Mycorrhizal Fungal Community Composition Research Articles

"Ectomycorrhizal exploration type" could be a functional trait explaining the spatial distribution of tree symbiotic fungi as a function of forest humus forms.

In European forests, most tree species form symbioses with ectomycorrhizal (EM) and arbuscular mycorrhizal (AM) fungi. The EM fungi are classified into different morphological types based on the development and structure of their extraradical mycelium. These structures could be root extensions that help trees to acquire nutrients. However, the relationship between these morphological traits and functions involved in soil nutrient foraging is still under debate.We described the composition of mycorrhizal fungal communities under 23 tree species in a wide range of climates and humus forms in Europe and investigated the exploratory types of EM fungi. We assessed the response of this tree extended phenotype to humus forms, as an indicator of the functioning and quality of forest soils. We found a significant relationship between the relative proportion of the two broad categories of EM exploration types (short- or long-distance) and the humus form, showing a greater proportion of long-distance types in the least dynamic soils. As past land-use and host tree species are significant factors structuring fungal communities, we showed this relationship was modulated by host trait (gymnosperms versus angiosperms), soil depth and past land use (farmland or forest).We propose that this potential functional trait of EM fungi be used in future studies to improve predictive models of forest soil functioning and tree adaptation to environmental nutrient conditions.

Greater change in arbuscular mycorrhizal fungal richness as a response to short-term rainfall exclusion across the North American monsoon season

Arid ecosystems around the world are projected to experience reduced and more infrequent precipitation events. The effects of reduced rainfall are well understood for plants and aboveground interactions; however, the effect of rainfall on belowground microbial interactions remains understudied. Here, we illustrate the strength and direction of change that short-term manipulative rainfall exclusion treatments have on the composition and relative abundance of Arbuscular Mycorrhizal (AM) fungal communities throughout the monsoon season in the Sonoran Desert. Additionally, we use these rainfall exclusion treatments to further understand the impact of soil moisture on labile forms of nitrogen and phosphorous in a natural environment. Rainfall exclusion treatments were installed to remove 0% (control), 60% (moderate exclusion), and 80% (high exclusion) of rainfall over a single wet season. AM fungal community composition varied among rainfall treatments and across the monsoon season, where change was dependent on initial conditions within treatments. Phosphorous content was also a strong predictor of AM fungal composition and relative abundance. By the end of the season, the difference in AM fungal richness was influenced by rainfall exclusion, with the greatest positive change in richness in the moderate rainfall exclusion treatments. Lastly, AM fungal community turnover was predicted by rainfall exclusion treatments, where rainfall contributed to greater turnover in the control treatment in comparison to other treatments. This study further illustrates the complex association between soil abiotic factors, how they are influenced by environmental stress, and how in turn cause shifts in AM fungal communities.

Transferred communities of arbuscular mycorrhizal fungal persist in novel climates and soils

Symbiotic mycorrhizal fungi strongly influence plant establishment and growth particularly in harsh environments, whereby sympatric, presumably co-adapted symbionts are considered particularly beneficial. However, the response of transferred sympatric mycorrhizal fungal communities to new environments remains largely ignored. We therefore studied the relative importance of initial inoculum, soil and climatic conditions on the composition, diversity and root colonization ability of arbuscular mycorrhizal fungal (AMF) communities. To do so, we analyzed the AMF communities in an extensive experiment with two ecotypes of Bouteloua gracilis planted in their sites of origin and in four new sites differing in climate and soil properties.After three seasons of growth, the sympatric AMF communities were little changed by the new abiotic conditions. The composition of the AMF communities in plant roots was most strongly determined by the initial inoculum, while the contribution of divergent soil and climatic conditions was an order of magnitude smaller. The levels of root colonization by AMF, in contrast, were significantly influenced by climatic and soil conditions and did not differ among communities of different origins. Their pattern indicates that mycorrhiza formation is facilitated in the plant's sympatric soil and climatic conditions, but also that transferred AMF communities adjust mycorrhiza formation to new abiotic conditions.

Electrical Conductivity and pH Are Two of the Main Factors Influencing the Composition of Arbuscular Mycorrhizal Fungal Communities in the Vegetation Succession Series of Songnen Saline-Alkali Grassland.

Arbuscular mycorrhizal fungi (AMF) are widely distributed microorganisms in the soil, playing an important role in vegetation succession, plant community diversity, and improving soil physicochemical properties. In this study, morphological identification and high-throughput sequencing technology were used to comprehensively analyze the AMF community composition and diversity at different succession stages of Songnen saline-alkali grassland. To determine the root colonization status of plants collected in the field, a colonization system was established using late-succession plants as host plants to verify the existence of mycorrhizal symbiosis and the matching phenomenon of AMF in Songnen saline-alkali grassland. The results indicated that both morphological methods and high-throughput sequencing technology showed that glomus was the dominant genus of AMF in Songnen saline grassland. Redundancy analysis (RDA) and linear regression analysis showed that electrical conductivity (EC) and pH were the main environmental factors affecting AMF species diversity and community structure in the succession sequence of Songnen saline grassland. In addition, the results of root colonization identification and the colonization system test in the field showed that AMF successfully colonized vegetation at different succession stages and had mycorrhizal symbiosis. The results of this study could help to understand the AMF community of Songnen saline-alkali grassland as well as provide a reference and basis for optimizing the AMF community structure of Songnen saline-alkali grassland through human intervention in the future and using mycorrhizal technology to restore and rebuild the degraded ecosystem of Songnen saline-alkali grassland.

Root diameter, host specificity and arbuscular mycorrhizal fungal community composition among native and exotic plant species.

Plant root systems rely on a functionally diverse range of arbuscular mycorrhizal fungi to, among other benefits, extend their nutrient foraging. Extended nutrient foraging is likely of greatest importance to coarse-rooted plants, yet few studies have examined the link between root traits and arbuscular mycorrhizal fungal community composition. Here, we examine the relationship between root diameter and the composition of arbuscular mycorrhizal fungal communities in a range of native and exotic plant species. We characterized the arbuscular mycorrhizal fungal communities of 30 co-occurring native and exotic montane grassland/shrubland plant species in New Zealand. We found that plant root diameter and native/exotic status both strongly correlated with arbuscular mycorrhizal fungal community composition. Coarse-rooted plants had a lower diversity of mycorrhizal fungi compared with fine-rooted plants and associated less with generalist fungal partners. Exotic plants had a lower diversity of fungi and fewer associations with nondominant families of arbuscular mycorrhizal fungi compared with native plants. These observational patterns suggest that plants may differentially associate with fungal partners based on their root traits, with coarse-rooted plants being more specific in their associations. Furthermore, exotic plants may associate with dominant arbuscular mycorrhizal fungal taxa as a strategy in invasion.

Spore traits mediate disturbance effects on arbuscular mycorrhizal fungal community composition and mutualisms.

Trait-based approaches in ecology are powerful tools for understanding how organisms interact with their environment. These approaches show particular promise in disturbance and community ecology contexts for understanding how disturbances like prescribed fire and bison grazing influence interactions between mutualists like arbuscular mycorrhizal (AM) fungi and their plant hosts. In this work we examined how disturbance effects on AM fungal spore community composition and mutualisms were mediated by selection for specific functional spore traits at both the species and community level. We tested these questions by analyzing AM fungal spore communities and traits from a frequently burned and grazed (bison) tallgrass prairie system and using these spores to inoculate a plant growth response experiment. Selection for darker, pigmented AM fungal spores, changes in the abundance and volume of individual AM fungal taxa, and altered sporulation, were indicators of fire and grazing effects on AM fungal community composition. Disturbance associated changes in AM fungal community composition were then correlated with altered growth responses of Schizachyrium scoparium grass. Our work shows that utilization of trait-based approaches in ecology can clarify the mechanisms that underly belowground responses to disturbance, and provide a useful framework for understanding interactions between organisms and their environment.

Impact of Aspect on Arbuscular Mycorrhizal Fungal Diversity and Community Composition in a Natural Toona ciliata var. pubescens Forest in Subtropical China

The aspect can affect plant communities and soil physical and chemical properties through different microclimates. However, little is known about the effect of aspect on arbuscular mycorrhizal (AM) fungal diversity and community composition, although AM fungi are beneficial for plant nutrient absorption and natural restoration. In this study, AM fungal community and diversity distribution patterns in the rhizosphere soil and roots of seven widespread plants in a natural Toona ciliata var. pubescens (Tc) forest on the north-facing (NF) aspect and south-facing (SF) aspect were investigated using Illumina PE250 high-throughput sequencing in the Guanshan National Nature Reserve, Jiangxi Province, China. Our results exhibited that aspect did not affect AM fungal diversity but significantly affected AM fungal community structure and composition. Glomeraceae was the most common and abundant family in the Tc natural forest. The Glomeromycota sequence proportion of root AM fungal community was significantly larger on NF than on SF (p < 0.05). The relative abundance of Acaulosporaceae of root AM fungal community differed significantly with aspect, being greater on NF than on SF (p < 0.05). In addition, the number of Glomeromycota sequences was significantly larger on SF than on NF, while the number of OTUs and the relative abundance of unclassified fungi in rhizosphere soil in Tc showed the opposite trend (p < 0.05). The soil properties (organic matter, nitrogen, potassium, phosphorus, and pH) were significantly correlated with these changes. These findings indicate that the habitat of NF with low insolation, high soil moisture, and high nutrient content might promote the functional realization of AM fungi; the habitat of SF with high insolation, low soil moisture, and low soil nutrient content might be beneficial for the proliferation and preservation of AM fungal groups. This study provides important information on the ecological processes of AM fungal community construction and microbiological mechanisms in natural Tc forests.

Mixed conifer-broadleaf trees on arbuscular mycorrhizal and ectomycorrhizal communities in rhizosphere soil of different plantation stands in the temperate zone, Northeast China.

In comparison with ectomycorrhizal (EM) tree species, arbuscular mycorrhizal (AM) trees have different litter quality and nitrogen cycle modes, which may affect mycorrhizal colonization and the community composition and diversity. However, available studies addressing the mycorrhizal fungal colonization rate, diversity and community composition in mixed forest stands composed of AM and EM trees are rare. In the present study, we assessed litter quality, soil physicochemical properties and correlated them with mycorrhizal community characteristics in rhizosphere soils of monoculture and mixture plantation stands of AM tree species (Fraxinus mandschurica Rupr.) and EM tree species (Larix gmelinii Rupr., Picea koraiensis Nakai) in Northeast China. We hypothesized that (1) the effect of mixture pattern on mycorrhizal colonization rate and diversity would change with tree species, (2) the effect of mixture pattern on mycorrhizal community composition would be less pronounced in comparison with that of tree species. We found that mixture did not change AMF colonization rate regardless of mixture identity, whereas mixture and tree species exerted significant effects on EMF colonization rate. For AMF community, both M-AS (Fraxinus mandschurica Rupr. and Picea koraiensis Nakai) and M-AL (Fraxinus mandschurica Rupr. and Larix gmelinii Rupr.) mixtures significantly increased Pielou index and Simpson index, whereas only M-AS significantly increased Sobs. For EMF community, mixture significantly affected examined diversity indices except for Chao1. Mixture significantly shifted AMF and EMF community, and the magnitude was tree species dependent. The dominant genera in AMF and EMF communities in plantation stands were Glomus and Tomentella, respectively. The EnvFit analysis showed that the determinant factors of EMF community are soil moisture, pH, nitrate nitrogen content, dissolved organic nitrogen content, soil organic matter content, soil organic carbon/total nitrogen and litter carbon/total nitrogen. In conclusion, mixed conifer-broadleaf trees significantly changed soil physicochemical properties, litter quality as well as mycorrhizal fungi community diversity and composition.

Land-use changes alter the arbuscular mycorrhizal fungal community composition and assembly in the ancient tea forest reserve

Understanding the effects of land-use changes on arbuscular mycorrhizal fungal (AMF) communities may greatly benefit ecosystem conservation and restoration. However, how AMF communities respond to anthropogenetic land-use change (e.g., from natural ecosystems to farmland ecosystems) is still under debate. To enhance the preservation of vegetation diversity in ancient tea forest (ATF) regions and understand how land-use changes influence the AMF community in acidic soils, the AMF community composition and assembly processes in the ATF region (soil pH: 3.5–4.2) were investigated. Our results showed that AMF α-diversity indices in ATF were significantly higher than those in conventional tea plantations (CTP) and Forest. Moreover, number of indicator species (as virtual taxa, VTX) showed a remarkable decrease when ATF (12 VTXs) changed to Forest (8 VTXs) and CTP (3 VTXs). In addition, neutral processes dominated the AMF community assembly, and Acaulospora was the dominant genus of AMF indicator species in ATF. Moreover, land-use changes eliminated the neutral process of AMF community assembly in CTP and Forest by enhancing the environmental filtering effects. The concentrations of soil nitrate, TK, Mg2+, and Cu2+ were important factors accounting for the AMF community change. In addition, we found that high acidity soils may exert an ecological selection on the AMF community, as only species that adapt to strongly acidic soils persisted. Overall, our results indicated that mitigating soil acidification has potential as a method of improving the AMF community diversity and conserving and restoring ATF ecosystems in southwest China.

Dominance, diversity, and niche breadth in arbuscular mycorrhizal fungal communities.

Classical theory identifies resource competition as the major structuring force of biotic communities and predicts that (i) levels of dominance and richness in communities are inversely related, (ii) narrow niches allow dense "packing" in niche space and thus promote diversity, and (iii) dominants are generalists with wide niches, such that locally abundant taxa also exhibit wide distributions. Current empirical support, however, is mixed. We tested these expectations using published data on arbuscular mycorrhizal (AM) fungal community composition worldwide. We recorded the expected negative relationship between dominance and richness and, to a degree, the positive association between local and global dominance. However, contrary to expectations, dominance was pronounced in communities where more specialists were present and, conversely, richness was higher in communities with more generalists. Thus, resource competition and niche packing appear to be of limited importance in AM fungal community assembly; rather, patterns of dominance and diversity seem more consistent with habitat filtering and stochastic processes.

Diversity of Arbuscular Mycorrhizal Fungi in Shola Forests of Kodaikanal, Southern India

Arbuscular mycorrhizal fungi establish symbiotic association with more than 80% of land plants and influence plant community composition and distribution. The mycorrhizal status of plant species in various ecosystems have been reported but failed to assess community composition of AM fungi in shola forests, therefore present study carried out to fulfill this research gap. A total of Seven AM fungal species could be isolated from Tiger and Kookal shoal and identified based on spore morphology. There is no significant difference among distribution of AM fungal spores in various seasons among sites. In both the sholas AM fungal spore numbers were high during the wet (September) season and the variation among spore numbers in different seasons among sites were insignificant. Arbuscular mycorrhizal spore of Funneliformis geosporum was the most frequent species and Funneliformis mosseae was the less frequent species. The frequency among various sites in both the Sholas was insignificant. The AM fungal species richness was high in Tiger Shola (six spores), whereas in Kookal Shola showed less species richness. The diversity indices like Shanon - Weaver index (H') and Simpson index (D) were calculated in all the sites and showed variation among shoals in four sites. Arbuscular mycorrhizal fungal community composition in this ecosystem have been elucidated to certain extent and used for conservation of shola species.

Amplicon sequencing reveals the arbuscular mycorrhizal fungal community composition in Cryptomeria japonica at one local site

ABSTRACT Arbuscular mycorrhizal fungi (AMF) colonize the plant root endosphere and extend the host’s resource network. However, little is known about the method to characterize the intraradical AMF communities of a specific tree species in forests. Therefore, we aimed at testing a method for characterizing and comparing the extra- and intraradical AMF communities of Cryptomeria japonica (Cupressaceae). In February 2020, we tracked and sampled roots from 5 target trees and the surrounding soil and confirmed their identity using plan DNA barcoding methods. After a microscopic analysis of mycorrhizal root colonization, we used Illumina amplicon sequencing to characterize the corresponding AMF communities. The C. japonica roots were colonized by AMF, displaying the Paris- and Arum-types of mycorrhizae. At 100% sequence identity, amplicon sequences of the small-subunit nuclear ribosomal RNA gene clustered into 155 operational taxonomic units (OTUs), 33 and 139 in the intra- and extraradical AMF communities, respectively, corresponding to three families and five genera. Nevertheless, only Acaulospora, Glomus, and Rhizophagus were detected in the root samples. The AMF communities did not significantly differ between the root and the surrounding soil, but we observed a significant nestedness pattern in the community. To avoid erroneous conclusions, combining plant DNA barcoding with amplicon sequencing is a reliable approach, which we recommend for future studies to describe the intraradical AMF community of a specific tree species in forests.

Origin makes a difference: Alternative responses of an AM-dependent plant to mycorrhizal inoculum from invaded and native soils under abiotic stress.

The presence of invasive alien plants (IAPs) alters the composition of soil arbuscular mycorrhizal (AM) fungal communities. Although fundamental for plant development, plant responses to AM from invaded soils have not been widely explored, especially under environmental stress.We compared plant growth, P accumulation, root colonization and the photosynthetic responses of the native AM‐dependent Plantago lanceolata growing in contact with AM fungi from communities invaded by Acacia dealbata Link (AMinv) or non‐invaded communities (AMnat) exposed to water and light restriction (shade).Under optimal growing conditions, plants in contact with AMnat produced higher leaf biomass and accumulated more P. However, plant responses to different AM inocula varied as the level of stress increased. Inoculation with AMinv promoted plant growth and root length under light restriction. When plants grew in contact with AMnat under drought, leaf P increased under severe water restriction, and leaf and root P increased under intermediate water irrigation. Growing in contact with the AMnat inoculum promoted root P content in both full light and light restriction. Colonization rates of P. lanceolata roots were comparable between treatments, and plants maintained photosynthetic activity within similar ranges, regardless of the level of stress applied.Our results suggest that origin of the inoculum (native soils versus invaded soils) did not affect the ability of AM species therein to establish effective mutualistic associations with P. lanceolata roots but did influence plant responses depending on the type and level of the abiotic stress.

Long-term P fertilization significantly altered the diversity, composition and mycorrhizal traits of arbuscular mycorrhizal fungal communities in a wheat-maize rotation

Phosphorus (P) fertilization rates have been dramatically increasing in intensive agro-ecosystems. However, the impact of such long-term P fertilization in intensive agro-ecosystems on the diversity, composition mycorrhizal traits of arbuscular mycorrhizal fungi (AMF) communities and the relationship between them remains poorly understood. By conducting a long-term field experiment (10 years) in north China in a typical calcareous soil with a wheat-maize rotation, we investigated the effects of six P fertilization rates on AMF community properties. We found that AMF alpha diversity (including OTU number and Shannon index) was positively correlated with both AMF root colonization of maize, hyphal density in soil and expression of the phosphate transporter gene ZmPht1;6 for maize. AMF community structure was significantly correlated with AMF colonization of maize roots, hyphal density and P concentrations in maize shoots. The relative abundance of the most dominant taxon Funneliformis caledonium OTU1 decreased while that of the second dominant taxon Claroideoglomus lamellosum OTU55 increased as the P fertilizer rate increased. AMF colonization of roots and hyphal density was positively correlated with the relative abundances of Glomus sp. (including OUT 29, OTU32, and OTU37) in soil but was negatively correlated with the relative abundances of Septoglomus viscosum OTU14. The relative abundances of Glomus sp. (OTU 5, OTU 25, OTU27, OTU23, and OTU29) were positively correlated with AMF colonization of roots, hyphal density and ZmPht1;6 expression under low rates of P fertilization (P0 and P12.5 treatments), while the relative abundance of Glomus sp. OTU20 was positively correlated with AMF colonization of roots, hyphal density and ZmPht1;6 expression under high rates of P fertilization (P100 and P200 treatments). Long-term P fertilization significantly altered the alpha diversity, structure, and composition of AM communities, which affected AMF colonization of maize roots and expression of a phosphate transporter gene. Our results indicate that different members of AMF communities differentially modulated their mycorrhizal traits with maize under different P fertilization rates. An improved understanding of how AMF taxa and functions are altered by P fertilization and the mycorrhizal traits impact on plant nutrition could help guide P fertilization practices in agro-ecosystems.

Diazotroph and arbuscular mycorrhizal fungal diversity and community composition responses to karst and non-karst soils

Diazotrophs and arbuscular mycorrhizal fungi (AMF) are important functional microbes that provide and transport nutrients to plants. Diazotroph and AMF diversity and community composition were investigated in karst mature forests (MFs) and non-karst forests, as well as in croplands (CRs) as a reference. Diazotroph diversity and community composition significantly shifted in MFs between karst and non-karst soils, with a higher diazotroph richness and Shannon index in karst MFs than in non-karst soils. Similar levels of AMF diversity and community composition were observed between karst and non-karst CRs and MFs. According to the co-occurrence network analysis results, the pairs of correlation links within the diazotroph and AMF groups were higher in karst MFs than in non-karst MFs, whereas this interaction was lower in karst CRs than in non-karst CRs. The diazotroph genera Bradyrhizobium and Anabaena and the AMF genera Glomus and Rhizophagus were mostly correlated with other species in both karst and non-karst soils. Diazotrophs and AMF communities were mainly affected available nutrients (e.g., nitrogen and phosphorus) and environmental factors (e.g., temperature and precipitation), respectively. Soil calcium content was an important factor that affected the distributions of diazotrophs and AMF between karst and non-karst soils. Overall, our study suggested that the increased interactions between diazotrophs and AMF in karst forests, as compared with those in non-karst soil, led to the stability of the diazotrophs and AMF co-occurrence patterns for maintaining nutrients that are effectively absorbed and utilized. Thus, strengthening the cooperative relationships between diazotrophs and AMF are important and necessary in calcareous soils during natural vegetation restoration.

Elevational distribution and occurrence of arbuscular mycorrhizal fungi in non-host Carex capillacea.

Little is known about Arbuscular mycorrhizal (AM) fungal colonization and community composition in non-mycorrhizal (NM) plants, especially along elevational gradients. This study explores this question using a NM plant, Carex capillacea, at Mount Segrila, Tibet. Here, C. capillacea, its rhizosphere soil, and the neighboring mycotrophic plant Poa annua were sampled at four elevations to evaluate and compare their AM fungi colonization and communities. The results showed that AM fungal colonization density of C. capillacea was negatively correlated with elevation and biomass of total NM plants per quadrat. AM fungal diversity and community composition between C. capillacea and P. annua showed a similar pattern. In addition, elevation and soil did not significantly influence the AM community in C. capillacea, while they were important abiotic factors for assemblages in rhizosphere soil and P. annua. These findings support that a broad array of AM fungi colonize the root of C. capillacea, and a mycelial network from a co-occurring host plant might shape the AM fungal communities in C. capillacea along the elevation gradient. The co-occurrence patterns of AM fungi associated with non-mycotrophic species and adjacent mycotrophic species have important implications for understanding AM fungal distribution patterns and plant-AM interactions.

Contrasting Responses of Arbuscular Mycorrhizal Fungal Families to Simulated Climate Warming and Drying in a Semiarid Shrubland.

We carried out a 4-year manipulative field experiment in a semiarid shrubland in southeastern Spain to assess the impacts of experimental warming (W), rainfall reduction (RR), and their combination (W + RR) on the composition and diversity of arbuscular mycorrhizal fungal (AMF) communities in rhizosphere soil of H. syriacum and G. struthium shrubs using single-molecule real-time (SMRT) DNA sequencing. Across climate treatments, we encountered 109 AMF operational taxonomic units (OTUs) that were assigned to four families: Glomeraceae (93.94%), Gigasporaceae (2.19%), Claroideoglomeraceae (1.95%), and Diversisporaceae (1.92%). AMF community composition and diversity at OTU level were unaffected by the climate manipulation treatments, except for a significant decrease in AMF OTU richness in the W treatment relative to the control. However, we found a significant decrease of AMF family richness in all climate manipulation treatments relative to the control treatment. Members of the Gigasporaceae and Diversisporaceae families appeared to be highly vulnerable to intensification of heat and drought stress, as their abundances decreased by 67% and 77%, respectively, in the W + RR treatment relative to current ambient conditions. In contrast, the relative abundance and dominance of the Glomeraceae family within the AMF community increased significantly under the W + RR treatment, with Glomeraceae being the indicator family for the W + RR treatment. The interaction between warming and rainfall reduction had a significant effect on AMF community structure at family level. These findings provide new insights to help in the conservation of the soil biodiversity facing climate change in dryland ecosystems.

Plant hosts may influence arbuscular mycorrhizal fungal community composition in mangrove estuaries

We investigated the role of plant host and soil variables in determining arbuscular mycorrhizal fungi (AMF) community composition in plant roots of two spatially separated mangrove estuaries on the rivers Aghanashini (14° 30' 30″ N-74° 22' 44″ E) and Gangavali (14° 35' 26″ N-74° 17' 51″ E) on the west coast of India. Both mangrove estuaries had similar plant species composition but differed in soil chemistries.We amplified a 550-bp portion of 18S small subunit (SSU) rDNA from mangrove plant roots and analysed it by restriction fragment length polymorphism (RFLP). Clones representing unique RFLP patterns were sequenced. A total of 736 clones were obtained from roots of seven and five plant species sampled at Aghanashini and Gangavali, respectively. AMF phylotype numbers in plant roots at Aghanashini (12) were higher than at Gangavali (9) indicating quantitative differences in the AMF community composition in plant roots at the two mangrove estuaries. Because both estuaries had similar plant species composition, the quantitative difference in AMF communities between the estuaries could be an attribute of the differences in rhizospheric chemistry between the two sites.Non-metric multidimensional scaling (NMDS) revealed overlap in the AMF communities of the two sites. Three and two AMF phylotypes had significant indicator value indices with specific hosts at Aghanashini and Gangavali, respectively. Environmental vector fitting to NMDS ordination did not reveal a significant effect of any soil variable on AMF composition at the two sites. However, significant effects of both plant hosts and sites were observed on rhizospheric P. Our results indicate that root AMF community composition may be an outcome of plant response to rhizospheric variables. This suggests that plant identity may have a primary role in shaping AMF communities in mangroves.

Alterations to arbuscular mycorrhizal fungal community composition is driven by warming at specific elevations.

BackgroundGlobal warming can alter plant productivity, and community composition which has consequences for soil-plant associated microorganisms. Arbuscular mycorrhizal fungi (AMF) are distributed widely and form symbiotic relationships with more than 80% of vascular plants and play a key role in nutrient cycling processes at the ecosystem scale.MethodsA simulated warming experiment at multiple elevations (3,000, 3,500, 3,800, and 4,170 m) was conducted utilizing an in-situ open-top chamber (OTC) for exploring the effect of global warming on AMF community structure in the Qinghai-Tibet Plateau (QTP). This region has been identified as one of the most sensitive areas to climatic changes. Soil DNA was extracted and sequenced using next the Mi-Seq platform for diversity profiling.ResultsAMF richness was higher under the simulated warming chamber, however this only occurred in the elevation of 3,500 m. Warming did not alter other AMF alpha diversity indices (e.g. Shannon, Ace, and Simpson evenness index). Glomus and Acaulospora were the dominate AMF genera as assessed through their relative abundance and occurrence in control and warming treatments at the different elevations.ConclusionWarming changed significantly AMF community. The effects of warming on AMF community structure varied depend on elevations. Moreover, the occurrences of AMF in different genera were also presented the different responses to warming in four elevations.

Arbuscular mycorrhizal fungal communities colonising the roots of indigenous legumes of South Africa as revealed by high-throughput DNA metabarcoding

The important ecological role of arbuscular mycorrhizal (AM) fungi on plant communities necessitates an understanding of the diversity and the factors that shape the community composition of AM fungi associated with plants. Therefore, this study investigated the diversity and composition of arbuscular mycorrhizal fungal (AMF) communities colonising the roots of eleven indigenous legumes in two South African provinces using high-throughput sequencing of the partial SSU rRNA gene. The analysis revealed 172 operational taxonomic units (OTUs, at 97% sequence similarity) belonging to eight genera. Arbuscular mycorrhizal fungal community composition varied among legumes within and between provinces, with the genus Glomus dominant. The AMF OTU richness and Shannon-Wiener index were significantly correlated with potassium, copper, manganese, zinc, and silt content. Canonical correspondence analysis indicated that nitrates, pH, manganese, and organic C were the principal soil properties significantly influencing AMF community composition. Overall, findings from this study elucidate that soil factors are pertinent environmental cues that shape legume-AMF symbiosis in semi-arid ecosystems.