Search Results (19)

Maize is considered to be one of the most significant crops in the world. On a global scale, the appropriate yield level of food can largely affect food security. During cultivation, this plant is exposed to many adverse environmental factors, including water deficiency. Plant stress is reduced by applying appropriate biostimulants or soil amendments. This study tested the effectiveness of preparations based on Rhizophagus irregularis, humic acids, Bacillus velezensis + Bacillus licheniformis and Methylobacterium symbioticum. The aim of the project was to assess the effect of selected microorganisms and substances on the growth, yield, and physiological parameters of maize. The hypothesis assumed that the preparations selected for this study could improve the condition of the plants in various soil moisture conditions. All treatments were carried out post-emergence. The experiments were conducted in greenhouse conditions, where, in conditions of different level of soil moisture, optimal and water deficiency, the effect of the above-mentioned substances and microorganisms on the height, mass of plants, and plant chlorophyll fluorescence was determined. Chlorophyll, anthocyanin, and flavonol content were also measured. In two-year field studies, the effect of the same preparations on plant height, grain yield, thousand-grain weight, oil, protein, and starch content in the grain was determined. It was shown that appropriately selected biostimulants have a positive effect on plant growth, physiological parameters, and the yield of maize grain. The impact of preparations on the grain yield depended on the conditions that prevailed in the growing season. Full article

Arbuscular mycorrhizal fungi (AMF) are symbiotic fungi that associate with the vast majority of terrestrial plants. Among non-vascular plants, while AMF associations are well-documented in liverworts and hornworts, there is a broad consensus that symbiotic associations do not occur in mosses. Here, we report the presence of AMF in the living material of mosses found in Chaco Serrano (Tucumán, Argentina). We found all characteristic structures of AMF when establishing an intimate connection with two moss species of Pottiaceae (Bryophyta). While Gertrudiella uncinicoma exhibited AMF with both Arum- and Paris-type morphologies, Pleurochaete luteola only displayed an Arum-type morphology. Plant tissue samples were subjected to high-throughput sequencing for AMF identification. We determined that Rhizophagus irregularis was a clear dominant species in both moss species, with Glomus sp. also being present as a less abundant element. In addition, we also reported the presence of vesicles, arbuscules, and spores adhered to the hyphae and the presence of septate endophytes. This finding expands our understanding of the interactions between AMF and non-vascular plants and prompt us to further characterize this interaction by considering the diversity of mycorrhizal associations with concurrent implications for the ecology of mosses and the functionality of the ecosystems. Full article

Arbuscular Mycorrhizal Fungi (AMF) play a key role in enduring stresses in desert ecosystems, as they enhance the moisture and nutrient supply to desert plants. An investigation was carried out to detect the existence of AMF in the root regions of five perennial native desert grasses of Kuwait (Cenchrus ciliaris L., Cenchrus setigerus Vahl, Lasiurus scindicus Henrard, Pennisetum divisum (Forssk.) Henr., and Panicum turgidum Forssk.) in comparison with a non-native grass (Panicum virgatum L.). The native plants, C. setigerus and P. divisum had the highest colonization (100%) with vesicles, followed by P. turgidum (90%). The colonization of arbuscules was highest in the non-native grass, P. virgatum (60%), followed by C. setigerus (50%). Phylogenetic analysis for molecular identification to determine the genetic diversity of the AMF community in association with the native plant roots of the two dominant desert species, i.e., L. scindicus and P. turgidum, against P. virgatum, revealed a rich diversity. The AMF, Claroideoglomus lamellosum, and Rhizophagus sp. were identified from L. scindicus roots, Rhizophagus iranicus from P. turgidum roots, and Claroideoglomus lamellosum, from the non-native grass, P. virgatum, with almost 98–100% sequence similarity, indicating a significant difference between the mycorrhizal species in the nativity of grasses. This research confirms the diversity of AMF associated with native desert plants and emphasizes their symbiosis and host specificity. Thus, this study provides insight into AMF community structures, functions, and profiling, allowing us to understand their ecological and economic impacts, and ultimately implement strategies for sustainable biodiversity, productivity, and ecosystem management. Full article

An indigenous consortium of arbuscular mycorrhizal fungi (AMF) from the Figuig oasis in southern Morocco, comprising Rhizophagus sp., Funneliformis sp., Acaulospora sp., Sclerocystis sp., and Scutellospora sp., was evaluated for its effects on the growth and sensitivity of Phoenix dactylifera L. variety (cv. Boufeggous Gharas) to Fusarium oxysporum f. sp. Albedinis (Foa), the causal agent of Bayoud disease. Despite its high fruit quality and local appreciation, the Boufeggous Gharas variety is highly susceptible to Foa and is currently at risk of extinction, underscoring the urgent need for its sustainable management. The results demonstrated that Boufeggous Gharas seedlings inoculated with a consortium of indigenous AMF showed significantly improved shoot and root length, leaf number, and biomass as compared to non-mycorrhized seedlings. In contrast, Foa-infected seedlings showed significantly reduced growth, with a 46.6% decrease in shoot height and a 50.4% reduction in root length compared to non-infected seedlings. Interestingly, AMF inoculation mitigated this sensitivity to Foa, significantly restoring growth parameters. Seedlings treated with AMF + Foa showed a 51% increase in shoot height and a 61% improvement in root length, along with over 100% gains in shoot and root biomass compared to seedlings infected solely with Foa. This study provides the first evidence of integrating AMF into sustainable date palm cultivation practices to mitigate the impacts of biotic stresses, thereby promoting the preservation and valorization of vulnerable date palm varieties. The protective effects of AMF are attributed to improved nutrient uptake, enhanced root architecture, and systemic resistance induced by AMF colonization. Full article

Due to shallow root systems, potato is a particularly drought-sensitive crop. To counteract these limitations, the application of plant growth-promoting microorganisms (PGPMs) is discussed as a strategy to improve nutrient acquisition and biotic and abiotic stress resilience. However, initial root colonization by PGPMs, in particular, can be affected by stress factors that negatively impact root growth and activity or the survival of PGPMs in the rhizosphere. In this study, perspectives for the use of commercial silicate-based soil conditioners (SCs) supposed to improve soil water retention were investigated. The SC products were based on combinations with lignocellulose polysaccharides (Sanoplant^® = SP) or polyacrylate (Geohumus^® = GH). It was hypothesized that SC applications would support beneficial plant–inoculant interactions (arbuscular mycorrhiza, AM: Rhizophagus irregularis MUCL41833, and Pseudomonas brassicacearum 3Re2-7) on a silty loam soil–sand mixture under water-deficit conditions (6–12 weeks at 15–20% substrate water-holding capacity, WHC). Although no significant SC effects on WHC and total plant biomass were detectable, the SC-inoculant combinations increased the proportion of leaf biomass not affected by drought stress symptoms (chlorosis, necrosis) by 66% (SP) and 91% (GH). Accordingly, osmotic adjustment (proline, glycine betaine accumulation) and ROS detoxification (ascorbate peroxidase, total antioxidants) were increased. This was associated with elevated levels of phytohormones involved in stress adaptations (abscisic, jasmonic, salicylic acids, IAA) and reduced ROS (H₂O₂) accumulation in the leaf tissue. In contrast to GH, the SP treatments additionally stimulated AM root colonization. Finally, the SP-inoculant combination significantly increased tuber biomass (82%) under well-watered conditions, and a similar trend was observed under drought stress, reaching 81% of the well-watered control. The P status was sufficient for all treatments, and no treatment differences were observed for stress-protective nutrients, such as Zn, Mn, or Si. By contrast, GH treatments had negative effects on tuber biomass, associated with excess accumulation of Mn and Fe in the leaf tissue close to toxicity levels. The findings suggest that inoculation with the PGPMs in combination with SC products (SP) can promote physiological stress adaptations and AM colonization to improve potato tuber yield, independent of effects on soil water retention. However, this does not apply to SC products in general. Full article

Coffee cultivation facilitates foreign trade, which is important to the Mexican economy, particularly to the coffee growers of Jilotepec, Veracruz. However, in this region, the soil in which the coffee plants are grown is acidic and has low nutrient availability, making plants susceptible to pests and diseases. In this context, the use of mycorrhizal fungi has gained importance, due to the benefits that they provide in terms of the transport of nutrients and the development of plants, contributing to a reduction in the use of chemical fertilizers. This work aimed to determine the dominant Arbuscular mycorrhizal fungi (AMF) in the soil of coffee farms and evaluate the potential of sorghum as a trap plant for these organisms. As a result, ten morphotypes of AMF were detected in the coffee soil, with Glomus and Acaulospora being the dominant genera. It was found that their presence was related to the pH, clay, organic matter, and total carbon of the soil from the farms. The abundance of spores increased significantly (p < 0.05) between the initial count in the soil and the final count after propagation in the sorghum trap plants. The characteristic structures of mycorrhizal colonization and a high percentage of mycorrhizal colonization of the roots of the trap plants (Sorghum vulgare) were observed at 120 days after sowing. It is concluded that Glomus sp1, Glomus sp2, Glomus sp3, Glomus sp4, Rhizophagus clarus, and Acaulospora scrobiculata are the dominant morphotypes in the considered coffee plantation soils and that sorghum has high potential for favoring the propagation of native AMF through increasing their abundance and favoring high mycorrhizal colonization. Full article

This study aimed to elucidate the impact of phosphate-solubilizing bacteria (PSB) and arbuscular mycorrhizal fungi (AMF) inoculation on sorghum growth within substrates derived from phosphate solid sludge, with the overarching objective of repurposing phosphate sludge to be a viable agricultural substrate. Four PSB strains (Serratia rubidaea, Enterobacter bugandensis, Pantoea agglomerans, Pseudomonas sp.) were meticulously selected from phosphate solid sludge, along with two AMF strains (Rhizophagus intraradices and Funneliformis mosseae), constituting the experimental inocula. Phosphate solid sludge was judiciously blended with peat at varying volumetric proportions (0%, 10%, 20%, 40%, and 60%), providing the matrix for sorghum cultivation, and concomitantly subjected to inoculation with PSB and AMF. Following a meticulously monitored two-month duration, a comprehensive evaluation of diverse morphological parameters, biomass accrual, nitrogen content, total phosphorus concentration, potassium levels, calcium content, and root colonization in sorghum plants was conducted. The empirical findings underscored a discernible decline in the assessed parameters with escalating concentrations of phosphate solid sludge. Particularly noteworthy was the pronounced amelioration observed in plants inoculated with AMF in comparison to both the control and PSB-inoculated counterparts. In conclusion, the application of raw phosphate solid sludge as an agricultural substrate is deemed unsuitable, prompting the imperative need for further in-depth investigations to ascertain the nuanced intricacies underlying these outcomes. Full article

Anthropogenic behaviors are causing the severe build-up of heavy metal (HM) pollutants in the environment, particularly in soils. Amongst a diversity of remediation technologies, phytoremediation is an environmentally friendly technology that, when coupling tolerant plants to selected rhizospheric microorganisms, can greatly stimulate HM decontamination of soils. Maize (Zea mays) is a plant with the reported capacity for HM exclusion from contaminated soil but also has energetic importance. In this study, Zea mays was coupled with Rhizophagus irregularis, an arbuscular mycorrhizal fungus (AMF), and Cupriavidus sp. strain 1C2, a plant growth-promoting rhizobacteria (PGPR), as a remediation approach to remove Cd and Zn from an industrial contaminated soil (1.2 mg Cd kg⁻¹ and 599 mg Zn kg⁻¹) and generate plant biomass, by contrast to the conservative development of the plant in an agricultural (with no metal pollution) soil. Biomass production and metal accumulation by Z. mays were monitored, and an increase in plant yield of ca. 9% was observed after development in the contaminated soil compared to the soil without metal contamination, while the plants removed ca. 0.77% and 0.13% of the Cd and Zn initially present in the soil. The resulting biomass (roots, stems, and cobs) was used for biogas generation in several biomethane (BMP) assays to evaluate the potential end purpose of the phytoremediation-resulting biomass. It was perceptible that the HMs existent in the industrial soil did not hinder the anaerobic biodegradation of the biomass, being registered biomethane production yields of ca. 183 and 178 mL of CH₄ g⁻¹ VS of the complete plant grown in non-contaminated and contaminated soils, respectively. The generation of biomethane from HM-polluted soils’ phytoremediation-derived maize biomass represents thus a promising possibility to be a counterpart to biogas production in an increasingly challenging status of renewable energy necessities. Full article

Mining and industrial activity are contributing to the increase in heavy metal (HM) pollution in soils. Phytoremediation coupled to selected rhizosphere microbiota is an environmentally friendly technology designed to promote HM bioremediation in soils. In this study, sunflower (Helianthus annuus L.) was used together with Rhizophagus irregularis, an arbuscular mycorrhizal fungi (AMF), and Cupriavidus sp. strain 1C2, a plant growth promoting rhizobacteria (PGPR), as a phytoremediation strategy to remove Zn and Cd from an industrial soil (599 mg Zn kg⁻¹ and 1.2 mg Cd kg⁻¹). The work aimed to understand if it is possible to gradually remediate the tested soil while simultaneously obtaining significant yields of biomass with further energetic values by comparison to the conventional growth of the plant in agricultural (non-contaminated) soil. The H. annuus biomass harvested in the contaminated industrial soil was 17% lower than that grown in the agricultural soil—corresponding to yields of 19, 620, 199 and 52 g m⁻² of roots, stems, flowers and seeds. It was possible to remove ca. 0.04 and 0.91% of the Zn and Cd of the industrial soil, respectively, via the HM accumulation on the biomass produced. The survival of applied microbiota was indicated by a high root colonization rate of AMF (about 50% more than in non-inoculated agricultural soil) and identification of strain 1C2 in the rhizosphere at the end of the phytoremediation assay. In this study, a phytoremediation strategy encompassing the application of an energetic crop inoculated with known beneficial microbiota applied to a real contaminated soil was successfully tested, with the production of plant biomass with the potential for upstream energetic valorisation purposes. Full article

The old Zn-Pb-contaminated (calamine) tailings in southern Poland are spontaneously colonized by metal-tolerant Anthyllis vulneraria L. (Fabaceae), which can form simultaneously symbiotic association with nitrogen-fixing rhizobia and phosphorus-acquiring arbuscular mycorrhizal fungi (AMF). So far, fungal colonization and the AMF diversity of calamine-inhabiting legumes have been poorly studied. Thus, we determined AMF spore density in the substratum and the mycorrhizal status of nodulated A. vulneraria plants occurring on calamine tailings (M) and on a reference non-metallicolous (NM) site. The results indicate the presence of the Arum-type of arbuscular mycorrhiza in the roots of both Anthyllis ecotypes. Despite the presence of AM fungi in M plant roots, the dark septate endophyte (DSE) fungi (hyphae and microsclerotia) were occasionally also detected. Metal ions were accumulated mainly in the nodules and intraradical fungal structures rather than thick plant cell walls. Mycorrhization parameters (frequency of mycorrhization and intensity of root cortex colonization) for M plants were markedly higher and differed in a statistically significant manner from the parameters for NM plants. Heavy metal excess had no negative effect on the number of AMF spores, the amounts of glomalin-related soil proteins and AMF species composition. Molecular identification of AMF using PCR-DGGE analysis based on the 18S rDNA ribosomal gene by nested-PCR with primers AM1/NS31 and NS31-GC/Glo1 revealed similar genera/species of AMF in the roots of both Anthyllis ecotypes: Rhizophagus sp., R. fasciculatus, and R. iranicus. The results of this work indicate the presence of unique fungal symbionts, which may enhance A. vulneraria tolerance to heavy metal stress and plant adaptation to extreme conditions on calamine tailings. Full article

The prominence of arbuscular mycorrhizal fungi (AMF) in sustainable rice production has long been recognized. However, there is little information about AMF response in aerobic rice cultivation under phosphorus (P)-deficient conditions. The aim of this experiment was to compare and determine the preeminent AMF effects on rice mycorrhizal colonization, responsiveness, P utilization, and different growth-promoting traits under P-deficient conditions. Different AMF genera viz. (Funneliformis sp., Rhizophagus sp., Glomus sp., Acaulospora sp., and Claroideoglomus sp.) in four different aerobic rice varieties developed by ICAR-NRRI, India (CR Dhan 201, CR Dhan 204, CR Dhan 205, and CR Dhan 207) were investigated using the check P-susceptible variety (IR 36) and the P-tolerant variety (Kasalath IC459373). Data analyzed through linear modeling approaches and bivariate associations found that AMF colonization was highly correlated with soil enzymes, particularly fluorescein diacetate (FDA) and plant P uptake. The microbial biomass carbon (MBC) and FDA content were significantly changed among rice varieties treated with AMF compared to uninoculated control. Out of four different rice varieties, CR Dhan 207 inoculated with AMF showed higher plant P uptake compared to other varieties. In all the rice varieties, AMF colonization had higher correlation coefficients with soil enzymes (FDA), MBC, and plant P uptake than uninoculated control. The present study indicates that AMF intervention in aerobic rice cultivation under P-deficient conditions significantly increased plant P uptake, soil enzymes activities and plant growth promotion. Thus, the information gathered from this study will help us to develop a viable AMF package for sustainable aerobic rice cultivation. Full article

Symbiotic associations with arbuscular mycorrhizal fungi (AMF) offer an effective indirect mechanism to reduce heavy metal (HM) stress; however, it is still not clear which AMF species are more efficient as bioremediating agents. We selected different species of AMF: Rhizoglomus custos (Custos); Rhizoglomus sp. (Aznalcollar); and Rhizophagus irregularis (Intraradices), in order to study their inoculation in wheat grown in two soils contaminated with two levels of HMs; we tested the phytoprotection potential of the different AMF symbioses, as well as the physiological responses of the plants to HM stress. Plants inoculated with indigenous Aznalcollar fungus exhibited higher levels of accumulation, mainly in the shoots of most of the HM analyzed in heavily contaminated soil. However, the plants inoculated with the non-indigenous Custos and Intraradices showed depletion of some of the HM. In the less-contaminated soil, the Custos and Intraradices fungi exhibited the greatest bioaccumulation capacity. Interestingly, soil enzymatic activity and the enzymatic antioxidant systems of the plant increased in all AMF treatments tested in the soils with both degrees of contamination. Our results highlight the different AMF strategies with similar effectiveness, whereby Aznalcollar improves phytoremediation, while both Custos and Intraradices enhance the bioprotection of wheat in HM-contaminated environments. Full article

Climate change prediction indicates an increased likelihood of precipitation variability and droughts in the Mediterranean region. Previous studies demonstrated that microbial symbionts combined with supplementary irrigation could mitigate climate change effects and boost chickpea production in low-fertility soils. The aim of the study was to assess the effects of inoculation with a consortium of plant growth-promoting rhizobacteria (PGPR) (Pseudomonas sp., Burkholderia sp. and Mesorhizobium sp.) and arbuscular mycorrhizal fungi (AMF) (Rhizophagus irregularis, Funneliformis geosporum and Claroideoglomus claroideum) on growth, grain yield and crude protein content of chickpeas under the following irrigation regimes: I1-no water stress, I2-moderate water stress, I3-strong water-stress, I4-no water stress in critical growth stages of plant cycle development and I5-severe water stress). Plants irrigated only during the critical growth stages of flowering and pod filling showed higher grain yields compared to plants from other water deficit irrigation treatments. Additionally, chickpeas co-inoculated with PGPR and AMF, and irrigated only during critical growth stages, presented higher grain yield than non-inoculated plants without water stress (1.45- and 1.33-fold increase in 2018 and 2019, respectively). Inoculation with beneficial microorganisms and supplemental irrigation at critical stages benefits chickpea growth and should be considered for increasing crop productivity and promoting agricultural sustainability. Full article

Fast growing, high biomass willows (Salix sp.) have been extensively used for the phytoremediation of trace element-contaminated environments, as they have an extensive root system and they tolerate abiotic stressors such as drought and metal toxicity. Being dual mycorrhizal plants, they can engage single or simultaneous symbiotic associations with both arbuscular mycorrhizal (AM) fungi and ectomycorrhizal (EM) fungi, which can improve overall plant health and growth. The aim of this study was to test the effect of these mycorrhizal fungi on the growth and trace element (TE) extraction potential of willows. A field experiment was carried out where we grew Salix miyabeana clone SX67 on the site of a decommissioned industrial landfill, and inoculated the shrubs with an AM fungus Rhizophagus irregularis, an EM fungus Sphaerosporella brunnea, or a mixture of both. After two growing seasons, the willows inoculated with the EM fungus S. brunnea produced significantly higher biomass. Ba, Cd and Zn were found to be phytoextracted to the aerial plant biomass, where Cd presented the highest bioconcentration factor values in all treatments. Additionally, the plots where the willows received the S. brunnea inoculation showed a significant decrease of Cu, Pb, and Sn soil concentrations. AM fungi inoculation and dual inoculation did not significantly influence biomass production and soil TE levels. Full article

The olive tree (Olea europaea L.) is an emblematic, long-living fruit tree species of profound economic and environmental importance. This study is a literature review of articles published during the last 10 years about the role of beneficial microbes [Arbuscular Mycorrhizal Fungi (AMF), Plant Growth Promoting Rhizobacteria (PGPR), Plant Growth Promoting Fungi (PGPF), and Endophytes] on olive tree plant growth and productivity, pathogen control, and alleviation from abiotic stress. The majority of the studies examined the AMF effect using mostly Rhizophagus irregularis and Glomus mosseae species. These AMF species stimulate the root growth improving the resistance of olive plants to environmental and transplantation stresses. Among the PGPR, the nitrogen-fixing bacteria Azospirillum sp. and potassium- and phosphorous-solubilizing Bacillus sp. species were studied extensively. These PGPR species were combined with proper cultural practices and improved considerably olive plant’s growth. The endophytic bacterial species Pseudomonas fluorescens and Bacillus sp., as well as the fungal species Trichoderma sp. were identified as the most effective biocontrol agents against olive tree diseases (e.g., Verticillium wilt, root rot, and anthracnose). Full article