Does Arbuscular Mycorrhiza Determine Soil Microbial Functionality in Nutrient-Limited Mediterranean Arid Ecosystems? (original) (raw)
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Mycorrhizal diversity and root colonization potential of agricultural soils – Doukkala, Morocco
Abstract— Underarid and semi-arid ecosystems where drought, soil salinity and low soil fertility considerably limit crop production. Under such stressful growing conditions, an appropriate management of mycorrhizae may have a determinant impact on plant production, on the improvement of soil quality and the diversification of cultivated crops. In this context, the diversity of the arbuscularmycorrhizae flora in semi-arid agricultural soils of OuledGhanem and SidiBennour sites of the Doukkala region, Morocco was evaluated and the impact of soil physico-chemical factors on their root-colonization potential studied. The two selected studied sites are respectively characterised by neutral to alkaline substrates, low level of organic matter but differed in their respective texture, sandy soil and muddy soil and their low to medium available P contents. The comparative analysis of the arbuscular mycorrhizal flora reveals a certain amount of shared species and is characterized in sandy soils by a good proportion of Diversisporales: Scutellosporacalospora, Acaulosporacavernata, Entrophosporainfrequens, Gigaspora margarita when the muddy soils are inhabited with a majority of Glomerales (Glomus.sp). Correlation between physico-chemical and biological soil data enlighted the negative impact of alkalinity and available phosphorus on the soil root colonization potential. The comparative data analyses bring in a critical look at the possible interaction between fungal diversity, mycotrophic plant and root colonization.
Soil Science, 2004
S TRESSED arid areas may be the result of progressive degradation of both vegetation cover (species diversity) and soil quality, both of which involve soil structure, nutrient availability, and microbial activity (Barea and Jeffries, 1995). Arbuscular mycorrhizal (AM) fungi constitute an important symbiotic association, not only for ameliorating plant nutrition but for enhancing water-stress tolerance (Ruiz-Lozano et al., 1995a, b, 1996) and other soil physiochemical character
Soil Biology and Biochemistry, 2013
The impact of nitrogen (N) fertilization and tillage on arbuscular mycorrhizal fungi (AMF) was studied in a Mediterranean arable system by combining molecular, biochemical and morphological analyses of field soil and of soil and roots from trap plants grown in microcosm. Canonical correspondence analysis (CCA) of PCReDGGE banding patterns evidenced that AMF communities in the field are affected by N-fertilization and tillage. N-fertilization was also the main factor shaping AMF communities in Medicago sativa trap plant soil and roots. The overall sporulation pattern of the different AMF species showed a predominant effect of tillage on AMF communities, as shown by CCA analysis. Funneliformis mosseae was the predominant species sporulating in tilled soils, while Glomus viscosum and Glomus intraradices prevailed in no-tilled soils. Field glomalin-related soil protein content was reduced by tillage practices. Our multimodal approach, providing data on two main production factors affecting soil AMF communities, may help implementing effective agricultural management strategies able to support the beneficial relationship between crops and native AMF symbionts.
Applied and environmental microbiology, 2016
We investigated arbuscular mycorrhizal fungi (AMF) communities in the roots and the rhizosphere soil ofBrachypodium retusum,in six different natural soils under field conditions. We explored phylogenetic patterns in AMF composition using indicator species analyses (ISA) to find AMF associated to a given habitat (root vs rhizosphere) and soil type. We tested whether the AMF characteristic of different habitats or contrasting soils were more closely related than expected by chance. Then we used principal component analyses and multivariate analyses of variance to test for the relative contribution of each factor to explain the variation in fungal community composition. Finally, we used redundancy analyses to identify the soil properties that significantly explained the differences in AMF communities across soil types. The results pointed out a tendency of AMF communities in roots to be closely related and different from those in the rhizosphere soil. The ISA revealed AMF associated to...
Assessment of natural mycorrhizal potential in a desertified semiarid ecosystem
Applied and environmental microbiology, 1996
A survey of the natural mycorrhizal potential has been carried out in a representative area of a desertified semiarid ecosystem in the southeast of Spain. Many indigenous plants from the field site were mycorrhizal, including the dominant Anthyllis cytisoides, which had high levels of colonization by arbuscular mycorrhizal fungi (AMF). Low numbers of AMF spores were present in the soil, although a range of species, including Scutellospora calospora, Glomus coronatum, Glomus constrictum, and several Acaulospora species, was represented. Soil infectivities, as determined by a soil dilution method, were similar for most plants tested but were significantly lower for Anthyllis cytisoides. Nevertheless, when a less disruptive method to determine soil infectivity was used, the importance of the mycelial network in maintaining the infectivity of soil under perennial shrubs, such as Anthyllis cytisoides, was highlighted. Seasonal variations in the mycorrhizal infectivity showed that it was ...
Applied Soil Ecology, 2020
Arbuscular mycorrhizal fungi (AMF) establish mutualistic symbioses with the roots of most plant species, playing a key role in crop productivity and ecosystem functioning. The characterization of local AMF genotypes assemblages is a prerequisite for the reproduction, both ex situ and on farm, of efficient native AMF communities, in order to improve soil quality and fertility through agricultural 2 management and to use selected AMF as inoculants in sustainable agriculture. Contrasting evidences have been found by studies addressing the influence of different environmental drivers, among which geographical distance, on the diversity and composition of AMF communities in agricultural soils. In the present study, a Mediterranean "hot-spot" of AMF species richness was studied to assess whether AMF display a spatial structure at a local scale and whether their spore distribution is affected by soil variables. AMF distribution patterns were estimated by spore analysis, in 12 field plots, which were characterized for their chemical and physical variables. Plots were distributed along a transect across the field, and sampling points distances ranged from 4 to 102 m. While most taxa displayed an aggregated distribution, no significant spatial correlation was detected among AMF communities. On the contrary, AMF communities were significantly correlated with the entire set of soil variables, and with distinct soil characteristics, such as pH and total N, but not P. Multiple regression analysis revealed that distribution of most AMF species was significantly related to nitrogen, clay, cation exchange capacity and pH. Multivariate (RDA) analysis confirmed results of multiple regression, with the best model selecting three soil variables (N, clay and pH). Variance partitioning analysis also showed that AMF distribution was mostly explained by environmental variables (36.4%) and by environmental variables spatial structure (16.4%). Overall, the results of this work revealed the importance of soil variables in shaping AMF community composition and spatial heterogeneity, within a site characterized by high AMF richness.
Agricultural Science Digest, Volume 44 Issue 1: 06-13 (February), 2024
Background: Medicago sativa, Medicago truncatula and Trifolium rubens are legumes widely distributed in Algeria. These species hold ecological and agricultural significance and serve as a natural resource for combating desertification and as livestock fodder. Methods: Comparative investigations of arbuscular mycorrhizal fungi (AMF) colonization in the roots of these leguminous species were conducted. The physicochemical and microbiological attributes of AMF's infectious potential were explored for all three species. The presence or absence of endomycorrhizal structures was assessed in these species. Result: The mycorrhizal infectious potential of the flora was significantly enhanced in the case of Medicago truncatula when compared to Trifolium rubens. Mycorrhization occurred at a frequency exceeding 80% in all three species. The impact of legume mycorrhizal fungi colonization on soil physicochemical properties was examined, revealing alterations in soil biological fertility, particularly in terms of phosphate and nitrogen content. Medicago truncatula exhibited a more pronounced positive influence on soil physical, chemical and microbiological characteristics when compared to Medicago sativa and Trifolium rubens. Consequently, these herbaceous species can be employed as nurse plants (facilitators) or as bio-fertilizers.
Plant and Soil, 2012
Aims To study the relationship between changes in soil properties and plant community characters produced by grazing in a meadow steppe grassland and the composition and diversity of spore-producing arbuscular mycorrhizal fungi (AMF). Methods A field survey was carried out in a meadow steppe area with a gradient of grazing pressures (a site with four grazing intensities and a reserve closed to grazing). The AMF community composition (characterized by spore abundance) and diversity, the vegetation characters and soil properties were measured, and root colonization by AMF was assessed. Results AMF diversity (richness and evenness) was higher under light to moderate grazing pressure and declined under intense grazing pressures. Results of multiple regressions indicated that soil electrical conductivity was highly associated with AMF diversity. The variation in AMF diversity was partially associated to the density of tillers of the dominant grass (Leymus chinensis), the above and below-ground biomass and the richness of the plant community. Conclusions We propose that the relationship between plants and AMF is altered by environmental stress (salinity) which is in turn influenced by animal grazing. Direct and indirect interactions between vegetation, soil properties, and AMF community need to be elucidated to improve our ability to manage these communities.