The effect of tree-root exudates on the growth rate of ectomycorrhizal and saprotrophic fungi

Sun, Yu-Ping; Fries, Nils

doi:10.1007/bf00206138

Cited by 19 publications

(10 citation statements)

References 13 publications

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“…Since the same group of saturated fatty acids which first increased in the roots appeared later in the extraradical mycelium, and since many of these fatty acids were absent from axenically growing fungus, they were most likely transferred from the roots to the fungus at contact sites. Interestingly, the growth of various ectomyorrhizal fungal species has been found to be stimulated after the addition of palmitic (n16:0) or stearic acid (n18:0); this effect was interpreted as stimulating activity rather than as a response to a carbon source (Sun & Fries 1992).…”

Section: Discussionmentioning

confidence: 99%

Lipids in roots of Pinus sylvestris seedlings and in mycelia of Pisolithus tinctorius during ectomycorrhiza formation: changes in fatty acid and sterol composition

Laczkó

Böller

Wiemken

2003

Plant Cell & Environment

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The composition of fatty acids and sterols in soil lipid fractions is often used as a global indicator for the status and changes of soil microbial communities. In order to validate such analyses in the context of ectomycorrhizal communities, an experiment was performed in which seedlings of Pinus sylvestris and the fungus Pisolithus tinctorius were grown separately, or combined to form ectomycorrhiza under axenic conditions. Fatty acids of the neutral lipid fraction (NLFAs) and the phospholipid fraction (PLFAs) as well as sterols were identified and quantified by gas chromatography-mass spectrometry. When grown separately, the two organisms differed strongly with respect to the sterol composition. Sterols had a much higher relative abundance in the fungus in comparison with the plant, and the two main fungal sterols, ergosterol and 24-ethyllanosta-8,24(24 ′ ′ ′ ′ )-diene-3beta,22zeta-diol (Et lano 8,24), as well as six minor fungal sterols were not found in the plant. On the other hand, the three sterols found in plant roots were absent from the fungus. With regard to fatty acids, the lipids of both organisms contained the same three major PLFAs, namely n16:0, 18:2-9,12c, and 18:1-9c. However, plant lipids contained, in addition, eight PLFAs and five NLFAs that were not present in the fungus. On the other hand, the fungus contained two PLFAs and two NLFAs that were not present in the plant. When the fungus and the plant were brought together, there was a drastic change in the lipid composition of the root: within a day, all the saturated fatty acids in the NLFA fraction increased very strongly and then slowly decreased but remained at an elevated level throughout the experiment. All these saturated fatty acids also started to appear in the extraradical fungal mycelium; they increased steadily and reached their highest levels at the end of the experiment. These results indicate that in symbiosis, the fungus transports plant lipids from the symbiotic interface to the extraradical mycelium. Concerning sterols, the extraradical mycelium acquired only a small amount of plant-specific sterols. However, its ergosterol content steadily decreased whereas the content of Et lano 8,24 remained high, causing the ratio of these two sterols to decrease from 1 : 7 to 1 : 20, whereas in the ectomycorrhizal root, the opposite phenomenon occurred, so that the ratio increased to a value of almost 1 : 1. The marked changes in the composition of the extraradical mycelium were well reflected in a principal component analysis of all lipid components. The present results show that a given ectomycorrhizal fungus may display markedly different lipid compositions in its intraradical and extraradical parts. In addition, they highlight a potential role of plant lipid transfer from the root to the fungus in the functioning of the ectomycorrhizal symbiosis.

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Section: Discussionmentioning

confidence: 99%

Lipids in roots of Pinus sylvestris seedlings and in mycelia of Pisolithus tinctorius during ectomycorrhiza formation: changes in fatty acid and sterol composition

Laczkó

Böller

Wiemken

2003

Plant Cell & Environment

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“…Melin (1954Melin ( , 1963 described stimulatory effects of platit root cultures, root exudates and root extracts on the growth of ectomycorrhizal fungi, but non-host roots were as active in these experiments as were host roots. Sun & Fries (1992) found palmitic acid and the cytokinin isopentenylaminopurine to be very active growth promoting compounds affecting saprophytic and ectomycorrhizal fungi alike. By contrast, specific growth promoting effects in arbuscular mycorrhiza have been reported by Giovannetti et al (1993) and Giovannetti, Sbrana & Logi (1994).…”

Section: Growth Stimulationmentioning

confidence: 99%

Induction of mycorrhiza‐like structures and defence reactions in dual cultures of spruce callus and ectomycorrhizal fungi

1995

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Spruce cells stimulated growth of the mycorrhizal fungi, whereas growth of the pathogenic fungus was not affected. Two of the mycorrhizal fungi, S. variegatus and L. deterrimus, caused hypersensitive reactions in spruce cells. In contact with the surface of the plant cells the mycorrhizal fungi developed densely interwoven lobed, hand-and fanshaped structures. They resembled morphological features occurring in the hyphal mantle and Hartig net of ectomycorrhizas. The ectomycorrhizal fungi did not show altered branching patterns when growing on cellophane sheets. These results demonstrate that callus cells of the host P. abies are able to stimulate fungal growth and to induce ectomycorrhizal fungi to form mycorrhiza-like structures which normally are only generated in the presence of host roots.

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“…Intimately linked with the unique biogeochemical capabilities of EM fungi are the quantity and chemical diversity of the secretions (such as degradative enzymes) produced by EM fungi and their forest tree host plants, which may represent key effect traits that have consequences for C and nutrient cycling in systems where these organisms are introduced. First, root secretions produced by different forest plant species may favor different mycorrhizal fungi and saprophytes (Ali and Jackson, 1988;Sun and Fries, 1992), which may contribute to the enrichment of specific EM fungi at plantation and invasion sites. For example, the flavonoid and phenolglycoside from Eucalyptus root exudates favor growth of S. bovinus but not Paxillus involutus (Jones et al, 2004), which could consequently amplify effects of secretions by the selected EM fungi.…”

Section: Potential Effects Of Ectomycorrhizal Introductions and Invasmentioning

confidence: 99%

Ectomycorrhizal Plant-Fungal Co-invasions as Natural Experiments for Connecting Plant and Fungal Traits to Their Ecosystem Consequences

Hoeksema

Averill

Bhatnagar

et al. 2020

Front. For. Glob. Change

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The effect of tree-root exudates on the growth rate of ectomycorrhizal and saprotrophic fungi

Cited by 19 publications

References 13 publications

Lipids in roots of Pinus sylvestris seedlings and in mycelia of Pisolithus tinctorius during ectomycorrhiza formation: changes in fatty acid and sterol composition

Lipids in roots of Pinus sylvestris seedlings and in mycelia of Pisolithus tinctorius during ectomycorrhiza formation: changes in fatty acid and sterol composition

Induction of mycorrhiza‐like structures and defence reactions in dual cultures of spruce callus and ectomycorrhizal fungi

Ectomycorrhizal Plant-Fungal Co-invasions as Natural Experiments for Connecting Plant and Fungal Traits to Their Ecosystem Consequences

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