The rhizosphere microbiome plays a crucial role in the ability of plants to colonize and thrive in stressful conditions such as drought, which could be decisive for the success of exotic plant ...invasion in the context of global climate change. The aim of this investigation was to examine differences in the composition, structure, and functional traits of the microbial community of the invader Nicotiana glauca R.C. Graham and native species growing at seven different Mediterranean semiarid locations under two distinct levels of water availability, corresponding to the wet and dry seasons. The results show that the phylum Actinobacteriota was an indicator phylum of the dry season as well as for the community of N. glauca. The dominant indicator bacterial families of the dry season were 67–14 (unclassified family), Pseudonocardiaceae, and Sphingomonadaceae, being relatively more abundant in the invasive rhizosphere. The relative abundances of the indicator fungal families Aspergillaceae (particularly the indicator genus Aspergillus), Glomeraceae, and Claroideoglomeraceae were higher in the invasive rhizosphere. The relative abundance of mycorrhizal fungi was higher in the invasive rhizosphere in the dry season (by about 40 % in comparison to that of native plants), without significant differences between invasive and native plants in the wet season. Bacterial potential functional traits related to energy and precursor metabolites production and also biosynthesis of cell wall, cofactors, vitamins, and amino acids as well as catabolic enzymes involved in the P cycle prevailed in the invasive rhizosphere under drought conditions. This study shows that the pronounced and beneficial shifts in the microbiome assembly and functions in the rhizosphere of N. glauca under conditions of low soil water availability can represent a clear advantage for its establishment.
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•Drought resistant bacteria were prevalent in the invader rhizosphere.•Actinobacteriota was an indicator phylum of the dry season and invader microbiome.•Relative abundance of AMF was higher in invasive rhizosphere in dry season.•Invader promoted specific bacterial functionality in response to drought.
The main goal of this study was to assess the effect of the inoculation of four autochthonous shrub species with the arbuscular mycorrhizal (AM) fungus Rhizophagus intraradices on the rhizosphere ...bacterial community and to ascertain whether such an effect is dependent on the host plant species. Additionally, analysis of rhizosphere soil chemical and biochemical properties was performed to find relationships between them and the rhizosphere bacterial communities. Non-metric multidimensional scaling analysis and subsequent permutational multivariate analysis of variance revealed differences in bacterial community composition and structure between non-inoculated and inoculated rhizospheres. Moreover, an influence of the plant species was observed. Different bacterial groups were found to be indicator taxonomic groups of non-inoculated and inoculated rhizospheres, Gemmatimonadetes and Anaerolineaceae, respectively, being the most notable indicators. As shown by distance based redundancy analysis, the shifts in bacterial community composition and structure mediated by the inoculation with the AM fungus were mainly related to changes in plant nutrients and growth parameters, such as the shoot phosphorus content. Our findings suggest that the AM fungal inoculum was able to modify the rhizosphere bacterial community assemblage while improving the host plant performance.
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•An AMF improved plant performance in the revegetation of a semiarid ecosystem.•AMF and plant species altered the rhizosphere bacterial community structure.•AMF-mediated bacterial community shifts were related to plant performance.•Anaerolineaceae family was an indicator of AMF-inoculated rhizospheres.
Exotic invasive plants may shape their own rhizosphere microbial community during global invasions. Nevertheless, the impacts of such plant invasions on the functional capacities of soil microbial ...communities remain poorly explored. We used an approach at a broad geographical scale to estimate the composition and abundance of the fungal functional groups, as well as the bacterial metabolic functions, associated with the rhizospheres of Carpobrotus edulis (L.) L. Bolus and the predominant native plants in coastal ecosystems located in different geographical regions. We used the ASV method to infer the potential functions of the soil microbial community with the PICRUSt2 and FUNGuild tools. The predictive functional profiling of the bacterial communities differed between the rhizospheres of the invasive and native plants, regardless of the biogeographic location of the invaded soil. Some predicted pathways related to the biosynthesis of nucleotides such as ppGpp and pppGpp, lipids, carbohydrates and secondary metabolites and the degradation of organic matter were enriched in the C. edulis rhizosphere. Moreover, the invasive microbiota was characterised by a greater richness and diversity of catabolic enzymes involved in nutrients cycling and higher relative abundances of saprotrophs and pathotrophs. Invasion by C. edulis promoted a shift in the potential functional versatility of the soil microbial communities, which can cope with nutrient limitations and biotic stress, and can favour the establishment of the invasive plant, but also alter the functioning and stability of the invaded ecosystems.
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•The effect of C. edulis on microbial functional capacities were tested at broad scale.•The bacteria functional profiling differed between invasive and native rhizospheres.•Pathways of nucleotides and lipid biosynthesis were enriched in invasive rhizosphere.•The invasive microbiota was enriched in catabolic enzymes related to nutrient cycling.•The invasive microbiota had higher relative abundances of saprotrophs and pathotrophs.
► Digestate was a source of available nitrogen and phosphorous in the short term. ► Digestate exerted positive effects on soil biological properties. ► Digestate led to good yield results for a ...summer watermelon crop. ► Organic amendments did not satisfy the nitrogen demand of a winter cauliflower crop.
The usefulness of a digestate from an anaerobic codigestion process as a fertiliser product was evaluated in a field experiment using two horticultural crops (watermelon and cauliflower), during two successive growing seasons. The effects of the digestate were compared with those of a traditional organic amendment (cattle manure) and a conventional mineral fertiliser. Digestate addition to soil provided a source of available nutrients (nitrogen and phosphorus) in the short-term and had positive effects on soil biological properties such as microbial biomass and enzyme activities, compared to the non-amended soil. The digestate application to soil led to yields comparable to the mineral fertilisation for the summer watermelon crop. However, for the winter cauliflower crop, only plots treated with the mineral fertiliser had good production. Nitrogen from the digestate is rapidly and highly available for plant growth in the short-term but also can be easily lost, together with a slow rate of microbial processes due to low temperatures, could reduce the fertilising capacity of the digestate. This seemed to be the main limiting factor for the winter cauliflower crop, where digestate or cattle manure, used as basal dressing, were not enough to satisfy the crop demand for nitrogen during its whole growth cycle.
The goal of this work was to evaluate the effects of fermented sugar beet residue and inoculation with a native arbuscular mycorrhizal (AM) fungus, Funneliformis mosseae (Nicol. and Gerd.) Gerd. and ...Trappe, or a native bacterium, Bacillus cereus Frankland & Frankland, alone or in combination, on the establishment of Lygeum spartum L. seedlings grown in a mine tailing under semiarid conditions. We conducted a field study to analyse root and shoot dry biomass, shoot nutrient contents, mycorrhization, plant nitrate reductase (NR) and acid phosphomonoesterase activities, soil enzyme activities and aggregate stability. Ten months after field transplanting, it was found that the three experimental factors had interacted synergistically with regard to shoot and root biomass, with increases of about 410% and 370%, respectively relative to plants in the untreated soil. The treatment combining all three factors increased the root content of all heavy metals, and the levels of nitrogen (N), phosphorus, potassium and NR activity in shoot tissues, whereas it decreased root acid phosphomonoesterase activity. Soil dehydrogenase, protease and β-glucosidase activities, total N content and aggregate stability were increased by the combined treatment. In conclusion, the combination of the organic amendment, the native AM fungus and the native bacterium can be regarded as a suitable tool for phytostabilization with L. spartum due to its ability to enhance the tolerance of plants to heavy metals, improve the plant nutritional status and increase the soil microbial function related to the C cycling.
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•Organic residue & native (AMF and bacterium) were tested as phytostabilization tools.•The three tools interacted synergistically on growth and nutrients of Lygeum spartum.•The combination of three tools increased shoot nitrate reductase (NR) activity.•Enhanced NR activity denoted plant tolerance to heavy metals by combined treatment.•The combined treatment increased soil microbial function related to N and C cycling.
Aims Our study was intended to elucidate the involvement of three species of arbuscular mycorrhizal fungi (AMF) in the formation and stabilization of aggregates in semiarid soils with different ...textures and calcium carbonate contents. Methods We used a root-hyphae compartment approach to compare the effect of three AMF (Rhizophagus irregularis, Septoglomus deserticola, and Gigaspora gigantea) on the structural stability of the hyphosphere (root-free hyphae) and mycorrhizosphere (hyphae + root) soil of Olea europaea plants grown in two soils differing in their texture (sandy loam and silty loam) and calcium carbonate content. Results Only the R. irregularis strain significantly increased the percentage of stable aggregates in both types of soil, being the increases higher in the hyphosphere compartment (on average, about 30 % compared to noninoculated soil). In the hyphosphere compartment of both soils, the hyphal length developed by plants inoculated with R. irregularis was 81 % greater than that of non-inoculated plants. The effect of the AMF on soil aggregation was mediated by mechanical entanglement of mycorrhizal fungal hyphae but without a contribution of labile carbohydrates. Conclusion The ability of extraradical hyphae to improve soil structure was independent of the soil texture and content of carbonates.
A field experiment was carried out to assess the effectiveness of combining mycorrhizal inoculation with a native AM fungus (Glomus sp.) and the addition of an urban organic waste compost (OWC) ...applied at two rates (0.5 and 2.0% (w:w)), with regard to promoting the establishment of Anthyllis cytisoides L. seedlings in a heavy metal polluted mine tailing, as well as stimulating soil microbial functions. The results showed that the combined use of the highest dose of OWC and AM inoculation significantly increased shoot biomass – by 64% – compared to the control value. However, the separate use of each treatment had no effect on the shoot biomass of this shrub species. At the 2% rate, OWC enhanced root colonisation by the introduced fungus as well as soil nutrient content and soil dehydrogenase and ß-glucosidase activities. The combined treatment increased the uptake of Zn and Mn in shoots, although only Zn reached excessive or potentially toxic levels. This study demonstrates that the combination of organic amendment and an AM fungus is a suitable tool for the phytomanagement of degraded mine tailings, although its effectiveness is dependent on the dose of the amendment.
•Phytomanagement using combination of compost and AMF was tested in field conditions.•The efficacy of combined treatment to increase shrub growth depended on compost dose.•Amendment promoted soil microbial function and AM formation.•The urban waste compost induced potentially toxic levels of Zn in shoots.
The COVID-19 pandemic has compelled university students to adapt to remote learning modalities resulting in increased of anxiety symptoms. This study explores levels of anxiety, and risk and ...protection factors among Social Work students at two universities in southern Spain. Thirty four percent were experiencing severe anxiety, and 28.5% mild to moderate, revealing that anxiety levels had increased significantly. Greater concern about academic situation and future economic scenario, living in an urban area and leave the habitual residence increased anxiety symptoms. By contrast, family income stability and higher social support from relatives reduced anxiety symptoms. These results support the planning of emotional support services for college students, as well as the incorporation in the study plans the acquisition of skills to live better in these conditions.
Exotic invasive plants have been reported to alter the soil microbial community composition and function in order to facilitate their further invasion. These changes in the soil microbiome could be ...influenced also by the characteristics of the soil and sites. We hypothesised that (i) the invasion of Mediterranean semiarid ecosystems by the woody shrub
Nicotiana glauca
(tree tobacco) would promote a specific rhizosphere microbial community with particular functions and (ii) the rhizosphere microbial community associated with the invasive plant would be independent of the edaphic characteristics of the invaded site. We tested these hypotheses by comparing the rhizosphere microbial community of
N. glauca
with that of the native plant community at four sites covering a broad range of distinctive edaphic characteristics, including two human-disturbed environments and two naturally harsh Mediterranean environments (one saline and one gypsum soil). The soil microbial community composition was analysed using Illumina MiSeq sequencing and the rhizosphere microbial function was predicted by PICRUSt and FUNGuild. Our results suggest that the composition of the rhizosphere bacterial and fungal communities differed between
N. glauca
and the dominant native plant species and according to the soil characteristics. The metabolic functions of indicator taxa also differed between the invader and the dominant native plant species. In particular, the functions involved in the metabolism of carbon (C) and sulphur (S) compounds were overrepresented in the rhizosphere community of the invader. In conclusion, invasive
N. glauca
shifts the soil microbial community composition and its function related to C and S cycling in semiarid Mediterranean environments, including soils affected by salinity and gypsum.
The importance of plant-microbe interactions to the success of invasive plants has rarely been studied at a global scale. Carpobrotus edulis (L.) N. E. Br is an aggressive invader in many areas ...around the world, forming dense mats in coastal environments. In an approach at a large geographical scale, over a wide latitudinal and climatic range, we tested the ability of C. edulis to alter the local bacterial and fungal community structure and microbial activity in eight invaded coastal locations. The factors invasiveness and geographical location had a significant effect on the soil microbiota, the microbial community composition and structure from the rhizosphere of native and C. edulis plants being distinct in every location. The effect of the invader on all the chemical, physico-chemical, and microbiological properties studied depended on the invaded location. The soil bacterial and fungal community composition and structure were related to the soil available nutrients and mean annual rainfall, and those of the soil bacterial community were also linked to the soil respiration and latitude. Overall, our results reveal that the ability of the invader C. edulis to alter soil microbial community structure harboring a specific microbiome was widespread across a large invaded range - leading to concurring changes in the rhizosphere microbial functioning, such as nutrient cycling.
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•Carpobrotus edulis is an aggressive invader in coastal areas around the world.•The invader shifted local bacterial and fungal community structure and composition.•The geographical location had a significant effect on the soil microbiota.•The invader altered microbial activities linked to nutrient cycling depending on site.•The invader rhizosphere promoted a specific microbiome over the entire invaded range.
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