Phosphate-solubilizing activity of ectomycorrhizal fungi in vitro

1991 ◽  
Vol 69 (2) ◽  
pp. 342-346 ◽  
Author(s):  
F. Lapeyrie ◽  
J. Ranger ◽  
D. Vairelles
Keyword(s):  
Ectomycorrhizal Fungi ◽  
Calcium Phosphates ◽  
Growth Stimulation ◽  
Field Trials ◽  
Ectomycorrhizal Fungus ◽  
Experimental Conditions ◽  
Phosphate Solubilizing ◽  
Phosphate Source ◽  
Solubilizing Activity

An easy to use method is presented here to compare and study the mineral phosphate-solubilizing activity of ectomycorrhizal fungi. This technique can discriminate between strains with differing phosphate-solubilizing activities. Synthetic mineral phosphates, crystalline or amorphous, were differentially solubilized by 10 ectomycorrhizal fungi. Natural crystalline phosphates studied do not seem to be solubilized by fungi under similar experimental conditions. Paxillus involutus 1 appears to be able to solubilize calcium phosphates using either ammonium or nitrate nitrogen, but the other isolates were able to effectively solubilize phosphate only in the presence of ammonium. This has implications regarding the possible mechanism used to solubilize phosphate by these isolates. Recrystallization can be seen in the culture medium if calcium ions are present. The type of crystals depends on the phosphate source and on the fungal strain. This technique is suitable for screening a large number of ectomycorrhizal strains. The significance of phosphate-solubilizing activity to plant growth stimulation needs to be determined by field trials. Key words: ectomycorrhizal fungus, phosphate, solubilization.

scholarly journals Improving Cassava Productivity by Soil Bioaugmentation with Phosphate-Solubilizing Actinomycetes and Fungi

2021 ◽  
Vol 16 (2) ◽  
pp. 89
Author(s):  
Alimuddin Ali ◽  
Muhammad Juanda ◽  
A. Farchan SJahid ◽  
Herlina Rante
Keyword(s):  
Gum Arabic ◽  
Field Trials ◽  
In Vitro Test ◽  
In Planta ◽  
South Sulawesi ◽  
Cassava Plant ◽  
Cultivation Technique ◽  
Food Commodities ◽  
Phosphate Solubilizing

<p>Cassava is one of the most important food commodities, but its cultivation technique must be improved, especially the technology in increasing soil fertility. Lack of phosphate (P), one of the major biological nutrients in soil, can reduce<br />agricultural production. Some P-solubilizing microbes can play an important role in increasing the availability of P for plants. The purpose of this study was to evaluate the ability of P-solubilizing microbes isolated from cassava rhizosphere in improving the growth of cassava after soil bioaugmentation with the formula of selected microbes. A total of 50 isolates were successfully isolated from cassava plant rhizosphere collected from several locations in South Sulawesi. In vitro screening on Pikovskaya agar media resulted in six Actinomycetes and six fungal isolates with the best P hydrolysis capacity. One Actinomycetes isolate<br />(Streptomyces sp. A-SDR01) and one fungal isolate (Penicillium sp. F-SKG17) with nonantagonistic effect to each other based on in vitro test were able to improve the vegetative growth of cassava under in planta test. Combination of both isolates in a gum arabic formulation increased plant height and productivity compared to untreated plants when applied as soil bioaugmentation in limited field trials at four locations in South Sulawesi. Therefore, application of P-solubilizing microbes that possess soil bioaugmentation properties is recommended for increasing the growth of cassava plants and their use as<br />microbial biofertilizers should be extended to wider areas.</p>

Isolation and identification of Rhizoctonia solani antagonist bacteria from the rhizosphere of pepper plants

2020 ◽  
Author(s):  
V.Zh. Nguyen ◽  
◽  
T.O. Dao ◽  
E. A. Kalashnikova ◽  
Th.H. Nguyen
Keyword(s):  
Rhizoctonia Solani ◽  
Inhibitory Activity ◽  
Soil Samples ◽  
Bacterial Strains ◽  
Isolation And Identification ◽  
Phosphate Solubilizing ◽  
Solubilizing Activity ◽  
Pepper Plants

The purpose of this work is to isolate bacteria from the pepper rhizosphere that inhibit Rhizoctoniasolani and evaluate in vitro their phosphate solubilizing activity and production of siderophore. Of the different soil samples taken from the pepper fields of An Thanh, An Ninh, Quynh My, QuynhPhudistrict, ThaiBinh province, 48 bacterial strains were isolated. Of these, 5 strains (AT16, VK 4.7, VK 4.8, VK 4.12, VK 4.13) expressed as higher inhibitory Rhizoctonia solani activity were selected. Their inhibitory activity is from 11.11% to 62.22%.

Ectomycorrhizal synthesis with Alaskan Alnus tenuifolia

1990 ◽  
Vol 68 (4) ◽  
pp. 761-767 ◽  
Author(s):  
I. L. Brunner ◽  
F. Brunner ◽  
O. K. Miller Jr.
Keyword(s):  
Ectomycorrhizal Fungi ◽  
Ectomycorrhizal Fungus ◽  
In Vitro Synthesis ◽  
First Report ◽  
Alnus Nepalensis ◽  
Hartig Net

The ability of Alnus tenuifolia to form ectomycorrhizae with potential ectomycorrhizal fungi was investigated. Alnus tenuifolia seedlings raised in growth pouches were inoculated with Frankia to induce nodulation and then with a putative ectomycorrhizal fungus. The fungi used were collected in nearly pure A. tenuifolia stands in Alaska or were found in Alnus nepalensis stands in Nepal. Five species of putative ectomycorrhizal symbionts of alders were tested. Alpova diplophloeus and Paxillus filamentosus formed both mantle and Hartig net. Cortinarius cf. saturninus developed a mantle but no Hartig net. Hebeloma cf. crustuliniforme and Gyrodon lividus developed neither mantle nor Hartig net. This is the first report of synthesis of P. filamentosus and C. cf. saturninus with Alnus. The ectomycorrhizal status of the genus Gyrodon is discussed, since in vitro synthesis has not yet been demonstrated. Synthesis with A. diplophloeus and H. crustuliniforme did not result in ectomycorrhizal formations with nonnodulated alder seedlings.

Effect of the ectomycorrhizal fungus Hebeloma hiemale on adventitious root formation in derooted Pinus halepensis shoot hypocotyls

1990 ◽  
Vol 68 (6) ◽  
pp. 1265-1270 ◽  
Author(s):  
Gilles Gay
Keyword(s):  
Acetic Acid ◽  
Ectomycorrhizal Fungi ◽  
Culture Filtrate ◽  
Root Formation ◽  
Pinus Halepensis ◽  
Hormonal Treatment ◽  
Adventitious Root Formation ◽  
Ectomycorrhizal Fungus ◽  
Indole 3 Acetic Acid

The effect of the ectomycorrhizal fungus Hebeloma hiemale and of its culture filtrate on in vitro rooting of Pinus halepensis derooted shoot hypocotyls was studied in an attempt to determine if ectomycorrhizal fungi could enhance adventitious root formation in gymnosperms. Pinus halepensis hypocotyls did not root in the absence of hormonal treatment, whereas the rooting percentage was 87.3% in the presence of 5 μM indole-3-acetic acid (IAA). In the presence of tryptophan, which is a precursor of IAA, H. hiemale strongly enhanced rooting of hypocotyls cultivated in the absence of any hormonal treatment. In the presence of 0.1 mM tryptophan, the rooting percentage of the inoculated hypocotyls was 96.6%, whereas it was only 7.6% in the absence of the fungus. Hebeloma hiemale culture filtrate obtained in the absence of tryptophan did not contain IAA and did not stimulate rooting of the hypocotyls. In contrast, a culture filtrate obtained in the presence of tryptophan contained IAA; an ethyl acetate extract from this filtrate allowed 100% rooting. Different fractions were isolated by preparative thin-layer chromatography from the IAA-containing filtrate and studied for their effect on rooting. It was demonstrated that IAA was responsible for the rhizogenic activity of H. hiemale. These results suggest that ectomycorrhizal fungi which rapidly metabolize exogenously supplied tryptophan to IAA could be a suitable tool to enhance in vitro rooting of micropropagated gymnosperms. Key words: ectomycorrhizal fungus, indole-3-acetic acid, rooting, shoot hypocotyl, Hebeloma hiemale, Pinus halepensis.

PHOSPHATSOLUBILIZING BACTERIA OF THE GENUS PSEUDOMONAS AND THE EFFICIENCY OF THEIR APPLICATION TO INCREASE THE AVAILABILITY OF PHOSPHORUS

2021 ◽  
Vol 0 (3) ◽  
pp. 11-16
Author(s):  
E.V. KUZINA ◽  
◽  
G.F. RAFIKOVA ◽  
T.YU. KORSHUNOVA ◽  
◽  
...  
Keyword(s):  
Nitrogen Fertilizers ◽  
Phosphate Solubilizing Bacteria ◽  
Mobile Phosphorus ◽  
Insoluble Phosphate ◽  
Treatment Facilities ◽  
Agar Media ◽  
Phosphate Solubilizing ◽  
Solid Nutrient Medium ◽  
Solubilizing Activity

Phosphorus is the second most important element for plants after nitrogen. Fertilizers based on it, used to stimulate productivity, are inaccessible for most crops, which leads to their accumulation in the soil and environmental pollution. The use of phosphate-solubilizing bacteria increases the amount of phosphorus absorbed by plants. In most publications describing this group of bacteria, their effectiveness is assessed only in vitro by the halo zones formed on agar media with calcium orthophosphate. The aim of this study was to compare the solubilizing properties of bacteria of the genus Pseudomonas on a solid nutrient medium, as well as in sand and soil. It was shown that all studied cultures of microorganisms are capable of solubilizing insoluble phosphate in Pikovskaya's medium. The most active strains were Pseudomonas laurentiana ANT 56 and Pseudomonas sp. IB 182, isolated from the activated sludge of biological treatment facilities and arable soil, respectively. Experiments with the introduction of strains showed that the amount of mobile phosphorus in the sand increased 2.6-3.8 times in two weeks (in the control 1.2 times), while in the experiment with soil, a significant increase in the content of mobile phosphorus compared to the control was recorded only for the strain P . laurentiana ANT 17 (by 29.1%). It is assumed that the high solubilizing activity of the P. laurentiana ANT 17 strain may be due to the complex action of mechanisms of different nature, including the synthesis of indolyl-3-acetic acid and exopolysaccharide. The studies carried out make it possible to consider this bacterial strain as a promising object for creating on its basis a biological preparation for agricultural purposes.

scholarly journals Involutin Is an Fe3+Reductant Secreted by the Ectomycorrhizal Fungus Paxillus involutus during Fenton-Based Decomposition of Organic Matter

2015 ◽  
Vol 81 (24) ◽  
pp. 8427-8433 ◽  
Author(s):  
Firoz Shah ◽  
Daniel Schwenk ◽  
César Nicolás ◽  
Per Persson ◽  
Dirk Hoffmeister ◽  
...  
Keyword(s):  
Organic Matter ◽  
Ectomycorrhizal Fungi ◽  
Brown Rot ◽  
Ectomycorrhizal Fungus ◽  
Organic Matter Decomposition ◽  
Mineral Nutrient ◽  
Paxillus Involutus ◽  
Fenton Chemistry ◽  
Content Type

ABSTRACTEctomycorrhizal fungi play a key role in mobilizing nutrients embedded in recalcitrant organic matter complexes, thereby increasing nutrient accessibility to the host plant. Recent studies have shown that during the assimilation of nutrients, the ectomycorrhizal fungusPaxillus involutusdecomposes organic matter using an oxidative mechanism involving Fenton chemistry (Fe2++ H2O2+ H+→ Fe3++ ˙OH + H2O), similar to that of brown rot wood-decaying fungi. In such fungi, secreted metabolites are one of the components that drive one-electron reductions of Fe3+and O2, generating Fenton chemistry reagents. Here we investigated whether such a mechanism is also implemented byP. involutusduring organic matter decomposition. Activity-guided purification was performed to isolate the Fe3+-reducing principle secreted byP. involutusduring growth on a maize compost extract. The Fe3+-reducing activity correlated with the presence of one compound. Mass spectrometry and nuclear magnetic resonance (NMR) identified this compound as the diarylcyclopentenone involutin. A major part of the involutin produced byP. involutusduring organic matter decomposition was secreted into the medium, and the metabolite was not detected when the fungus was grown on a mineral nutrient medium. We also demonstrated that in the presence of H2O2, involutin has the capacity to drive anin vitroFenton reaction via Fe3+reduction. Our results show that the mechanism for the reduction of Fe3+and the generation of hydroxyl radicals via Fenton chemistry by ectomycorrhizal fungi during organic matter decomposition is similar to that employed by the evolutionarily related brown rot saprotrophs during wood decay.

p-Hydroxybenzoylformic acid and (R)-(−)-p-hydroxymandelic acid, two antifungal compounds isolated from the liquid culture of the ectomycorrhizal fungus Pisolithus arhizus

1991 ◽  
Vol 37 (4) ◽  
pp. 258-264 ◽  
Author(s):  
H. H. Kope ◽  
Y. S. Tsantrizos ◽  
J. A. Fortin ◽  
K. K. Ogilvie
Keyword(s):  
Ectomycorrhizal Fungi ◽  
Mandelic Acid ◽  
Liquid Culture ◽  
Fungal Growth ◽  
Hyphal Growth ◽  
Growth Stimulation ◽  
Ectomycorrhizal Fungus ◽  
Antifungal Compounds ◽  
Cell Turgor ◽  
Pisolithus Arhizus

Two antifungal compounds isolated from the liquid culture medium of Pisolithus arhizus were identified as p-hydroxybenzoylformic acid and (R)-(−)-p-hydroxymandelic acid and given the trivial names pisolithin A and pisolithin B, respectively. The efficacy of the compounds to inhibit the germination of conidia of Truncatella hartigii was compared with that of commercially available structural analogues, and a comparable range of effectiveness for 50% germination inhibition (GI50) of conidia was recorded. The commercially available synthetic compounds (R)-mandelic acid, benzoylformic acid, and racemic p-hydroxymandelic acid, had GI50 values of 82, 72, and 59 μg/mL, respectively, as compared with the natural compounds pisolithin A, 67 μg/mL, and pisolithin B, 71 μg/mL. Two synthetic S enantiomers of mandelic acid, (S)-mandelic acid and (S)-(+)-p-hydroxymandelic acid, were the most effective compounds, with GI50 values of 31 and 33 μg/mL, respectively. A sodium salt of mandelic acid had no activity below 500 μg/mL. Pisolithin A and pisolithin B were compared with polyoxin D for inhibition of hyphal growth, as measured by protein estimation. Both pisolithin A and B measured higher levels of putative extractable protein than polyoxin D, but less mycelial wet weight was measured. It is suggested that the pisolithins caused a disruption of cell turgor. A measurement of mycelial dry weights of phytopathogens, incubated with the commercially available analogues, benzoylformic acid and racemic p-hydroxymandelic acid, indicated that benzoylformic acid was either more effective than, or as effective as, racemic p-hydroxymandelic acid or nystatin in arresting fungal growth. For ectomycorrhizal fungi confronted with the pisolithins, both compounds were effective in inhibiting the growth of an equal number of fungi, but benzoylformic acid caused a growth stimulation of some ectomycorrhizal fungi. The result of growth stimulation by the compound is discussed. Key words: Pisolithus, antifungal, ectomycorrhizal, biological control.

Observations of Frozen-Hydrated Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 504-505
Author(s):  
D. Chrétien ◽  
D. Job ◽  
R.H. Wade
Keyword(s):  
Fourier Transforms ◽  
Structural Complexity ◽  
Image Contrast ◽  
Phase Behaviour ◽  
Experimental Conditions ◽  
Thin Sections ◽  
Surface Lattice ◽  
Cilia And Flagella ◽  
Outstanding Question

Microtubules are filamentary structures found in the cytoplasm of eukaryotic cells, where, together with actin and intermediate filaments, they form the components of the cytoskeleton. They have many functions and show various levels of structural complexity as witnessed by the singlet, doublet and triplet structures involved in the architecture of centrioles, basal bodies, cilia and flagella. The accepted microtubule model consists of a 25 nm diameter hollow tube with a wall made up of 13 paraxial protofilaments (pf). Each pf is a string of aligned tubulin dimers. Some results have suggested that the pfs follow a superhelix. To understand how microtubules function in the cell an accurate model of the surface lattice is one of the requirements. For example the 9x2 architecture of the axoneme will depend on the organisation of its component microtubules. We should also note that microtubules with different numbers of pfs have been observed in thin sections of cellular and of in-vitro material. An outstanding question is how does the surface lattice adjust to these different pf numbers?We have been using cryo-electron microscopy of frozen-hydrated samples to study in-vitro assembled microtubules. The experimental conditions are described in detail in this reference. The results obtained in conjunction with thin sections of similar specimens and with axoneme outer doublet fragments have already allowed us to characterise the image contrast of 13, 14 and 15 pf microtubules on the basis of the measured image widths, of the the image contrast symmetry and of the amplitude and phase behaviour along the equator in the computed Fourier transforms. The contrast variations along individual microtubule images can be interpreted in terms of the geometry of the microtubule surface lattice. We can extend these results and make some reasonable predictions about the probable surface lattices in the case of other pf numbers, see Table 1. Figure 1 shows observed images with which these predictions can be compared.

Superoxide, Xanthine Oxidase and Platelet Reactions: Further Studies on Mechanisms by which Oxidants Influence Platelets

1981 ◽  
Vol 45 (03) ◽  
pp. 290-293 ◽  
Author(s):  
Peter H Levine ◽  
Danielle G Sladdin ◽  
Norman I Krinsky
Keyword(s):  
Superoxide Dismutase ◽  
Cytochrome C ◽  
Xanthine Oxidase ◽  
Direct Effect ◽  
Platelet Function ◽  
Experimental Conditions ◽  
Release Reaction

SummaryIn the course of studying the effects on platelets of the oxidant species superoxide (O- 2), Of was generated by the interaction of xanthine oxidase plus xanthine. Surprisingly, gel-filtered platelets, when exposed to xanthine oxidase in the absence of xanthine substrate, were found to generate superoxide (O- 2), as determined by the reduction of added cytochrome c and by the inhibition of this reduction in the presence of superoxide dismutase.In addition to generating Of, the xanthine oxidase-treated platelets display both aggregation and evidence of the release reaction. This xanthine oxidase induced aggreagtion is not inhibited by the addition of either superoxide dismutase or cytochrome c, suggesting that it is due to either a further metabolite of O- 2, or that O- 2 itself exerts no important direct effect on platelet function under these experimental conditions. The ability of Of to modulate platelet reactions in vivo or in vitro remains in doubt, and xanthine oxidase is an unsuitable source of O- 2 in platelet studies because of its own effects on platelets.

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