scholarly journals Disease ecology across soil boundaries: effects of below-ground fungi on above-ground host–parasite interactions

2015 ◽  
Vol 282 (1817) ◽  
pp. 20151993 ◽  
Author(s):  
Leiling Tao ◽  
Camden D. Gowler ◽  
Aamina Ahmad ◽  
Mark D. Hunter ◽  
Jacobus C. de Roode
Keyword(s):  
Indirect Effects ◽  
Mycorrhizal Fungi ◽  
Disease Ecology ◽  
Danaus Plexippus ◽  
Arbuscular Mycorrhizal ◽  
Protozoan Parasite ◽  
Monarch Butterfly ◽  
Host Parasite Interactions ◽  
Below Ground ◽  
Host Parasite

Host–parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus ) and its protozoan parasite ( Ophryocystis elektroscirrha ), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host–parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host–parasite systems.

Virulence determinants in a natural butterfly-parasite system

Parasitology ◽  
2006 ◽  
Vol 134 (5) ◽  
pp. 657-668 ◽  
Author(s):  
J. C. de ROODE ◽  
L. R. GOLD ◽  
S. ALTIZER
Keyword(s):  
Adult Development ◽  
Danaus Plexippus ◽  
Protozoan Parasite ◽  
Monarch Butterfly ◽  
Adult Longevity ◽  
Virulence Determinants ◽  
Host Fitness ◽  
Inoculation Dose ◽  
Host Sex ◽  
Host Parasite

SUMMARYMuch evolutionary theory assumes that parasite virulence (i.e. parasite-induced host mortality) is determined by within-host parasite reproduction and by the specific parasite genotypes causing infection. However, many other factors could influence the level of virulence experienced by hosts. We studied the protozoan parasite Ophryocystis elektroscirrha in its host, the monarch butterfly, Danaus plexippus. We exposed monarch larvae to wild-isolated parasites and assessed the effects of within-host replication and parasite genotype on host fitness measures, including pre-adult development time and adult weight and longevity. Per capita replication rates of parasites were high, and infection resulted in high parasite loads. Of all host fitness traits, adult longevity showed the clearest relationship with infection status, and decreased continuously with increasing parasite loads. Parasite genotypes differed in their virulence, and these differences were maintained across ecologically relevant variables, including inoculation dose, host sex and host age at infection. Thus, virulence appears to be a robust genetic parasite trait in this system. Although parasite loads and genotypes had strong effects on virulence, inoculation dose, host sex and age at infection were also important. These results have implications for virulence evolution and emphasize the need for a detailed understanding of specific host-parasite systems for addressing theory.

Biology and ecology of mycoparasitism

1995 ◽  
Vol 73 (S1) ◽  
pp. 1284-1290 ◽  
Author(s):  
Peter Jeffries
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Fungal Communities ◽  
Fungal Ecology ◽  
Natural Ecosystems ◽  
Nutrient Source ◽  
Fungicolous Fungi ◽  
Host Parasite ◽  
The Relationship

The term mycoparasitism applies strictly to those relationships in which one living fungus acts as a nutrient source for another, but fungicolous relationships may also be included in which nutrient exchange has not been shown. Fungicolous fungi have a constant but indeterminate association with another fungus, and it can be difficult to demonstrate a true parasitic relationship. Mycoparasitic relationships can be necrotrophic or biotrophic, and can be classified on the basis of the host–parasite interface as contact necrotrophs, invasive necrotrophs, haustorial biotrophs, intracellular biotrophs, or fusion biotrophs depending on the intimacy of the relationship. In natural ecosystems, it is proposed that mycoparasitic relationships play an important role in the development of fungal communities. Two specific examples have been chosen to illustrate the general principles of mycoparasitism: the necrotrophic invasion of spores of arbuscular mycorrhizal fungi and the biotrophic invasion of mucoralean hosts by haustorial mycoparasites. Key words: mycoparasitism, fungicolous fungi, arbuscular mycorrhizal fungi, fungal ecology.

scholarly journals Predicting missing links in global host-parasite networks

2020 ◽  
Author(s):  
Maxwell J. Farrell ◽  
Mohamad Elmasri ◽  
David Stephens ◽  
T. Jonathan Davies
Keyword(s):  
Disease Surveillance ◽  
Disease Ecology ◽  
Global Network ◽  
Major Health ◽  
Host Parasite Interactions ◽  
Literature Searches ◽  
Association Data ◽  
Multiple Species ◽  
Health Burdens ◽  
Host Parasite

Parasites that infect multiple species cause major health burdens globally, but for many, the full suite of susceptible hosts is unknown. Proactive disease surveillance involves gathering host-parasite association data, predicting missing links, and targeting efforts towards the most likely undocumented interactions. Using the largest global network of mammal host-parasite interactions amalgamated to date (>29,000 interactions), we predict undocumented links and conduct targeted literature searches. We find evidence for many of the top “missing” links, including parasites of humans, domesticated animals, and endangered wildlife, and identify regions such as tropical and central America as likely hotspots of undocumented associations. This approach of iterated prediction and targeted surveillance can efficiently guide the collection of host-parasite interaction data critical for developing broad-scale theories in disease ecology and evolution, help to identify previously undocumented hosts, and inform predictions of future host-parasite interactions.

scholarly journals A symbiotic balancing act: arbuscular mycorrhizal specificity and specialist fungus gnat pollination in the mycoheterotrophic genus Thismia (Thismiaceae)

2019 ◽  
Vol 124 (2) ◽  
pp. 331-342 ◽  
Author(s):  
Xing Guo ◽  
Zhongtao Zhao ◽  
Shek Shing Mar ◽  
Dianxiang Zhang ◽  
Richard M K Saunders
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Single Species ◽  
Symbiotic Association ◽  
Mycorrhizal Associations ◽  
Fungus Gnats ◽  
Floral Phenology ◽  
Fungus Gnat ◽  
Below Ground ◽  
Yellow Pigments

Abstract Background and Aims Mycorrhizal associations in mycoheterotrophic plants are generally more specialized than in autotrophs. Mycoheterotrophs typically bear small, inconspicuous flowers that often self-pollinate to maximize seed set, although some have structurally complex flowers indicative of xenogamy. A trade-off has previously been proposed between specialization in these above- and below-ground symbioses, although empirical data are lacking. Methods We used next-generation DNA sequencing to compare the mycorrhizal communities from the roots of a mycoheterotrophic species, Thismia tentaculata (Thismiaceae), and its neighbouring autotrophs. We furthermore conducted detailed assessments of floral phenology and pollination ecology, and performed artificial pollination experiments to determine the breeding system. Key Results Thismia tentaculata maintains a symbiotic association with a single arbuscular mycorrhizal Rhizophagus species. The flowers are pollinated by a single species of fungus gnats (Corynoptera, Sciaridae), which are attracted by the yellow pigments and are temporarily restrained within the perianth chamber before departing via apertures between the anthers. The plants are self-compatible but predominantly xenogamous. Conclusions Our findings demonstrate that T. tentaculata maintains highly specialized associations with pollinators and mycorrhizal fungi, both of which are widely distributed. We suggest that specialization in multiple symbiotic interactions is possible in mycoheterotrophs if redundant selective pressures are not exerted to further restrict an already constrained suite of life-history traits.

scholarly journals Influence of herbicide on plants in connection with formation of arbuscular mycorrhizal symbiosis

2018 ◽  
Vol 23 ◽  
pp. 369-373
Author(s):  
Zh. Z. Guralchuk ◽  
A. M. Sychuk ◽  
O. V. Gumenyuk
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mechanism Of Action ◽  
Indirect Effects ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Arbuscular Mycorrhizal Symbiosis ◽  
Mycorrhizal Symbiosis ◽  
Direct And Indirect Effects ◽  
Factors Influencing

Aim. The aim of the work is to analyze the available literature data on the effect of herbicides on the formation of mycorrhizal symbiosis. Results. The article gives a brief overview of the influence of herbicides with different mechanism of action on the formation and functioning of arbuscular mycorrhizal symbiosis. The direct and indirect effects of herbicides on the AM fungi, the different selectivity of AM fungi to herbicides and other factors influencing the effect of herbicides on biodiversity of AM fungi and the formation of mycorrhizal symbiosis are considered. Conclusions. Herbicides with different mechanism of action can have a significant effect on the diversity of AM fungi present in the soil, the formation and functioning of mycorrhizal symbiosis. Their effect on the AM fungi can be either direct or indirect due to the influence on the host plant. AM fungi, in turn, can also influence the selectivity of the plant to herbicides. Studies on the effect of herbicides on mycorrhizal symbiosis may be important for increasing the herbicide efficiency. Keywords: herbicides, arbuscular mycorrhizal fungi, mycorrhizal symbiosis.

scholarly journals Arbuscular Mycorrhizae of Phormium Tenax in a restored New Zealand wetland across hydrological gradients

2021 ◽  
Author(s):  
◽  
Alexandra Coles
Keyword(s):  
New Zealand ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Community Dynamics ◽  
Woody Species ◽  
Arbuscular Mycorrhizal ◽  
Native Woody Species ◽  
Below Ground ◽  
Amf Communities ◽  
Generation Sequencing

<p>New Zealand has lost over 90% of its former wetlands and many that remain are in a degraded state. Restoration projects are often impeded by the failure of native plants to establish back into non-native dominated communities. Phormium tenax is fast growing and acts a nurse plant in wetlands, accelerating the establishment of slower growing native woody species. The roles of below ground organisms are increasingly recognised as affecting plant community dynamics, and this study investigates the diversity of a group of pervasive organisms, the arbuscular mycorrhizal fungi (AMF), growing in symbiosis with Phormium tenax. Next generation sequencing was used to create two libraries to determine the sensitivity of coding and non-coding molecular markers when characterising the AMF community associated with Phormium tenax.  AMF communities colonising individual plants were found to be diverse, and varied across restoration stages, but uncorrelated with soil moisture. The composition of of AMF communities changed seasonally and I observed more AMF hyphae and arbuscules in winter.</p>

Assemblages of arbuscular mycorrhizal fungi in tropical humid and dry forests in the Northeast of Brazil

Botany ◽  
2018 ◽  
Vol 96 (12) ◽  
pp. 859-871 ◽  
Author(s):  
Daniele Magna Azevedo de Assis ◽  
Mayara Alice Correia de Melo ◽  
Danielle Karla Alves da Silva ◽  
Fritz Oehl ◽  
Gladstone Alves da Silva
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Dry Forest ◽  
Northeastern Brazil ◽  
Sampling Effort ◽  
Humid Forest ◽  
Below Ground ◽  
Amf Communities ◽  
High Diversity

Tropical forests concentrate most of the world’s biodiversity. In the Northeast of Brazil it is possible to record mosaics of tropical dry and moist forests growing nearby but with completely different biotic and abiotic characteristics. These forests are constantly threatened by intense environmental devastation that affect not only above-ground communities but also those hidden below-ground, such as arbuscular mycorrhizal fungi (AMF), which act in maintaining ecosystem balance. This work aimed to determine the composition of native AMF communities in areas of humid forest (HF) and dry forest (DF) in northeastern Brazil. A total of 70 taxa of AMF were identified in the study areas, with Acaulospora (17) and Glomus (16) being the most representative genera. The sampling effort allowed the evaluation of 70%–73% of the species estimated for the areas. AMF communities differed between HF and DF areas. Species of the genus Glomus occurred predominantly in humid forest areas, whereas representatives of the order Gigasporales were associated more specifically with the dry forest area. Four soil attributes showed approximately 50% correlation with the composition of the AMF community (silt, clay, K, and CEC). Humid and dry forest areas presented a high diversity of AMF, and the soil properties were an important factor for the community composition of these fungi.

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