The significance of grazing on fungi in nutrient cycling

1995 ◽  
Vol 73 (S1) ◽  
pp. 1370-1376 ◽  
Author(s):  
Terence P. McGonigle
Keyword(s):  
Nutrient Cycling ◽  
Mycorrhizal Fungi ◽  
Fold Increase ◽  
Net N Mineralization ◽  
Release Studies ◽  
Mycorrhizal Effectiveness ◽  
Combined Action ◽  
Dominant Process ◽  
Microcosm Studies ◽  
Mycorrhizal Hyphae

Excretion of N by fungal grazers is not the dominant process by which N is released in nutrient cycling: it accounts for one eighth or less of total net N mineralization. Fungivores comprise between 21 and 76% of the fauna biomass. Other fauna, as well as fungi and bacteria, all participate in the mineralization process. Microcosm studies have shown fungal grazing can promote release of N, but immobilization by concomitant microbe production can occur in tandem with that release. Studies using field applications of biocides have had inconsistent outcomes. Fungivores contribute to nutrient cycling by the combined action of comminution, mixing, and dispersal of inoculum, which promote microbial activity. Passage through the Collembola gut has been estimated to have the capacity to bring about a 42-fold increase in nitrate concentration from food to faeces, which on an ecosystem scale could conceivably translate into a doubling of levels of nitrate. Recent laboratory work has shown that fungivores may prefer the thinner mycorrhizal hyphae that occur some distance away from the more coarse mycorrhizal hyphae in the rhizoplane. Where this occurs, grazing can be expected to have only a small impact on the effectiveness of mycorrhizal fungi for the promotion of plant nutrient absorption in the field. Key words: fungivores, fauna, soil, litter, mineralization, mycorrhizal effectiveness.

scholarly journals Effects of selenium (Se) application and arbuscular mycorrhizal (AMF) inoculation on soybean (Glycine max) and forage grass (Urochloa decumbens) development in oxisol

2019 ◽  
Vol 13 ((03) 2019) ◽  
pp. 380-385 ◽  
Author(s):  
Soraya Marx Bamberg ◽  
Silvio Junio Ramos ◽  
Marco Aurelio Carbone Carneiro ◽  
José Oswaldo Siqueira
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Fold Increase ◽  
Tropical Soils ◽  
Fertilizer Application ◽  
Growth And Yield ◽  
Forage Grass ◽  
Urochloa Decumbens ◽  
Soybean Plants ◽  
Amf Inoculation

Fertilizer application can enhance the nutritional value of plants, such effects being influenced by the presence of arbuscular mycorrhizal fungi (AMF). Nutrients × AMF interactions are well-known for variety of elements but very little has been addressed on biofortification of selenium (Se) in plants grown in tropical soils. The purpose of this study was to evaluate the effect of Se application and AMF inoculation on growth and micronutrient contents on soybean plants as forage grass. The experiments were conducted in a completely randomized factorial design with five Se doses (0.0, 0.5, 1.0, 2.0 and 3.0 mg kg-1 for soybean plants, and 0.0, 0.5, 1.0, 3.0 and 6.0 mg kg-1 for forage plants), with and without AMF inoculation in three replicates. The results showed that soil Se had only slight effect on soybean growth but it caused a two-fold increase on grain yield. However, the growth of forage grass was enhanced by Se application when AMF was present. The AMF inoculation reduced benefit for soybean growth and yield but marked positive effect on forage grass at high doses of Se. Selenium contents in both plants were increased by its application in soil, being such effect proportional to soil applied doses. Selenium application and AMF inoculation had marked effects on micronutrients contents in both soybean plants and forage grass and they may contribute to Se and micronutrient biofortification.

Short-term stimulation of the thiazide-sensitive Na+-Cl− cotransporter by vasopressin involves phosphorylation and membrane translocation

2010 ◽  
Vol 298 (3) ◽  
pp. F502-F509 ◽  
Author(s):  
K. Mutig ◽  
T. Saritas ◽  
S. Uchida ◽  
T. Kahl ◽  
T. Borowski ◽  
...  
Keyword(s):  
Fold Increase ◽  
Short Term ◽  
Nephron Segments ◽  
Mediated Effects ◽  
Effector System ◽  
Apical Trafficking ◽  
Fine Regulation ◽  
Combined Action ◽  
Effective Site ◽  
Stimulation Of

Vasopressin influences salt and water transport in renal epithelia. This is coordinated by the combined action of V2 receptor-mediated effects along distinct nephron segments. Modulation of NaCl reabsorption by vasopressin has been established in the loop of Henle, but its role in the distal convoluted tubule (DCT), an effective site for fine regulation of urinary electrolyte composition and the target for thiazide diuretics, is largely unknown. The Na+-Cl− cotransporter (NCC) of DCT is activated by luminal trafficking and phosphorylation at conserved NH2-terminal residues. Here, we demonstrate the effects of short-term vasopressin administration (30 min) on NCC activation in Brattleboro rats with central diabetes insipidus (DI) using the V2 receptor agonist desmopressin (dDAVP). The fraction of NCC abundance in the luminal plasma membrane was significantly increased upon dDAVP as shown by confocal microscopy, immunogold cytochemistry, and Western blot, suggesting increased apical trafficking of the transporter. Changes were paralleled by augmented phosphorylation of NCC as detected by antibodies against phospho-threonine and phospho-serine residues (2.5-fold increase at Thr53 and 1.4-fold increase at Ser71). dDAVP-induced phosphorylation of NCC, studied in tubular suspensions in the absence of systemic effects, was enhanced as well (1.7-fold increase at Ser71), which points to the direct mode of action of vasopressin in DCT. Changes were more pronounced in early (DCT1) than in late DCT as distinguished by the distribution of 11β-hydroxysteroid dehydrogenase 2 in DCT2. These results suggest that the vasopressin-V2 receptor-NCC signaling cascade is a novel effector system to adjust transepithelial NaCl reabsorption in DCT.

Host response to inoculation and behaviour of introduced and indigenous ectomycorrhizal fungi of jack pine grown on oil-sands tailings

1989 ◽  
Vol 19 (11) ◽  
pp. 1412-1421 ◽  
Author(s):  
R. M. Danielson ◽  
S. Visser
Keyword(s):  
Ectomycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Oil Sands ◽  
Host Response ◽  
Fold Increase ◽  
Growing Season ◽  
Jack Pine ◽  
Short Root ◽  
Replacement Process ◽  
Shoot Weight

Pinusbanksiana Lamb, seedlings were inoculated with nine mycorrhizal fungi and outplanted on an oil-sands containment dyke that had been amended with muskeg peat. After one growing season, E-strain (Complexipes), Hebeloma sp., Thelephoraterrestris Ehrh.:Fr., and Laccariaproximo Boudier each formed mycorrhizae with greater than 40% of the new short roots within 10 cm of the stem. Cenococcumgeophilum Fr., Pisolithustinctorius (Pers.) Coker & Couch, Astraeushygrometricus (Pers.) Morgan, Lactariusparadoxus Beardslee & Burlingham, and Sphaerosporellabrunnea (Alb. & Schw.:Fr.) Svrcek & Kubika each formed mycorrhizae with less than 6% of the short roots on egressed laterals. Of the introduced fungi, only E-strain was present in substantial quantities after 3 years. The quantity of short roots converted to mycorrhizae by indigenous fungi was 4, 33, and 72% after 1, 2, and 3 years, respectively. The change in mycorrhizal fungi appeared to be a noncompetitive replacement process, in which the original short root resident fungus died in the near absence of mycorrhizal fungi. At the end of the 3rd year, the major indigenous fungi converting short roots to mycorrhizae were E-strain, Tuber sp., Suillus-like spp., Myceliumradicisatrovirens Melin, and an unidentified basidiomycete. Inoculation with E-strain and Thelephoraterrestris resulted in a 2- to 3-fold increase in shoot weight after 2 years compared with uninoculated seedlings.

scholarly journals Phosphite and mycorrhizal formation in seedlings of three Australian Myrtaceae

2000 ◽  
Vol 48 (6) ◽  
pp. 725 ◽  
Author(s):  
Kay Howard ◽  
Bernie Dell ◽  
Giles E. Hardy
Keyword(s):  
Ectomycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Phytophthora Cinnamomi ◽  
Fold Increase ◽  
Native Plant ◽  
Negative Effects ◽  
Eucalyptus Marginata ◽  
Collar Rot ◽  
The Impact ◽  
Different Levels

Currently in Western Australia, phosphite is being used to contain the root and collar rot pathogen, Phytophthora cinnamomi, in native plant communities. There have been reports of negative effects of phosphite on arbuscular mycorrhiza (AM), so there are concerns that it may have a deleterious effect on other mycorrhizal fungi. Two glasshouse experiments were undertaken to determine the impact of phosphite on eucalypt-associated ectomycorrhizal fungi. In the first experiment, non-mycorrhizal seedlings of Eucalyptus marginata, Eucalyptus globulus and Agonis flexuosa were sprayed to runoff with several concentrations of phosphite, and then planted into soil naturally infested with early colonising mycorrhizal species. Assessments were made of percentage of roots infected with mycorrhizal fungi. There was no significant effect on ectomycorrhizal formation but there was a four-fold increase in AM colonisation of A. flexuosa roots with phosphite application. In the second experiment, E. globulus seedlings mycorrhizal with Pisolithus, Scleroderma and Descolea were treated with different levels of phosphite and infection of new roots by ectomycorrhizal fungi was assessed. There was no significant effect on ectomycorrhizal formation when phosphite was applied at the recommended rate (5 g L–1), while at 10 g L–1 phosphite significantly decreased infection by Descolea.

scholarly journals ARBUSCULAR MYCORRHIZAL FUNGI (AMF) CHARACTERIZATION IN RHIZOSPHERE of Gigantochloa atter

Jurnal BIOTEK ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 22
Author(s):  
Fatimah Mansir ◽  
Hafsan Hafsan ◽  
Eka Sukmawaty ◽  
Masriany Masriany
Keyword(s):  
Mycorrhizal Fungi ◽  
Scientific Information ◽  
Arbuscular Mycorrhizal ◽  
Filter Method ◽  
Root Structure ◽  
Phosphorus Absorption ◽  
Symbiotic Mutualism ◽  
Staining Techniques ◽  
Mycorrhizal Hyphae ◽  
Infection Stage

Mycorrhizae are typical structures found in a plant's root system found symbiotic mutualism between fungi (myces) and roots (rhiza). Mycorrhizae have an essential role for plants because they can increase water and nutrient uptake, especially phosphorus absorption. The purpose of this study was to determine the mycorrhizal genera on the roots of parring bamboo plants (Gigantochloa atter) in Sabantang Hamlet, Toddopulia Village, Tanralili District, Maros Regency because there is no scientific information regarding this issue. This research was conducted with the wet filter method or sieving. The isolation of spores from the rhizosphere of Gigantochloa atter samples was carried out by referring to the pouring method and wet sieving using a stratified filter set. Staining techniques were used to observe the colonization of arbuscular mycorrhizal structures in the roots of the sample plants. The results showed that 27 spores were found, consisting of 15 spores of the Glomus genera, three spores of the Gigaspora genera, and nine Acaulospora genera. Observation of the root structure has not shown the presence of vesicular and arbuscular. However, only hyphae and spore structures were found because the mycorrhizal hyphae in Gigantochloa atter have not yet reached the infection stage to form arbuscular or vesicular structures

Deer browsing effects on temperate forest soil nitrogen cycling shift from positive to negative across fertility gradients

2020 ◽  
Vol 50 (12) ◽  
pp. 1281-1288
Author(s):  
Jacqueline M.A. Popma ◽  
Knute J. Nadelhoffer
Keyword(s):  
Nutrient Cycling ◽  
Forest Soil ◽  
Nutrient Availability ◽  
Soil Nitrogen ◽  
N Mineralization ◽  
Temperate Forest ◽  
Net N Mineralization ◽  
Deer Browsing ◽  
Respiration Rates ◽  
High Nutrient

Herbivores impact soil biogeochemical processes, often increasing nutrient cycling rates under high nutrient availability and decreasing nutrient cycling rates under low nutrient availability. These patterns are far from universal, and interactions between habitat fertility and herbivore effects are under continuing investigation. By sampling inside and outside a network of deer exclosures, we determined deer browsing effects on temperate forest soil nitrogen (N) and carbon (C) cycling along a gradient of soil and litter C–N ratios across our network of sites. Deer browsing increased net N mineralization rates in high nutrient environments and decreased N mineralization rates in low nutrient environments, whereas browsing decreased CO2 respiration rates in high nutrient environments and increased CO2 respiration rates in low nutrient environments. Differences in deer browsing effects on soil processes could be explained by plant responses to herbivory across gradients of resource availability. To our knowledge, our study is one of the first to show that deer browsing can have significant effects on net N mineralization and C respiration in temperate forest soils and that the direction and magnitude of deer browsing effects on soil N and C cycling vary across fertility gradients.

scholarly journals Metatranscriptomic Analysis and In Silico Approach Identified Mycoviruses in the Arbuscular Mycorrhizal Fungus Rhizophagus spp.

Viruses ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 707 ◽  
Author(s):  
Achal Neupane ◽  
Chenchen Feng ◽  
Jiuhuan Feng ◽  
Arjun Kafle ◽  
Heike Bücking ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Mycorrhizal Fungi ◽  
High Efficiency ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Pathogenic Fungi ◽  
P Uptake ◽  
Mitochondrial Translation ◽  
Reverse Transcription Pcr ◽  
Virus Diversity

Arbuscular mycorrhizal fungi (AMF), including Rhizophagus spp., can play important roles in nutrient cycling of the rhizosphere. However, the effect of virus infection on AMF’s role in nutrient cycling cannot be determined without first knowing the diversity of the mycoviruses in AMF. Therefore, in this study, we sequenced the R. irregularis isolate-09 due to its previously demonstrated high efficiency in increasing the N/P uptake of the plant. We identified one novel mitovirus contig of 3685 bp, further confirmed by reverse transcription-PCR. Also, publicly available Rhizophagus spp. RNA-Seq data were analyzed to recover five partial virus sequences from family Narnaviridae, among which four were from R. diaphanum MUCL-43196 and one was from R. irregularis strain-C2 that was similar to members of the Mitovirus genus. These contigs coded genomes larger than the regular mitoviruses infecting pathogenic fungi and can be translated by either a mitochondrial translation code or a cytoplasmic translation code, which was also reported in previously found mitoviruses infecting mycorrhizae. The five newly identified virus sequences are comprised of functionally conserved RdRp motifs and formed two separate subclades with mitoviruses infecting Gigaspora margarita and Rhizophagus clarus, further supporting virus-host co-evolution theory. This study expands our understanding of virus diversity. Even though AMF is notably hard to investigate due to its biotrophic nature, this study demonstrates the utility of whole root metatranscriptome.

scholarly journals Arbuscule Frequency in Grapevine Roots Is More Responsive to Reduction in Photosynthetic Capacity Than to Increased Levels of Shoot Phosphorus

2016 ◽  
Vol 141 (2) ◽  
pp. 151-161 ◽  
Author(s):  
R. Paul Schreiner ◽  
Carolyn F. Scagel
Keyword(s):  
Mycorrhizal Fungi ◽  
Root Colonization ◽  
Photosynthetic Capacity ◽  
Arbuscular Mycorrhizal ◽  
Fold Increase ◽  
Fertilizer Application ◽  
Pinot Noir ◽  
Foliar Fertilizer ◽  
Growth And Nutrition ◽  
Plant Photosynthesis

An interplay between carbon and phosphorus is known to regulate root colonization by arbuscular mycorrhizal fungi (AMF); however, it is unclear whether plant C or plant P status plays a bigger role in controlling the abundance of arbuscules (the primary site of nutrient exchange in AMF symbiosis) in roots. In this study, ‘Pinot noir’ grapevine (Vitis vinifera) was grown in an unsterilized vineyard soil and colonized by indigenous AMF in two experiments, where photosynthetic capacity (defoliation or shading) and shoot nutrition (foliar fertilizer) were manipulated. Temporal changes in root colonization by AMF and plant growth and nutrition were determined. Foliar fertilizer application increased P and K uptake, but reduced Cu uptake in both experiments. Decreasing the photosynthetic capacity of shoots due to defoliation or shading rapidly reduced arbuscules in fine roots (within 7 to 14 days). In contrast a 3-fold increase in shoot P status from foliar fertilizer only reduced arbuscules after a more prolonged time (28 to 56 days). The combination of shading (15% of full sun) and foliar P application reduced arbuscules more than shading alone within the first month, whereas foliar P use in full sun had no influence on arbuscules within a month. Returning plants to full sun after 28 days in shade resulted in a resurgence of arbuscules in roots regardless of plant P status. Arbuscules in grapevine roots are regulated by the interaction between plant C and P status, such that high shoot P reduces arbuscule formation or maintenance more when combined with reduced plant photosynthesis. This indicates that grapevines do not reduce AMF nutrient transfer as an immediate response to elevated shoot P as long as plants are maintained in a high light environment.

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