Impacts of Urbanization Undermine Nestedness of the Plant–Arbuscular Mycorrhizal Fungal Network

Cities are prone to ecological problems, yet the impacts of rapid global urbanization on the feedback between above- and belowground subsystems remain largely unknown. We sampled the roots of 8 common herbaceous plants within the Fifth Ring (urban areas) and in Jiufeng National Forest Park (rural areas) in Beijing (China) to assess the impacts of urbanization on the network of plant-arbuscular mycorrhizal (AM) fungal associations. Using Illumina MiSeq sequencing, 81 AM fungal OTUs were identified in 78 herb root samples. The Shannon, Simpson, and Pielou indices of root AM fungi in urban areas were significantly higher than those in rural areas. In this study, a significantly nested mycorrhizal association network was observed in rural areas (NODF = 64.68), whereas a non-nested pattern was observed in urban areas (NODF = 55.50). The competition index C-score (0.0769) of AM fungi in urban areas was slightly lower than that in rural areas (0.1431), and the species specialization (d’) of 8 host plants and fungal dissimilarity among 8 host plants in urban areas were significantly lower than those in rural areas. Convergent associations among hosts may be an important factor influencing this non-nested pattern of the plant-AM fungi network in urban areas. Generalists, rather than specialists, were enhanced during the establishment of mycorrhizal associations in urban areas. Our results suggest that reduced selectivity of host plants, and generalist promotion and specialist reduction of AM fungi during urbanization may contribute to the non-nested network of plant-AM fungal associations.

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Nitrogen Fertilisation Increases Specific Root Respiration in Ectomycorrhizal but Not in Arbuscular Mycorrhizal Plants: A Meta-Analysis

Frontiers in Plant Science ◽

10.3389/fpls.2021.711720 ◽

2021 ◽

Vol 12 ◽

Author(s):

Bahareh Bicharanloo ◽

Timothy R. Cavagnaro ◽

Claudia Keitel ◽

Feike A. Dijkstra

Keyword(s):

Root Respiration ◽

Meta Analysis ◽

Soil Nutrient ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

P Uptake ◽

N Availability ◽

Mycorrhizal Associations ◽

Mycorrhizal Association ◽

Multi Level

Plants spend a high proportion of their photosynthetically fixed carbon (C) belowground to support mycorrhizal associations in return for nutrients, but this C expenditure may decrease with increased soil nutrient availability. In this study, we assessed how the effects of nitrogen (N) fertiliser on specific root respiration (SRR) varied among mycorrhizal type (Myco type). We conducted a multi-level meta-analysis across 1,600 observations from 32 publications. SRR increased in ectomycorrhizal (ECM) plants with more than 100 kg N ha−1 applied, did not change in arbuscular mycorrhizal (AM) and non-mycorrhizal (NM) plants, but increased in plants with a dual mycorrhizal association in response to N fertilisation. Our results suggest that high N availability (>100 kg N ha−1) could disadvantage the growth of ECM plants because of increased C costs associated with maintaining higher root N concentrations, while the insensitivity in SRR by AM plants to N fertilisation may be because AM fungi are more important for phosphorus (P) uptake.

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Arbuscular Mycorrhizal Fungal Communities in the Soils of Desert Habitats

Microorganisms ◽

10.3390/microorganisms9020229 ◽

2021 ◽

Vol 9 (2) ◽

pp. 229

Author(s):

Martti Vasar ◽

John Davison ◽

Siim-Kaarel Sepp ◽

Maarja Öpik ◽

Mari Moora ◽

...

Keyword(s):

Plant Root ◽

Significant Proportion ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Illumina Miseq ◽

Desert Ecosystems ◽

Fungal Dna ◽

Root Symbionts ◽

Arbuscular Mycorrhizal Fungal

Deserts cover a significant proportion of the Earth’s surface and continue to expand as a consequence of climate change. Mutualistic arbuscular mycorrhizal (AM) fungi are functionally important plant root symbionts, and may be particularly important in drought stressed systems such as deserts. Here we provide a first molecular characterization of the AM fungi occurring in several desert ecosystems worldwide. We sequenced AM fungal DNA from soil samples collected from deserts in six different regions of the globe using the primer pair WANDA-AML2 with Illumina MiSeq. We recorded altogether 50 AM fungal phylotypes. Glomeraceae was the most common family, while Claroideoglomeraceae, Diversisporaceae and Acaulosporaceae were represented with lower frequency and abundance. The most diverse site, with 35 virtual taxa (VT), was in the Israeli Negev desert. Sites representing harsh conditions yielded relatively few reads and low richness estimates, for example, a Saudi Arabian desert site where only three Diversispora VT were recorded. The AM fungal taxa recorded in the desert soils are mostly geographically and ecologically widespread. However, in four sites out of six, communities comprised more desert-affiliated taxa (according to the MaarjAM database) than expected at random. AM fungal VT present in samples were phylogenetically clustered compared with the global taxon pool, suggesting that nonrandom assembly processes, notably habitat filtering, may have shaped desert fungal assemblages.

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Mycorrhizal association and influence on growth of Asian pigeonwings (Clitoria ternatea L.)

International Journal of Bioassays ◽

10.21746/ijbio.2017.06.006 ◽

2017 ◽

Vol 6 (06) ◽

pp. 5415

Author(s):

Mane S. R. ◽

Kumbhar V. R. ◽

Birajdar G. M. ◽

Naryankar R. S. ◽

Gavali M. T. ◽

...

Keyword(s):

Root Colonization ◽

Biomass Productivity ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Spore Density ◽

Clitoria Ternatea ◽

Treated Condition ◽

Mycorrhizal Association ◽

Maximum Root ◽

Herbal Medicinal

Clitoria ternatea L. is an excellent herbal medicinal plant. Arbusular Mycorrhizal fungal (AMF) colonization and biomass of three different tested conditions of Clitoria ternatea plant was investigated. Inoculums of indigenous AMF and Trichoderma harzianum was tested greenhouse experiment and compared with natural condition after 60th days of treatment. Percentage of Arbuscular mycorrhizal (AM) infection, number of resting spores and AM fungi species varies in different land. Among three different conditions, natural conditions showed maximum root colonization (75.89%) than treated one but minimum spore density (358.8/100gsoil). Highest spore density (481.6/100g soil) was found in T. harzianum treated condition followed by indigenous AMF treatment Acaulospora Glomus and Sclerocystis these three genera were found frequently. AMF inoculums and T.harzianum treatments conditions were observed promising biomass data of 60th days after treatment (DAT).When AMF are more colonized to plants then enhanced the biomass productivity.

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Effect of Biochar Amendments on Mycorrhizal Associations and Fusarium Crown and Root Rot of Asparagus in Replant Soils

Plant Disease ◽

10.1094/pdis-10-10-0741 ◽

2011 ◽

Vol 95 (8) ◽

pp. 960-966 ◽

Cited By ~ 114

Author(s):

Wade H. Elmer ◽

Joseph J. Pignatello

Keyword(s):

Root Rot ◽

Root Colonization ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

First Year ◽

Root Weight ◽

Fusarium Spp ◽

Biomass Waste ◽

Mycorrhizal Associations ◽

Crown And Root Rot

Pyrolyzed biomass waste, commonly called biochar, has attracted interest as a soil amendment. A commercial prototype biochar produced by fast pyrolysis of hardwood dust was examined in soils to determine if it could reduce the damaging effect of allelopathy on arbuscular mycorrhizal (AM) root colonization and on Fusarium crown and root rot of asparagus. In greenhouse studies, biochar added at 1.5 and 3.0% (wt/wt) to asparagus field soil caused proportional increases in root weights and linear reductions in the percentage of root lesions caused by Fusarium oxysporum f. sp. asparagi and F. proliferatum compared with a control. Concomitant with these effects was a 100% increase in root colonization by AM fungi at the 3.0% rate. Addition of aromatic acids (cinnamic, coumaric, and ferulic) that are known allelopathic agents affecting asparagus reduced AM colonization but the deleterious effects were not observed following the application of biochar at the higher rate. When dried, ground, asparagus root and crown tissues infested with Fusarium spp. were added to soilless potting mix at 0, 1, or 5 g/liter of potting mix and then planted with asparagus, there was a decrease in asparagus root weight and increase in disease at 1 g/liter of potting mix but results were inconsistent at the higher residue rate. However, when biochar was added at 35 g/liter of potting mix (roughly 10%, vol/vol), these adverse effects on root weight and disease were equal to the nontreated controls. A small demonstration was conducted in field microplots. Those plots amended with biochar (3.5% [wt/wt] soil) produced asparagus plants with more AM colonization in the first year of growth but, in the subsequent year, biochar-treated plants were reduced in size, possibly due to greater than average precipitation and the ability of biochar to retain moisture that, in turn, may have created conditions conducive to root rot. These studies provide evidence that biochar may be useful in overcoming the deleterious effects of allelopathic residues in replant soils on asparagus.

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Arbuscular mycorrhiza and dark septate endophyte fungal associations of Oryza sativa L. under field condition: colonization features and their occurrence

Plant Science Today ◽

10.14719/pst.2019.6.1.474 ◽

2019 ◽

Vol 6 (1) ◽

pp. 63-70

Author(s):

Kripamoy Chakraborty ◽

Subam Banik ◽

Atithi Debnath ◽

Aparajita Roy Das ◽

Ajay Krishna Saha ◽

...

Keyword(s):

Oryza Sativa L ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Fungal Species ◽

Chemical Fertilizers ◽

Dark Septate Endophyte ◽

Root Cortex ◽

The Third ◽

Fungal Associations ◽

Local Farmers

The present study was aimed to study monthly colonization of arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal associations in rice. The presence of mycorrhizal structures in the roots confirms the colonization by AM fungi. The pattern of hyphae and arbuscules denotes Arum type of AM fungal morphology. The presence of dark coloured septate hyphae running frequently on the epidermal layer and in root cortex and the occurrence of microsclerotia marks the colonization by DSE fungi. The co-occurrence of both AM and DSE fungi ensure dual colonization by two distinct fungal groups. There was significant increase in arbuscules, vesicles and hyphal percentages from first to third month in both the samples collected from two sites. In the third month, AM colonization significantly higher in both the sites. DSE colonization percentages do not differ significantly in first to third month. A total of nine AM fungal species were recovered from two sites. This study is an effort to make aware the local farmers about the usefulness of these native AM mycobiota which can be a preferable choice over chemical fertilizers leading to ecofriendly organic farming.

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Illumina-based identification of arbuscular mycorrhizal fungi from Karachay-Cherkessia soils for development of bio-fertilizers

E3S Web of Conferences ◽

10.1051/e3sconf/202128503001 ◽

2021 ◽

Vol 285 ◽

pp. 03001

Author(s):

Andrey Yurkov ◽

Alexey Kryukov ◽

Yulia Mikhaylova ◽

Peter Zhurbenko

Keyword(s):

Mycorrhizal Fungi ◽

Biological Diversity ◽

Arbuscular Mycorrhizal ◽

Its Region ◽

Am Fungi ◽

Illumina Miseq ◽

Universal Primers ◽

Its2 Region ◽

North Caucasus ◽

The Future

The aim of the study was to investigate the species diversity of AM fungi in different parts of the North Caucasus, biodiversity hotspot, the center of the world’s biological diversity. Samples were taken from 5 locations (stationary trial plots, STPs) in different ecosystems and at various altitudes. Identification was performed using sequencing for ITS1 and ITS2 regions, amplified with universal primers, Illumina MiSeq was employed. 19 genera of AM fungi were found on all STPs. The work did not reveal a correlation between the altitude and the species composition of AM fungi. At the same time, it should be assumed that a correlation could be found between the biodiversity of AM fungi and the type of ecosystem, which should be done in the future. The study shows it is necessary to use an analysis for both ITS regions, since the data obtained for each ITS region differ and complement each other. Analysis for the ITS2 region revealed 1.3 times more virtual taxa than for the ITS1, while the number of OTUs identified per species was similar for both regions. The highest biodiversity of AM fungi was found in STP #3 (with meadow flora). Only 4 species (Rhizophagus irregularis, R. intraradices, Paraglomus laccatum, and Claroideoglomus claroideum) were found on all five analyzed STPs. We found unexpectedly that with such a high biodiversity among the identified fungi, no different species were found in the Paraglomus genus, all the sequences of Paraglomus belonged to Paraglomus laccatum, whereas at least 9 species are distinguished in the genus by morphology. Further research will allow us to identify new strains of AM fungi, the efficiency of which may be higher than already studied ones. In the future this will make it possible to create more effective microbial biofertilizers for agriculture.

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Elucidating the Mechanisms Underlying Enhanced Drought Tolerance in Plants Mediated by Arbuscular Mycorrhizal Fungi

Frontiers in Microbiology ◽

10.3389/fmicb.2021.809473 ◽

2021 ◽

Vol 12 ◽

Author(s):

Shen Cheng ◽

Ying-Ning Zou ◽

Kamil Kuča ◽

Abeer Hashem ◽

Elsayed Fathi Abd_Allah ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Mycorrhizal Fungi ◽

Host Plants ◽

Molecular Mechanisms ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Host Cells ◽

Future Research ◽

Symbiotic Association

Plants are often subjected to various environmental stresses during their life cycle, among which drought stress is perhaps the most significant abiotic stress limiting plant growth and development. Arbuscular mycorrhizal (AM) fungi, a group of beneficial soil fungi, can enhance the adaptability and tolerance of their host plants to drought stress after infecting plant roots and establishing a symbiotic association with their host plant. Therefore, AM fungi represent an eco-friendly strategy in sustainable agricultural systems. There is still a need, however, to better understand the complex mechanisms underlying AM fungi-mediated enhancement of plant drought tolerance to ensure their effective use. AM fungi establish well-developed, extraradical hyphae on root surfaces, and function in water absorption and the uptake and transfer of nutrients into host cells. Thus, they participate in the physiology of host plants through the function of specific genes encoded in their genome. AM fungi also modulate morphological adaptations and various physiological processes in host plants, that help to mitigate drought-induced injury and enhance drought tolerance. Several AM-specific host genes have been identified and reported to be responsible for conferring enhanced drought tolerance. This review provides an overview of the effect of drought stress on the diversity and activity of AM fungi, the symbiotic relationship that exists between AM fungi and host plants under drought stress conditions, elucidates the morphological, physiological, and molecular mechanisms underlying AM fungi-mediated enhanced drought tolerance in plants, and provides an outlook for future research.

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Anthropogenic Disturbance Impacts Mycorrhizal Communities and Abiotic Soil Properties: Implications for an Endemic Forest Disease

Frontiers in Forests and Global Change ◽

10.3389/ffgc.2020.593243 ◽

2021 ◽

Vol 3 ◽

Author(s):

Sarah J. Sapsford ◽

Trudy Paap ◽

Giles E. St. J. Hardy ◽

Treena I. Burgess

Keyword(s):

Soil Properties ◽

Soil Nutrients ◽

Large Scale ◽

Stand Structure ◽

Disease Incidence ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Illumina Miseq ◽

Fungal Communities ◽

Canker Disease

In forest ecosystems, habitat fragmentation negatively impacts stand structure and biodiversity; the resulting fragmented patches of forest have distinct, disturbed edge habitats that experience different environmental conditions than the interiors of the fragments. In southwest Western Australia, there is a large-scale decline of the keystone tree species Corymbia calophylla following fragmentation and land use change. These changes have altered stand structure and increased their susceptibility to an endemic fungal pathogen, Quambalaria coyrecup, which causes chronic canker disease especially along disturbed forest habitats. However, the impacts of fragmentation on belowground processes in this system are not well-understood. We examined the effects of fragmentation on abiotic soil properties and ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungal communities, and whether these belowground changes were drivers of disease incidence. We collected soil from 17 sites across the distribution range of C. calophylla. Soils were collected across a gradient from disturbed, diseased areas to undisturbed, disease-free areas. We analysed soil nutrients and grew C. calophylla plants as a bioassay host. Plants were harvested and roots collected after 6 months of growth. DNA was extracted from the roots, amplified using fungal specific primers and sequenced using Illumina MiSeq. Concentrations of key soil nutrients such as nitrogen, phosphorus and potassium were much higher along the disturbed, diseased edges in comparison to undisturbed areas. Disturbance altered the community composition of ECM and AM fungi; however, only ECM fungal communities had lower rarefied richness and diversity along the disturbed, diseased areas compared to undisturbed areas. Accounting for effects of disturbance, ECM fungal diversity and leaf litter depth were highly correlated with increased disease incidence in C. calophylla. In the face of global change, increased virulence of an endemic pathogen has emerged in this Mediterranean-type forest.

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Novel Insights into Host Receptors and Receptor-mediated Signaling that Regulate Arbuscular Mycorrhizal Symbiosis

Journal of Experimental Botany ◽

10.1093/jxb/eraa538 ◽

2020 ◽

Author(s):

Fahad Nasir ◽

Ali Bahadur ◽

Xiaolong Lin ◽

Yingzhi Gao ◽

Chunjie Tian

Keyword(s):

Host Plant ◽

Host Plants ◽

Agronomic Traits ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Land Plant ◽

Physical Contact ◽

Mycorrhizal Symbiosis ◽

Downstream Signaling ◽

Am Symbiosis

Abstract More than 80% of land plant species benefit from symbiotic partnerships with arbuscular mycorrhizal (AM) fungi that assist in nutrient acquisition and enhance the ability of host plants to adapt to environmental constraints. Host-generated plasma membrane-residing receptor-like kinases and the α/β-hydrolases, e.g. DWARF14-LIKE (D14L), a putative karrikin receptor, are used to detect the presence of AM fungi prior to physical contact between the host and fungus. Detection induces the activation of symbiosis-related transcriptional programming, enabling the successful establishment of AM symbiosis. In order to prevent hyper-colonization and to maintain a mutually beneficial association, the host plants precisely monitor and control AM symbiosis during the post-symbiotic stage via different molecular strategies. While previous studies have elucidated how host plant receptors and receptor-mediated signaling regulate AM symbiosis, the molecular details underlying these processes remain poorly understood. The recent identification of a rice (Oryza sativa) CHITIN-ELICITOR RECEPTOR-KINASE 1 (OsCERK1) interaction partner MYC FACTOR RECEPTOR 1 (OsMYR1), as well as new insights into D14L-receptor- and SUPER NUMERIC NODULES 1 (SUNN1) receptor-mediated signaling have improved our understanding of how host plant receptors and their corresponding signaling regulate AM symbiosis. The present review summarizes these and other current findings that have increased our limited understanding of receptor-mediated signaling mechanisms involved in the regulation of AM symbiosis. The identified receptors and/or their downstream signaling components could potentially be used to engineer economically-important crops with improved agronomic traits by conferring the ability to control the colonization of AM fungi in a precise manner.

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Response of Arbuscular Mycorrhizal Fungi to Hydrologic Gradients in the Rhizosphere ofPhragmites australis(Cav.) Trin ex. Steudel Growing in the Sun Island Wetland

BioMed Research International ◽

10.1155/2015/810124 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 4

Author(s):

Li Wang ◽

Jieting Wu ◽

Fang Ma ◽

Jixian Yang ◽

Shiyang Li ◽

...

Keyword(s):

Host Plant ◽

Mycorrhizal Fungi ◽

Plant Biomass ◽

Growth Parameters ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

The Sun ◽

Vegetative Period ◽

Hydrologic Gradients ◽

Mycorrhizal Association

Within the rhizosphere, AM fungi are a sensitive variable to changes of botanic and environmental conditions, and they may interact with the biomass of plant and other microbes. During the vegetative period of thePhragmites australisgrowing in the Sun Island Wetland (SIW), the variations of AM fungi colonization were studied. Root samples of three hydrologic gradients generally showed AM fungi colonization, suggesting that AM fungi have the ability for adaptation to flooded habitats. There were direct and indirect hydrological related effects with respect to AM fungi biomass, which interacted simultaneously in the rhizosphere. Though water content in soil and reed growth parameters were both positively associated with AM fungi colonization, only the positive correlations between reed biomass parameters and the colonization could be expected, or both the host plant biomass and the AM fungi could be beneficial. The variations in response of host plant to the edaphic and hydrologic conditions may influence the effectiveness of the plant-mycorrhizal association. This study included a hydrologic component to better assess the role and distribution of AM fungi in wetland ecosystems. And because of that, the range of AM fungi was extended, since they actually showed a notable adaptability to hydrologic gradients.

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