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Joseph B Morton - One of the best experts on this subject based on the ideXlab platform.
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Gigasporaceae versus Glomeraceae (phylum Glomeromycota): A biogeographic tale of dominance in maritime sand dunes
Fungal Ecology, 2018Co-Authors: Sidney L Sturmer, Laio Z. Oliveira, Joseph B MortonAbstract:Abstract Community composition of arbuscular mycorrhizal fungi (AMF) is influenced by host, soil chemistry, and climatic conditions at the local and regional scale, but little is known about factors shaping community composition on a global scale. In this study, the pattern of dominance by families in Glomeromycota in maritime sand dunes worldwide was examined to test the hypothesis that soil pH is a major factor shaping AMF community structure. We analyzed 38 publications from the literature containing data on soil chemistry and species composition and calculated relative species richness (RSR) for each of the families Gigasporaceae, Glomeraceae, and Acaulosporaceae. Regression and multivariate analyses were performed to determine the relationship and association of RSR of families with soil pH, temperature and precipitation and biogeographical realms. Of the 119 AMF species found in sand dunes, members of Gigasporaceae and Glomeraceae dominated in all studies. In Nearctic dunes, Gigasporaceae and Glomeraceae co-dominated fungal communities while Gigasporaceae dominated in Neotropical dunes and Glomeraceae dominated Palearctic and Oriental/Sino-Japanese realms. Overall, the proportion of species in Gigasporaceae was above 40% in soil pH 6.5. Soil pH was negatively correlated with RSR of Gigasporaceae but positively correlated with RSR of Glomeraceae. Thirteen species were detected in at least four biogeographical realms and are considered cosmopolitan. Redundancy analysis evidenced soil pH and one Moran's spatial variable as significant predictors of Glomeromycota family composition. Moran's I correlograms showed positive spatial autocorrelation only at distances
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Taxonomic revision transferring species in Kuklospora to Acaulospora (Glomeromycota) and a description of Acaulospora colliculosa sp. nov. from field collected spores
Mycologia, 2010Co-Authors: Wittaya Kaonongbua, Joseph B Morton, James D. BeverAbstract:In a phylogenetic study of arbuscular mycorrhizal fungal species in Acaulospora (Acaulosporaceae, Glomeromycota) we discovered that species classified in genus Kuklospora, a supposed sister clade of Acaulospora, did not partition as a monophyletic clade. Species in these two genera can be distinguished only by the position of the spore relative to a precursor structure, the sporiferous saccule, as either within (entrophosporoid) or laterally (acaulosporoid) on the saccule subtending hypha. Subsequent spore differentiation follows identical patterns and organization. Molecular phylogeny reconstructed from nrLSU gene sequences, together with developmental data, support the hypothesis that the entrophosporoid mode of spore formation evolved many times and thus represents a convergent trait of little phylogenetic significance. Therefore genus Kuklospora is rejected as a valid monophyletic group and it is integrated taxonomically into genus Acaulospora. Thus Acaulospora colombiana and Acaulospora kentinensis a...
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Patterns of species composition and distribution of arbuscular mycorrhizal fungi in arid regions of southwestern North America and Namibia, Africa
Canadian Journal of Botany, 2000Co-Authors: Jean C Stutz, Ruth Copeman, Chris A Martin, Joseph B MortonAbstract:Arbuscular mycorrhizal (AM) fungal communities at 13 sampling sites in two arid regions (Chihuahuan and Sonoran Deserts) and semi-arid grasslands in North America were compared with each other and with AM fungal communities in the Namib Desert in Africa using successive trap cultures to induce sporulation. Twenty-one AM fungal species were recovered, eight of which were undescribed. Species richness at each sampling site ranged from 6 to 12 species. There was considerable overlap in the species composition of the two desert regions surveyed in North America. Glomus microaggregatum Koske, Gemma & Olexia, Glomus etunicatum Becker & Gerd., Glomus intraradices Schenck & Smith, Glomus mosseae (Nicol. & Gerd.) Gerd. & Trappe, Glomus spurcum Pfeiffer, Walker & Bloss, and two undescribed Glomus species (AZ112 and AZ123) were detected in over 50% of the sampling sites in North America. Similarities in species composition of arid regions of Namibia and North America also was high, ranging from 54 to 79%. The taxonomic range of AM fungi was limited mostly to small-spored fungi in Glomaceae and Acaulosporaceae. Acaulospora trappei Ames & Linderman, Glomus etunicatum, Glomus intraradices, Glomus occultum Walker, Glomus microaggregatum, Glomus mosseae, Glomus spurcum, and an undescribed Glomus species (AZ123) were detected in all three desert regions and in semi-arid grasslands. Gigaspora rosea Nicolson & Schenck was the only species in Gigasporaceae detected, and then only at one sampling site in North America. Scutellospora species were not found. These results indicate involvement of both historical processes such as dispersal and selective variables at the local level in determining species composition in arid environments.Key words: biogeography, Chihuahuan Desert, community structure, diversity, Glomales, Namib Desert, species richness, Sonoran Desert.
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taxonomic reinterpretation of morphological characters in Acaulosporaceae based on developmental patterns
Mycologia, 1999Co-Authors: Sidney L Sturmer, Joseph B MortonAbstract:Sequences in the development of subcel- lular organization in soil-borne spores of Acaulospora laevis, A. spinosa and Entrophospora colombiana were analyzed to define discrete morphological characters informative in taxonomic and phylogenetic analyses of arbuscular mycorrhizal fungi in the family Acau- losporaceae, Glomales. A sporiferous saccule initially forms terminally on a sporogenous hypha, followed by spore formation. Spore ontogenesis proceeds in a linear series of discontinuous stages that are identical in all three species studied, with each stage recog- nized by addition of a new subcellular structure from the spore cytoplasm. The juvenile spore wall is a sin- gle hyaline layer continuous with the wall of the spo- riferous saccule hypha, followed by differentiation of a pigmented spore wall layer with thin adherent sub- layers (or laminae) which varies phenotypically among species. A third spore wall layer then is dif- ferentiated in spores of Acaulospora, which varies phenotypically between species. Once the spore wall is completely differentiated and spores have ceased expansion, species in both genera sequentially form two discrete and separate bilayered flexible hyaline inner walls. Layers of the first inner wall are thin (< 1 ,um) and adherent. The inner layer of the second flexible wall increasingly reacts in Melzer's reagent as it matures in E. colombiana, indicating the layers are formed sequentially rather than concurrently. After both inner walls are fully differentiated, a "germi- nation orb" is synthesized, although this structure rarely is observed in newly harvested spores from pot cultures. Structures formed in each stage of spore differentiation vary in the extent to which they are conserved among species, indicating different levels of taxonomic resolution. All layers of the spore wall and process-related features such as spore size define species-level variation, and flexible inner walls resolve taxa not yet recognized in glomalean classification.
Christopher Walker - One of the best experts on this subject based on the ideXlab platform.
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Environmental factors driving arbuscular mycorrhizal fungal communities associated with endemic woody plant Picconiaazorica on native forest of Azores
Annals of Microbiology, 2020Co-Authors: Catarina Melo, Sara Luna, Claudia Krüger, Christopher Walker, D. Mendonça, Henrique M.a.c. Fonseca, Paulo A. V. Borges, Artur Da Câmara MachadoAbstract:Arbuscular mycorrhizal fungi (AMF) play important key roles in the soil ecosystems as they link plants to the root-inaccessible part of soil. The aims of this study were to investigate which environmental factors influence the spatial and temporal structuring of AMF communities associated to Picconia azorica in two Azorean islands (Terceira and Sao Miguel islands), and investigate the seasonal variation in AMF communities between the two islands. Communities of AMF associated with P. azorica in native forest of two Azorean islands (Terceira and Sao Miguel) were characterised by spore morphology or molecular analysis. Forty-five AMF spore morphotypes were detected from the four fragments of P. azorica forest representing nine families of AMF. Acaulosporaceae (14) and Glomeraceae (9) were the most abundant families. AMF density and root colonisation varied significantly between islands and sampling sites. Root colonisation and spore density exhibited temporal patterns, which peaked in spring and were higher in Terceira than in Sao Miguel. The relative contribution of environmental factors showed that factors such as elevation, relative air humidity, soil pH, and soil available P, K, and Mg influenced AMF spore production and root colonisation. Different sporulation patterns exhibited by the members of the commonest families suggested different life strategies. Adaptation to a particular climatic and soil condition and host phenology may explain seasonal differences in sporulation patterns. Cohorts of AMF associated to P. azorica are shaped by regional processes including environmental filters such as soil properties and natural disturbance.
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Distribution of arbuscular mycorrhizal fungi (AMF) in Terceira and São Miguel Islands (Azores)
Biodiversity Data Journal, 2020Co-Authors: Catarina Melo, Christopher Walker, Artur Da Câmara Machado, Helena Freitas, Paulo A. V. BorgesAbstract:The data, presented here, come from samples collected during three research projects which aimed to assess the impact of land-use type on Arbuscular Mycorrhizal Fungi (AMF) diversity and community composition in pastures of Terceira Island (Azores, Macaronesia, Portugal) and also in the native forest of two Azorean Islands (Terceira and São Miguel; Azores, Macaronesia, Portugal). Both projects contributed to improving the knowledge of AMF community structure at both local and regional scales. Little is known on the AMF communities from Azores islands and this study reports the first survey in two Azorean Islands (Terceira and São Miguel). A total of 18,733 glomeromycotan spores were classified at the species level from 244 field soil samples collected in three different habitat types - native forests (dominated by Juniperus brevifolia and Picconia azorica), semi-natural and intensively-managed pastures. Thirty-seven distinct spore morphotypes, representing ten glomeromycotan families, were detected. Species of the family Acaulosporaceae dominated the samples, with 13 species (38% of the taxa), followed by Glomeraceae (6 spp.), Diversisporaceae (4 spp.), Archaeosporaceae (3 spp.), Claroideoglomeraceae (3 spp.), Gigasporaceae (3 spp.), Ambisporaceae and Paraglomeraceae, both with the same number of AMF species (2 spp.), Sacculosporaceae (1 sp.) and Entrophospora (family insertae sedis). Members of the family Acaulosporaceae occurred almost exclusively in the native forests especially associated with the Picconia azorica rhizosphere, while members of Gigasporaceae family showed a high tendency to occupy the semi-natural pastures and the native forests of Picconia azorica. Members of Glomeraceae family were broadly distributed by all types of habitat which confirm the high ecological plasticity of this AMF family to occupy the more diverse habitats. Catarina Drumonde Melo, Christopher Walker, Helena Freitas, Artur Câmara Machado, Paulo A. V. Borges.
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Environmental factors driving arbuscular mycorrhizal fungal communities associated with endemic woody plant Picconiaazorica on native forest of Azores
Annals of Microbiology, 2019Co-Authors: Catarina Drumonde Melo, Sara Luna, Claudia Krüger, Christopher Walker, Henrique M.a.c. Fonseca, Duarte Mendonça, Paulo A. V. Borges, Artur Câmara MachadoAbstract:Purpose Arbuscular mycorrhizal fungi (AMF) play important key roles in the soil ecosystems as they link plants to the root-inaccessible part of soil. The aims of this study were to investigate which environmental factors influence the spatial and temporal structuring of AMF communities associated to Picconia azorica in two Azorean islands (Terceira and São Miguel islands), and investigate the seasonal variation in AMF communities between the two islands. Methods Communities of AMF associated with P. azorica in native forest of two Azorean islands (Terceira and São Miguel) were characterised by spore morphology or molecular analysis. Results Forty-five AMF spore morphotypes were detected from the four fragments of P. azorica forest representing nine families of AMF. Acaulosporaceae (14) and Glomeraceae (9) were the most abundant families. AMF density and root colonisation varied significantly between islands and sampling sites. Root colonisation and spore density exhibited temporal patterns, which peaked in spring and were higher in Terceira than in São Miguel. The relative contribution of environmental factors showed that factors such as elevation, relative air humidity, soil pH, and soil available P, K, and Mg influenced AMF spore production and root colonisation. Conclusion Different sporulation patterns exhibited by the members of the commonest families suggested different life strategies. Adaptation to a particular climatic and soil condition and host phenology may explain seasonal differences in sporulation patterns. Cohorts of AMF associated to P. azorica are shaped by regional processes including environmental filters such as soil properties and natural disturbance.
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Communities of arbuscular mycorrhizal fungi under Picconia azorica in native forests of Azores
Symbiosis, 2017Co-Authors: Catarina Drumonde Melo, Sara Luna, Claudia Krüger, Christopher Walker, Henrique M.a.c. Fonseca, Maria Jaizme-vega, Duarte Mendonça, Artur Câmara MachadoAbstract:Arbuscular mycorrhizal fungi (AMF) from the rhizosphere of the endemic Laurisilva tree, Picconia azorica , w ere characterised at two sites in each of two Azorean islands (Terceira and São Miguel). Forty-six spore morphotypes were found, and DNA extraction was attempted from individual spores of each of these. DNA was obtained from 18 of the morphotypes, from which a 1.5 kb long fragment of the nuclear ribosomal RNA gene (SSU-ITS-LSU) was sequenced. A total of 125 AMF sequences were obtained and assigned to 18 phylotypes. Phylogenetic analysis revealed sequences belonging to the families, Acaulosporaceae , Archaeosporaceae , Claroideoglomeraceae, Gigasporaceae and Glomeraceae . Phylotype richness changed between islands and between sampling sites at both islands suggesting that geographical and historical factors are determinant in shaping AMF communities in native forest of Azores. Ecological analysis of the molecular data revealed differences in AMF community composition between islands. In Terceira, the rhizosphere of P. azorica was dominated by species belonging to Acaulosporaceae and Glomeraceae , while São Miguel was dominated by members of Glomeraceae and Gigasporaceae . This is the first molecular study of AMF associated with P. azorica in native forest of the Azores. These symbiont fungi are key components of the ecosystem. Further research is needed to develop their use as promoters of plant establishment in conservation and restoration of such sites.
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Arbuscular mycorrhizal fungal community composition associated with Juniperus brevifolia in native Azorean forest
Acta Oecologica-international Journal of Ecology, 2017Co-Authors: Catarina Melo, Sara Luna, Claudia Krüger, Christopher Walker, D. Mendonça, Henrique M.a.c. Fonseca, Maria Jaizme-vega, Artur Da Câmara MachadoAbstract:Abstract The communities of glomeromycotan fungi (arbuscular mycorrhizal fungi, AMF) under native Juniperus brevifolia forest from two Azorean islands, Terceira and Sao Miguel, were compared, mainly by spore morphology, and when possible, by molecular analysis. Thirty-nine morphotypes were detected from 12 genera. Glomeromycotan fungal richness was similar in Terceira and Sao Miguel, but significantly different among the four fragments of native forest. Spore diversity and community composition differed significantly between the two islands. The less degraded island, Terceira, showed 10 exclusive morphotypes including more rare types, whereas the more disturbed forest on Sao Miguel showed 13 morphs, mostly of common types. Forests from Terceira were dominated by Acaulosporaceae and Glomeraceae. Whereas members of Acaulosporaceae, Glomeraceae and Ambisporaceae were most frequent and abundant in those from Sao Miguel. Spore abundance was greatest on Terceira, and correlated with soil chemical properties (pH), average monthly temperature and relative humidity.
Fritz Oehl - One of the best experts on this subject based on the ideXlab platform.
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Diversity of arbuscular mycorrhizal fungi in Brazil's Caatinga and experimental agroecosystems
Biotropica, 2017Co-Authors: Juliana Souza De Pontes, Fritz Oehl, Frederico Marinho, Danny Coyne, Danielle Karla Alves Da Silva, Adriana Mayumi Yano-melo, Leonor Costa MaiaAbstract:Cowpea (Vigna unguiculata) is a nutritious legume crop for both its grain and leaves and comprises an important component in both human and animal nutrition. In Brazil, the use of mulch, such as coconut fiber, and organic fertilizers to maximize cowpea production offers an alternative to conventional mineral fertilizer strategies. Farming practices affect the diversity and activity of soil microorganisms, including arbuscular mycorrhizal fungi (AMF), important plant growth promoters for legumes. Our objective was to determine the effect of mulching with coconut fiber and manure on AMF diversity in cowpea. Soil samples were collected from an Experimental Station in Petrolina, NE Brazil: one Caatinga (natural dry-forest vegetation), one fallow, and one experimental site established in the fallow area and cultivated with cowpea receiving cattle manure and four doses (0, 12, 24, 48 t/ha) of coconut fiber. AMF species richness, abundance, and diversity were evaluated. Sixty-four AMF species were recorded, with predominance of Glomeraceae and Acaulosporaceae. Highest species richness (47) was recovered from the Caatinga but AMF diversity was also high in the cultivated sites, demonstrating the importance of mycotrophic plants, such as cowpea, in crop production systems for the maintenance of AMF species richness. Although several species, such as Claroideoglomus etunicatum, Acaulospora scrobiculata, Glomus trufemii, and Paraglomus pernambucanum, revealed pronounced sporulation patterns, even high doses of coconut fiber did not affect AMF richness and diversity, compared to fallow. Consequently, cultivation of mycotrophic plants and use of organic manures are able to maintain high AMF species richness in tropical agroecosystems.
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Acaulospora pustulata and Acaulospora tortuosa , two new species in the Glomeromycota from Sierra Nevada National Park (southern Spain)
Nova Hedwigia, 2013Co-Authors: Javier Palenzuela, Gladstone Alves Da Silva, Concepción Azcón-aguilar, José Miguel Barea, Fritz OehlAbstract:Two new Acaulospora species were found in two wet mountainous grassland ecosystems of Sierra Nevada National Park (Spain), living in the rhizosphere of two endangered plants, Ophioglossum vulgatum and Narcissus nevadensis, which co-occurred with other plants like Holcus lanatus, Trifolium repens, Mentha suaveolens and Carum verticillatum, in soils affected by ground water flow. The two fungi produced spores in pot cultures, using O. vulgatum, N. nevadensis, H. lanatus and T. repens as bait plants. Acaulospora pustulata has a pustulate spore ornamentation similar to that of Diversispora pustulata, while A. tortuosa has surface projections that resemble innumerous hyphae-like structures that are more rudimentary than the hyphae-like structures known for spores of Sacculospora baltica or Glomus tortuosum. Phylogenetic analyses of sequences of the ITS and partial LSU of the ribosomal genes reveal that both fungi are new species within the Acaulosporaceae. They are most closely related to A. alpina and undescribed Acaulospora species. With 45–72 μm spore size, Acaulospora pustulata is the smallest Acaulospora species known so far, while A. tortuosa has slightly larger spores (61–84(–94) μm), which is in the range known for several other Acaulospora species like A. longula, A. alpina, A. nivalis and A. sieverdingii that have either smooth or pitted spore surfaces. These two fungi might play an important role in helping their endangered hosts O. vulgatum and N. nevadensis to survive under the stressed environments of the high mountains of Sierra Nevada.
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Revision of Entrophospora and description of Kuklospora and Intraspora, two new genera in the arbuscular mycorrhizal Glomeromycetes
Journal of applied botany and food quality, 2012Co-Authors: Ewald Sieverding, Fritz OehlAbstract:Five mycorrhizal fungal species of the Glomeromycetes which were organized in the genus Entrophospora are revised. They all form their spores within the hyphal stalk directly beneath or in some distance of a sporiferous saccule formed intercalary or terminally in the mycelium. Based on differences respective similarities in spore morphologies and root infection characteristics only Entrophospora infrequens and Entrophospora baltica remain in this genus. The genus is the type genus for the new family Entrophosporaceae. The other three species are organized in two new genera. Kuklospora gen. nov. with Kuklospora colombiana and Kuklospora kentinensis (formerly Entrophospora colombiana and Entrophospora kentiniensis ) is placed into the family of the Acaulosporaceae. Intraspora gen. nov. so far contains only Intraspora schenckii (the former Entrophospora schenckii ) and is included into the family of the Archaeosporaceae. The morphological differences between the genera and the distribution of these fungal species in ecosystems are discussed.
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Arbuscular mycorrhizal fungal communities in sub-Saharan Savannas of Benin, West Africa, as affected by agricultural land use intensity and ecological zone
Mycorrhiza, 2008Co-Authors: Atti Tchabi, Danny Coyne, Andres Wiemken, Fabien Hountondji, Louis Lawouin, Fritz OehlAbstract:The rapid decline of soil fertility of cultivated lands in the sub-Saharan savannas of West Africa is considered to be the main cause of the increasingly severe constraints of food production. The soils in this tropical area are highly fragile, and crop yields are limited by characteristically low levels of available phosphorus. Under such preconditions, the multiple benefits of the arbuscular mycorrhizal (AM) symbiosis are likely to play a pivotal role for maintaining natural soil fertility by enhancing plant nutrient use efficiency, plant health, and stabilization of a favorable soil structure. Thus, it is important to explore the impact of the commonly applied farming practices on the native AM fungal community. In the present study, we determined the AM fungal species composition in three ecological zones differing by an increasingly prolonged dry season from South to North, from the Southern Guinea Savanna (SG), to the Northern Guinea Savanna (NG), to the Sudan Savanna (SU). In each zone, four “natural” and four “cultivated” sites were selected. “Natural” sites were three natural forest savannas (at least 25–30 years old) and a long-term fallow (6–7 years old). “Cultivated” sites comprised a field with yam ( Dioscorea spp.) established during the first year after forest clearance, a field under mixed cropping with maize ( Zea mays ) and peanut ( Arachis hypogaea ), a field under peanut, and a field under cotton ( Gossypium hirsutum ) which was the most intensively managed crop. Soil samples were collected towards the end of the wet season in each zone. AM fungal spores were extracted and morphologically identified. Soil subsamples were used to inoculate AM fungal trap cultures using Stylosanthes guianensis and Brachiaria humidicola as host plants to monitor AM root colonization and spore formation over 10 and 24 months, respectively. A total of 60 AM fungal species were detected, with only seven species sporulating in the trap cultures. Spore density and species richness were generally higher in the natural savannas and under yam than at the other cultivated sites and lowest under the intensively managed cotton. In the fallows, species richness was intermediate, indicating that the high richness of the natural savannas was not restored. Surprisingly, higher species richness was observed in the SU than in the SG and NG, mainly due to a high proportion of species in the Gigasporaceae, Acaulosporaceae, and Glomeraceae. We conclude that the West African savannas contain a high natural AM fungal species richness, but that this natural richness is significantly affected by the common agricultural land use practices and appears not to be quickly restored by fallow.
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Impact of long-term conventional and organic farming on the diversity of arbuscular mycorrhizal fungi
Oecologia, 2004Co-Authors: Fritz Oehl, Ewald Sieverding, Paul Mäder, David Dubois, Kurt Ineichen, Thomas Boller, Andres WiemkenAbstract:Previous work has shown considerably enhanced soil fertility in agroecosystems managed by organic farming as compared to conventional farming. Arbuscular mycorrhizal fungi (AMF) play a crucial role in nutrient acquisition and soil fertility. The objective of this study was to investigate the diversity of AMF in the context of a long-term study in which replicated field plots, at a single site in Central Europe, had been cultivated for 22 years according to two “organic” and two “conventional” farming systems. In the 23rd year, the field plots, carrying an 18-month-old grass-clover stand, were examined in two ways with respect to AMF diversity. Firstly, AMF spores were isolated and morphologically identified from soil samples. The study revealed that the AMF spore abundance and species diversity was significantly higher in the organic than in the conventional systems. Furthermore, the AMF community differed in the conventional and organic systems: Glomus species were similarly abundant in all systems but spores of Acaulospora and Scutellospora species were more abundant in the organic systems. Secondly, the soils were used to establish AMF-trap cultures using a consortium of Plantago lanceolata, Trifolium pratense and Lolium perenne as host plants. The AMF spore community developing in the trap cultures differed: after 12 months, two species of the Acaulosporaceae (A. paulinae and A. longula) were consistently found to account for a large part of the spore community in the trap cultures from the organic systems but were found rarely in the ones from the conventional systems. The findings show that some AMF species present in natural ecosystems are maintained under organic farming but severely depressed under conventional farming, indicating a potentially severe loss of ecosystem function under conventional farming.
Alejandra G. Becerra - One of the best experts on this subject based on the ideXlab platform.
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Arbuscular Mycorrhizal Fungal Communities of High Mountain Ecosystems of South America: Relationship with Microscale and Macroscale Factors
Fungal Biology, 2020Co-Authors: Florencia Soteras, Gabriel Grilli, Eugenia Menoyo, Alejandra G. BecerraAbstract:The high mountain ecosystems of South America represent one of the main hotspots of biodiversity. There is an increasing interest in disentangling global patterns of arbuscular mycorrhizal fungi (AMF). Recently studies postulated that the majority of AMF taxa are cosmopolitan, although community composition changes depend on microscale and macroscale factors. In this Chapter we reviewed the studies performed at high mountain ecosystems of South America analyzing the richness of morphospecies and structure of AMF communties in relation to microscale (host species, pH, N, P) and macroscale factors (latitude, temperature, precipitation). AMF communities differed in both scales being associated with sampling site, vegetation type or host identity. Glomeraceae and Gigasporaceae families were related to micro- and macro-scale factors, while Acaulosporaceae did not show significant relationships with neither micro- nor with macro-scale factors. At higher scales, AMF community composition of tropical and temperate ecosystems differed due to latitude, precipitation and temperature. Meanwhile, at lower scales soil characteristics and host species became the most relevant factors in differentiating AMF composition of sites. AMF communities of high mountain forests of South America are differentially affected by the particular characteristics of these environments different from the cosmopolitan pattern.
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Soil lead pollution modifies the structure of arbuscular mycorrhizal fungal communities
Mycorrhiza, 2019Co-Authors: Valeria Soledad Faggioli, Eugenia Menoyo, József Geml, Minna Kemppainen, Alejandro G. Pardo, M. Julieta Salazar, Alejandra G. BecerraAbstract:The impact of lead (Pb) pollution on native communities of arbuscular mycorrhizal fungi (AMF) was assessed in soil samples from the surroundings of an abandoned Pb smelting factory. To consider the influence of host identity, bulk soil surrounding plant roots soil samples of predominant plant species (Sorghum halepense, Bidens pilosa, and Tagetes minuta) growing in Pb-polluted soils and in an uncontaminated site were selected. Molecular diversity was assessed by sequencing the 18S rDNA region with primers specific to AMF (AMV4.5NF/AMDGR) using Illumina MiSeq. A total of 115 virtual taxa (VT) of AMF were identified in this survey. Plant species did not affect AMF diversity patterns. However, soil Pb content was negatively correlated with VT richness per sample. Paraglomeraceae and Glomeraceae were the predominant families while Acaulosporaceae, Ambisporaceae, Archaeosporaceae, Claroideoglomeraceae, Diversisporaceae, and Gigasporaceae were less abundant. Acaulosporaceae and Glomeraceae were negatively affected by soil Pb, but Paraglomeraceae relative abundance increased under increasing soil Pb content. Overall, 26 indicator taxa were identified; four of them were previously reported in Pb-polluted soils (VT060; VT222; VT004; VT380); and five corresponded to cultured spores of Scutellospora castaneae (VT041), Diversispora spp. and Tricispora nevadensis (VT060), Diversispora epigaea (VT061), Glomus proliferum (VT099), and Gl. indicum (VT222). Even though AMF were present in Pb-polluted soils, community structure was strongly altered via the differential responses of taxonomic groups of AMF to Pb pollution. These taxon-specific differences in tolerance to soil Pb content should be considered for future phytoremediation strategies based on the selection and utilization of native Glomeromycota.
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Arbuscular mycorrhizal fungal diversity in rhizosphere spores versus roots of an endangered endemic tree from Argentina: Is fungal diversity similar among forest disturbance types?
Applied Soil Ecology, 2016Co-Authors: Florencia Soteras, Bruno Coutinho Moreira, Gabriel Grilli, Nicolás Pastor, Flávia Carneiro Mendes, Daniele Ruela Mendes, Daniel Renison, Maria Catarina Megumi Kasuya, Francisco Adriano De Souza, Alejandra G. BecerraAbstract:Abstract The aim of this study was to compare the arbuscular mycorrhizal fungal (AMF) community of the rhizosphere and inside the roots of the perennial Polylepis australis tree. Three forest types differing in their structural complexity due to anthropogenic disturbances were chosen at three different sites at the high mountains of central Argentina. Rhizosphere spores and P. australis roots of four randomly selected trees were isolated from 36 soil samples, DNA was extracted and the 18S rDNA fragments were amplified by nested-PCR. The products were analyzed by DGGE and the bands were excised for sequencing. In total, 36 OTUs were defined from 56 DGGE bands successfully sequenced. Forest disturbance types showed similar communities of AMF, as rhizosphere spores and within the roots of P. australis. However, DGGE clustering showed mainly differences between rhizosphere spores and root-colonizing AMF. Members of Glomeraceae, Pacisporaceae, Acaulosporaceae and Gigasporaceae were shown in rhizosphere spore samples. Root samples showed only members of Acaulosporaceae and Gigasporaceae, which might be complementary in terms of soil resources exploration. The prevalence of the root system with their community of symbionts might explain the resilience of AMF soil communities to forests structural changes. This study presents evidence of a possible preference in the AMF–P. australis interaction.
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Growth response, phosphorus content and root colonization of Polylepis australis Bitt. seedlings inoculated with different soil types
New Forests, 2013Co-Authors: Florencia Soteras, Daniel Renison, Alejandra G. BecerraAbstract:Polylepis forests are one of the most endangered high mountain ecosystems of South America and reforestation with native Polylepis species has been highly recommended. Greenhouse bioassays were set up to determine the influence of three different soils on growth and phosphorous nutrition of Polylepis australis seedlings. Soils were collected from a grassland, a rare mature forest and a forest degraded due to repeated fires. We identified the arbuscular mycorrhizal fungi (AMF) present in the three soils and after 12 months we harvested the seedlings to evaluate root and shoot biomass, plant P content and root colonization by native AMF and dark septate endophytes (DSE). The soil inocula contained 26 AMF morphospecies. Grassland inoculum showed the highest AMF richness, and mature forest showed a different AMF community assembly from grassland and degraded forest inocula. Root biomass and root colonization were highest in seedlings inoculated with mature forest soil, meanwhile shoot biomass and plant P content were similar between all treatments. AMF colonization correlated negatively with DSE and root biomass was negatively correlated with DSE colonization, thus these fungal symbionts could be competing for resources. Our results indicate that AMF inoculum from the mature forest stand has the potential to improve P. australis performance, probably due to the dominance of Glomeraceae and Acaulosporaceae families. However, other soil microorganisms could be together with AMF in the natural inocula, affecting the growth response of P. australis seedlings. Future studies evaluating the effect of these inocula under field conditions should be carried out.
Artur Da Câmara Machado - One of the best experts on this subject based on the ideXlab platform.
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Environmental factors driving arbuscular mycorrhizal fungal communities associated with endemic woody plant Picconiaazorica on native forest of Azores
Annals of Microbiology, 2020Co-Authors: Catarina Melo, Sara Luna, Claudia Krüger, Christopher Walker, D. Mendonça, Henrique M.a.c. Fonseca, Paulo A. V. Borges, Artur Da Câmara MachadoAbstract:Arbuscular mycorrhizal fungi (AMF) play important key roles in the soil ecosystems as they link plants to the root-inaccessible part of soil. The aims of this study were to investigate which environmental factors influence the spatial and temporal structuring of AMF communities associated to Picconia azorica in two Azorean islands (Terceira and Sao Miguel islands), and investigate the seasonal variation in AMF communities between the two islands. Communities of AMF associated with P. azorica in native forest of two Azorean islands (Terceira and Sao Miguel) were characterised by spore morphology or molecular analysis. Forty-five AMF spore morphotypes were detected from the four fragments of P. azorica forest representing nine families of AMF. Acaulosporaceae (14) and Glomeraceae (9) were the most abundant families. AMF density and root colonisation varied significantly between islands and sampling sites. Root colonisation and spore density exhibited temporal patterns, which peaked in spring and were higher in Terceira than in Sao Miguel. The relative contribution of environmental factors showed that factors such as elevation, relative air humidity, soil pH, and soil available P, K, and Mg influenced AMF spore production and root colonisation. Different sporulation patterns exhibited by the members of the commonest families suggested different life strategies. Adaptation to a particular climatic and soil condition and host phenology may explain seasonal differences in sporulation patterns. Cohorts of AMF associated to P. azorica are shaped by regional processes including environmental filters such as soil properties and natural disturbance.
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Distribution of arbuscular mycorrhizal fungi (AMF) in Terceira and São Miguel Islands (Azores)
Biodiversity Data Journal, 2020Co-Authors: Catarina Melo, Christopher Walker, Artur Da Câmara Machado, Helena Freitas, Paulo A. V. BorgesAbstract:The data, presented here, come from samples collected during three research projects which aimed to assess the impact of land-use type on Arbuscular Mycorrhizal Fungi (AMF) diversity and community composition in pastures of Terceira Island (Azores, Macaronesia, Portugal) and also in the native forest of two Azorean Islands (Terceira and São Miguel; Azores, Macaronesia, Portugal). Both projects contributed to improving the knowledge of AMF community structure at both local and regional scales. Little is known on the AMF communities from Azores islands and this study reports the first survey in two Azorean Islands (Terceira and São Miguel). A total of 18,733 glomeromycotan spores were classified at the species level from 244 field soil samples collected in three different habitat types - native forests (dominated by Juniperus brevifolia and Picconia azorica), semi-natural and intensively-managed pastures. Thirty-seven distinct spore morphotypes, representing ten glomeromycotan families, were detected. Species of the family Acaulosporaceae dominated the samples, with 13 species (38% of the taxa), followed by Glomeraceae (6 spp.), Diversisporaceae (4 spp.), Archaeosporaceae (3 spp.), Claroideoglomeraceae (3 spp.), Gigasporaceae (3 spp.), Ambisporaceae and Paraglomeraceae, both with the same number of AMF species (2 spp.), Sacculosporaceae (1 sp.) and Entrophospora (family insertae sedis). Members of the family Acaulosporaceae occurred almost exclusively in the native forests especially associated with the Picconia azorica rhizosphere, while members of Gigasporaceae family showed a high tendency to occupy the semi-natural pastures and the native forests of Picconia azorica. Members of Glomeraceae family were broadly distributed by all types of habitat which confirm the high ecological plasticity of this AMF family to occupy the more diverse habitats. Catarina Drumonde Melo, Christopher Walker, Helena Freitas, Artur Câmara Machado, Paulo A. V. Borges.
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Arbuscular mycorrhizal fungal community composition associated with Juniperus brevifolia in native Azorean forest
Acta Oecologica-international Journal of Ecology, 2017Co-Authors: Catarina Melo, Sara Luna, Claudia Krüger, Christopher Walker, D. Mendonça, Henrique M.a.c. Fonseca, Maria Jaizme-vega, Artur Da Câmara MachadoAbstract:Abstract The communities of glomeromycotan fungi (arbuscular mycorrhizal fungi, AMF) under native Juniperus brevifolia forest from two Azorean islands, Terceira and Sao Miguel, were compared, mainly by spore morphology, and when possible, by molecular analysis. Thirty-nine morphotypes were detected from 12 genera. Glomeromycotan fungal richness was similar in Terceira and Sao Miguel, but significantly different among the four fragments of native forest. Spore diversity and community composition differed significantly between the two islands. The less degraded island, Terceira, showed 10 exclusive morphotypes including more rare types, whereas the more disturbed forest on Sao Miguel showed 13 morphs, mostly of common types. Forests from Terceira were dominated by Acaulosporaceae and Glomeraceae. Whereas members of Acaulosporaceae, Glomeraceae and Ambisporaceae were most frequent and abundant in those from Sao Miguel. Spore abundance was greatest on Terceira, and correlated with soil chemical properties (pH), average monthly temperature and relative humidity.
