Glomalin-related Soil Protein Research Articles

模拟氮沉降对杉木丛枝菌根真菌侵染率和球囊霉素的影响

模拟氮沉降对杉木丛枝菌根真菌侵染率和球囊霉素的影响

Soil fungal communities across land use types

Abstract: Land use change is one of the major causes of biodiversity loss, mostly due to habitat change and fragmentation. Belowground fungal diversity is very important in terrestrial ecosystems, however, the effect of land use change on soil fungal community is poorly understood. In this review, a total of 190 studies worldwide were analyzed. To monitor the effect of land use change, different fungal parameters such as richness, diversity, community composition, root colonization by arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi, spore density, ergosterol, and phospholipid fatty acid (PLFA) content and AM fungal glomalin related soil protein (GRSP) were studied. In general, results from analyzed studies often showed a negative response of fungal quantitative parameters after land use change from less-intensive site management to intensive site management. Land use change mostly showed significant shifts in fungal community composition. Considering land use change types, only 18 out of 91 land use change types were included in more than 10 studies, conversion of primary and secondary forest to various, more intensive land use was most often represented. All these 18 types of land use change influenced fungal community composition, however, the effects on quantitative parameters were mostly inconsistent. Current knowledge is not sufficient to conclude general land use impacts on soil fungi as the reviewed studies are fragmented and limited by the local context of land use change. Unification of the methodology, detailed descriptions of environmental factors, more reference sequences in public databases, and especially data on ecology and quantitative parameters of key fungal species would significantly improve the understanding of this issue.

Service crops improve a degraded monoculture system by changing common bean rhizospheric soil microbiota and reducing soil-borne fungal diseases.

Intensive agricultural practices have resulted in progressive soil degradation, with consequences on soil ecosystem services. The inclusion of service crops is a promising alternative to support the sustainability of the agricultural system. The aim of this study was to analyze in a six-year field experiment the effect of Brachiaria brizantha (perennial tropical grass) and Zea mays as service crops in a degraded common bean monoculture system in northwest Argentina. After six years, service crop treatments revealed a significant increase in most physical, chemical and biological properties of the soil (enzyme activities, microbial biomass, respiration and glomalin-related soil protein), compared with common bean monoculture. Also, a lower disease incidence was observed under B. brizantha treatments, associated with increased populations of Trichoderma spp. and Gliocladium spp. The phospholipid fatty acid profiles detected higher values of total microbial biomass under service crops. Our results suggest that the inclusion of several cycles of B. brizantha constitutes a promising soil management for recovering degraded agroecosystems.

Glomalin – Truths, myths, and the future of this elusive soil glycoprotein

The term “Glomalin” was originally used to describe a hypothetical gene product of arbuscular mycorrhizal fungi (AMF) that was assumed to be a nearly ubiquitous, thermostable and highly recalcitrant glycoprotein, deposited in soils in large amounts, and deemed to indicate soil health and quality. It was defined operationally as the fraction of soil organic matter (SOM) extractable by a hot citrate buffer and assessed either by Bradford assay or by cross-reactivity with monoclonal antibody MAb32B11. Later, it was recognized that the extracts contained a variety of compounds, including some of non-AMF origin, cross-reactive with both Bradford assay and the monoclonal antibody. This led to re-describing the pertinent (and still only operationally defined) SOM as “glomalin-related soil proteins (GRSP)”, albeit without any substantial change in the underlying concepts. Consequently, a great deal of confusion in this area arose among researchers in soil, plant, and environmental sciences. Glomalin or GRSP (often used interchangeably) has previously been linked to various soil features, including stability of soil aggregates, size of soil C and N pools, sequestration of heavy metals, and alleviation of various plant stresses. GRSP concentrations in soil often, but not always, have been correlated with AMF biomass measured by alternative (mainly microscopic) approaches. GRSP formation, deposition, and/or decomposition in soils seem to be largely dependent on a multitude of interactions among plants, AMF, and other soil microorganisms, including prokaryotes. The chemical structure of GRSP extracted from soil remains unclear and generally complex. That is due to the unspecific mode of its extraction and purification, as well as the great variety of analytical approaches that have been used heretofore to assess it. Future research needs to elucidate the exact composition of this operationally defined SOM fraction, the controls over its production and accumulation in soils, and its exact role in soil ecology generally and soil food webs in particular. Furthermore, novel and independent tools should be established to more specifically (as compared to current glomalin assays) assess AMF biomass and functioning in roots and soil and its involvement in soil processes.

Effects of five mycorrhizal fungi on biomass and leaf physiological activities of walnut

Arbuscular mycorrhizal fungi (AMF) can benefit many plants, but their effects on walnuts are not yet known. The present study aimed to analyze the effect of five AMF species, namely, Acaulospora scrobiculata, Diversispora spurca, Glomus etunicatum, G. mosseae and G. versiforme on biomass production, chlorophyll contents, sugar fraction contents, and mineral element contents of walnut (Juglans regia L.) seedlings. The five AMF species colonized roots of walnut, established mycorrhizas in roots and hyphae in soil, and released easily extractable glomalin-related soil protein into soil, whilst D. spurca exhibited the best effect. All the AMF inoculations, except A. scrobiculata, stimulated shoot and root biomass production. Mycorrhizal fungal inoculations collectively increased leaf chlorophyll a, chlorophyll b, and total chlorophyll a+b concentrations, and thus promoted leaf sucrose accumulation, which provides an important mycorrhiza-carbon source to roots. AMF inoculations conferred a positive effect on leaf N, P, K, Mg, Fe, B, Zn and Cu contents, while they reduced leaf Mn contents. These results concluded that AMF were beneficial to the growth and physiological activities of walnut, which gives the support for the AMF application in walnut.

An arbuscular mycorrhizal fungus increased the macroaggregate proportion and reduced cadmium leaching from polluted soil

A pot experiment was conducted using maize (Zea mays L.) as the host plant grown in cadmium (Cd)-polluted soil and inoculated with an arbuscular mycorrhizal fungus (AMF), Funneliformis mosseae. The effects of AMF on Cd uptake by maize, water-stable aggregate proportion, Cd concentration in pore water and Cd leaching were investigated. The results showed that AMF significantly promoted maize biomass and Cd uptake in shoots, and increased the content of total and easily extractable glomalin-related soil protein in the 0–40 cm soil layers. Furthermore, AMF increased the proportion of >0.85 mm water-stable aggregates (macroaggregates) by 47–88% and decreased the available Cd content in soil by 20–24%. During the first and second leaching events, AMF significantly decreased the Cd concentration in pore water, and reduced the Cd leaching loss from soil by 12.6% and 19.9%, respectively. Correlation analysis indicated that the macroaggregate proportion was positively correlated with the total and easily extractable glomalin-related soil protein content and negatively correlated with the Cd concentration in pore water, and the Cd concentration in pore water was positively correlated with the Cd leaching loss from soil. Therefore, the AMF-reduced Cd leaching was closely related to the increased macroaggregate proportion in soil. Novelty statement AMF significantly increased the GRSP content and the macroaggregate proportion in soil, which contributed to reducing the Cd concentration in pore water and its leaching loss from soil.

Alteration in the amount of Glomalin in transition from forest to field/meadow

AbstractGlomalin produced by fungal mycelium represents a significant stabilizing element of soil aggregates and a relatively stable carbon reservoir in the soil. The aim of our research was to investigate the changes in the amount of glomalin‐related soil protein (GRSP) associated with the transition from forest to meadow or field conditions at the four transects during the 2016 growing season. The method Near Infrared Spectrometry was applied for measuring the amount of GRSP. The measurements have demonstrated that the amount of GRSP decreased both in the points adjacent to the ecotone in the meadow and the field at the Bukovinka and the Proklest A transects. At the two transects, the changes in the amount of GRSP between the forest, the ecotone and the meadow were statistically insignificant except for the point 4 where more GRSP was found out in the meadow and the ecotone than in the forest.

Carbon sequestration in artificial silicate soils facilitated by arbuscular mycorrhizal fungi and glomalin‐related soil protein

AbstractIn urban areas, pre‐existing concrete‐based demolition wastes and purposely introduced crushed dolerite have been used to create artificial soils, which capture carbon (C) as carbonate minerals and offset greenhouse gas (GHG) emissions. Arbuscular mycorrhizal fungi (AMF) can enhance capture of C in artificial soils through production of glomalin‐related soil protein (GRSP), which facilitates soil organic carbon (SOC) storage and aggregation, and may also enhance precipitation of soil inorganic carbon (SIC). In this paper, we show how different mixtures of dolerite and concrete affect AMF community structure and function, GRSP fractions, and soil organic and inorganic carbon contents. We used nine demonstration plots, 1 m deep, to simulate a constructed urban soil, consisting of different proportions (0, 30, 50, 70 and 100%) of either crushed concrete demolition waste or dolerite quarry fines and sown to a species‐rich meadow mixture, to investigate AMF colonization and community structure (using DNA terminal restriction fragment length polymorphism), contents of easily‐extractable and difficultly‐extractable GRSP, and both organic and inorganic carbon contents. All artificial soils supported functioning AMF communities with different levels of GRSP, SIC and SOC. The 100% dolerite and 100% concrete soils had higher values of difficultly‐to‐extract GRSP andSOC than pure sand, whereas 100% concrete had higher AMF colonization and SOC than sand. AMF community analysis indicated that high GRSP producing species were abundant in 100% dolerite and 100% concrete. These findings demonstrate that there is potential to incorporate demolition waste or dolerite products into the land to support environmental sustainability and enhance soil C sequestration.Highlights In constructed soils, crushed concrete and dolerite more effectively enhance GRSP and soil organic and inorganic carbon contents than sand. Use of crushed concrete and dolerite in plant‐growing substrates is a novel way to combat climate change.

High rates of agricultural gypsum affect the arbuscular mycorrhiza fungal community and coffee yield

ABSTRACT High rates of agricultural gypsum, above the recommended levels, have been used on a regular basis to deepen plant roots and to alleviate recurrent water stress in Cerrado areas. However, very little is known about the consequences of this practice to arbuscular mycorrhizal fungi (AMF). Therefore, the objective of this study was to evaluate whether or not applying high rates of agricultural gypsum affects the mycorrhizal fungi community, glomalin content and coffee yield. The study rates were: 0; 3.5; 7.0; 14 and 56 t·ha-1 of agricultural gypsum applied in the planting row of the coffee plantation on top of the previous recommended gypsum application. Samples were collected for analysis at the depths of 0-20, 20-40 and 40-60 cm at the end of dry and rainy seasons of the year. In the coffee plantation, 16 AMF species were identified. Gigaspora sp. and Glomus macrocarpum were dominant in all situations. The rate of 7 t·ha-1 favored greater diversity of AMF species and the rate of 56 t·ha-1 reduced AMF diversity and mycorrhizal colonization in deeper layers. In the rainy season, there was a linear decrease of easily extractable glomalin-related soil protein (EE-GRSP) levels as the agricultural gypsum rate was increased. Coffee yield was reduced with the highest gypsum rate (56 t·ha-1), even though the coffee plantation had higher phosphorus contents in beans and leaves. This may have resulted from a number of reasons, including a negative effect on the AMF community.

Soil aggregates, aggregate-associated carbon and nitrogen, and water retention as influenced by short and long-term no-till systems

No-till (NT) management can improve soil aggregate formation and stability, porosity, and organic carbon (SOC) through the addition of crop residues and less soil disturbance. However, conventional-till (CT) can deteriorate soil structure and cause loss of SOC. This study aimed to quantify the impacts of long-term (NTL) and short-term NT (NTS) on changes in soil aggregate stability, aggregates associated SOC and total nitrogen (TN), bulk density (ρb), glomalin related soil protein (GRSP), pore-size distribution, and water retention compared to the long-term CT treatment at three different locations (Garretson, Crooks, and Beresford). The treatments included: CT (>20 years), NTS (<7 years), and NTL (>25 years). The mean weight diameter, geometric mean diameter, and wet aggregate stability of NTL were greater than the CT at Garretson and Crooks. Long-term NT had a significantly higher concentration and preservation capacity of SOC under different aggregate fractions than the CT treatment. The NT reduced soil ρb compared to the CT treatment at all the three sites for 0−10 cm depth. At Crooks and Beresford, the SOC was 33.3 and 13.7 % higher under NTS compared to that under CT, respectively, at 0−10 cm depth. The GRSP content in bulk soil was significantly higher under NTL and NTS treatments compared to that under CT at Garretson and Crooks. At saturation (0 kPa), the NTL had significantly higher (p < 0.05) soil water retention compared to the CT at all three sites. The NTL increased the proportion of coarse and fine mesopores and had a significantly higher proportion of >4, 2, and 1 mm aggregates than the CT at Crooks and Beresford. These results demonstrate the short- and long-term beneficial effects of the NT treatment on soil water retention and physical quality compared to the CT treatment.

The Effect of Organic and Conventional Farming Systems with Different Tillage on Soil Properties and Enzymatic Activity

The chemical properties and enzymatic activity of the surface soil horizon were compared between an organic farm (OF) (crop rotation with legume plants, fertilisation with manure) and a conventional farm (CF) (simplified crop rotation, mineral fertilisation, chemical crop protection products). In the years 2001-2017 on the OF (near the village of Juchowo, northern Poland), a reduced tillage system (ploughless) was used, while plough cultivation was used on a CF located in its immediate vicinity. The parameters used to assess the properties of soils were: particle size composition, pH, total organic carbon (TOC) and total nitrogen (TN), dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). The activity of dehydrogenases (DEH), catalase (CAT), alkaline phosphatase (AlP) and acid phosphatase (AcP) and the content of easily extractable glomalin-related soil protein (EEGRSP) were also determined. Sixteen years of soil use in accordance with ecological principles significantly increased the average content of TOC, NT, DOC and DON. Soil samples rich in TOC and DOC showed significantly higher DEH and AcP activity, and EEGRSP content. Statistical analysis showed that the activity of DEH, AlP and CAT in the soil was significantly higher for the OF than for the conventional cultivation system. Limiting soil cultivation procedures on the OF improved the balance of soil organic matter (SOM) and pH value, and significantly increased the content of EEGRSP as compared to the cultivation system used on the CF.

Potential role of common mycorrhizal networks in improving plant growth and soil physicochemical properties under varying nitrogen levels in a grassland ecosystem

Majority of plants are linked below-ground through common mycorrhizal networks (CMNs). The formation of CMNs between the roots of conspecific and heterospecific plant individuals influences the distribution of limiting nutrients, e.g., nitrogen (N) among the interconnected plants. In various ecosystems, the availability of N is being increased substantially; however, the effect of elevated N on the existence and functionality of CMNs in semi-arid regions of Inner Mongolia remains largely unexplored. Therefore, to verify the development of CMNs and their functionality under increasing N concentration, we incorporated different levels of N fertilizer, i.e., N0 = 0, N1 = 7.06, N2 = 14.12, and N3 = 21.18 mg kg−1, and established Leymus chinensis (L. chinensis) as a donor and the recipient plant in a specially designed portioned root-box. For the establishment of CMNs among the plants, compartments were separated via 37 μm mesh. The 15N isotope tracer technique and microscopic analysis evidenced the presence of CMNs because the extraradical hyphae originated from the donor side and crossed 37 μm mesh of the recipient plant compartment. The 15N recovery was highest at N1 in the donor (18.38%) and recipient (7.89%) plants, while the average transfer rate of 15N to recipient plant was 21–65% with a maximum transfer rate at N2 treatment. The establishment of CMNs significantly improved the donor and recipient plants chlorophyll contents and plant biomass at low N levels. Moreover, the AM fungal extraradical hyphae also released a special kind of protein called glomalin-related soil proteins (GRSPs) that improved the soil structure in terms of mean weight diameter (MWD), thereby improving the soil organic carbon (SOC). Interestingly, the mycorrhizal network had a more profound impact on its neighboring plants than the host plant. In short, the present investigation emphasizes the presence of CMNs in the typical steppe of Inner Mongolia with vital roles in nutrient transfer and improvement of plant growth and soil properties.

Physicochemical and Enzymatic Soil Properties Influenced by Cropping of Primary Wheat under Organic and Conventional Farming Systems

The aim of the study was to assess the content of total organic carbon (TOC), macronutrients (P, K, and Mg), and glomalin (easily extractable glomalin-related soil protein (EEGRSP)) in soil, micronutrients (Zn and Cu) in soil and wheat, and the number of insects on plots in an organic (OF) and a conventional farming (CF) system, all against the background of alkaline phosphatase (AlP) and acid phosphatase (AcP) activity. The experimental design included two spring wheat species, Triticum sphaerococcum Percival and Triticum persicum Vavilov, and three sowing densities (grains m−2): 400, 500, 600. Statistical analysis (ANOVA, η2 effect size) showed significant variation in parameters under the influence of experimental factors. In the duration of the field experiment, TOC content in soil had decreased by 61% compared to the content before starting the experiment. The contents of P, K, and Mg and activity of AlP and AcP were higher in soil under T. sphaerococcum. With a sowing density of 600 grains m−2 under OF and CF, the significantly lowest macronutrient content and the highest AlP and AcP activity were found. The parameters tested (TOC, EEGRSP, P, K, Mg, TZn, TCu, AZn, CU in plant, AlP, AcP) were higher under the CF than under the OF system. The experimental factors (spring wheat species and number of germinating grains) were demonstrated to influence the content of the forms of both microelements in soil and plants. In CF, more content in the amount of Zn and Cu was found than in OF. But the content they had did not exceed the standards set for arable soils. Both wheat species had a significant impact on the concentration of glomalin in the soil from the fields cultivated in the OF system. In CF, a significant difference was caused by sowing density and by interaction between wheat species and sowing density. Insects preferred plants grown in the OF system compared to CF. Regardless of cultivation system, the number of insects was greater on the plots of T. sphaerococcum than on plots of T. persicum. There were more insects at higher sowing densities in plants grown in the OF system only.

Glomalin contribution to soil organic carbon under different pasture managements in a saline soil environment

ABSTRACT The glomalin produced by arbuscular mycorrhizal fungi has beneficial effects on soils. We studied the vertical profile of glomalin-related soil protein (GRSP) in pasturelands grown under saline soils and exposed to different management practices. Treatments included haying and grazing of Chloris gayana subject to either N-fertilization or not. We measured mycorrhizal colonization, spores, root biomass, total GRSP, GRSP-carbon (GRSP-C), organic carbon (OC) and total nitrogen (TN). In the meanwhile, we also developed a mathematical procedure to fit continuous power functions to binned soil data. Power decay functions adjusted excellently well the measured data across the 1-meter soil profile. Meaningful increases of root biomass, OC, TN, GRSP and GRSP-C values were associated with grazing and fertilization. Particularly, GRSP-C averaged 1,134 kg C ha−1 at the beginning experiments and increased significantly up to 1,261 kg C ha−1 in grazed and fertilized pastures at the end of the study period. Carbon accounted for between 17% and 50% of GRSP, representing in turn 0.52–1.62% of SOC stock. So, a tropical perennial grass can contribute to the carbon stock in saline soils by promoting production of GRSP. This contribution increases when inputs and cycling of nutrients are enhanced (grazing and N-fertilization).

Effects of Arbuscular Mycorrhizal Fungi on Growth and Physiological Performance of Catalpa bungei C.A.Mey. under Drought Stress

Catalpa bungei C.A.Mey. is a common ornamental timber species. Its survival and growth are greatly affected by water scarcity in arid and semi-arid areas of Northwest China. Evidence suggests arbuscular mycorrhizal fungus (AMF) may improve plant drought resistance. However, there is limited information on the systematic effects of AMF on drought resistance in C. bungei seedlings. Here, a pot experiment was used to explore the effects of inoculation with the AMF Rhizophagus intraradices on the growth and physiological performance of C. bungei under different water treatment conditions. Three water levels and two mycorrhizal inoculation treatments were used with factorial design. The results showed that drought stress noticeably affected the growth and physiological performance of C. bungei seedlings. However, inoculation with R. intraradices significantly ameliorated the growth, and alleviated the effects of drought stress. The growth parameters of AMF-inoculated seedlings significantly increased regardless of water status. AMF changed the biomass allocation in seedlings by reducing the root mass ratio (RMR) and root/shoot ratio. AMF-inoculated seedlings displayed higher gas exchange parameters, photosynthetic pigment concentrations, specific leaf area (SLA), but lower specific leaf weight (SLW), regardless of water status. AMF alleviated drought-induced oxidative stress by attenuating the excess generation of reactive oxygen species (ROS), especially H2O2 and O2−, in leaves. Inoculation with AMF under drought stress also dramatically augmented indole-3-acetic acid (IAA) and gibberellins (GA3) levels and the IAA/abscisic acid (ABA) and GA3/ABA ratios, but reduced ABA and zeatin (ZT) levels in leaves. AMF symbiosis improved root morphology and promoted the absorption of nitrogen (N) and phosphorus (P) in seedlings. We conclude that inoculation with R. intraradices is potentially useful for afforestation and cultivation of C. bungei in Northwest China. Furthermore, AMF improved soil structure by increasing the glomalin-related soil protein (GRSP) contents and the proportion of macro-aggregates (0.25–0.5 mm) in the rhizosphere soil.

Fungal Community, Metabolic Diversity, and Glomalin-Related Soil Proteins (GRSP) Content in Soil Contaminated With Crude Oil After Long-Term Natural Bioremediation.

Fungi have increased tolerance to environmental stress (also related to the access of pollutants, e.g., trace elements and polycyclic aromatic hydrocarbons PAHs). The aim of the study was to evaluate the mycobiome and functional diversity of fungi in long-term crude-oil contaminated soils as the potential bioremediators of oil contaminated sites. Samples were taken from three historical oil wells (over a century old) at two distances: within a 0.5 m radius of the oil wells (OWP1, OWP2, and OWP3) and within a 3 m radius from the oil wells as the controls (OW1, OW2, and OW3). Next generation sequencing (for the ITS region) was accompanied with determination of the functional fungal community based on Biolog FFPlates, glomalin related soil protein (GRSP) content, trace element and PAHs concentration. The research hypothesis assumed that long-term natural bioremediation of crude oil contaminated soils can contribute to intensive development of a unique fungal community adapted to the contamination conditions. The identification of such fungi can be of particular importance in soil bioremediation. There were significant differences in the fungal community and functional diversity between the soil samples. The soils collected directly from the oil wells were characterized by higher biological activity and higher diversity of PAH-degrading fungal candidates compared to the soils collected within 3 m of the oil wells. The total glomalin-related soil proteins (T-GRSP) and easily-extractable glomalin-related soil proteins (EE-GRSP) contents were lower in soil samples taken directly from the crude oil well. The control soil (OW) subjected to a long-term natural remediation may already have sufficient conditions for the growth and development of mycorrhizal fungi. The mycobiome of the soils collected directly from the oil wells (OWP1, OWP2, and OWP3) was characterized by a 35% share of PAH-degrading candidates, compared to the soil collected at the 3 m distance from the oil wells (OW1, OW2, and OW3) at < 5%. The main PAH-degrading fungal candidates belong to genera Ilyonectria, Chaetomium, Gibberella, Paraphoma, Schizothecium, Pseudorobillarda, Tetracladium, Ganoderma, Cadophora, Exophiala, Knufia, Mycoleptodiscus, Cyphellophora, Fusicolla, Devriesia, Didymella, Plenodomus, Pyrenochaetopsis, Symbiotaphrina, Phallus, Coprinellus, Plectosphaerella, Septoriella, and Hypholoma. The share of three- and four-ringed PAHs in soil was higher as the distance from the oil well increased. These results may indicate that more effective degradation processes occur closer to the oil wells.

Arbuscular mycorrhizal fungal diversity in soils underlying moss biocrusts in coal mining subsidence areas.

The potentially symbiotic mycorrhizal associations dominated by arbuscular mycorrhizal (AM) fungi have become a new topic in bioremediation research in response to global change. Biological soil crusts (biocrusts) play an important role in arid and semi-arid ecosystems. However, AM fungal diversity in the soils underlying moss biocrusts in coal mining subsidence areas remains poorly understood. Here, samples of the soil underlying moss biocrusts in an area inoculated with an AM fungus (AM-BS) and an uninoculated area (CK-BS) plus soil samples from an uninoculated bare area (CK-NBS) were collected from the subsidence area of Shendong Daliuta mine at Yulin, northwest China. AM fungal community diversity indices were maximum in AM-BS, intermediate in CK-BS, and minimum in CK-NBS (P < 0.05). In addition, redundancy analysis (RDA) indicates that the importance of moss biocrust to soil properties followed the sequence: soil water content (SWC) > glomalin-related soil protein (TG) > available phosphorus (Olsen-P) > soil organic matter (SOM) > easily extractable glomalin-related soil protein (EEG) > pH > available nitrogen (alkali-N). SWC, alkali-N, Olsen-P, and SOM were significantly related to the abundance of Glomus and Claroideoglomus, and TG, EEG, and pH were positively related to Diversisipora. In summary, inoculation with the exotic AM fungus and moss biocrust cover created a eutrophic microhabitat for AM fungi in the soils underlying moss biocrusts in the coal mining subsidence area.

Molecular dynamics simulation of homology modeled glomalin related soil protein (Rhizophagus irregularis) complexed with soil organic matter model

Glomalin related soil protein produced by mycorrhizal fungus such as Rhizophagus irregularis (GiHsp60) has been termed as a miracle protein for soil sustainability. In this study we propose an integrative in silico approach to explain the mode of interaction between GiHsp60 and the soil organic matter (SOM). In the first step of the study, the three-dimensional (3D) structure of GiHsp60 was constructed using the SWISS-MODEL server; while in the second step, the SOM model was optimized using the Gaussian program, followed by docking-molecular dynamics simulation studies to investigate the stability and interactions of GiHsp60_SOM complex, using Dock and Amber packages respectively. The quality of the modeled 3D structure of GiHsp60 was reasonably good based on reports generated by different validation servers. The docking results suggested that both Van der Waals (grid_vdw = −34.73 kcal mol−1) and electrostatic interactions (grid_es = −3.28 kcal mol−1) were responsible for the interaction between the protein and the ligand. Molecular dynamics simulation was used to compute the free energy of binding of GiHsp60_SOM complex under explicit conditions. The study further revealed that H-bonding, electrostatic, and Van der Waals forces, followed by hydrophilic and hydrophobic interactions were the forces responsible for the binding of GiHsp60 with SOM. The present investigation is perhaps a benchmark study, which explains the interaction between GiHsp60 and SOM at the molecular level using computational approach. Results from this study can enable agriculture molecular biologists in their efforts to explore GiHsp60 as a potential soil conditioner, which in turn will lead ways to enhance inputs for sustainable agricultural systems and boost agricultural productivity.

Long-term effects of organic manure and inorganic fertilization on biological soil quality indicators of soybean-wheat rotation in the Indian mid-Himalaya

A field experiment was accompanied to scrutinize the effect of long-term (21-year) mineral and organic manure fertilizer treatments on carbon mineralization, glomalin related soil protein and some microbial characteristics of arable soils in Indian mid-Himalaya. The experiment was initiated in 1995 includes six treatments: Control, N 120, NPK, FYM, N + FYM and NPK + FYM. Long-term chemical fertilization has been reported to negative effects on soil biological properties, however, the impact of combined use of organic and inorganic fertilization on soil biological properties and its relationship remains poorly understood. Results showed that integrated use of organic and inorganic (NPK + FYM) for 21 years significantly increased in carbon mineralization, easily extractable glomalin related soil protein (EEGRSP) and total glomalin related soil protein (TGRSP). Soil microbial indices (microbial quotient: qMIC, microbial metabolic quotient: qCO2 and metabolic potential: MP) were enhanced in the NPK + FYM treatment as compared to rest of the treatments. The activities of seven enzymes, viz. dehydrogenase (DHA), β-glucosidase (β-GA), invertase (IA), acid phosphatase (Acid-PA), alkaline phosphatase (Alkaline-PA), arylsulphatase (ASA) and urease activity (UA) were significantly influenced by the application of NPK + FYM as compared rest of treatments. Soil fertilization with NPK and FYM was significantly higher fluorescein diacetate assay (FDA) activity as compared to other treatments. Soil microbial properties had strong positive correlation with qMIC, microbial biomass carbon (MBC) and soil organic carbon (SOC), while qCO2 had negative correlation under both soil layers. Results showed that the 21-year fertilization experiment clearly indicated that NPK + FYM embodied the best management practice (BMPs) for soil biological sustainability and for sustainable food production.

Relative roles of Arbuscular Mycorrhizae in establishing a correlation between soil properties, carbohydrate utilization and yield in Cicer arietinum L. under As stress

Accumulation of As (metalloid) degrades soil by negatively affecting the activities of soil enzymes, which in turn reduce growth and yield of the inhabiting plant. Arbuscular mycorrhizal (AM) symbiosis can impart metalloid tolerance in plants by secreting glomalin-related soil protein (GRSP) which binds with As or inertly adsorb in the extraradical mycelial surface. However, profitable use of AM requires selection of the most efficient combination of host plant and fungal species. The current study, therefore designed to study the efficacy of 3 a.m. fungal species: Rhizoglomus intraradices (Ri), Funneliformis mosseae (Fm) and Claroideoglomus claroideum (Cc) in imparting arsenate As(V) and arsenite As(III) stress tolerance in Cicer arietinum (chickpea) genotypes (G) – relatively metalloid tolerant- HC 3 and sensitive- C 235. Roots were found to be more severly affected as compared to shoots which resulted into a major decline in uptake of nutrients, chlorophyll concentrations and yield with As(III) inducing more toxic effects than As(V). HC 3 established more effective mycorrhizal symbiosis and was able to extract higher nutrients from the soil than C 235. Ri was most beneficial in improving plant biomass, carbohydrate utilization and productivity followed by Fm and Cc which could be due to its capability to initiate highest percent colonization and least metalloid uptake in roots through higher glomalin production in the soil. Moreover, Ri was highly efficient in improving soil enzymes activities-phosphatases (PHAs), β-glucosidase (BGA) and invertase (INV), thereby, imparting metalloid tolerance in chickpea genotypes. The results suggested use of Ri-chickpea symbiosis as a promising strategy for ameliorating As stress in chickpea.