Effects of red pine (Pinus resinosa Ait.) mycorrhizoplane-associated actinomycetes onin vitro growth of ectomycorrhizal fungi

Richter, Dana L.; Zuellig, Timothy R.; Bagley, Susan T.; Bruhn, Johann N.

doi:10.1007/bf02220700

Cited by 19 publications

(18 citation statements)

References 15 publications

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“…Richter et al [36] used red pine roots for actinomycete isolations, and they observed similar in vitro effects on ectomycorrhizal fungi as we did in our analysis. Most actinomycete isolates exerted effects on fungal growth, inhibiting some while stimulating other fungi.…”

Section: Discussionsupporting

confidence: 80%

Production of fungal and bacterial growth modulating secondary metabolites is widespread among mycorrhiza-associated streptomycetes

Schrey¹,

Erkenbrack²,

Früh³

et al. 2012

BMC Microbiol

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BackgroundStudies on mycorrhiza associated bacteria suggest that bacterial-fungal interactions play important roles during mycorrhiza formation and affect plant health. We surveyed Streptomyces Actinobacteria, known as antibiotic producers and antagonists of fungi, from Norway spruce mycorrhizas with predominantly Piloderma species as the fungal partner.ResultsFifteen Streptomyces isolates exhibited substantial variation in inhibition of tested mycorrhizal and plant pathogenic fungi (Amanita muscaria, Fusarium oxysporum, Hebeloma cylindrosporum, Heterobasidion abietinum, Heterobasidion annosum, Laccaria bicolor, Piloderma croceum). The growth of the mycorrhiza-forming fungus Laccaria bicolor was stimulated by some of the streptomycetes, and Piloderma croceum was only moderately affected. Bacteria responded to the streptomycetes differently than the fungi. For instance the strain Streptomyces sp. AcM11, which inhibited most tested fungi, was less inhibitory to bacteria than other tested streptomycetes. The determined patterns of Streptomyces-microbe interactions were associated with distinct patterns of secondary metabolite production. Notably, potentially novel metabolites were produced by strains that were less antagonistic to fungi. Most of the identified metabolites were antibiotics (e.g. cycloheximide, actiphenol) and siderophores (e.g. ferulic acid, desferroxiamines). Plant disease resistance was activated by a single streptomycete strain only.ConclusionsMycorrhiza associated streptomycetes appear to have an important role in inhibiting the growth of fungi and bacteria. Additionally, our study indicates that the Streptomyces strains, which are not general antagonists of fungi, may produce still un-described metabolites.

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Section: Discussionsupporting

confidence: 80%

Production of fungal and bacterial growth modulating secondary metabolites is widespread among mycorrhiza-associated streptomycetes

Schrey¹,

Erkenbrack²,

Früh³

et al. 2012

BMC Microbiol

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“…However, the observation that streptomycetes are able to promote fungal growth is not novel, and streptomycete isolates having such activity with ECM fungi have been characterized previously (3,39). Auxofuran, the growth-promoting compound produced by Streptomyces strain AcH 505, exhibits structural similarity to the biologically inactive compound ulufuranol (21) and to the benzopyran-type compound koninginin B (8) that exhibits herbicidal activity.…”

Section: Discussionmentioning

confidence: 99%

“…When 12 actinomycete isolates were tested to determine their effects on mycelial growth of ectomycorrhizal fungi (39), the bacterial isolates inhibited, promoted, or had no significant effect on hyphal extension in dual cultures. Thus, there is an opportunity to select for actinomycetes that stimulate certain symbiotic fungi and plant growth but are antagonistic to pathogenic organisms.…”

mentioning

confidence: 99%

Auxofuran, a Novel Metabolite That Stimulates the Growth of Fly Agaric, Is Produced by the Mycorrhiza Helper Bacterium Streptomyces Strain AcH 505

Riedlinger¹,

Schrey

Tarkka

et al. 2006

Appl Environ Microbiol

150

126

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The mycorrhiza helper bacterium Streptomyces strain AcH 505 improves mycelial growth of ectomycorrhizal fungi and formation of ectomycorrhizas between Amanita muscaria and spruce but suppresses the growth of plant-pathogenic fungi, suggesting that it produces both fungal growth-stimulating and -suppressing compounds. The dominant fungal-growth-promoting substance produced by strain AcH 505, auxofuran, was isolated, and its effect on the levels of gene expression of A. muscaria was investigated. Auxofuran and its synthetic analogue 7-dehydroxy-auxofuran were most effective at a concentration of 15 M, and application of these compounds led to increased lipid metabolism-related gene expression. Cocultivation of strain AcH 505 and A. muscaria stimulated auxofuran production by the streptomycete. The antifungal substances produced by strain AcH 505 were identified as the antibiotics WS-5995 B and C. WS-5995 B completely blocked mycelial growth at a concentration of 60 M and caused a cell stress-related gene expression response in A. muscaria. Characterization of these compounds provides the foundation for molecular analysis of the fungus-bacterium interaction in the ectomycorrhizal symbiosis between fly agaric and spruce.Actinomycetes are known for their capacity to control plant diseases. A number of investigations have reported antagonism of root-pathogenic fungi by soil actinomycetes (6, 40) and that especially streptomycetes are a rich source of antifungal compounds (20).Ectomycorrhizas (ECM) are widespread symbiotic organs that are formed during interactions between most tree species or perennials and soil fungi (44). The establishment of the symbiosis is affected by other soil microbes, such as bacteria and other fungi (18,29). Understanding the interactions between the soil-inhabiting microorganisms in the mycorrhizosphere is very important, as they are key players in nutrient cycling in forest soils (29).Under natural conditions, the plant partner is able to select for bacterial strains that are beneficial for the ECM symbiosis and for plant growth (16). Specifically, the growth of ectomycorrhizal fungi and mycorrhiza formation are promoted by some of the mycorrhizosphere bacteria (mycorrhiza helper bacteria [MHB] [18]), which belong to the genera Bacillus, Burkholderia, Pseudomonas, Rhodococcus, and Streptomyces (15,19,30,37,42).When 12 actinomycete isolates were tested to determine their effects on mycelial growth of ectomycorrhizal fungi (39), the bacterial isolates inhibited, promoted, or had no significant effect on hyphal extension in dual cultures. Thus, there is an opportunity to select for actinomycetes that stimulate certain symbiotic fungi and plant growth but are antagonistic to pathogenic organisms. To do this, we isolated a collection of actinomycetes from the hyphosphere of a spruce (Picea abies) stand and examined their effects on symbiotic and plant-pathogenic fungi (30,31). One member of this collection, streptomycete strain AcH 505, exhibited the desired qualities, as it significantly pro...

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“…In another study, a Tt isolate from Pseudotsuga menziesii efficiently colonised Pinus radiata seedlings but was incompatible with 11 Eucalyptus species (Malajczuk et al 1982). Growth-promoting MHB typically associated with Tt have not been studied (Garbaye 1994), although Richter et al (1989) isolated mycorrhizoplane-associated actinomycetes that stimulated growth of Tt in vitro. However, fructification of Tt and typical Tt mycorrhizas have been observed on seedlings of Eucalyptus dalrympleana and Eucalyptus macarthuri in France (Mousain et al 1977).…”

Section: Anatomy Of Ecmmentioning

confidence: 99%

Thelephora

Colpaert

1999

Ectomycorrhizal Fungi Key Genera in Profile

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Effects of red pine (Pinus resinosa Ait.) mycorrhizoplane-associated actinomycetes onin vitro growth of ectomycorrhizal fungi

Cited by 19 publications

References 15 publications

Production of fungal and bacterial growth modulating secondary metabolites is widespread among mycorrhiza-associated streptomycetes

Production of fungal and bacterial growth modulating secondary metabolites is widespread among mycorrhiza-associated streptomycetes

Auxofuran, a Novel Metabolite That Stimulates the Growth of Fly Agaric, Is Produced by the Mycorrhiza Helper Bacterium Streptomyces Strain AcH 505

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