Arbuscular mycorrhizal fungi increase Pb uptake of colonized and non-colonized Medicago truncatula root and deliver extra Pb to colonized root

Abstract Aims Arbuscular mycorrhizal (AM) fungi form symbiosis with terrestrial plants and improve lead (Pb) tolerance of host plants. The AM plants accumulate more Pb in root than their non-mycorrhizal counterparts. However, the direct contribution of the mycorrhizal pathway to host plant Pb uptake was less reported. Methods In this study, the AM fungi colonized and non-colonized root of Medicago truncatula was separated by a split-root system, and their differences in responding to Pb application was compared. Results Inoculation of Rhizophagus irregularis increased shoot biomass accumulation and transpiration, and decreased both colonized and non-colonized root biomass accumulation. Application of Pb in the non-colonized root compartment increased the colonization rate of R. irregularis and up-regulated the relative expressions of MtPT4 and MtBCP1 in the colonized root compartment. Inoculation of R. irregularis increased the Pb uptake in both colonized and non-colonized plant root, while R. irregularis transferred Pb to the colonized root. The Pb transferred through the mycorrhizal pathway had low mobility move from root to shoot, and might be sequestrated and compartmented by R. irregularis. Conclusions The Pb uptake of plant root might follow water flow that facilitated by the aquaporin MtPIP2. The quantification of Pb transfer via mycorrhizal pathway and the involvement of MtPIP2 deserve further study.

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Arbuscular Mycorrhizal Fungi Increase Pb Uptake of Colonized and Non-Colonized Medicago truncatula Root and Deliver Extra Pb to Colonized Root Segment

Microorganisms ◽

10.3390/microorganisms9061203 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1203

Author(s):

Haoqiang Zhang ◽

Wei Ren ◽

Yaru Zheng ◽

Yanpeng Li ◽

Manzhe Zhu ◽

...

Keyword(s):

Medicago Truncatula ◽

Mycorrhizal Fungi ◽

Biomass Accumulation ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Rhizophagus Irregularis ◽

Root Segment ◽

Shoot Biomass ◽

Split Root System ◽

Long Term Impact

Arbuscular mycorrhizal (AM) fungi establish symbiosis and improve the lead (Pb) tolerance of host plants. The AM plants accumulate more Pb in roots than their non-mycorrhizal counterparts. However, the direct and long-term impact of AM fungi on plant Pb uptake has been rarely reported. In this study, AM fungus (Rhizophagus irregularis) colonized and non-colonized roots of Medicago truncatula were separated by a split-root system, and their differences in responding to Pb application were compared. The shoot biomass accumulation and transpiration were increased after R. irregularis inoculation, whereas the biomass of both colonized and non-colonized roots was decreased. Lead application in the non-colonized root compartment increased the R. irregularis colonization rate and up-regulated the relative expressions of MtPT4 and MtBCP1 in the colonized root compartments. Rhizophagus irregularis inoculation increased Pb uptake in both colonized and non-colonized roots, and R. irregularis transferred Pb to the colonized root segment. The Pb transferred through the colonized root segment had low mobility and might be sequestrated and compartmented in the root by R. irregularis. The Pb uptake of roots might follow water flow, which is facilitated by MtPIP2. The quantification of Pb transfer via the mycorrhizal pathway and the involvement of MtPIP2 deserve further study.

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Use of the Signature Fatty Acid 16:1ω5 as a Tool to Determine the Distribution of Arbuscular Mycorrhizal Fungi in Soil

Journal of Lipids ◽

10.1155/2012/236807 ◽

2012 ◽

Vol 2012 ◽

pp. 1-8 ◽

Cited By ~ 43

Author(s):

Christopher Ngosong ◽

Elke Gabriel ◽

Liliane Ruess

Keyword(s):

Fatty Acid ◽

Mycorrhizal Fungi ◽

Plant Root ◽

Background Level ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Biomass Estimation ◽

Lipid Fatty Acid ◽

Neutral Lipid Fatty Acid ◽

Root Symbionts

Biomass estimation of arbuscular mycorrhiza (AM) fungi, widespread plant root symbionts, commonly employs lipid biomarkers, predominantly the fatty acid 16:1ω5. We briefly reviewed the application of this signature fatty acid, followed by a case study comparing biochemical markers with microscopic techniques in an arable soil following a change to AM non-host plants after 27 years of continuous host crops, that is, two successive cropping seasons with wheat followed by amaranth. After switching to the non-host amaranth, spore biomass estimated by the neutral lipid fatty acid (NLFA) 16:1ω5 decreased to almost nil, whereas microscopic spore counts decreased by about 50% only. In contrast, AM hyphal biomass assessed by the phospholipid (PLFA) 16:1ω5 was greater under amaranth than wheat. The application of PLFA 16:1ω5 as biomarker was hampered by background level derived from bacteria, and further enhanced by its incorporation from degrading spores used as microbial resource. Meanwhile, biochemical and morphological assessments showed negative correlation for spores and none for hyphal biomass. In conclusion, the NLFA 16:1ω5 appears to be a feasible indicator for AM fungi of the Glomales group in the complex field soils, whereas the use of PLFA 16:1ω5 for hyphae is unsuitable and should be restricted to controlled laboratory studies.

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Haustorium Formation in Medicago truncatula Roots Infected by Phytophthora palmivora Does Not Involve the Common Endosymbiotic Program Shared by Arbuscular Mycorrhizal Fungi and Rhizobia

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-06-15-0130-r ◽

2015 ◽

Vol 28 (12) ◽

pp. 1271-1280 ◽

Cited By ~ 18

Author(s):

Rik Huisman ◽

Klaas Bouwmeester ◽

Marijke Brattinga ◽

Francine Govers ◽

Ton Bisseling ◽

...

Keyword(s):

Medicago Truncatula ◽

Mycorrhizal Fungi ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Phytophthora Palmivora ◽

Living Plant ◽

Mutualistic Symbiosis ◽

Membrane Compartment ◽

Microbe Interactions ◽

Host Genes

In biotrophic plant-microbe interactions, microbes infect living plant cells, in which they are hosted in a novel membrane compartment, the host-microbe interface. To create a host-microbe interface, arbuscular mycorrhizal (AM) fungi and rhizobia make use of the same endosymbiotic program. It is a long-standing hypothesis that pathogens make use of plant proteins that are dedicated to mutualistic symbiosis to infect plants and form haustoria. In this report, we developed a Phytophthora palmivora pathosystem to study haustorium formation in Medicago truncatula roots. We show that P. palmivora does not require host genes that are essential for symbiotic infection and host-microbe interface formation to infect Medicago roots and form haustoria. Based on these findings, we conclude that P. palmivora does not hijack the ancient intracellular accommodation program used by symbiotic microbes to form a biotrophic host-microbe interface.

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Plant Salinity Tolerance Conferred by Arbuscular Mycorrhizal Fungi and Associated Mechanisms: A Meta-Analysis

Frontiers in Plant Science ◽

10.3389/fpls.2020.588550 ◽

2020 ◽

Vol 11 ◽

Author(s):

Khondoker M. G. Dastogeer ◽

Mst Ishrat Zahan ◽

Md. Tahjib-Ul-Arif ◽

Mst Arjina Akter ◽

Shin Okazaki

Keyword(s):

Superoxide Dismutase ◽

Arbuscular Mycorrhizal Fungi ◽

Salinity Stress ◽

Mycorrhizal Fungi ◽

Root Biomass ◽

Meta Analysis ◽

Biomass Accumulation ◽

Arbuscular Mycorrhizal ◽

Shoot Biomass ◽

Shoot And Root Biomass

Soil salinity often hinders plant productivity in both natural and agricultural settings. Arbuscular mycorrhizal fungal (AMF) symbionts can mediate plant stress responses by enhancing salinity tolerance, but less attention has been devoted to measuring these effects across plant-AMF studies. We performed a meta-analysis of published studies to determine how AMF symbionts influence plant responses under non-stressed vs. salt-stressed conditions. Compared to non-AMF plants, AMF plants had significantly higher shoot and root biomass (p < 0.0001) both under non-stressed conditions and in the presence of varying levels of NaCl salinity in soil, and the differences became more prominent as the salinity stress increased. Categorical analyses revealed that the accumulation of plant shoot and root biomass was influenced by various factors, such as the host life cycle and lifestyle, the fungal group, and the duration of the AMF and salinity treatments. More specifically, the effect of Funneliformis on plant shoot biomass was more prominent as the salinity level increased. Additionally, under stress, AMF increased shoot biomass more on plants that are dicots, plants that have nodulation capacity and plants that use the C3 plant photosynthetic pathway. When plants experienced short-term stress (<2 weeks), the effect of AMF was not apparent, but under longer-term stress (>4 weeks), AMF had a distinct effect on the plant response. For the first time, we observed significant phylogenetic signals in plants and mycorrhizal species in terms of their shoot biomass response to moderate levels of salinity stress, i.e., closely related plants had more similar responses, and closely related mycorrhizal species had similar effects than distantly related species. In contrast, the root biomass accumulation trait was related to fungal phylogeny only under non-stressed conditions and not under stressed conditions. Additionally, the influence of AMF on plant biomass was found to be unrelated to plant phylogeny. In line with the greater biomass accumulation in AMF plants, AMF improved the water status, photosynthetic efficiency and uptake of Ca and K in plants irrespective of salinity stress. The uptake of N and P was higher in AMF plants, and as the salinity increased, the trend showed a decline but had a clear upturn as the salinity stress increased to a high level. The activities of malondialdehyde (MDA), peroxidase (POD), and superoxide dismutase (SOD) as well as the proline content changed due to AMF treatment under salinity stress. The accumulation of proline and catalase (CAT) was observed only when plants experienced moderate salinity stress, but peroxidase (POD) and superoxide dismutase (SOD) were significantly increased in AMF plants irrespective of salinity stress. Taken together, arbuscular mycorrhizal fungi influenced plant growth and physiology, and their effects were more notable when their host plants experienced salinity stress and were influenced by plant and fungal traits.

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Mycorrhizal Fungi and Sustainable Agriculture

10.5772/intechopen.99262 ◽

2021 ◽

Author(s):

Soibam Helena Devi ◽

Ingudam Bhupenchandra ◽

Soibam Sinyorita ◽

S.K. Chongtham ◽

E. Lamalakshmi Devi

Keyword(s):

Arbuscular Mycorrhizal Fungi ◽

Mycorrhizal Fungi ◽

Farming Systems ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

High Rate ◽

Natural Ecosystem ◽

Terrestrial Plants ◽

Nitrogen And Phosphorus ◽

Nutrient Assimilation

The 20thcentury witnessed an augmentation in agricultural production, mainly through the progress and use of pesticides, fertilizers containing nitrogen and phosphorus, and developments in plant breeding and genetic skills. In the naturally existing ecology, rhizospheric soils have innumerable biological living beings to favor the plant development, nutrient assimilation, stress tolerance, disease deterrence, carbon seizing and others. These organisms include mycorrhizal fungi, bacteria, actinomycetes, etc. which solubilize nutrients and assist the plants in up taking by roots. Amongst them, arbuscular mycorrhizal (AM) fungi have key importance in natural ecosystem, but high rate of chemical fertilizer in agricultural fields is diminishing its importance. The majority of the terrestrial plants form association with Vesicular Arbuscular Mycorrhiza (VAM) or Arbuscular Mycorrhizal fungi (AMF). This symbiosis confers benefits directly to the host plant’s growth and development through the acquisition of Phosphorus (P) and other mineral nutrients from the soil by the AMF. They may also enhance the protection of plants against pathogens and increases the plant diversity. This is achieved by the growth of AMF mycelium within the host root (intra radical) and out into the soil (extra radical) beyond. Proper management of Arbuscular Mycorrhizal fungi has the potential to improve the profitability and sustainability of agricultural systems. AM fungi are especially important for sustainable farming systems because AM fungi are efficient when nutrient availability is low and when nutrients are bound to organic matter and soil particles.

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Artificial intelligence enables the identification and quantification of arbuscular mycorrhizal fungi in plant roots

10.1101/2021.03.05.434067 ◽

2021 ◽

Author(s):

Edouard Evangelisti ◽

Carl Turner ◽

Alice McDowell ◽

Liron Shenhav ◽

Temur Yunusov ◽

...

Keyword(s):

Mycorrhizal Fungi ◽

Plant Root ◽

Lotus Japonicus ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Root Systems ◽

Experimental Conditions ◽

Root Colonisation ◽

Fungal Colonisation ◽

Identification And Quantification

Soil fungi establish mutualistic interactions with the roots of most vascular land plants. Arbuscular mycorrhizal (AM) fungi are among the most extensively characterised mycobionts to date. Current approaches to quantifying the extent of root colonisation and the relative abundance of intraradical hyphal structures in mutant roots rely on staining and human scoring involving simple, yet repetitive tasks prone to variations between experimenters. We developed the software AMFinder which allows for automatic computer vision-based identification and quantification of AM fungal colonisation and intraradical hyphal structures on ink-stained root images using convolutional neural networks. AMFinder delivered high-confidence predictions on image datasets of colonised roots of Medicago truncatula, Lotus japonicus, Oryza sativa and Nicotiana benthamiana obtained via flatbed scanning or digital microscopy enabling reproducible and transparent data analysis. A streamlined protocol for sample preparation and imaging allowed us to quantify dynamic increases in colonisation in whole root systems over time. AMFinder adapts to a wide array of experimental conditions. It enables accurate, reproducible analyses of plant root systems and will support better documentation of AM fungal colonisation analyses. AMFinder can be accessed here: https://github.com/SchornacklabSLCU/amfinder.git

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Effect of arbuscular mycorrhizal fungi and pesticides on Cynara cardunculus growth

Agricultural and Food Science ◽

10.23986/afsci.5728 ◽

2002 ◽

Vol 11 (3) ◽

pp. 245-251 ◽

Cited By ~ 16

Author(s):

M. MARIN ◽

M. YBARRA ◽

A. FÉ

Keyword(s):

Mycorrhizal Fungi ◽

Glomus Mosseae ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Shoot Biomass ◽

Cynara Cardunculus ◽

Mycorrhizal Inoculation ◽

Positive Effect ◽

Wild Cardoon ◽

Glomus Sp

Wild cardoon (Cynara cardunculus L.) is a promising crop for biomass production. A nursery trial was conducted to investigate the effectiveness of mycorrhizal inoculation on the biomass yield of wild cardoon seedlings and the effect of the pesticides fosetyl-Al, folpet and propamocarb, as fungicides, and isofenphos, phoxim and oxamyl, as insecticides, on cardoon plant growth and the mycorrhization. The arbuscular mycorrhizal (AM) fungi inocula were: commercial inoculum with Glomus mosseae spores, and an inoculum of a Glomus sp. strain (AMF-i) isolated locally. Mycorrhizal inoculation with either inoculum increased cardoon shoot biomass compared to non-inoculated control plants. The pesticide applications had a neutral or positive effect on cardoon seedling growth. However, the AM fungi colonisation did not decrease except for plants colonised by G. mosseae and treated with the insecticides isofenphos and oxamyl. Thus, the mycorrhiza can survive to pesticide concentrations employed in commercial nursery, and enhance cardoon plant productivity.

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Suppression of fungal and nematode plant pathogens through arbuscular mycorrhizal fungi

Biology Letters ◽

10.1098/rsbl.2011.0874 ◽

2011 ◽

Vol 8 (2) ◽

pp. 214-217 ◽

Cited By ~ 91

Author(s):

Stavros D. Veresoglou ◽

Matthias C. Rillig

Keyword(s):

Mycorrhizal Fungi ◽

Fungal Pathogens ◽

Host Plants ◽

Plant Pathogens ◽

Meta Analysis ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Terrestrial Plants ◽

Pathogen Suppression ◽

Mycorrhizal Ecology

Arbuscular mycorrhizal (AM) fungi represent ubiquitous mutualists of terrestrial plants. Through the symbiosis, plant hosts, among other benefits, receive protection from pathogens. A meta-analysis was conducted on 106 articles to determine whether, following pathogen infection of AM-colonized plants, the identity of the organisms involved (pathogens, AM fungi and host plants) had implications for the extent of the AM-induced pathogen suppression. Data on fungal and nematode pathogens were analysed separately. Although we found no differences in AM effectiveness with respect to the identity of the plant pathogen, the identity of the AM isolate had a dramatic effect on the level of pathogen protection. AM efficiency differences with respect to nematode pathogens were mainly limited to the number of AM isolates present; by contrast, modification of the ability to suppress fungal pathogens could occur even through changing the identity of the Glomeraceae isolate applied. N-fixing plants received more protection from fungal pathogens than non-N-fixing dicotyledons; this was attributed to the more intense AM colonization in N-fixing plants. Results have implications for understanding mycorrhizal ecology and agronomic applications.

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Arbuscular Mycorrhizal Fungi in Agriculture

Encyclopedia ◽

10.3390/encyclopedia1040085 ◽

2021 ◽

Vol 1 (4) ◽

pp. 1132-1154

Author(s):

Thomas I. Wilkes

Keyword(s):

Mycorrhizal Fungi ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Soil Disturbance ◽

Terrestrial Plants ◽

Fungal Host ◽

Tillage Practices ◽

Plant Growth Promoting ◽

Am Fungus ◽

Growth Promoting

Arbuscular mycorrhizal (AM) fungi are biotrophic symbionts forming close relationships with an estimated 80% of terrestrial plants suitable as their host. Via an established AM fungal–host relationship, soil-bound nutrients are made available to the host plant through root cortical arbuscules as the site of exchange. At these sites, photosynthetic carbohydrates are provided to the AM fungus—carbohydrates that cannot be produced by the fungus. AM fungal–host symbiosis is very sensitive to soil disturbance, for example, agricultural tillage practices can damage and reduce AM fungal abilities to interact with a host and provide plant growth-promoting properties.

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The Pre-Symbiotic Growth of Arbuscular Mycorrhizal Fungi Is Induced by a Branching Factor Partially Purified from Plant Root Exudates

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2000.13.6.693 ◽

2000 ◽

Vol 13 (6) ◽

pp. 693-698 ◽

Cited By ~ 207

Author(s):

M. Buee ◽

M. Rossignol ◽

A. Jauneau ◽

R. Ranjeva ◽

G. Bécard

Keyword(s):

Plant Species ◽

Root Exudates ◽

Mycorrhizal Fungi ◽

Plant Root ◽

Fungal Growth ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Flavonoid Pathway ◽

Highly Active ◽

Nonhost Plant

Arbuscular mycorrhizal (AM) symbiosis is an association between obligate biotrophic fungi and more than 80% of land plants. During the pre-symbiotic phase, the host plant releases critical metabolites necessary to trigger fungal growth and root colonization. We describe the isolation of a semipurified fraction from exudates of carrot hairy roots, highly active on germinating spores of Gigaspora gigantea, G. rosea, and G. margarita. This fraction, isolated on the basis of its activity on hyphal branching, contains a root factor (one or several molecules) that stimulates, directly or indirectly, G. gigantea nuclear division. We demonstrate the presence of this active factor in root exudates of all mycotrophic plant species tested (eight species) but not in those of nonhost plant species (four species). We negatively tested the hypothesis that it was a flavonoid or a compound synthesized via the flavonoid pathway. We propose that this root factor, yet to be chemically characterized, is a key plant signal for the development of AM fungi.

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