fungi are currently recognized, some of which are host specific and will only associate with a single tree species, for example, Suillus grevillei with larch. Mycorrhizae are a strong sink for plant C, differences in mycorrhizal anatomy, particularly the presence and extent of emanating hyphae, can affect the amount of plant C allocated to these assemblages. Mycorrhizal morphology affects not only spatial distribution of C in forests, but also differences in the longevity of these diverse structures may have important consequences for C sequestration in soil. Mycorrhizal growth form has been used to group fungi into distinctive functional groups that vary qualitatively and spatially in their foraging and nutrient acquiring potential. Through new genomic techniques we are beginning to understand the mechanisms involved in the specificity and selection of ectomycorrhizal associations though much less is known about arbuscular mycorrhizal associations. In this review we examine evidence for tree species- mycorrhizal specificity, and the mechanisms involved (e.g., signal compounds). We also explore what is known about the effects of these associations and interactions with other soil organisms on the quality and quantity of C flow into the mycorrhizosphere (the area under the influence of mycorrhizal root tips), including spatial and seasonal variations. The enormity of the mycorrhizosphere biome in forests and its potential to sequester substantial C belowground highlights the vital importance of increasing our knowledge of the dynamics of the different mycorrhizal functional groups in diverse forests.

No MeSH data available.


Related in: MedlinePlus

Diagram of soil profiles with depth and the relative proportion of collembola/protozoa, bacteria and fungi at each of these depths. L, characterized by the accumulation of organic matter; F: characterized by the accumulation of partially decomposed organic matter; H: characterized by the accumulation of decomposed organic matter where the original structure is indescernable. A: mineral horizon characterized by eluviation of materials in solution, or accumulation of organic matter, or both. B: mineral horizon characterized by enrichment of clay, organic matter, and iron and aluminium oxides or by in situ weathering. C: mineral horizon characterized by little or no alteration through the soil-forming processes, usually represents the parent material.
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Figure 2: Diagram of soil profiles with depth and the relative proportion of collembola/protozoa, bacteria and fungi at each of these depths. L, characterized by the accumulation of organic matter; F: characterized by the accumulation of partially decomposed organic matter; H: characterized by the accumulation of decomposed organic matter where the original structure is indescernable. A: mineral horizon characterized by eluviation of materials in solution, or accumulation of organic matter, or both. B: mineral horizon characterized by enrichment of clay, organic matter, and iron and aluminium oxides or by in situ weathering. C: mineral horizon characterized by little or no alteration through the soil-forming processes, usually represents the parent material.

Mentions: Hyphae have the ability to move carbon both horizontally, over long distances, extending well beyond the roots of trees and vertically, down the soil profile. Most ECM are found in the F and H soil layer (area of highly decomposed leaves beneath surface of forest floor, Figure 2), but also can be found in the mineral soil, whereas other ECM prefer decaying wood (Amaranthus and Perry, 1989; Tedersoo et al., 2003). Some ECM are able to mobilize minerals from rocks in soil (Landeweert et al., 2001), whereas others access nutrients from coarse woody debris (Amaranthus et al., 1994). Some ECM fungi also have saprophytic growth capabilities e.g., Tomentella sp. (Kõljalg et al., 2000). It is hypothesized that these ECM may switch to a saprophytic lifestyle when photosynthate C becomes scarce e.g., during winter (Courty et al., 2008).


Specificity of plant-microbe interactions in the tree mycorrhizosphere biome and consequences for soil C cycling.

Churchland C, Grayston SJ - Front Microbiol (2014)

Diagram of soil profiles with depth and the relative proportion of collembola/protozoa, bacteria and fungi at each of these depths. L, characterized by the accumulation of organic matter; F: characterized by the accumulation of partially decomposed organic matter; H: characterized by the accumulation of decomposed organic matter where the original structure is indescernable. A: mineral horizon characterized by eluviation of materials in solution, or accumulation of organic matter, or both. B: mineral horizon characterized by enrichment of clay, organic matter, and iron and aluminium oxides or by in situ weathering. C: mineral horizon characterized by little or no alteration through the soil-forming processes, usually represents the parent material.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4042908&req=5

Figure 2: Diagram of soil profiles with depth and the relative proportion of collembola/protozoa, bacteria and fungi at each of these depths. L, characterized by the accumulation of organic matter; F: characterized by the accumulation of partially decomposed organic matter; H: characterized by the accumulation of decomposed organic matter where the original structure is indescernable. A: mineral horizon characterized by eluviation of materials in solution, or accumulation of organic matter, or both. B: mineral horizon characterized by enrichment of clay, organic matter, and iron and aluminium oxides or by in situ weathering. C: mineral horizon characterized by little or no alteration through the soil-forming processes, usually represents the parent material.
Mentions: Hyphae have the ability to move carbon both horizontally, over long distances, extending well beyond the roots of trees and vertically, down the soil profile. Most ECM are found in the F and H soil layer (area of highly decomposed leaves beneath surface of forest floor, Figure 2), but also can be found in the mineral soil, whereas other ECM prefer decaying wood (Amaranthus and Perry, 1989; Tedersoo et al., 2003). Some ECM are able to mobilize minerals from rocks in soil (Landeweert et al., 2001), whereas others access nutrients from coarse woody debris (Amaranthus et al., 1994). Some ECM fungi also have saprophytic growth capabilities e.g., Tomentella sp. (Kõljalg et al., 2000). It is hypothesized that these ECM may switch to a saprophytic lifestyle when photosynthate C becomes scarce e.g., during winter (Courty et al., 2008).

Bottom Line: Mycorrhizal morphology affects not only spatial distribution of C in forests, but also differences in the longevity of these diverse structures may have important consequences for C sequestration in soil.Through new genomic techniques we are beginning to understand the mechanisms involved in the specificity and selection of ectomycorrhizal associations though much less is known about arbuscular mycorrhizal associations.The enormity of the mycorrhizosphere biome in forests and its potential to sequester substantial C belowground highlights the vital importance of increasing our knowledge of the dynamics of the different mycorrhizal functional groups in diverse forests.

View Article: PubMed Central - PubMed

Affiliation: Belowground Ecosystem Group, Department of Forest and Conservation Sciences, University of British Columbia Vancouver, BC, Canada.

ABSTRACT
Mycorrhizal associations are ubiquitous and form a substantial component of the microbial biomass in forest ecosystems and fluxes of C to these belowground organisms account for a substantial portion of carbon assimilated by forest vegetation. Climate change has been predicted to alter belowground plant-allocated C which may cause compositional shifts in soil microbial communities, and it has been hypothesized that this community change will influence C mitigation in forest ecosystems. Some 10,000 species of ectomycorrhizal fungi are currently recognized, some of which are host specific and will only associate with a single tree species, for example, Suillus grevillei with larch. Mycorrhizae are a strong sink for plant C, differences in mycorrhizal anatomy, particularly the presence and extent of emanating hyphae, can affect the amount of plant C allocated to these assemblages. Mycorrhizal morphology affects not only spatial distribution of C in forests, but also differences in the longevity of these diverse structures may have important consequences for C sequestration in soil. Mycorrhizal growth form has been used to group fungi into distinctive functional groups that vary qualitatively and spatially in their foraging and nutrient acquiring potential. Through new genomic techniques we are beginning to understand the mechanisms involved in the specificity and selection of ectomycorrhizal associations though much less is known about arbuscular mycorrhizal associations. In this review we examine evidence for tree species- mycorrhizal specificity, and the mechanisms involved (e.g., signal compounds). We also explore what is known about the effects of these associations and interactions with other soil organisms on the quality and quantity of C flow into the mycorrhizosphere (the area under the influence of mycorrhizal root tips), including spatial and seasonal variations. The enormity of the mycorrhizosphere biome in forests and its potential to sequester substantial C belowground highlights the vital importance of increasing our knowledge of the dynamics of the different mycorrhizal functional groups in diverse forests.

No MeSH data available.


Related in: MedlinePlus