Effects of Mycorrhizal Fungus Species and Metalaxyl Application on Microbial Suppression of Mycorrhizal Symbiosis

Mycologia ◽  
1991 ◽  
Vol 83 (1) ◽  
pp. 97 ◽  
Author(s):  
B. A. D. Hetrick ◽  
G. W. T. Wilson
Keyword(s):  
Mycorrhizal Fungus ◽  
Mycorrhizal Symbiosis ◽  
Fungus Species ◽  
Microbial Suppression

Some nutritional aspects of the biology of ericaceous mycorrhizas

1985 ◽  
Vol 85 (3-4) ◽  
pp. 317-331 ◽  
Author(s):  
D. J. Read ◽  
R. Bajwa
Keyword(s):  
Amino Acids ◽  
Mycorrhizal Fungus ◽  
Amino Nitrogen ◽  
Nitrogen Sources ◽  
Acid Protease ◽  
Mycorrhizal Symbiosis ◽  
Mycorrhizal Infection ◽  
Plant Nitrogen ◽  
Low Concentrations

SynopsisSome aspects of the role of the ericoid mycorrhizal symbiosis in the ecology and physiology of ericaceous plants are described. Mycorrhizal infection leads to enhancement of plant nitrogen content and an experimental analysis of the basis of this effect is reported. In addition to improving the efficiency of ammonium absorption at low concentrations, the mycorrhizal endophyte utilises amino acids, peptides and proteins as nitrogen substrates for growth. These are the predominant nitrogen sources in organic heathland soil. It is suggested that the success of ericaceous plants in such soils may arise through the capacity of the mycorrhizal fungus to provide its host with access to this nutrient resource. A model is described in which absorption of ammonium and amino nitrogen leads to soil acidification, increased acid protease activity and improved vigour of the ericaceous plants.

scholarly journals Identification of a cDNA from the Arbuscular Mycorrhizal Fungus Glomus intraradices that is Expressed During Mycorrhizal Symbiosis and Up-Regulated by N Fertilization

2002 ◽  
Vol 15 (4) ◽  
pp. 360-367 ◽  
Author(s):  
Juan M. Ruiz-Lozano ◽  
Carlos Collados ◽  
Rosa Porcel ◽  
Rosario Azcón ◽  
JoséM. Barea
Keyword(s):  
Gene Expression ◽  
Gene Product ◽  
Time Course ◽  
Glomus Intraradices ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
N Fertilization ◽  
Mycorrhizal Symbiosis ◽  
Transcript Accumulation ◽  
Reading Frame

A cDNA library was constructed with RNA from Glomus intraradices-colonized lettuce roots and used for differential screening. This allowed the identification of a cDNA (Gi-1) that was expressed only in mycorrhizal roots and was of fungal origin. The function of the gene product is unknown, because Gi-1 contained a complete open reading frame that was predicted to encode a protein of 157 amino acids which only showed little homology with glutamine synthetase from Helicobacter pylori. The time-course analysis of gene expression during the fungal life cycle showed that Gi-1 was expressed only during the mycorrhizal symbiosis and was not detected in dormant or germinating spores of G. intraradices. P fertilization did not significantly change the pattern of Gi-1 expression compared with that in the unfertilized treatment, whereas N fertilization (alone or in combination with P) considerably enhanced the Gi-1 transcript accumulation. This increase in gene expression correlated with plant N status and growth under such conditions. The possible role of the Gi-1 gene product in intermediary N metabolism of arbuscular mycorrhizal symbiosis is further discussed.

scholarly journals Coordinated Changes In The Accumulation Of Metal Ions In Maize (Zea mays ssp. mays L.) In Response To Inoculation With The Arbuscular Mycorrhizal Fungus Funneliformis mosseae

2017 ◽  
Author(s):  
M. Rosario Ramirez-Flores ◽  
Ruben Rellan-Alvarez ◽  
Barbara Wozniak ◽  
Mesfin-Nigussie Gebreselassie ◽  
Iver Jakobsen ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Mycorrhizal Fungus ◽  
Principal Component ◽  
Arbuscular Mycorrhizal ◽  
Mycorrhizal Symbiosis ◽  
Plant Host ◽  
Funneliformis Mosseae ◽  
Maize Varieties ◽  
External Hyphae ◽  
The Impact

AbstractArbuscular mycorrhizal symbiosis is an ancient interaction between plants and fungi of the phylum Glomeromycota. In exchange for photosynthetically fixed carbon, the fungus provides the plant host with greater access to soil nutrients via an extensive network of root-external hyphae. Here, to determine the impact of the symbiosis on the host ionome, the concentration of nineteen elements was determined in the roots and leaves of a panel of thirty maize varieties, grown under phosphorus limiting conditions, with, or without, inoculation with the fungus Funneliformis mosseae. Although the most recognized benefit of the symbiosis to the host plant is greater access to soil phosphorus, the concentration of a number of other elements responded significantly to inoculation across the panel as a whole. In addition, variety-specific effects indicated the importance of plant genotype to the response. Clusters of elements were identified that varied in a coordinated manner across genotypes, and that were maintained between non-inoculated and inoculated plants.AbbreviationsNCnon-colonizedMmycorrhizalSDWshoot dry weightICP-MSinductively coupled plasma mass spectrometryPCprincipal component

scholarly journals Effect of Mycorrhizal Inoculation and Compost Supply on Growth and Nutrient Uptake of Young Leek Plants Grown on Peat-based Substrates

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 628-632 ◽  
Author(s):  
Henrike Perner ◽  
Dietmar Schwarz ◽  
Eckhard George
Keyword(s):  
Plant Growth ◽  
Production Systems ◽  
Mycorrhizal Fungus ◽  
Nutrient Deficiency ◽  
Am Fungi ◽  
Organic Production ◽  
Growth And Yield ◽  
Mycorrhizal Symbiosis ◽  
Test Plant ◽  
Substrate Quality

Organic horticultural production systems often are characterized by the use of beneficial soil microorganisms because the application of soluble inorganic P or N fertilizers is not endorsed. Due to the limited supply of soluble nutrients in organic production systems, nutrient deficiency may limit plant growth and yield. The sole use of peat for pot-based cultures is also discouraged in organic production systems. Therefore, we have studied viable alternatives for highly soluble fertilizers and pure peat substrates using leek [Allium ampeloprasum L. var. Porrum] as a test plant. Plants were grown on peat-based substrates with different rates of compost additions, and with and without inoculation with arbuscular mycorrhizal (AM) fungi. Inoculation with a commercial AM fungus inoculum resulted in colonization rates of up to 70% of total root length, whereas not inoculated plants remained free of root colonization. Mycorrhizal fungus colonization increased shoot Zn and K concentrations, but did not significantly affect shoot dry matter or shoot N and P concentrations. In contrast, compost addition increased plant growth, and also increased P and K concentrations in plants. We conclude that plants with high rates of mycorrhizal colonization can be obtained on peat-based substrates, but that under these conditions plants may not consistently benefit in growth from the mycorrhizal symbiosis. In contrast, additions of compost are a possible means to improve the substrate quality in organic horticultural production.

scholarly journals Phosphorus uptake and toxicity is delimited by mycorrhizal symbiosis in P-sensitive Eucalyptus marginata but not in P-tolerant Acacia celastrifolia

2021 ◽  
Author(s):  
Mark Tibbett ◽  
Matthew I Daws ◽  
Megan H Ryan
Keyword(s):  
Mycorrhizal Fungus ◽  
Phosphorus Uptake ◽  
Arbuscular Mycorrhizal ◽  
Evidence Base ◽  
Dry Mass ◽  
P Uptake ◽  
Mycorrhizal Symbiosis ◽  
Eucalyptus Marginata ◽  
Mycorrhizal Associations ◽  
Leaf P

Many plant species from regions with ancient, highly-weathered nutrient-depleted soils have specialised adaptations for acquiring P and are sensitive to excess P-supply. Mycorrhizal associations may regulate P-uptake at high external P-concentrations, potentially reducing P-toxicity. We predicted that excess P-application will negatively impact species from the nutrient-depleted jarrah forest of Western Australia and that mycorrhizal inoculation will reduce P-toxicity by regulating P-uptake. For seedlings of the N2-fixing legume Acacia celastrifolia and the tree species Eucalyptus marginata, we measured growth at P-concentrations of 0 to 90 mg kg-1 soil and in relation to inoculation with the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis. Non-inoculated A. celastrifolia maintained leaf P-concentrations at <2 mg g-1 dry mass (DM) across the range of external P-concentrations. However, for non-inoculated E. marginata, as external P-concentrations increased leaf P also increased, reaching >9 mg g-1 DM at 30 mg P kg-1 soil. A. celastrifolia DM increased with increasing external P-concentrations, while E. marginata DM was maximal at 15 mg P kg-1 soil, declining at higher external P concentrations. Neither DM nor leaf P of A. celastrifolia were affected by inoculation with AMF. For E. marginata, even at 90 mg P kg-1 soil, inoculation with AMF resulted in leaf P remaining <1 mg g-1 DM, and DM being maintained. These data strengthen the evidence base that AMF may not only facilitate P-uptake at low external P-concentrations, but are also important for moderating P-uptake at elevated external P-concentrations and maintaining plant P concentrations within a relatively narrow concentration range.

scholarly journals Phytohormone production by the arbuscular mycorrhizal fungus Rhizophagus irregularis

2020 ◽  
Author(s):  
Simon Pons ◽  
Sylvie Fournier ◽  
Christian Chervin ◽  
Guillaume Bécard ◽  
Soizic Rochange ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Rhizophagus Irregularis ◽  
Mycorrhizal Symbiosis ◽  
Potential Contribution ◽  
Mutualistic Interaction ◽  
Isopentenyl Adenosine ◽  
Acid Pathway

AbstractArbuscular mycorrhizal symbiosis is a mutualistic interaction between most land plants and fungi of the glomeromycotina subphylum. The initiation, development and regulation of this symbiosis involve numerous signalling events between and within the symbiotic partners. Among other signals, phytohormones are known to play important roles at various stages of the interaction. During presymbiotic steps, plant roots exude strigolactones which stimulate the fungus, and favour the initiation of symbiosis. At later stages, different plant hormone classes can act as positive or negative regulators of the interaction. Although the fungus is known to reciprocally emit regulatory signals, its potential contribution to the phytohormonal pool has received little attention, and has so far only been addressed by indirect assays. In this study, using mass spectrometry, we analyzed phytohormones released into the medium by germinated spores of the arbuscular mycorrhizal fungus Rhizophagus irregularis. We detected the presence of a cytokinin (isopentenyl-adenosine) and an auxin (indole-acetic acid). In addition, we identified a gibberellin (gibberellic acid 4) in spore extracts. We also used gas chromatography to show that R. irregularis produces ethylene from methionine and the α-keto γ-methylthiobutyric acid pathway. These results highlight the possibility for AM fungi to use phytohormones to interact with their host plants, or to regulate their own development.

scholarly journals Mycorrhizal dependency and growth response of Gliricidia sepium (Jacq.) Kunth ex Walp. under saline condition

2017 ◽  
Vol 4 (4) ◽  
pp. 154-160 ◽  
Author(s):  
Bhoopander Giri
Keyword(s):  
Salinity Stress ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Gliricidia Sepium ◽  
Mycorrhizal Symbiosis ◽  
Saline Condition ◽  
Mycorrhizal Dependency ◽  
Mycorrhizal Association ◽  
Significant Difference ◽  
High Degree

In pursuit of salinity-mycorrhiza interaction, a pot experiment was conducted to determine the dependence of Gliricidia sepium on arbuscular mycorrhizal association under salinity stress, which was imposed using different concentrations of sodium chloride solutions. The present study revealed that arbuscular mycorrhizal fungus; Rhizophagus fasciculatus significantly increased growth and biomass of G. sepium plants under saline condition. G. sepium showed a high degree of dependence on mycorrhizal symbiosis under saline as compared to non-saline condition. Under non-saline condition (SS0), G. sepium plants exhibited 23.9% dependence on R. fasciculatus, which increased with increase in the levels of salinity. At SS3 level, G. sepium plants showed 46.6% mycorrhizal dependency followed by SS2 and SS1 levels of salinity. However, there was no significant difference between mycorrhizal dependency of G. sepium at SS1 and SS2 levels of salinity. Improved growth of G. sepium under salinity stress revealed R. fasciculatus a promising inoculant for the reclamation of degraded saline soils.

Identification of a Putative P-Transporter Operon in the Genome of a Burkholderia Strain Living inside the Arbuscular Mycorrhizal Fungus Gigaspora margarita

1999 ◽  
Vol 181 (13) ◽  
pp. 4106-4109 ◽  
Author(s):  
J. M. Ruiz-Lozano ◽  
P. Bonfante
Keyword(s):  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
P Uptake ◽  
Mycorrhizal Symbiosis ◽  
Intracellular Bacteria ◽  
Gigaspora Margarita ◽  
Burkholderia Strain

ABSTRACT This article reports the identification of a putative P-transporter operon in the genome of a Burkholderia sp. living in the cytoplasm of the arbuscular mycorrhizal fungus Gigaspora margarita. Its presence suggests that Burkholderiasp. has the potential for P uptake from this environment. This finding raises new questions concerning the importance of intracellular bacteria for mycorrhizal symbiosis.

Microtubules of the mycorrhizal fungus Glomus intraradices in symbiosis with tomato roots

2001 ◽  
Vol 79 (3) ◽  
pp. 307-313 ◽  
Author(s):  
S Timonen ◽  
F A Smith ◽  
S E Smith
Keyword(s):  
Lycopersicon Esculentum ◽  
Filamentous Fungi ◽  
Glomus Intraradices ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Mycorrhizal Symbiosis ◽  
Tomato Roots ◽  
External Mycelium ◽  
First Time

In this study the presence and orientation of fungal microtubules were recorded in arbuscular mycorrhizal symbiosis for the first time. Visualization of the fungal microtubules was achieved by using a protocol specifically labelling only fungal tubulins. Microtubules of external mycelium, intraradical hyphae, arbuscules, and vesicles of the arbuscular mycorrhizal fungus Glomus intraradices Schenck & Smith were examined when in symbiosis with tomato (Lycopersicon esculentum Mill.). Microtubules were organized as bundles in both external and intraradical hyphae. The bundles of microtubules extended directly from intraradical hyphae into the arbuscules, where the microtubules remained as bundles in the larger hyphae. In the fine fungal branches of the arbuscules, microtubules were seen as thinner filaments. Fungal microtubules were seen to connect the intraradical hyphae and arbuscules. In addition, microtubules of adjacent arbuscules could continue directly from one arbuscule to another. Microtubules reached to the basal cone of each vesicle, but the live vesicles, containing many nuclei, seemed devoid of any microtubular labelling.Key words: cytoskeleton, endomycorrhiza, filamentous fungi, tomato, tubulin, Zygomycota.

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