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.
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.
The involvement of mutualistic plant-fungal interactions in invasion processes, especially in some climatic regions including semiarid areas, has not been sufficiently investigated. We compared the ...arbuscular mycorrhizal fungi (AMF) communities hosted by the invasive plant Pennisetum setaceum with those from the co-occurring native Hyparrhenia hirta at five Mediterranean semiarid locations with different edaphic characteristics. Illumina technology was used to investigate the AMF communities in the roots. The subsequent multivariate analysis showed that native and non-native host plants shared a similar AMF community, whereas the invaded locations differed in AMF communities harbored in the plant roots. The indicator species analysis revealed the absence of indicator virtual taxa for the fungal communities of the roots of native or invasive plants. In contrast, different numbers of indicator species were recorded in different sampling locations. According to the canonical correspondence analysis, the variability in the AMF communities between sampling sites was related to changes in soil total carbon, electrical conductivity, respiration, and protease and urease activities. These findings reveal the unspecificity of P. setaceum in relation to its association with the AMF community encountered in the invaded locations, which could have facilitated its successful establishment and spread.
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•P. setaceum is an invader in Mediterranean semiarid ecosystems of Southeast Spain.•AMF communities from P. setaceum and a native plant species were compared.•The invasive and the native species were co-occurring at five different locations.•AMF communities varied between locations but not between invasive and native plants.•P. setaceum is able to associate with local AMF communities outside its native range.
Background and aims
Exotic invasive plants may have adverse effects on native plant communities and ecosystem functions by altering communities of belowground mutualistic mycorrhizal fungi. However, ...little is known about how such alterations change over time. The aim of this work was to determine the arbuscular mycorrhizal fungi (AMF) communities colonizing the roots of
Nicotiana glauca
populations of distinct ages (1 and 20 years old), and of co-occurring native plants, growing at four different Mediterranean semiarid locations. The short-term and long-term effects of the invader on rhizosphere activity and nutrient pools were also determined.
Methods
Illumina MiSeq technology was used for high-throughput sequencing of AMF communities and basal respiration and enzymatic activities were determined for assessing rhizosphere activity.
Results
The composition and structure of AMF communities differed according to the invasive character of plant and the invaded site. The AMF community belonging to the young invasive plants had a significantly different structure and composition in comparison to the native plants and the adult invasive plants. However, the native plants and the adult invasive plants harboured a similar AMF community. In general, basal respiration, enzymatic activities and nutrients of the rhizospheres of two populations of
N. glauca
of distinct ages were significantly different from those of the rhizosphere of native plants, but these differences were independent of the time after the invasion.
Conclusions
The invasion of semiarid Mediterranean sites by
N. glauca
mediated temporary changes in mycorrhizal associations, whereas the early effect of this invasive plant decreasing rhizosphere activity remained across time.
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 objective of this study was to determine whether native and invasive plants harbor different bacterial communities in their rhizospheres and whether there are bacterial indicator species ...associated with the invasive rhizosphere. Additionally, physico-chemical, biochemical, and biological properties have been determined in the native and invasive rhizospheres in order to ascertain the relationships between these soil properties and the rhizosphere bacterial communities. We carried out a study in five independent locations under Mediterranean semiarid conditions, where the native Hyparrhenia hirta is being displaced by Pennisetum setaceum. Partial 16S rRNA genes of the rhizosphere bacterial communities were amplified and 454-pyrosequenced. Principal coordinate analysis revealed differences in the composition and structure of the rhizosphere bacterial communities between native and invasive plants, the values of the richness index being higher in the invasive microbial community. Rhizosphere microbial community structure was also influenced by invaded location. The indicator species analysis showed a higher number of indicators for the invasive community at all the taxonomic levels studied, the genus Ohtaekwangia being the most abundant indicator. As shown by canonical correspondence analysis, the protease and dehydrogenase activities and soil respiration were related to the rhizosphere bacterial community of invasive plant. However, only protease activity was significantly affected by the plant type, being higher in the invasive plant rhizosphere. Our results show that P. setaceum invasion has produced an intense interaction with the soil bacterial community, shifting its structure, composition, and protease activity related to N cycling, which may be altering the function of the invaded ecosystem.
•P. setaceum is an invader in Mediterranean semiarid ecosystems of Southeast Spain.•Invasive plant had higher bacterial community richness than H. hirta.•The genus Ohtaekwangia was the most abundant indicator of P. setaceum rhizosphere.•Protease activity and pH were significantly higher in invasive plant rhizosphere.•Protease activity was related to bacterial community structure of invasive plant.
The epiphytic vascular mycobiota is scarce and facultative in semi-arid Mediterranean ecosystems. However, unlike in soil conditions, little is known about the factors driving mycorrhizal communities ...in epiphytic environments. Here, we investigated the arbuscular mycorrhizal fungi (AMF) harboured by 31 plant species occurring on the trunks of Phoenix dactylifera. We wanted to ascertain if host identity and plant functional traits shape mycorrhizal communities. Specifically, we tested the plant life-cycle (perennial versus annual), the plant life-form (herbaceous versus woody), the plant origin (exotic versus native) and the plant species. The plant affiliation to species strongly influenced the AMF community composition. Plant life-form and plant life-cycle also shaped indicator taxa. The AMF structure differed between annual and perennial species and higher AMF richness was detected in perennial plants. The epiphytic plants associated with AMF irrespective of whether they were native or not, probably because here no functional differences derive from plant origin.
•AM fungal DNA was amplified from roots of 31 facultative epiphytic species on palms.•23 AM fungal OTUs were detected, 11 matched with previously identified sequences.•Plant species, life-cycle and life-form factors influenced the AMF communities.•Epiphytic plants associated with AMF irrespective of whether they are native or not.
•Amplify knowledge about plasma-treated surface modifications with dyestuff molecule.•Acrylic fiber surface modification by corona plasma treatment.•Plasma main effects: ablation, plasma-migration, ...functionalization of the surface.•Study of the kinetics of the dyeing process of acrylic fiber under Tg temperature.•Initial rate of dyeing and dyestuff exhaustion increased by plasma treatment.
Fiber surface modification with air corona plasma has been studied through dyeing kinetics under isothermal conditions at 30°C on an acrylic-fiber fabric with a cationic dye (CI Basic Blue 3) analyzing the absorption, desorption and fixing on the surface of molecules having defined cationic character.
The initial dyeing rate in the first 60s indicates an increase of 58.3% in the dyeing rate due to the effect of corona plasma on the acrylic fiber surface. At the end of the dyeing process, the plasma-treated fabrics absorb 24.7% more dye, and the K/S value of the acrylic fabric increases by 8.8%. With selected dyestuff molecules, new techniques can be designed to amplify the knowledge about plasma-treated surface modifications of macromolecules.
Knowledge of the arbuscular mycorrhizal fungal assemblages in the Trachypogon savanna ecosystems is very important to a better understanding of the ecological processes mediated by this soil ...microbial group that affects multiple ecosystem functions. Considering the hypothesis that the biocrusts can be linked to vegetation through the arbuscular fungi mycelial network, the objectives proposed in this study were to determine (i) whether there are arbuscular mycorrhizal fungi (AMF) in the biocrusts (ii) whether arbuscular mycorrhizal fungal assemblages are linked to the Trachypogon patches, and (iii) whether the composition of the assemblages is related to soil properties affected by microbiological activity. The community structure of the AMF was investigated in three habitats: rhizospheric soil and roots of Trachypogon vestitus, biological soil crusts, and bare soil. The canonical correspondence analysis showed that two soil properties related to enzymatic activity (protease and β-glucosidase) significantly affected the community composition of the AMF. The biocrusts in the Venezuelan savanna are colonized by an AM fungal community linked to that of the bare soil and significantly different from that hosted by the roots of the surrounding T. vestitus, suggesting that assemblages of AMF in biocrusts might be related more closely to those of annual plant species appearing in favorable conditions.
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•The biocrusts in the Trachypogon savanna are colonized by AMF.•AMF assemblages in biocrusts could be related to the occurrence of annual species.•Protease and β-glucosidase significantly affected the AMF community composition.
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