Search Results (25)

The synergistic application of biochar and straw could improve soil properties and influence soil microbial community. However, its impacts on microbial community interactions and functions within various aggregate fractions remain unclear. We conducted a three-year field trial in black soil in northeastern China, under the restoration measures of biochar application (BR, 30 t ha⁻¹ once), straw return (SR, 5 t ha⁻¹ year⁻¹), and the combination of BR and SR (BS, BR at 30 t ha⁻¹ once and SR at 5 t ha⁻¹ year⁻¹). Utilizing high-throughput sequencing, we assessed the influence of different straw-returning methods on the structure and function of microbial communities in the mega-aggregates (ME, >2 mm), macroaggregates (MA, 0.25–2 mm), and microaggregates (MI, <0.25 mm). Relative to the control (CK), the BR, SR and BS treatments significantly decreased the bacterial Shannon index, mainly dependent on ME (p < 0.05). Conversely, compared with the CK and SR treatments, both BR and BS treatments notably reduced the fungal Shannon index, largely influenced by MI (p < 0.05). Moreover, the BS treatment significantly increased the relative abundance (RA) of Mortierellomycota (p < 0.05) compared to the CK, BR and SR treatments. Meanwhile, the SR and BS treatments substantially reduced the RA of Nitrospirae (p < 0.05) in comparison to the CK and BR treatments. Furthermore, compared with the CK, the BR and SR treatments enhanced microbial network connectivity, while the BS treatment diminished it, especially in ME and MI. Concurrently, the keystone of co-occurrence networks shifted from Phycisphaeraceae, Blastocatellaceae, and Glomeraceae in the CK treatment to uncultured_bacterium_c_JG37-AG-4 and DA111 in the BS treatment. Additionally, BR and SR exhibited synergistic effects on most microbial community functions (e.g., enhanced chitinolysis and carbon fixation but reduced nitrogen-cycling functions), but they also possessed distinct differential functions. In short, the combined application of biochar and straw adversely impacted soil microbial community diversity and stability, especially in ME and MI. Full article

Arbuscular mycorrhizal fungi (AMF) taxa, glomalin protein, and hyphal density are potential indicators of soil functionality of temperate grasslands in marginal environments subject to grazing over the years. This study evaluated how the AMF community composition, glomalin protein, and hyphal density vary in response to grazing intensity (low or high) and seasonality (spring and autumn) in sodic soils of Argentinian temperate grasslands. The AMF community was dominated by Glomeraceae species. Funneliformis geosporus and Glomus brohultii were the most abundant in both seasons and all grasslands. No AMF species were associated with a particular grazing intensity. However, Entrophospora etunicata, Glomus fuegianum, Septoglomus constrictum, and Acaulospora sp. occurred only in spring, and no species were exclusive to autumn. Hyphal density was highest in grasslands with low grazing intensity and can be considered an indicator of soil functionality. Glomalin protein was the highest in spring in all grasslands. The lower grazing intensity in grasslands with poor livestock control showed no changes in AMF diversity. The AMF community showed high adaptation to soil conditions, indicating high resilience. We concluded that longer periods of controlled grazing management are needed to improve soil conditions and, consequently, change the AMF species composition. Full article

Arbuscular mycorrhizal fungi (AMF) and Trichoderma spp. (T) are known as plant-beneficial fungi effective against root-knot nematodes, but their interactions in the rhizosphere are not well understood. This study examined how Meloidogyne javanica influences AMF colonization and community diversity at the root-soil interface of tomato plants. A 60-day growth chamber experiment was conducted with tomato plants grown in non-sterile agricultural soil, either infected or not with M. javanica, that received a single inoculation with AMF or Trichoderma (strains T363 or TJ15), combined AMF + T inoculations, or no inoculation (Control). Both single and combined inoculations significantly reduced root galls, eggs, and soil nematode larvae. An AMF community analysis via single-strand conformation polymorphism of the D1 region of 28S rDNA gene (Glomeraceae family) revealed that M. javanica decreased AMF diversity and altered community structure, in plants single-inoculated with AMF. However, a combined inoculation with Trichoderma appears to prevent this reduction and maintain AMF diversity. While M. javanica reduced root mycorrhizal colonization, it did not affect Trichoderma abundance. These results suggest that Trichoderma may be more resilient to nematode infection, helping stabilize AMF communities and enhance biocontrol. Thus, combining AMF and Trichoderma inoculations could better preserve root health and improve biological control effectiveness against M. javanica. Full article

Sabkha (inland and coastal—saline beds or saline lands) are widespread in Saudi Arabia and are distinguished by their hypersaline nature. These hypersaline habitats are commonly covered by halophytic vegetation. Moreover, Arbuscular mycorrhizal fungi (AMF) are an essential component of these habitats and exhibit a unique adaptation and contribute significantly to ecosystem variability, diversity, and function. Additionally, AMF from saline habitats are an essential component for the successful rehabilitation of salinity-affected areas. Despite their importance, little is known about the distribution and abundance of AMF along inland and coastal sabkhat of Saudi Arabia. Therefore, the main objective of this study was to investigate the abundance and diversity of AMF in the coastal and inland sabkhat of Saudi Arabia. Five soil samples, each from five randomly selected spots (considering the presence of dominant and co-dominant halophytic species), were collected from every location and were used to assess the AMF abundance and diversity. The study indicated that the highest number of AMF spores was recorded from Jouf, averaging ≈ 346 spores 100 g⁻¹ dry soil, and the lowest from Uqair, averaging ≈ 96 spores 100 g⁻¹ dry soil. A total of 25 AMF species were identified, belonging to eight identified genera viz., Acaulospora, Diversispora, Gigaspora, Scutellospora, Claroideoglomus, Funneliformis, Glomus, and Rhizophagus and five families. Of the total identified species, 52% belonged to the family Glomeraceae. Moreover, the highest number of species was isolated from the sabkha in Qasab. Additionally, Glomeraceae was abundant in all the studied locations with the highest relative abundance in Uqair (48.34%). AMF species Claroideoglomus etunicatum, Funneliformis mosseae, Glomus ambisporum, and Rhizophagus intraradices were the most frequently isolated species from all the Sabkha locations with isolation frequency (IF) ≥ 60%, and Claroideoglomus etunicatum (Ivi ≥ 50%) was the dominant species in all the studied locations. Furthermore, data on the Shannon–Wiener diversity index showed that the highest AMF species diversity was in Qaseem and Qasab habitats. The highest Pielou’s evenness index was recorded in Jouf. Moreover, the soil parameters that positively affected the diversity of identified species included Clay%, Silt%, HCO₃¹⁻, OM, MC, N, and P, while some soil parameters such as EC, Na⁺, SO₄²⁻, and Sand% had a significant negative correlation with the isolated AMF species. This study revealed that AMF can adapt and survive the harshest environments, such as hypersaline sabkhas, and thus can prove to be a vital component in the potential restoration of salinity-inflicted/degraded ecosystems. Full article

Based on molecular phylogenetic analyses, and also considering morphological characters, four new families are separated from the family Glomeraceae within the order Glomerales and the class Glomeromycetes. The revised family Glomeraceae comprises only four genera: the type genus Glomus, Complexispora, Sclerocarpum and Simiglomus. Septoglomeraceae fam. nov. comprises, besides Septoglomus, Funneliformis, Funneliglomus, Blaszkowskia and Viscospora. Sclerocystaceae fam. nov. is represented by the type genus Sclerocystis but also by Halonatospora, Oehlia, Parvocarpum, Rhizoglomus and Silvaspora. Kamienskiaceae fam. nov. encompasses Kamienskia, Microkamienskia and Epigeocarpum. Finally, Dominikiaceae fam. nov. includes the genera Dominikia, Macrodominikia gen. nov., Microdominikia, Nanoglomus and Orientoglomus. The genera Oehlia and Halonatospora form two other clades well separated from Silvaspora, Sclerocystis and Rhizoglomus and might represent two further families within Glomerales. This deeper separation is, in our opinion, fully supported by molecular phylogeny, but in view of the low numbers of taxa, the separation is not yet proposed at this stage of research progress. Full article

Cephalostachyum pingbianense (Hsueh & Y.M. Yang ex Yi et al.) D.Z. Li & H.Q. Yang is unique among bamboo species for its ability to produce bamboo shoots in all seasons under natural conditions. Apart from the physiological mechanism, information regarding the effects of endophytic microorganisms on this full-year shooting characteristic is limited. We hypothesize that root endophytic microorganisms will have a positive impact on the full-year bamboo shooting characteristic of C. pingbianense by increasing the availability or supply of nutrients. To identify the seasonal variations in the root endophytic bacterial and fungal communities of C. pingbianense, and to assess their correlation with bamboo shoot productivity, the roots of C. pingbianense were selected as research materials, and the 16S rRNA and ITS rDNA genes of root endophytic microorganisms were sequenced using the Illumina platform. Following this sequencing, raw sequencing reads were processed, and OTUs were annotated. Alpha and beta diversity, microbial composition, and functional predictions were analyzed, with correlations to bamboo shoot numbers assessed. The results showed that seasonal changes significantly affected the community diversity and structure of root endophytic microbes of C. pingbianense. Bacterial communities in root samples from all seasons contained more nitrogen-fixing microorganisms, with members of the Burkholderiales and Rhizobiales predominating. The relative abundances of ectomycorrhizal and arbuscular mycorrhizal fungi in the autumn sample were significantly higher than in other seasons. Correlation analysis revealed that the bamboo shoot productivity was significantly and positively correlated with bacterial functions of nitrogen fixation, arsenate detoxification, and ureolysis, as well as with symbiotrophic fungi, ectomycorrhizal fungi, and arbuscular mycorrhizal fungi. At the genus level, the bacterial genus Herbaspirillum and the fungal genera Russula, unclassified_f_Acaulosporaceae, and unclassified_f_Glomeraceae were found to have a significant positive correlation with bamboo shoot number. Our study provides an ecological perspective for understanding the highly productive attribute of C. pingbianense and offers new insights into the forest management of woody bamboos. Full article

Glomus mongioiense, a new species of arbuscular mycorrhizal fungi (AMF) in the family Glomeraceae, was isolated from rhizosphere soil collected from a meadow in the Italian Alps. The novelty of the species and its relationship with other species of the same genus were obtained by morphological and phylogenetic (45S nrDNA + RPB1 gene) analyses. Two glomoid spore-producing AMF isolates from a saltmarsh of the Scottish Highlands and maritime sand dunes of the Baltic Sea in Poland, were also included in this study and later found to be conspecific with G. rugosae. Phylogenetic placement analysis using environmental sequences indicated that G. mongioiense sp. nov. seems to be a rare species. Furthermore, the molecular and phylogenetic analysis provided important insights into the presence of highly divergent ribosomal variants in several Glomus species, with potential negative implication in phylogeny and species recognition. Full article

In the face of persistent soil degradation in Benin caused by poor agricultural practices, including excessive use of chemical fertilizers, it is urgent to find solutions that take into account the microorganisms of interest. This study aimed to assess the effect of combining three strains of indigenous arbuscular mycorrhizal fungi (AMF) on maize production in northern Benin. The study involved 34 growers in Ouénou, Bagou and Kokey. The experimental setup consisted of three elementary plots with three treatments. Growth parameters were measured every 15 days, from the 15^th to the 60^th day after sowing, on ten plants per plot. Plant nutritional status, grain yield and mycorrhization were measured. The results showed that biostimulant + 50% NPK_Urea (N = nitrogen, P = phosphorus and K = potassium) had similar positive effects on growth parameters to those induced by the application of 100% NPK_Urea. Gains of 30.25% to 36.35% were recorded in plant height at Kokey. On the other hand, biostimulant+ 50% NPK_Urea induced a better phosphorus uptake of 21.08% to 27.77%. In addition, the grain yield of mycorrhizal plants was 8.37% higher than that of plants receiving 100% NPK_Urea at Ouénou. These results show that this technology could be integrated into the agricultural system to promote sustainable maize growing in Benin. Full article

Glomalin-related soil protein (GRSP), an important arbuscular mycorrhizal (AM) fungal by-product, plays a key role in preserving or sequestrating soil organic carbon (C). Silver nanoparticles (AgNPs) have become an emerging contaminant and their impacts on soil ecosystems attract increasing concerns. The dynamics of AM fungi and GRSP could therefore form the basis for an in-depth exploration of the influences of AgNPs on soil ecosystems. This study investigated the effects of AgNPs on mycorrhizal growth and AM fungal communities, as well as the GRSP contents in maize (Zea mays L.) soils, with a pot experiment. The contributions of GRSP to soil organic C and the correlations of GRSP with soil organic C were also evaluated. The results indicated that AgNPs decreased the mycorrhizal colonization, AM fungal biomass, and diversity indices, and strongly shifted the community composition of AM fungi with a reduction in Acaulosporaceae and an enrichment in Glomeraceae. Additionally, AgNPs also decreased the soil’s easily extractable (EE) GRSP and total (T) GRSP contents, resulting in lower contributions of EE-GRSP-C and T-GRSP-C to the soil organic C. Linkage analyses revealed that AM fungal abundances have positive correlations with EE- and T-GRSP, and EE- and T-GRSP also positively correlated with soil organic C, indicating that the negative effects of AgNPs on AM fungal abundances and communities were extended to AM-fungal-associated C processes. Altogether, our study found that AgNPs decreased the AM fungal abundances shaped AM fungal communities, and reduced the soil GRSP content, which might subsequently be unfavorable for soil C storage. Full article

Elevated nitrogen (N) deposition may stimulate a plant’s dependency on arbuscular mycorrhizal (AM) fungi in phosphorus (P)-deficient subtropical forests. However, the ecological assembly processes and the responses of AM fungal diversity and community structure to N deposition in both the roots and rhizosphere are still unclear. We collected root and soil samples from a Cunninghamia lanceolata plantation forest after four years of N addition and examined the community structure and assembly of AM fungi. Elevated N deposition decreased the AM fungal community diversity in both rhizosphere soil and roots. Glomeraceae was the dominant family of the AM fungal community in both soil and roots across all N addition treatments, followed by Gigasporaceae and Ambisporaceae. However, N addition induced differential variation in the community composition of AM fungi between soil and roots. For soil AM fungi, N addition decreased the Glomeraceae abundance and increased the Gigasporaceae and Ambisporaceae abundance. In contrast, the root AM fungal community was dominated by Glomeraceae under N addition treatments. Furthermore, N addition increased the deterministic community assembly that acted as an environmental filter for soil AM fungi. In contrast, N addition decreased the importance of determinism, implying that the selection of plants on root AM fungi decreased with increasing N addition. Altogether, our findings suggest that the community structure of AM fungi responds differently to N deposition in the soil and roots in subtropical forests and highlight the important role of soil AM fungi in helping host plants respond to N deposition. Full article

Coffee (Coffea arabica) is among the world’s most economically important crops. Coffee was shown to be highly dependent on arbuscular mycorrhizal fungi (AMF) in traditionally managed coffee plantations in the tropics. The objective of this study was to assess AMF species richness in coffee plantations of four provinces in Perú, to isolate AMF isolates native to these provinces, and to test the effects of selected indigenous AMF strains on coffee growth. AMF species were identified by morphological tools on the genus level, and if possible further to the species level. Two native species, Rhizoglomus variabile and Nanoglomus plukenetiae, recently described from the Peruvian mountain ranges, were successfully cultured in the greenhouse on host plants. In two independent experiments, both species were assessed for their ability to colonize coffee seedlings and improve coffee growth over 135 days. A total of 35 AMF morphospecies were identified from 12 plantations. The two inoculated species effectively colonized coffee roots, which resulted in 3.0–8.6 times higher shoot, root and total biomass, when compared to the non-mycorrhizal controls. R. variabile was superior to N. plukenetiae in all measured parameters, increasing shoot, root, and total biomass dry weight by 4.7, 8.6 and 5.5 times, respectively. The dual inoculation of both species, however, did not further improve plant growth, when compared to single-species inoculations. The colonization of coffee by either R. variabile or N. plukenetiae strongly enhances coffee plant growth. R. variabile, in particular, offers enormous potential for improving coffee establishment and productivity. Assessment of further AMF species, including species from other AMF families should be considered for optimization of coffee growth promotion, both alone and in combination with R. variabile. Full article

Soil salinization is detrimental to crop growth, agricultural yields, and environmental protection. Echinochloa frumentacea (Roxb.) Link is a pioneer species for the alteration of saline–alkali lands. In this paper, we examined the effects of intercropping between E. frumentacea and leguminous forages on saline land improvement in the saline–alkali soil of the Hetao-Ningxia Plain, China. We found that intercropping increased the diversity and richness of the arbuscular mycorrhizal fungi (AMF) community in the rhizosphere soil of E. frumentacea. Glomus was the dominant genus in the saline–alkali soil of the Hetao-Ningxia Plain, where Glomeraceae, VTX00067, VTX000193, and VTX000165 were the dominant species. Intercropping improved the activities of soil urease, sucrase, alkaline phosphatase, and catalase. The hay yields of E. frumentacea were correlated positively with soil enzyme activities, Chao1 index, and ACE index, and negatively with total water-soluble salt content. Together, intercropping between E. frumentacea and leguminous forages enhances AMF diversity and soil enzyme activities, which provides an agricultural practice for improving sustainability of the agro-ecosystem in saline–alkali areas. Full article

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. Full article

Intensive fertilizer use can constrain contributions from soil biological processes in pastures, including those associated with arbuscular mycorrhizal (AM) fungi. We evaluated the effect of fertilizers of different P solubility on the colonization of the roots of two common pasture plants by a community of AM fungi in a pasture soil. The treatments were a rock mineral fertilizer, a chemical fertilizer and a microbial inoculant. Subterranean clover and annual ryegrass were grown in pots for 10 weeks. Both fertilizers reduced the proportion and length of roots colonized by naturally occurring AM fungi. However, by 10 weeks, there was a much greater length of mycorrhizal root for annual ryegrass than for subterranean clover. The relative abundance of mycorrhizal fungi in the families Glomeraceae and Acaulosporaceae in roots was not affected by the form of fertilizer, but diversity indices of AM fungi in roots were altered. The chemical fertilizer had a greater negative effect on AM fungal diversity indices in the annual ryegrass roots compared with the subterranean clover roots. The reduction in OTU richness of AM fungi with fertilizer application corresponded with reduced soil pH. Differential effects of P fertilizers on naturally occurring AM fungi in this agricultural soil have the potential to influence the efficacy of P fertilizer use and dominance of plant species in grasslands. Full article

Remediation of mercury (Hg)-contaminated soil by mycorrhizal technology has drawn increasing attention because of its environmental friendliness. However, the lack of systematic investigations on arbuscular mycorrhizal fungi (AMF) community composition in Hg-polluted soil is an obstacle for AMF biotechnological applications. In this study, the AMF communities within rhizosphere soils from seven sites from three typical Hg mining areas were sequenced using an Illumina MiSeq platform. A total of 297 AMF operational taxonomic units (OTUs) were detected in the Hg mining area, of which Glomeraceae was the dominant family (66.96%, 175 OTUs). AMF diversity was significantly associated with soil total Hg content and water content in the Hg mining area. Soil total Hg showed a negative correlation with AMF richness and diversity. In addition, the soil properties including total nitrogen, available nitrogen, total potassium, total phosphorus, available phosphorus, and pH also affected AMF diversity. Paraglomeraceae was found to be negatively correlated to Hg stress. The wide distribution of Glomeraceae in Hg-contaminated soil makes it a potential candidate for mycorrhizal remediation. Full article