Arbuscular Mycorrhizal Fungi Richness Research Articles

Diversity, Abundance, and Richness of Arbuscular Mycorrhizal Fungi associated with some Solanaceous medicinal plants of Ballavpur Wildlife Sanctuary in West Bengal

Diversity, Abundance, and Richness of Arbuscular Mycorrhizal Fungi associated with some Solanaceous medicinal plants of Ballavpur Wildlife Sanctuary in West Bengal

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.

Influence of plant species, mycorrhizal inoculant, and soil phosphorus level on arbuscular mycorrhizal communities in onion and carrot roots.

Arbuscular mycorrhizal fungi (AMF) are ancient and ecologically important symbionts that colonize plant roots. These symbionts assist in the uptake of water and nutrients, particularly phosphorus, from the soil. This important role has led to the development of AMF inoculants for use as biofertilizers in agriculture. Commercial mycorrhizal inoculants are increasingly popular to produce onion and carrot, but their specific effects on native mycorrhizal communities under field conditions are not known. Furthermore, adequate availability of nutrients in soils, specifically phosphorus, can reduce the diversity and abundance of AMF communities in the roots. The type of crop grown can also influence the composition of AMF communities colonizing the plant roots. This study aimed to investigate how AMF inoculants, soil phosphorus levels, and plant species influence the diversity of AMF communities that colonize the roots of onion and carrot plants. Field trials were conducted on high organic matter (muck) soil in the Holland Marsh, Ontario, Canada. The treatments included AMF-coated seeds (three to five propagules of Rhizophagus irregularis per seed) and non-treated onion and carrot seeds grown in soil with low (~46 ppm) and high (~78 ppm) phosphorus levels. The mycorrhizal communities colonizing the onion and carrot roots were identified by Illumina sequencing. Five genera, Diversispora, Claroideoglomus, Funneliformis, Rhizophagus, and Glomus, were identified in roots of both plant species. AMF communities colonizing carrot roots were more diverse and richer than those colonizing onion roots. Diversispora and Funneliformis had a 1.3-fold and 2.9-fold greater abundance, respectively, in onion roots compared to carrots. Claroideoglomus was 1.4-fold more abundant in carrot roots than in onions. Inoculation with R. irregularis increased the abundance and richness of Rhizophagus in AMF communities of onion roots but not in carrot roots. The soil phosphorus level had no effect on the richness and diversity of AMF in the roots of either crop. In summary, AMF inoculant and soil phosphorus levels influenced the composition of AMF communities colonizing the roots of onion and carrot plants, but the effects varied between plant species.

Mycorrhizal effects on crop yield and soil ecosystem functions in a long-term tillage and fertilization experiment.

It is well understood that agricultural management influences arbuscular mycorrhizal (AM) fungi, but there is controversy about whether farmers should manage for AM symbiosis. We assessed AM fungal communities colonizing wheat roots for three consecutive years in a long-term (> 14 yr) tillage and fertilization experiment. Relationships among mycorrhizas, crop performance, and soil ecosystem functions were quantified. Tillage, fertilizers and continuous monoculture all reduced AM fungal richness and shifted community composition toward dominance of a few ruderal taxa. Rhizophagus and Dominikia were depressed by tillage and/or fertilization, and their abundances as well as AM fungal richness correlated positively with soil aggregate stability and nutrient cycling functions across all or no-tilled samples. In the field, wheat yield was unrelated to AM fungal abundance and correlated negatively with AM fungal richness. In a complementary glasshouse study, wheat biomass was enhanced by soil inoculum from unfertilized, no-till plots while neutral to depressed growth was observed in wheat inoculated with soils from fertilized and conventionally tilled plots. This study demonstrates contrasting impacts of low-input and conventional agricultural practices on AM symbiosis and highlights the importance of considering both crop yield and soil ecosystem functions when managing mycorrhizas for more sustainable agroecosystems.

Impacts of Lithology and Slope Position on Arbuscular Mycorrhizal Fungi Communities in a Karst Forest Soil.

The influence of lithology and slope position on arbuscular mycorrhizal fungi (AMF) communities has been explored in various ecosystems, but there is a limited understanding of these mechanisms in karst regions. This study focused on typical karst hills with contrasting lithologies, specifically dolomite and limestone. Additionally, three slope positions (upper, middle, and lower) were investigated within each hill in karst forest ecosystems. Total phosphorus (TP) content in the soil was higher in dolomite compared to limestone. Conversely, exchangeable calcium (Ca) was lower in dolomite than in limestone. Notably, the lithology, rather than the slope position, exerted a significant impact on AMF diversity and abundance and the presence of specific AMF taxa. Dolomite exhibited greater AMF richness and a higher Shannon index in comparison to limestone when not accounting for slope position. The AMF community composition differed between dolomite and limestone. For instance, without considering slope position, the relative abundance of Acaulospora, Diversispora, and Paraglomus was higher in dolomite than in limestone, while the relative abundance of Claroideoglomus displayed an opposing trend. Furthermore, a more complex interaction among AMF taxa was observed in dolomite as compared to limestone, as evidenced by an increase in the number of nodes and edges in the co-occurrence networks within the dolomite. The genera Glomus, Claroideoglomus, and Diversispora exhibited a higher number of links with each other and with other AMF taxa. The study identified TP and Ca as the primary factors determining variations in AMF diversity between dolomite and limestone. Consequently, it is imperative to consider the underlying lithology and soil conditions when addressing the restoration of degraded karst hilly areas.

Nitrogen addition drives changes in arbuscular mycorrhizal fungal richness through changes in plant species richness in revegetated alpine grassland

Nitrogen (N) addition not only promotes the restoration of degraded grasslands, but also threatens ecosystem functioning through the loss of species richness. Thus, a deep understanding of the effect of N addition on the richness of key organisms in restored grasslands is critical to sustainably restoring degraded grasslands. We conducted a 4-year N addition experiment to investigate the response of both plant and arbuscular mycorrhizal (AM) fungal richness to the combined addition of ammonium (Am) and nitrate (Ni) in a revegetated grassland rehabilitated (with a focus on restoration) on the Qinghai–Tibet Plateau. Both nitrogen forms were added at three levels: 0, 10, and 20 g N m−2 year−1. By itself, Ni addition of 20 g N m−2 year−1 (Ni20) reduced both plant and AM fungal richness, while Am addition of 20 g N m−2 year−1 (Am20) had no significant effect on them. However, when Ni and Am were combined, only Ni20 plus Am20 among all combinations reduced both plant and AM fungal richness. Both soil nitrate-N and plant species richness jointly drove changes in AM fungal richness, but plant species richness was the main factor affecting AM fungal richness under N addition. Our results suggest that minimizing the loss of AM fungi caused by plant species loss resulting from N addition is a key means to sustainably restore degraded grasslands.

Cover crop identity determines root fungal community and arbuscular mycorrhiza colonization in following main crops

AbstractCover crops (CC) can promote nutrient retention and recycling for main crops yet may also promote soilborne pathogens or suppress beneficial root symbionts such as arbuscular mycorrhizal fungi (AMF). We investigated how root fungal communities of main crop are affected by preceding CC monocultures and mixtures and by main crop identity. We expected that AMF abundance and diversity in main crops are promoted by AM‐host CC, and suppressed by non‐AM‐host CC, and that mixtures of CC species can promote beneficial and suppress pathogenic root fungi. Our full‐factorial field experiment comprised crop rotation in sand soil with different CC treatments (monocultures of radish [AM non‐host], ryegrass, clover, vetch [AM hosts], mixtures of radish + vetch, ryegrass + clover and fallow) and two main crops (oat and endive). At peak crop growth, we investigated the root fungal communities in the main crops using microscopy and high throughput sequencing (Illumina MiSeq). Cover crop identity was of prime importance and CC legacy overruled main crop identity in determining root fungal communities in main crops. Compared with fallow, CC with ryegrass increased AMF colonization and richness in both main crops and of non‐AMF in oat. Legacies of ryegrass, ryegrass + clover and vetch resulted in distinct root fungal communities in the main crops, while the legacy of CC with radish were similar to the legacy of fallow. Root fungal community in crops after clover had highest abundance of representative fungal pathogens in contrast with the other CC treatments that resulted in fungal communities where pathogens were scarce. Oppositely to expected, CC mixtures did not enhance fungal symbionts or suppressed pathogens. Overall, fungal communities in roots of the main crops in our field experiment were determined by the preceding CC species in monoculture, rather than by the CC AMF preference or functional group. This research highlights that the choice of CC determines the root fungal community in main crop which may influence crop quality.

Mycorrhizal fungal communities associated with three metal accumulator plants growing in an abandoned Pb smelting factory.

Plants associated with mycorrhizal fungi has the ability to establish on metal-contaminated soils playing an important role in phytoremediation programs. The objective of this study was to examine the presence of arbuscular mycorrhizal fungi (AMF) (spores density, diversity, indicator species, and root colonization) and dark septate endophytic fungi (DSE fungal root colonization) in three metal accumulator plants (Sorghum halepense, Bidens pilosa, and Tagetes minuta) growing in soils with high Pb content. The Pb content in AMF spores and plant biomass were also assessed. Rhizosphere soil samples were taken from the three dominant plant species at six study sites surrounding the abandoned Pb smelter and one uncontaminated site. The three studied plants were colonized by AMF and DSE fungi. A total of 24 AMF morphospecies were present in the Pb-contaminated areas. The AMF indicator species in the control site (non-contaminated area) was Funneliformis mosseae and in the most contaminated site were Gigaspora decipiens and Denticustata biornata. There was an increase in mycorrhizal variables such as the number of AMF vesicles, spore number, Pb content in AMF spores and plant biomass and DSE colonization (in Sorghum) with increasing soil Pb contamination, but a decrease in AMF diversity and richness was found. For upcoming soil restoration projects, it is crucial to understand the mycorrhizal fungi as well as the plant community that has adapted to the highly contaminated environment.

Symbiosis—A Perspective on the Effects of Host Traits and Environmental Parameters in Arbuscular Mycorrhizal Fungal Richness, Colonization and Ecological Functions

Arbuscular mycorrhizal fungi are biotrophic fungi that form an association with plant roots and render benefits in nutrient uptake, disease control and plant tolerance to stress conditions. Plant–mycorrhizal fungi interaction has been proposed as a suitable tool for contributing to sustainable agriculture and reducing the dependence on agrochemicals. Interactions between plants and arbuscular mycorrhizal fungi are regulated by several factors ranging from host traits to environmental conditions that affect the species richness, diversity and functions. In this review, we highlight recent advances on how host traits and environmental conditions in farming systems and/or in natural ecosystems affect the richness, physiology and ecological functions of arbuscular mycorrhizal fungi while specifying the gaps that need to be filled through research.

Impact of ecological stages on the soil microbiota and soil abiotic factors in tropical and subtropical Brazilian regions.

Our aim was to test if ecological stages may influence the arbuscular mycorrhizal fungi (AMF), nematodes, and the soil chemical properties in agroforestry systems (AF), unassisted forest restoration (UFR), and natural ecosystem (Ne) located in the Brazilian Tropical and Subtropical regions. We collected soil samples to determine AMF, nematodes, soil pH, P, and soil organic carbon (SOC). AMF and nematode richness in the AF and Ne were similar in the tropical region. The redundancy analysis (RDA) indicated that the abundance of AMF and soil nematodes was mainly affected by soil pH, P, and SOC. Differences were associated with (1) ecological stages, as we found differences in AMF and nematode abundance as affected by habitat simplification, and (2) changes in soil pH, SOC, and P. Our work increases the understanding of the AMF and soil nematode community in the rhizosphere of AF and Ne in tropical and subtropical regions.

Habitat heterogeneity drives arbuscular mycorrhizal fungi and shrub communities in karst ecosystems

Arbuscular mycorrhizal fungi (AMF) constitute one of the factors that regulate the success of vegetation restoration. Karst ecosystems are heterogenous in nutrient content and plant communities because of preferential water fluxes within cracks and gullies in the soil parent material. The effects of habitat on soil nutrients, shrub, and AMF diversity in karst ecosystems are yet to be established. Thus, we investigated the diversity of shrubs and AMF within three habitats: i) rocky soil surface (Rock), ii) soil surface (Soil), and iii) rocky gully (Gully) in a typical karst shrub ecosystem. We observed that AMF diversity was independent of the sampling location, whereas AMF abundance and the shrub Shannon index increased with sampling distance, reaching a plateau in a sampling area of 1000 m2. The AMF community composition was driven by dominating shrubs (Vitex negundo, Tirpitzia ovoidea). Higher shrub diversity and AMF abundance occurred in Rock than in Soil and Gully areas, suggesting higher habitat heterogeneity in Rock areas. Based on co-occurrence network analysis, interactions with a high link number among the AMF taxa were stronger in Rock than in Gully because the network complexity in the Rock areas strongly depended on symbiosis with AMF taxa to cope with high habitat heterogeneity. The Random forest model revealed that AMF abundance was mainly affected by available phosphorous, total potassium, and shrub diversity. Available phosphorous, soil pH, and exchangeable Ca2+, rather than plant diversity, were the main factor controlling AMF community composition. Overall, the results suggest that the increase in shrub diversity raised AMF abundance and richness, and strengthened the interactions among AMF taxa because of nutrient exchange. Thus, increasing habitat heterogeneity with abundant shrub diversity, but soil nutrient limitation, enriches AMF abundance and diversity.

The Diversity of Arbuscular Mycorrhizal Fungi and Their Associations in South America: A Case Study of Argentinean and Brazilian Cattle Raising Productive Ecosystems: A Review

Mycorrhizal fungus diversity is an ecosystem health indicator, and thus, the appreciation of the aboveground as well as the belowground biota, such as fungi associated with natural and managed ecosystems, is essential to provide sustainable products and suggestions to farmers. Less is known about the totally arbuscular mycorrhizal fungi (AMF) and fungal endophytes useful to agroecology, which are environment friendly microbial biofertilizers to mitigate the complications of conventional farming. Specific AMF are found in most covers; grassy ecosystems are increasingly investigated through their exclusive fungal species that improve sustainable cultivation. Different grazed pastures, forages, and their diversity are important objects of study either in economic or ecological scope. Based on recent reports, the occurrence of AMF in grasslands and pastures is significant, supporting more diverse AMF than native forests. Therefore, we show current information on these topics. We conducted a Web of Science search of published articles on AMF, pastures, and grasslands and analyzed them. The results confirmed the important role of pH as the driver of AMF diversity distribution between the grassy ecosystems from Argentina and Brazil. In grasslands, the main family represented was Glomeraceae, while pastures maintain predominantly Acaulosporaceae. Brazilian grasslands and pastures presented four times the AMF richness of those from Argentina.

Evolutionary characteristics of arbuscular mycorrhizal fungi in Eucalyptus soil and driving changes in biologically‐based phosphorus across Eucalyptus plantations

AbstractArbuscular mycorrhizal fungi (AMF) symbiosis plays essential roles in shaping rhizosphere soil available phosphorus (P) and organic P mobilization. However, current methods for assessing soil P often do not fully consider the potential role of arbuscular mycorrhizal fungi (AMF) in supplying biologically‐based phosphorus (BBP) to Eucalyptus. This study aims to investigate the effects of AMF on the soil BBP of Eucalyptus plantations and which species prefer to translocate them in phosphorus‐deficient soils. Rhizosphere soil samples of Eucalyptus plantations (in south China) exhibiting different ages (varying between 1 to 12 years) were selected to investigate the evolution of AMF and BBP in soils, as well as their interaction mechanism. The impacts of eight AMF families on BBP were investigated in rhizosphere soil. All BBP contents are significantly positively correlated with Olsen P in the rhizosphere soil of Eucalyptus plantations (p < 0.01). The BBP in soil was notably influenced by AMF diversity, while AMF richness showed little effect on BBP. The abundance of Glomeraceae taxa showed a positive correlation with BBP and a negative correlation with Paraglomeraceae. In contrast, the relative abundance of Glomeraceae was higher in older plantations (including Archaeosporaceae, Claroideoglomeraceae). From the above results, we concluded that different species of the AMF modulated their mycorrhizal traits by improving BBP uptake in the rhizosphere soil. AMF groups (such as Glomeraceae, Archaeosporaceae, Claroideoglomeraceae) should be introduced or amplified at the beginning of planting to promote the uptake and utilization of bioavailable P in Eucalyptus plantations. This study will deepen our understanding of AMF for effective BBP utilization in Eucalyptus plantations.

Native mycorrhizal communities in maize roots as affected by plant genotype, starter fertilization and a seed-applied biostimulant

Background and aimsOne of the most promising strategies for sustainable intensification of crop production involves the utilization of beneficial root-associated microorganisms, such as plant growth-promoting bacteria and arbuscular mycorrhizal fungi (AMF). The aim of this study was to investigate whether a seed-applied biostimulant, based on the bacterial strain Bacillus amyloliquefaciens IT-45 and a plant polysaccharide extract, and crop enhancement tools, such as hybrids with contrasting early vigor and nitrogen (N) plus phosphorus (P) starter fertilization, and their interactions, shape the communities of native root-colonizing AMF symbionts in maize.MethodsA factorial growth chamber experiment was set up with two maize genotypes in natural soil. Mycorrhizal colonization was evaluated after root staining. The diversity and composition of AMF communities were assessed by PCR-DGGE of the 18S rRNA gene and amplicon sequencing.ResultsN and P fertilization determined a consistent reduction of AMF root colonization and, in combination of biostimulant, a reduction of AMF richness. The biostimulant alone generally did not affect AMF colonization or the community biodiversity. In addition the effect of the two factors were modulated by maize genotype. In all treatments, predominant AMF were represented by Glomus sp. and Funneliformis mosseae, while populations of the genus Rhizoglomus were rarely detected in biostimulant and NP fertilization treatments.ConclusionThe results of this study increase our understanding of how the biostimulant seed treatment may affect native AMF communities, depending on NP fertilization and maize genotype and may improve the implementation of innovative tools in sustainable and resilient agroecosystems.

Biochemical characterization and mycorrhizal fungal community of plant species in the Brazilian seasonal dry forest.

Invasive alien plant species (IAPS) have the ability to change the biochemical properties and the arbuscular mycorrhizal fungal (AMF) community structure in their rhizosphere. Organic acids, microbial activity, and AMF play a key role in the invader's spread and also has interactions with the soil chemical factors. Our aim here was to assess the rhizosphere's biochemical factors, AMF community composition, and soil chemical properties associated with Cryptostegia madagascariensis (IAPS) and Mimosa tenuiflora (endemic plant species) from the Brazilian Seasonal Dry Forest. The highest values of total glomalin (5.87 mg g-1 soil), root colonization (54.5%), oxalic and malic acids (84.21 and 3.01 μmol g-1 , respectively), microbial biomass C (mg kg-1 ), Na+ (0.080 cmolc kg-1 ), Ca2+ (7.04 cmolc kg-1 ), and soil organic carbon (4.59 g kg-1 ) were found in the rhizosphere of C. madagascariensis. We found dissimilarities on AMF community structure considering the studied plant species: (i) Racocetra coralloidea, Dentiscutata heterogama, Dentiscutata cerradensis, Gigaspora decipiens, and AMF's richness were highly correlated with the rhizosphere of M. tenuiflora; and (ii). The rhizosphere of C. madagascariensis was highly correlated with the abundance of Claroideoglomus etunicatum, Rhizoglomus aggregatum, Funneliformis mosseae, and Funneliformis geosporum. The results of our study highlight the importance of considering C. madagascariensis as potential hosts for AMF species from Glomerales, and a potential plant species that increase the bioavailability of exchangeable Na and Ca at semi-arid conditions.

Ecotype and fungal endophyte status differentially affect soil arbuscular mycorrhizal community of the native grass Bromus auleticus

In wild native grasses, the colonization of arbuscular mycorrhizal fungi (AMF) is higher in Epichloë-infected plants (E+) compared to Epichloë-free plants (E−). To explore the correlation between the host ecotype, Epichloë association, and the soil AMF community, a common garden experiment was conducted. To achieve this, the soil AMF community of two Bromus auleticus ecotypes, El Palmar (EP) and La Pampa (LP), with either E+ or E−endophyte status, was analyzed using high throughput sequencing. The total mycorrhizal colonization of E+ plants from both EP and LP ecotypes showed significantly higher values (178.68% and 132.34% respectively) compared to E−plants, regardless of the ecotype. Alpha and Beta diversity analysis revealed significant differences in AMF richness and composition between the El Palmar (EP) and La Pampa (LP) ecotypes. However, no differences were observed in the soil AMF communities between E+ and E−plants. In conclusion, this study demonstrates that Epichloë symbiosis and host ecotype have distinct effects on various aspects of the AMF-Bromus auleticus association.

Arbuscular Mycorrhizal Fungi and Diazotrophic Diversity and Community Composition Responses to Soybean Genotypes from Different Maturity Groups

Soybeans can simultaneously form tripartite symbiotic associations with arbuscular mycorrhizal fungi (AMF) and diazotrophs. However, no studies have explored whether soybean genotypes differing in their maturity groups (MGs) may have implications for the recruitment of rhizosphere soil AMF and diazotrophs. We investigated the diversity and community compositions of AMF and diazotrophs in three soybean genotypes differing in their maturity groups (MG) using high-throughput sequencing. The soybean MGs were MG1.4, MG2.2, and MG3.8, representing early, standard, and late maturity, respectively, for the study region. Soil chemical properties and yield-related traits were determined, and co-occurrence network patterns and drivers were also analyzed. The results obtained demonstrated that AMF richness and diversity were relatively stable in the three soybean genotypes, but noticeable differences were observed in diazotrophs, with late maturity being significantly higher than early maturity. However, there were differences in AMF and diazotrophic composition among different MG genotypes, and the changes in the proportion of dominant species in the community were necessarily related to MG genotypes. Co-occurrence network analysis showed that the positive correlation between AMF and diazotrophs gradually decreased in earlier MG genotypes than in the other later MG genotypes. The results of the structural equation model analysis showed that soil organic carbon, AMF, diversity of soil nutrients, and extracellular enzyme activities were important factors driving soybean yield change, with organic carbon accounting for more than 80% of the pathways analyzed. These results suggest that soybean genotype selection based on MG plays an important role in recruiting both AMF and diazotrophic communities, and in comparison to AMF, diazotrophs are more responsive to the different MG genotypes.

Positive plant diversity effects on soil microbial drought resistance are linked to variation in labile carbon and microbial community structure

Abstract Biodiversity loss and drought are substantially altering both above‐ and below‐ground terrestrial ecosystem functioning, but mechanistic understanding of plant diversity effects on the drought resistance of soil microbial biomass remains limited. We designed a mesocosm experiment to examine drought resistance of soil microbial biomass along a plant species richness gradient (five plant species richness levels based on old‐field communities). We calculated resistance of microbial biomass to drought and recorded key below‐ground properties which may influence microbial resistance to drought (i.e. microbial diversity, microbial community structure, soil carbon stocks and root biomass). Plant species richness had a positive effect on microbial resistance to drought. Variation in microbial resistance to drought was linked to properties of the fungal community in ambient soil (Shannon diversity, arbuscular mycorrhizal fungal richness and abundance) but not soil bacterial diversity. Moreover, microbial resistance to drought increased with increasing root biomass and dissolved organic carbon recorded under ambient conditions. These results highlight the importance of plant diversity for microbial biomass stability in our old‐field study system with implications for biogeochemical cycling, and suggest that indirect effects of plant species richness on labile soil carbon and soil fungi may drive resistance of soil microbial biomass to drought. Read the free Plain Language Summary for this article on the Journal blog.

Increased copper concentrations in soil affect indigenous arbuscular mycorrhizal fungi and physiology of grapevine plantlets

Continuous use of fungicides in vineyards leads to soil copper (Cu) accumulation, adversely affecting plants and soil organisms. Arbuscular mycorrhizal fungi (AMF) provide adaptative mechanisms for plant survival and growth in environments with high Cu contents. Using a low-Cu soil from a young vineyard, we evaluated how increasing additions of this element (0, 50, 100, and 150 mg kg-1) affected the AMF community and growth and physiology of grapevine (Vitis berlandieri x Vitis rupestris) rootstock, in greenhouse conditions. Mycorrhizal colonization and AMF richness decreased linearly with increased soil Cu additions. Stomatal conductance and transpiration increased with Cu additions, affecting plant growth. Increasing Cu additions to the soil decreased mycorrhizal root colonization and diversity, with no adverse effects on grapevines.

Counteracting effects of soil biota on emergence and growth of herbaceous plants

BackgroundPlants condition the biotic composition of their rhizosphere. In turn, this plant legacy on the soil biota may affect the performance of plants recruiting in their vicinity. Unravelling how plant-soil legacies drive plant recruitment is key to understand vegetation dynamics and plant community assembly. Studies on the topic usually focus on the effects of soil microbiota as a whole, while the relative role of different guilds of soil organisms in the plant recruitment processes is not usually dissected.AimsHere, we used soils of Mediterranean woody plant species to test whether arbuscular mycorrhizal fungi (AMF) and small-size microbiota (< 50 µm) (MB) affect the germination success and growth of eight herbaceous plants.ResultsWe documented a significant increase in seedling emergence probability when small-sized MB was present and no effect of AMF. In contrast, the aboveground plant biomass decreased with the presence of MB and increased with that of AMF. Interestingly, those plants growing in the absence of MB and in soils from woody plants associated with higher AMF richness developed higher aboveground biomass.ConclusionThis study brings new evidence on how soil microbial communities can determine the performance of their associated herb community, and also, how the effects of different microbial guilds may change across the plant ontogeny. Given these results, the differential effect of soil microbial functional guilds should be considered to better understand plant soil legacies and feedbacks, potentially driving plant recruitment and community assembly.