Plant health status effects on arbuscular mycorrhizal fungi associated with Lavandula angustifolia and Lavandula intermedia infected by Phytoplasma in France (original) (raw)
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Environmental microbiology, 2015
Arbuscular mycorrhizal fungi (AMF) are essential constituents of most terrestrial ecosystems. AMF species differ in terms of propagation strategies and the major propagules they form. This study compared the AMF community composition of different propagule fractions- colonised roots, spores and extraradical mycelium (ERM)-associated with five Mediterranean plant species in Sierra de Baza Natural Park (Granada, Spain). AMF were identified using 454 pyrosequencing of the SSU rRNA gene. A total of 96 AMF phylogroups (virtual taxa, VT) were detected in the study site, including 31 novel VT. After per-sample sequencing depth standardisation, 71 VT were recorded from plant roots, and 47 from each of the spore and ERM fractions. AMF communities differed significantly among the propagule fractions, and the root-colonizing fraction differed among host plant species. Indicator VT were detected for the root (13 Glomus VTs), spore (Paraglomus VT281, VT336, Pacispora VT284) and ERM (Diversispora...
Applied and Environmental Microbiology, 2003
The impact of land use intensity on the diversity of arbuscular mycorrhizal fungi (AMF) was investigated at eight sites in the "three-country corner" of France, Germany, and Switzerland. Three sites were low-input, species-rich grasslands. Two sites represented low-to moderate-input farming with a 7-year crop rotation, and three sites represented high-input continuous maize monocropping. Representative soil samples were taken, and the AMF spores present were morphologically identified and counted. The same soil samples also served as inocula for "AMF trap cultures" with Plantago lanceolata, Trifolium pratense, and Lolium perenne. These trap cultures were established in pots in a greenhouse, and AMF root colonization and spore formation were monitored over 8 months. For the field samples, the numbers of AMF spores and species were highest in the grasslands, lower in the low-and moderate-input arable lands, and lowest in the lands with intensive continuous maize monocropping. Some AMF species occurred at all sites ("generalists"); most of them were prevalent in the intensively managed arable lands. Many other species, particularly those forming sporocarps, appeared to be specialists for grasslands. Only a few species were specialized on the arable lands with crop rotation, and only one species was restricted to the high-input maize sites. In the trap culture experiment, the rate of root colonization by AMF was highest with inocula from the permanent grasslands and lowest with those from the high-input monocropping sites. In contrast, AMF spore formation was slowest with the former inocula and fastest with the latter inocula. In conclusion, the increased land use intensity was correlated with a decrease in AMF species richness and with a preferential selection of species that colonized roots slowly but formed spores rapidly.
Mycorrhiza, 2020
Arbuscular mycorrhizal fungi (AMF) colonization in roots of putative non-mycotrophic species has been known for decades, but our knowledge of AMF community structure in non-mycotrophic plants is limited. Here, we compared AMF species composition and diversity in roots of co-occurring mycotrophic and putative non-mycotrophic herbs in two wetlands. A SSU-ITS-LSU fragment in AMF rDNA was amplified, cloned and sequenced, and used to characterize the AMF community in the roots of 16 putative non-mycotrophic and 18 mycotrophic herbs. The results showed that AMF hyphae and vesicles, but not arbuscules, were commonly present in putative non-mycotrophic plants. A total of 971 AMF sequences were obtained, and these were finally assigned to 28 operational taxonomic units (OTUs). At both sites, AMF taxon richness and Hill number based on Shannon's index in the putative non-mycotrophic herbs were similar to those for mycotrophic plants, but AMF community composition between mycotrophic and non-mycotrophic plants was significantly different. Ten AMF OTUs were uniquely detected in the putative non-mycotrophic species, and two were identified as the AMF indicators in non-mycotrophic plants. These results implied that non-mycotrophic plants may harbor a potential source of AMF diversity previously ignored which should be included in our understanding of diversity, distribution pattern, and ecological significance of root-colonizing AMF. As the first direct comparison of AMF diversity and species composition between mycotrophic and putative non-mycotrophic species in wetlands, our study has important implications for the understanding of AMF distribution patterns.
Functional Ecology, 2004
1. An experiment was carried out to determine whether the community composition of root-colonizing arbuscular mycorrhizal fungi (AMF) influences the growth and nutrient status of two congeneric Pulsatilla species, one rare and one common in Estonia. We hypothesized that: (i) establishment and growth of plants is influenced by the composition of native AMF communities; (ii) growth of congeneric plant species with different abundances differs due to their response to specific AMF communities; and (iii) distribution of a plant species may depend on the composition of local root symbiotic AMF communities. 2. Rare Pulsatilla patens and common Pulsatilla pratensis were grown in pots, under homogeneous soil nutrient and microbial community conditions, containing either one from two (grassland and forest sites) of natural AMF soil inocula, or no AMF. 3. Lower establishment was observed in the non-mycorrhizal soil compared to AMF inoculated soils. Plant biomass, phosphorus concentration and root AMF colonization of both species were higher, and nitrogen concentration lower, in grassland as opposed to forest inoculum. 4. The common species displayed more vigorous growth than the rare counterpart in the presence of grassland inoculum. Conversely, slightly better growth of a rare species was recorded in the forest inoculum, in which plant biomass was an order of magnitude lower compared to the grassland inoculum. 5. As Pulsatilla spp. roots hosted site-characteristic AMF small-subunit rDNA sequence groupings, we suggest that the presence of AM fungi that are more beneficial for the common species may be one factor behind the observed differential distribution and performance of the two plant species.
Arbuscular mycorrhizal fungal communities in plant roots are not random assemblages
FEMS Microbiology Ecology, 2011
The landscape of Mexican seasonal dry forests is affected by various periodic (long and drastic drought) and random (elimination of the forest coverage for agricultural purposes) disturbance events. The community of arbuscular mycorrhizal fungi (AMF) responds to these changes, sporulating and reducing its activity during the dry season, and slowly reestablishing itself following abandonment of cultivated fields.
New Phytologist, 2007
Sequencing of the 5 ′ end of the large ribosomal subunit (LSU rDNA) and quantitative polymerase chain reaction (qPCR) were combined to assess the impact of four annual Medicago species ( Medicago laciniata , Medicago murex , Medicago polymorpha and Medicago truncatula ) on the genetic diversity of arbuscular mycorrhizal (AM) fungi, and on the relative abundance of representative AM fungal genotypes, in a silty-thin clay soil (Mas d'Imbert, France).
Environmental Microbiology, 2007
Most studies on the species composition of arbuscular mycorrhizal fungi (AMF) have solely analysed mycorrhizal roots or AM spores collected from soil samples. However, the spore production rate and proportions of AMF mycelium in roots and soils have all been shown to vary substantially in a taxon-specific manner. Therefore, in the study presented here we used a molecular approach to analyse the species composition of AMF in spores, intra-radical and extraradical mycelium in an intensively farmed meadow in central Germany. By polymerase chain reaction and sequencing of the ITS region members of seven different families and species groups within Glomeromycota were identified. The data revealed remarkable differences in the composition of AMF taxa both between the spores and the mycelia, and between the two types of mycelia. Glomus group Ab was dominant in roots and spores, in accordance with previous research. However, members of this group were rarely detected as extra-radical mycelium, in which Paraglomeraceae were dominant, although we found no evidence for the presence of Paraglomeraceae in roots or spores, even when a specific primer set was used. These results may be interpreted as a further indication that AMF are not necessarily obligate symbionts of plants.
Mycorrhiza, 2012
Arbuscular mycorrhizal fungal (AMF) communities have been demonstrated to respond to a variety of biotic and abiotic factors, including various aspects of land management. Numerous studies have specifically addressed the impact of land use on AMF communities, but usually have been confined to one or a few sites. In this study, soil AMF assemblages were described in four different long-term observatories (LTOs) across Europe, each of which included a sitespecific high-intensity and a low-intensity land use. AMF communities were characterized on the basis of 454 sequencing of the internal transcribed spacer 2 (ITS2) rDNA region. The primary goals of this study were (i) to determine the main factors that shape AMF communities in differentially managed sites in Europe and (ii) to identify individual AMF taxa or combinations of taxa suitable for use as biomarkers of land use intensification. AMF communities were distinct among LTOs, and we detected significant effects of management type and soil properties within the sites, but not across all sites. Similarly, indicator species were identified for specific LTOs and land use types but not universally for high-or lowintensity land uses. Different subsets of soil properties, including several chemical and physical variables, were found to be able to explain an important fraction of AMF community variation alone or together with other examined factors in most sites. The important factors were different from those for other microorganisms studied in the same sites, highlighting particularities of AMF biology.
Ecology, 1998
Almost all natural plant communities contain arbuscular mycorrhizal fungi (AMF). We hypothesized that the species composition of AMF communities could have the potential to determine plant community structure if the growth response to different AMF species or to communities of AMF species varies among plant species. To test the existence of such a differential response we conducted a pot experiment where each of three plant species, Hieracium pilosella, Bromus erectus, and Festuca ovina were inoculated with each of four AMF species, or with a mixture of these four AMF species, or were uninoculated. The AMF species originated from a calcareous grassland in which the three plant species also coexisted.
Scientia Horticulturae
The structure of arbuscular mycorrhizal fungi (AMF) communities in areas under strawberry cultivation in the Brazilian subtropics has been poorly studied. Thus, we characterized cultivated and native forest soils, of reference-sites in strawberry cultivation in southern Brazil, regarding the AMF community and investigate if there is variability in the diversity in the mycorrhizal communities of these soils. For this, we evaluated eight soils, in a completely randomized design experiment. We observed that the species Claroideoglomus aff. luteum, Claroideoglomus claroideum, C. etunicatum, Funneliformis mosseae and Glomus sp2 were the most frequent. Native forest soils had more fungal species than cultivated soils. Soils little anthropized under strawberry cultivation resembled the natural soils regarding the AMF heterogeneity. We conclude that there are AMF diversity in soils of reference-sites in strawberry cultivation, and that C. claroideum and C. etunicatum are generalist, independent of the ecosystem. This study contributes significantly to our knowledge about the community composition of AMF in soils of reference-sites in the strawberry cultivation in the Brazilian subtropics. Thus, it becomes possible the development of inoculants for this horticultural crop, with the role of making their cultivation more sustainable.