scholarly journals Symbiont switching and alternative resource acquisition strategies drive mutualism breakdown

2018 ◽  
Vol 115 (20) ◽  
pp. 5229-5234 ◽  
Author(s):  
Gijsbert D. A. Werner ◽  
Johannes H. C. Cornelissen ◽  
William K. Cornwell ◽  
Nadejda A. Soudzilovskaia ◽  
Jens Kattge ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Resource Acquisition ◽  
Comparative Approach ◽  
Acquisition Strategies ◽  
Potential Benefits ◽  
Root Symbionts ◽  
Life On Earth ◽  
Alternative Resource ◽  
Mutualism Breakdown

Cooperative interactions among species, termed mutualisms, have played a crucial role in the evolution of life on Earth. However, despite key potential benefits to partners, there are many cases in which two species cease to cooperate and mutualisms break down. What factors drive the evolutionary breakdown of mutualism? We examined the pathways toward breakdowns of the mutualism between plants and arbuscular mycorrhizal fungi. By using a comparative approach, we identify ∼25 independent cases of complete mutualism breakdown across global seed plants. We found that breakdown of cooperation was only stable when host plants (i) partner with other root symbionts or (ii) evolve alternative resource acquisition strategies. Our results suggest that key mutualistic services are only permanently lost if hosts evolve alternative symbioses or adaptations.

scholarly journals Symbiont switching and alternative resource acquisition strategies drive mutualism breakdown

2018 ◽  
Author(s):  
Gijsbert DA Werner ◽  
Johannes HC Cornelissen ◽  
William K Cornwell ◽  
Nadejda A Soudzilovskaia ◽  
Jens Kattge ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Resource Acquisition ◽  
Comparative Approach ◽  
Cooperative Interactions ◽  
Evolutionary Innovation ◽  
Acquisition Strategies ◽  
Root Symbionts ◽  
Alternative Resource ◽  
Mutualism Breakdown

AbstractCooperative interactions among species, termed mutualisms, have played a crucial role in the evolution of life on Earth. However, despite key potential benefits to partners, there are many cases where two species cease to cooperate, and mutualisms break down. What factors drive the evolutionary breakdown of mutualism? We examined the pathways towards breakdowns of the mutualism between plants and arbuscular mycorrhizal (AM) fungi. Using a comparative approach, we identify ~25 independent cases of complete mutualism breakdown across global seed plants. We found that breakdown of cooperation was only stable when host plants either: (i) partner with other root symbionts or (ii) evolve alternative resource acquisition strategies. Our results suggest that key mutualistic services are only permanently lost if hosts evolve alternative symbioses or adaptations.Significance StatementCooperative interactions among species – mutualisms – are major sources of evolutionary innovation. However, despite their importance, two species that formerly cooperated sometimes cease their partnership. Why do mutualisms breakdown? We asked this question in the partnership between arbuscular mycorrhizal (AM) fungi and their plant hosts, one of the most ancient mutualisms. We analyse two potential trajectories towards evolutionary breakdown of their cooperation, symbiont switching and mutualism abandonment. We find evidence that plants stop interacting with AM fungi when they switch to other microbial mutualists or when they evolve alternative strategies to extract nutrients from the environment. Our results show vital cooperative interactions can be lost - but only if successful alternatives evolve.

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

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
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.

scholarly journals Effects of arbuscular mycorrhizal fungi and phosphorus fertilization on post vitro growth of micropropagated Zingiber officinale roscoe

2010 ◽  
Vol 34 (3) ◽  
pp. 765-771 ◽  
Author(s):  
Rosilda dos Santos ◽  
Carla Giovana Girardi ◽  
Rosete Pescador ◽  
Sidney Luiz Stürmer
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Zingiber Officinale ◽  
Phosphorus Fertilization ◽  
Zingiber Officinale Roscoe ◽  
P Application ◽  
Root Symbionts ◽  
Rhizome Biomass ◽  
P Addition

The rhizomes of Zingiber officinale Roscoe (ginger) are widely used for their medicinal and flavoring properties, whereas the influence of root symbionts on their growth is poorly understood. In this study, the effects of phosphate fertilization and inoculation with a mixture of arbuscular mycorrhizal fungi (AMF) (isolates Glomus clarum RGS101A, Entrophospora colombiana SCT115A and Acaulospora koskei SPL102A) on survival, growth and development of micropropagated ginger were investigated. After transplanting to post vitro conditions, the ginger microplants were subjected to the following treatments: a) AMF mixture, b) P addition (25 mg kg-1), c) AMF + P, and d) non-mycorrhizal control without P addition. After eight months of growth, survival ranged from 86 to 100 % in the AMF and AMF+P treatments versus 71 % survival in control and P treatments. In the AMF, P and AMF+P treatments, the shoot, root and rhizome biomass production were significantly larger than in the control plants. In the non-mycorrhizal control plants the leaf number, leaf area, number of shoots/plants, and shoot length were significantly lower than in the AMF, P and AMF+P treatments. Root colonization ranged from 81 to 93 % and was not affected by P application. The data confirmed the response of several growth variables of micropropagated ginger to mycorrhizal colonization and P addition.

scholarly journals Influence on Different Types of Mycorrhizal Fungi on Crop Productivity in Ecosystem

2015 ◽  
Vol 38 ◽  
pp. 9-15 ◽  
Author(s):  
K. Ramakrishnan ◽  
G. Bhuvaneswari
Keyword(s):  
Mycorrhizal Fungi ◽  
Current Knowledge ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Heavy Metal Stress ◽  
Crop Productivity ◽  
Symbiotic Relationships ◽  
Potential Benefits ◽  
Mycorrhizal Interactions

Mycorrhizal fungi greatly enhanced the ability of plants to take up phosphorus and other nutrients those are relatively immobile and exist in low concentration in the soil solution. Fungi can be important in the uptake of other nutrients by the host plant. Mycorrhizae establish symbiotic relationships with plants and play an essential role in plant growth, disease protection, and overall soil quality. Of the seven types of mycorrhizae described in current scientific literature (arbuscular, ecto, ectendo, arbutoid, monotropoid, ericoid and orchidaceous mycorrhizae), the arbuscular and ectomycorrhizae are the most abundant and widespread. This chapter presents an overview of current knowledge of mycorrhizal interactions, processes, and potential benefits to society. The molecular basis of nutrient exchange between arbuscular mycorrhizal (AM) fungi and host plants is presented; the role of AM fungi in disease protection, alleviation of heavy metal stress and increasing grain production. Most land plants form associations with mycorrhizal fungi. Mycorrhizas are mutualistic associations between fungi and plant roots. They are described as symbiotic because the fungus receives photo synthetically derived carbon compounds and the plant has increased access to mineral nutrients and sometimes water.

scholarly journals Symbiotic Root-Endophytic Soil Microbes Improve Crop Productivity and Provide Environmental Benefits

Scientifica ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-25 ◽  
Author(s):  
Gary E. Harman ◽  
Norman Uphoff
Keyword(s):  
Gene Expression ◽  
Mycorrhizal Fungi ◽  
Crop Yields ◽  
Plant Root ◽  
Arbuscular Mycorrhizal ◽  
Crop Productivity ◽  
Environmental Benefits ◽  
Cellular Environment ◽  
Visible Part ◽  
Root Symbionts

Plants should not be regarded as entities unto themselves, but as the visible part of plant-microbe complexes which are best understood as “holobiomes.” Some microorganisms when given the opportunity to inhabit plant roots become root symbionts. Such root colonization by symbiotic microbes can raise crop yields by promoting the growth of both shoots and roots, by enhancing uptake, fixation, and/or more efficient use of nutrients, by improving plants’ resistance to pests, diseases, and abiotic stresses that include drought, salt, and other environmental conditions, and by enhancing plants’ capacity for photosynthesis. We refer plant-microbe associations with these capabilities that have been purposefully established as enhanced plant holobiomes (EPHs). Here, we consider four groups of phylogenetically distinct and distant symbiotic endophytes: (1) Rhizobiaceae bacteria; (2) plant-obligate arbuscular mycorrhizal fungi (AMF); (3) selected endophytic strains of fungi in the genusTrichoderma; and (4) fungi in the Sebicales order, specificallyPiriformospora indica. Although these exhibit quite different “lifestyles” when inhabiting plants, all induce beneficial systemic changes in plants’ gene expression that are surprisingly similar. For example, all induce gene expression that produces proteins which detoxify reactive oxygen species (ROS). ROS are increased by environmental stresses on plants or by overexcitation of photosynthetic pigments. Gene overexpression results in a cellular environment where ROS levels are controlled and made more compatible with plants’ metabolic processes. EPHs also frequently exhibit increased rates of photosynthesis that contribute to greater plant growth and other capabilities. Soil organic matter (SOM) is augmented when plant root growth is increased and roots remain in the soil. The combination of enhanced photosynthesis, increasing sequestration of CO2from the air, and elevation of SOM removes C from the atmosphere and stores it in the soil. Reductions in global greenhouse gas levels can be accelerated by incentives for carbon farming and carbon cap-and-trade programs that reward such climate-friendly agriculture. The development and spread of EPHs as part of such initiatives has potential both to enhance farm productivity and incomes and to decelerate global warming.

scholarly journals Photosynthetic Traits and Nitrogen Uptake in Crops: Which Is the Role of Arbuscular Mycorrhizal Fungi?

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1105
Author(s):  
Raffaella Balestrini ◽  
Cecilia Brunetti ◽  
Walter Chitarra ◽  
Luca Nerva
Keyword(s):  
Mycorrhizal Fungi ◽  
Extreme Temperature ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Fruit Trees ◽  
Growth Stress ◽  
Nitrogen Acquisition ◽  
Positive Effects ◽  
Root Symbionts ◽  
Photosynthetic Traits

Arbuscular mycorrhizal (AM) fungi are root symbionts that provide mineral nutrients to the host plant in exchange for carbon compounds. AM fungi positively affect several aspects of plant life, improving nutrition and leading to a better growth, stress tolerance, and disease resistance and they interact with most crop plants such as cereals, horticultural species, and fruit trees. For this reason, they receive expanding attention for the potential use in sustainable and climate-smart agriculture context. Although several positive effects have been reported on photosynthetic traits in host plants, showing improved performances under abiotic stresses such as drought, salinity and extreme temperature, the involved mechanisms are still to be fully discovered. In this review, some controversy aspects related to AM symbiosis and photosynthesis performances will be discussed, with a specific focus on nitrogen acquisition-mediated by AM fungi.

scholarly journals Dispersal, distribution and establishment of arbuscular mycorrhizal fungi: a review

2017 ◽  
pp. 33 ◽  
Author(s):  
Sara Lucía Camargo-Ricalde
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Genetic Compatibility ◽  
Natural Ecosystems ◽  
Erosion Processes ◽  
Fungal Genetic ◽  
The Common ◽  
Root Symbionts ◽  
Animal Transport

The aim of this paper is to review and assess scientific literature relevant to arbuscular mycorrhizal fungi (AMF) population dynamics: reproduction and dispersal mechanisms, and establishment and distribution in natural ecosystems. Arbuscular mycorrhizal fungi (AMF) are obligated root symbionts with an extraordinary capacity for growing, dispersing and surviving, but their life history is not well understood yet. Although there is information concerning AMF dispersal, distribution and establishment, some data are still ambiguous and contradictory. Arbuscular mycorrhizal fungi (AMF) life cycle responds to surrounding environment but even when they only reproduce asexually, their populations encompass a high genetic and functional diversity within ecosystems. Environmental disturbances create new habitats for AMF dispersal, which can take place by root to root contact, animal transport and erosion processes. These agents are the common dispersal mechanisms of AMF in nature. Distribution of AMF is influenced mainly by the environment and soil and plant communities, but the specific AMF-host plant association is thought to be secondary because the AMF must invade and colonize any host root for establishment. Thus, inoculum density, host and fungal genetic compatibility, edaphic factors and plant-microbial activity determine the formation of mycorrhizal infections.

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