Arbuscular Mycorrhizal Research Articles

The use of biostimulants as a key to sustainable hydroponic lettuce farming under saline water stress

BackroundThe utilization of high-quality water in agriculture is increasingly constrained by climate change, affecting availability, quality, and distribution due to altered precipitation patterns, increased evaporation, extreme weather events, and rising salinity levels. Salinity significantly challenges salt-sensitive vegetables like lettuce, particularly in a greenhouse. Hydroponics water quality ensures nutrient solution stability, enhances nutrient uptake, prevents contamination, regulates pH and electrical conductivity, and maintains system components. This study aimed to mitigate salt-induced damage in lettuce grown via the floating culture method under 50 mM NaCl salinity by applying biostimulants.ResultsWe examined lettuce’s physiological, biochemical, and agronomical responses to salt stress after applying biostimulants such as amino acids, arbuscular mycorrhizal fungi, plant growth-promoting rhizobacteria (PGPR), fulvic acid, and chitosan. The experiment was conducted in a greenhouse with a randomized complete block design, and each treatment was replicated four times. Biostimulant applications alleviated salt’s detrimental effects on plant weight, height, leaf number, and leaf area. Yield increases under 50 mM NaCl were 75%, 51%, 31%, 34%, and 33% using vermicompost, PGPR, fulvic acid, amino acid, and chitosan, respectively. Biostimulants improved stomatal conductance (58–189%), chlorophyll content (4–10%), nutrient uptake (15–109%), and water status (9–107%). They also reduced MDA content by 26–42%. PGPR (1.0 ml L‒1), vermicompost (2 ml L‒1), and fulvic acid (40 mg L‒1) were particularly effective, enhancing growth, yield, phenol, and mineral content while reducing nitrate levels under saline conditions.ConclusionsBiostimulants activated antioxidative defense systems, offering a sustainable, cost-effective solution for mitigating salt stress in hydroponic lettuce cultivation.

Can earthworms and root traits improve plant struvite-P uptake? A field mesocosm study

The availability of conventional linear mineral phosphorus (P) fertilization will become lower as phosphate rock stocks are limited and strongly concentrated in a few locations. Therefore, we need to increase agronomic P use efficiency and find alternative, recycled, sources of P. Two possible solutions mentioned in the literature are (i) using struvite, a mineral circular P fertilizer; and (ii) making use of earthworm activity, which has been shown to increase P availability. Here, we study the interaction between these two approaches, with the hypothesis that earthworms could increase the P availability from the poorly soluble struvite. We set up a field-based mesocosm experiment in a sandy soil with a low agronomic P status with 13 different treatments combining three earthworms species (Lumbricus rubellus Hoffmeister, Aporrectodea caliginosa Savigny and A. longa Ude alone or in a threes species mixture), different P fertilizers (no P, Triple Super Phosphate (TSP) and struvite). The experiment lasted 13 months (five fertilisation-harvest cycles). We found that, in field conditions, the yield and P uptake of Lolium perenne did not differ between fertilization with struvite or TSP. Earthworms only played a minor role in explaining ryegrass P uptake compared to fertilisation. We did not see either positive nor negative interactions between earthworms and struvite, meaning that earthworms did not further increase the P availability from struvite. The equal performances of struvite and TSP are explained by an enhanced effort from plants to actively take up P through a modification of root traits. This includes increased arbuscular mycorrhizal fungi colonisation and the production of finer and longer roots. Our results show that struvite performs comparably to TSP under realistic field conditions, making it a viable alternative to phosphate rock-based fertilizers.

Extraction, identification and mass production of arbuscular mycorrhizal fungi (AMF) from faba bean (Vicia faba L.) rhizosphere soils using maize (Zea mays L.) as a host plant

Ethiopia is the second-largest grower of faba bean in the world next to China. The crop is highly useful with its edible seed serving as an essential protein complement of the Ethiopian diet, especially for those who cannot afford animal protein. Even though faba bean is mycotrophic to Arbuscular Mycorrhizal fungi (AMF), the different genera and species that are associated with the crop are not determined in yet at the maturity time of the crop (harvesting period). Sixteen faba bean rhizospheric soils were collected to isolate and identify AMF. Spores were extracted using the wet-sieving and decanting method. The Glomus genera was the most dominant, followed by the Acaulospora and Gigaspora genera. The highest spore load per 100 g of soil was observed in the sample that contained the lowest soil phosphorus. Furthermore, an inverse relationship between the spore load and soil phosphorus was observed. Three treatments were considered for mass multiplication of AMF, viz, Treatment (1) Glomus aggregatum, treatment (2) Glomus sp.BZ, and treatment (3) Glomus sp.AZ. However, the highest number of AMF's spore and root colonization was seen in treatment 3 with significant difference (P < 0.05) from the others. In conclusion, AMF constituted an important component of the faba bean rhizosphere during its harvesting period (dry season) and its multiplication using maize favored the viability and infectivity of the fungi.

Enhanced Soil Fertility and Carbon Dynamics in Organic Farming Systems: The Role of Arbuscular Mycorrhizal Fungal Abundance.

Arbuscular mycorrhizal fungi (AMF) are critical for soil ecosystem services as they enhance plant growth and soil quality via nutrient cycling and carbon storage. Considering the growing emphasis on sustainable agricultural practices, this study investigated the effects of conventional and organic farming practices on AMF diversity, abundance, and ecological functions in maize, pepper, and potato-cultivated soils. Using next-generation sequencing and quantitative PCR, we assessed AMF diversity and abundance in addition to soil health indicators such as phosphorus content, total nitrogen, and soil organic carbon. Our findings revealed that, while no significant differences in soil physicochemical parameters or AMF diversity were observed across farming systems when all crop data were combined, organic farming significantly enhances AMF abundance and fosters beneficial microbial ecosystems. These ecosystems play vital roles in nutrient cycling and carbon storage, underscoring the importance of organic practices in promoting robust AMF communities that support ecosystem services. This study not only deepens our understanding of AMF's ecological roles but also highlights the potential of organic farming to leverage these benefits for improving sustainability in agricultural practices.

Regulation of arbuscular mycorrhizal fungi in citrus root hairs mediated by auxin efflux carrier protein PtPINs

Arbuscular mycorrhizal fungi (AMF) and auxins are critical in the development of root hairs, but the interaction mechanism by which they jointly regulating the development of citrus needs further clarification. This study investigated the influence of Funneliformis mosseae on the growth, root architecture, root hair traits, indole-3-acetic acid (IAA) content and flow rate, and auxins efflux carrier protein genes (PtPINs) expression in potted trifoliate orange (Poncirus trifoliata L.) over 4, 6, 8, 10, and 12 weeks of inoculation. Results indicated continuous increases in mycorrhizal colonization and soil hyphae length over time. Compared with the non-AMF, AMF significantly enhanced plant growth and biomass, and notably increased total root length, projected area, surface area, volume, and the number of 2nd-order lateral roots, with these parameters improving further over the treatment duration. Whereas root hair growth was inhibited at 4 w, 6 w and 8 w, it was promoted at 10 w and 12 w following AMF treatment. AMF also significantly increased the content of indole-3-acetic acid (IAA) over time. And the expression patterns of auxins flow rate and PtPINs vary across different treatment periods, showing a strong correlation with citrus growth and root hair development. Specifically, PtPINs were significantly correlated with total IAA flow rate and total root hair growth, with PtPIN6 potentially playing a positive role in root hair development. These findings suggested that auxins are involved in AMF-regulated citrus root hair growth, with PtPIN6 identified as a potentially key gene in auxin transport regulation.

Potential of Arbuscular Mycorrhizal Fungi to Overcome Drought Stress and Low Nutrient Availability in Dryland Farming

There is an increasing rate of land conversion in Indonesia that can threaten food self-sufficiency. Therefore farmers and the government must expand agriculture by developing agriculture on potential available lands such as drylands. However, drylands in Indonesia have low productivity due to low water and nutrient availability. This article aims to determine the potential use of arbuscular mycorrhizal fungi to overcome drought stress and low nutrient availability in drylands. The method used in writing this article is a desk literature study conducted by collecting data from various sources, such as scientific journals, seminar proceedings, and online reports available in related government office in West Nusatenggara Province. The data obtained were then analyzed qualitatively by identifying, reviewing, and synthesizing information to produce a complete and comprehensive explanation. The results of the literature study showed that arbuscular mycorrhizal fungi have the potential to overcome drought stress and low nutrient availability in drylands. The use of arbuscular mycorrhizal fungi can be a sustainable solution to increase agricultural productivity in drylands.

Potential of Arbuscular Mycorrhizal Fungi to Overcome Drought Stress and Low Nutrient Availability in Dryland Farming

There is an increasing rate of land conversion in Indonesia that can threaten food self-sufficiency. Therefore farmers and the government must expand agriculture by developing agriculture on potential available lands such as drylands. However, drylands in Indonesia have low productivity due to low water and nutrient availability. This article aims to determine the potential use of arbuscular mycorrhizal fungi to overcome drought stress and low nutrient availability in drylands. The method used in writing this article is a desk literature study conducted by collecting data from various sources, such as scientific journals, seminar proceedings, and online reports available in related government office in West Nusatenggara Province. The data obtained were then analyzed qualitatively by identifying, reviewing, and synthesizing information to produce a complete and comprehensive explanation. The results of the literature study showed that arbuscular mycorrhizal fungi have the potential to overcome drought stress and low nutrient availability in drylands. The use of arbuscular mycorrhizal fungi can be a sustainable solution to increase agricultural productivity in drylands.

Arbuscular Mycorrhizal Fungi and Soil Enzyme Activities in Different Fonio Millet (Digitaria exilis Stapf.) Agroecosystems in Senegal

In plant roots, arbuscular mycorrhizal fungi (AMF) are the most prevalent microsymbionts, and thereby provide many key ecosystem services to natural and agricultural ecosystems. Despite AMF’s significance for the environment and the economy, little is known about the mycorrhizal inoculum potential and diversity of AMF associated with orphan African cereal crops, specially fonio millet (Digitaria exilis stapf.) under field conditions. We hypothesized that the type of fonio millet agroecosystem influences the AMF density and distribution in soils. We therefore, assessed the inoculum potential, density and diversity of AMF spores and soil enzyme activities in five fonio millet agroecosystems belonging to three climatic zones (Sudanian, Sudano-Sahelian and Sudano-Guinean). By combining AMF spore identification from field-collected soils and trap culture, 20 species belonging to 8 genera (Acaulospora, Ambispora, Dendiscutata, Gigaspora, Glomus, Racocetra, Sclerocystis and Scutellospora) were identified. Glomus was the most represented genus with 8 species, followed by Gigaspora (5 species) and Acaulospora (2 species); the remaining genera were each represented by one species. Except for Ambispora which was not found in the Sudanian area, all genera occurred in the three climatic zones. The abundance and diversity of AMF species and FDA-hydrolytic and phosphatase activities varied between fonio millet agroecosystems as well as between climatic zones. Soil pH and soil texture were the variables that best explained the density and distribution of AMF spores. Our results contribute to paving the way towards the development of microbial engineering approaches for agronomic improvement of fonio millet.

Arbuscular mycorrhizal fungi improves yield and quality attributes of melon fruit grown under greenhouse

ABSTRACT Melon (Cucumis melo) is the most popular fruit with indisputable socio-economic and nutritional value, as evidenced by its significant acreage (1 Mha) and production (28 Mt) worldwide. However, melon farming is facing the triple challenge of producing enough to meet growing consumer demand, improving the concentration of human wellness compounds, while minimising chemical inputs. This scientific research was carried out to assess the effectiveness of two arbuscular mycorrhizal fungi (AMF), Rhizophagus irregularis (Ri), R. fasciculatus (Rf), and their complex, in improving yield and quality attributes in melon variety ‘Ananas’ grown in greenhouse. Results showed that production and fruit quality were significantly improved in mycorrhizal plants (M-plants) compared to non-mycorrhizal (NM-plants) ones, regardless of AMF treatments. M-plants performance varied according to AMF strains. Indeed, Ri-plant exhibited the highest increases in yield (54%), fresh weight (65%), longitudinal (20%) and equatorial (33%) perimeters, Brix degree (20.6%), polyphenols (315.4%), carotenoids (353%), proteins (209.1%), flavonoids (114.38%), ascorbic acid (31.3%), reducing power (77.04%), DPPH radical inhibition (16.43%), and the highest decrease in titrable acidity (62.5%). In addition, Ri-plant fruits were highly rated by participants in the sensory evaluation test. Therefore, R. irregularis application could be recommended for the sustainable production of high-quality fruits of melon.

Characteristics of Rhizosphere Microbiome, Soil Chemical Properties, and Plant Biomass and Nutrients in Citrus reticulata cv. Shatangju Exposed to Increasing Soil Cu Levels.

The prolonged utilization of copper (Cu)-containing fungicides results in Cu accumulation and affects soil ecological health. Thus, a pot experiment was conducted using Citrus reticulata cv. Shatangju with five Cu levels (38, 108, 178, 318, and 388 mg kg-1) to evaluate the impacts of the soil microbial processes, chemistry properties, and citrus growth. These results revealed that, with the soil Cu levels increased, the soil total Cu (TCu), available Cu (ACu), organic matter (SOM), available potassium (AK), and pH increased while the soil available phosphorus (AP) and alkali-hydrolyzable nitrogen (AN) decreased. Moreover, the soil extracellular enzyme activities related to C and P metabolism decreased while the enzymes related to N metabolism increased, and the expression of soil genes involved in C, N, and P cycling was regulated. Moreover, it was observed that tolerant microorganisms (e.g., p_Proteobacteria, p_Actinobacteria, g_Lysobacter, g_Sphingobium, f_Aspergillaceae, and g_Penicillium) were enriched but sensitive taxa (p_Myxococcota) were suppressed in the citrus rhizosphere. The citrus biomass was mainly positively correlated with soil AN and AP; plant N and P were mainly positively correlated with soil AP, AN, and acid phosphatase (ACP); and plant K was mainly negatively related with soil β-glucosidase (βG) and positively related with the soil fungal Shannon index. The dominant bacterial taxa p_Actinobacteriota presented positively correlated with the plant biomass and plant N, P, and K and was negatively correlated with plant Cu. The dominant fungal taxa p_Ascomycota was positively related to plant Cu but negatively with the plant biomass and plant N, P, and K. Notably, arbuscular mycorrhizal fungi (p_Glomeromycota) were positively related with plant P below soil Cu 108 mg kg-1, and pathogenic fungi (p_Mortierellomycota) was negatively correlated with plant K above soil Cu 178 mg kg-1. These findings provided a new perspective on soil microbes and chemistry properties and the healthy development of the citrus industry at increasing soil Cu levels.

Morphological type and taxonomic diversity of arbuscular mycorrhizal fungi along an altitudinal gradient at Mount Ibuki, Japan

ABSTRACT Arbuscular mycorrhiza (AM) associations are among the most widespread interactions between plants and fungi. However, little is known about the AM distribution along altitudinal gradients in forest ecosystems, where the gradients are accompanied by shifts in climatic conditions and soil properties as well as the identity of host plant species. This study aimed to clarify AM fungal associations along an altitudinal gradient. Therefore, we determined the colonization rate and community composition of AM fungi at different elevations on Mount Ibuki, Japan. Root and soil samples were collected from Cryptomeria japonica at altitudes of 200, 500, and 800 m, Acer shirasawanum at an altitude of 1100 m, and Chrysanthemum japonicum at the summit of 1350 m. To evaluate AM fungal colonization, 15 root samples from each altitude were examined microscopically. These samples were identified by targeting V4 and V5 regions of a partial small subunit rRNA gene using Sanger sequencing. AM fungal colonization rates were significantly and positively correlated with altitude. The Arum and Paris types were observed in all plant species examined at each altitude. In total, 101 molecular operational taxonomic units belonging to two genera were identified: Glomus and Diversispora. No significant clustering among elevations was observed in the AM fungal community composition. Among environmental variables, soil temperature, and pH significantly affected AM fungal structure patterns. These results suggest that as altitude increases, plants require more tight mycorrhizal associations, which are selectively filtered by the surrounding environment.

Growth, profitability, nutritional, and anti-nutritional properties of seven Manihot esculenta Crantz (cassava) varieties as affected by arbuscular mycorrhizal fungi

Despite a range of methods used to promote modern agriculture with several outcomes, food quality and availability problems remain. This work aims to evaluate the effect of AM fungi inoculation on the growth, yield, nutritional, and antinutritional properties of 7 varieties of cassava. Growth characteristics, yields, rentability, nutritional, and antinutritional of tubers of each treatment were determined at harvest. All the cassava varieties used form a symbiosis with AM fungi at various frequencies, with the I090590 variety being the best (61.66 %). The best amount of chlorophyll, carotenoid, and height of plants were recorded at 9 months old. The 96/1414, TME/693 and MD varieties respectively show the best amount of chlorophyll, size, and carotenoids at 9 months old. Following AM fungi inoculation, an increase in the content of chlorophyll, size, and carotenoids was recorded for all the varieties with the best rate attributed respectively to 92/0326, MD, and 92/0326. Tuber yields vary significantly depending on the cassava varieties, with the best (56.16 t/ha) recorded for the I090590 variety. Following inoculation with AM fungi, a significant increase in yields was recorded, with the best ratio (2.7) obtained with the AE variety. The I090590 variety shows the best yield and by then the most profitable. Inoculation with AM fungi leads to a significant increase in the sugar, protein, fibre, and phosphorus content of all cassava varieties, with the best ratios obtained in 96/1414, 01/1797, and I090590 varieties respectively. Similarly, the inoculation of cassava varieties with AM fungi leads to a significant reduction in the content of cyanides, oxalates, and phytates. The best ratio of reduction for cyanide was 1.91 for the MD variety. AM fungi inoculation is an important way to ensure safe, exponential production and high economic profitability of foodstuffs.

Soil Traits and Grapevine Rootstock Genotypes Modulate Arbuscular Mycorrhizal Rate and Species in a Mediterranean Environment

The soil microbiota is a key component of agroecosystems, and understanding its traits is crucial for effective agronomic management. Among beneficial microorganisms, arbuscular mycorrhizal fungi (AMFs) are mutually associated with grapevine (Vitis vinifera L.), enhancing the ability of this cropping system to adapt to soil conditions and bolstering its resistance and resilience against abiotic stresses, particularly drought, by promoting root growth and enhancing the roots’ absorption surface. The objective of this on-field study was to determine AMF species richness and diversity along with their relation to soil chemical, physical, and biological characteristics in two adjacent organic vineyards in Central Italy. The two tested vineyards of the autochthonous cv. Aleatico differed by the presence of grafted (Vitis berlandieri × V. riparia rootstock; AL-420) or own-rooted (ungrafted V. vinifera L.; AL-ORV) vines. To this aim, soil and root samples were collected and geo-referenced. Analysis of the AMF species colonizing roots of both AL-ORV and AL-420 revealed the presence of four species: Scutellospora alterata, Paraglomus laccatum, Acaulospora laevis, and A. baetica, with S. alterata being the most frequent. Mycorrhization parameters were higher in the roots of grafted plants compared to ungrafted ones. A high beta-glucosidase (BG):N-acetylglusosaminidase (NAG) ratio in two tested vineyards indicated that microbes utilized more cellulose than chitin and peptidoglycan as dominant C resources. A negative correlation between mycorrhization rate (MyCP) and BG was observed, likely because AMFs form mutualistic relationships with plants, depending on the host plant for carbon. Results revealed a positive correlation between the degree of mycorrhizal association and the species involved, with the presence of copper and nickel among metals. Negative correlations were found concerning soil clay content along with beta-glucosidase. In conclusion, the grapevine root system was characterized by a differential symbiotic relationship with AMF species, whose development is influenced by the root genotype, soil texture, and biochemistry. Specifically, the increased frequency of AMFs in relation to copper content strengthens the evidence of their role in maintaining a vine’s production capacity in the event of soil contamination by this element.

Water availability and accessions of Passiflora cincinnata Mast. can shape the communities of arbuscular mycorrhizal fungi

Understanding how water availability affects different caatinga passionfruit accessions (Passiflora cincinnata Mast.) and their drought tolerance is crucial for successful cultivation in semi-arid environments. Additionally, assessing the impact of this stress on arbuscular mycorrhizal fungi (AMF) communities' structure and dynamics is also essential. A greenhouse experiment was conducted with the purpose of identifying tolerant and sensitive P. cincinnata accessions under drought stress and how the water availability would affect AMF communities, which were taxonomically identified based on morphological characters. Results show that water availability influenced height, stem diameter, total chlorophyll, dry and fresh shoot biomass, fresh root biomass, leaf area, number of leaves and tendrils, and root/shoot ratio of accessions of P. cincinnata. However, water availability did not influence root dry biomass, only the identity of P. cincinnata accessions differed from each other. In the PCA-based ranking, based on the morpho-descriptors traits, and on the indices of drought stress tolerance, accessions 01 and 48 were considered tolerant and sensitive to drought, respectively. The abundance of glomerospores and the AMF richness are not influenced by the factors studied, but water availability has increased the frequency of mycorrhizal colonization, diversity, and evenness of AMF species, in addition to reducing its dominance. AMF communities’ composition was modulated by P. cincinnata accessions and by water availability. Utilizing morpho-agronomic traits, it becomes feasible to differentiate P. cincinnata accessions exhibiting tolerance and sensitivity to drought stress. Particular emphasis is placed on fresh and dry shoot biomass, leaf area, and height, each contributing approximately 12% to these outcomes. Changes on the composition of AMF communities after imposition of water deficit suggest that some AMF species may show some drought tolerance and that preferences for P. cincinnata genotypes may exist.

Assessing extraradical mycelium of mycorrhizal fungi in tropical forests using armored in-growth mesh bags

The extraradical mycelium of mycorrhizal fungi is among the major carbon pools in soil that is hard to quantitatively assess in-situ. Established method of in-growth mesh bags in temperate ecosystems is difficult to apply in the tropics, where mesh bags are often damaged by termites. Here we introduce a modification of the in-growth mesh bag technique, in which mesh bags are enforced by stainless steel mesh. Its performance was tested in the Đồng Nai (Cát Tiên) National Park in Vietnam across two monsoon tropical forests, dominated by tree species associated with either ectomycorrhizal (ECM) or arbuscular mycorrhizal (AM) fungi. Armored in-growth mesh bags remained intact, while about 60 % of non-armored mesh bags were damaged by termites after 180 days of exposure. The biomass of extraradical mycelium of ectomycorrhizal fungi estimated by PLFA analysis was similar in the armored and non-armored mesh bags and did not differ between studied forests. However, fungal community composition slightly differed between armored and non-armored mesh bags in the ECM- but not in the AM-dominated forest. Fungal mycelium gathered in the AM-dominated forest was depleted in 15N compared to that collected in the ECM-dominated forest. Overall, our results argue for using armored mesh bags as a robust tool for harvesting the biomass of extraradical mycelium of mycorrhizal fungi in tropical ecosystems.

The impact of arbuscular mycorrhizal fungi on soybean growth strategies in response to salt stress

The impact of arbuscular mycorrhizal fungi on soybean growth strategies in response to salt stress

Micro PIXE mapping proves a differential distribution and concentration of trace elements in fungal structures of Rhizophagus intraradices

Arbuscular mycorrhizal (AM) fungi can sequester different potentially toxic elements, such as trace elements (TEs), within their structures to alleviate the toxicity for its host plant and themselves. To elucidate the role of AM fungi in TEs immobilization in the rhizosphere of host plants, it is important to know the TEs distribution in AM fungal structures. In the present study, we investigated the distribution and concentration of TEs within extraradical spores and mycelium of the AM fungus Rhizophagus intraradices, collected from the rhizosphere of Senecio bonariensis plants grown in a soil polluted with multiple TEs, by using Particle-Induced X-ray Emission with a micro-focused beam (micro PIXE). This technique enabled the simultaneous micrometric mapping of elements in a sample. The calculated values were compared with those in the polluted substrate, measured by the Wavelength Dispersive X-ray Fluorescence technique. The highest concentrations of Fe, P, Ti, Mn, Cr, Cu and Zn were found in AM fungal spores, where they were accumulated, while extraradical mycelium was enriched in Cu. Finally, we demonstrated that AM fungi can simultaneously accumulate high amounts of different TEs in their structures, thus reducing the toxicity of these elements to its host plant.

The root microlandscape of arbuscular mycorrhizal fungi.

Understanding the drivers of assemblages of arbuscular mycorrhizal fungi (AMF) is essential to leverage the benefits of AMF for plant growth and health. Arbuscular mycorrhizal fungi are heterogeneously distributed in space even at small scale. We review the role of plant distribution in driving AMF assemblages (the passenger hypothesis), using a transposition of the conceptual framework of landscape ecology. Because rooting systems correspond to habitat patches with limited carrying capacity that differ in quality due to host-preference effects, we suggest considering plant communities as mosaics of AMF microhabitats. We review how predictions from landscape ecology apply to plant community effects on AMF, and the existing evidence that tests these predictions. Although many studies have been conducted on the effect of plantcompositional heterogeneity on AMF assemblages, they mostly focused on the effect ofplant richness, while only a few investigated the effect of configurational heterogeneity, plant connectivity or plant community temporal dynamics. We propose key predictions and future prospects to fill these gaps. Considering plant communities as landscapes extends the passenger hypothesis by including a spatially explicit dimension and its associated ecological processes and may help understand and manipulate AMF assemblages at small spatial scales.

No-tillage facilitates soil organic carbon sequestration by enhancing arbuscular mycorrhizal fungi-related soil proteins accumulation and aggregation

No-tillage is known to optimize soil structure and enhance soil organic carbon (SOC) stocks in cropland. However, the exact mechanisms driving the accumulation of SOC are still unclear, especially concerning the regulation of arbuscular mycorrhizal fungi (AMF) communities and diversity in SOC sequestration. Here, this study aims to elucidate the intricate relationship between AMF community, glomalin-related soil proteins (GRSP), and SOC within bulk soil and aggregates across four tillage treatments (i.e. FA, fallow; RT, rotary tillage; DT, deep tillage; NT, no-tillage) based on a 7-year tillage experiment. Results showed that the contents of SOC and GRSP were significantly higher by 1.14–1.46 mg/g and 0.43–0.72 mg/g in the bulk soil under NT relative to RT and DT, respectively. The contribution of GRSP-C to SOC under NT was also higher than RT and DT, especially in > 53 μm particle size. Additionally, NT increased AMF diversity and the abundance of glomerales and diversisporales, all showing a strong positive correlation with GRSP (p < 0.05), indicating their potential regulatory role in GRSP production. The positive correlations between GRSP and the mass percentage of the > 53 μm particle size fraction (R2 = 0.74; p < 0.01) and MWD (R2 = 0.63; p < 0.01) suggested that no-tillage may drive large aggregates (>53 μm) formation and enhance aggregate stability through GRSP levels. Overall, increased AMF diversity and keystone taxa abundance at the order level via no-tillage promoted SOC accumulation through the production of GRSP and the protection of large aggregates. This study highlights that no-tillage is an effective and sustainable soil management strategy for enhancing soil quality in agricultural ecosystems.

Strategies for Achieving High and Sustainable Plant Productivity in Saline Soil Conditions

The accumulation of salt in arable lands is a source of significant abiotic stress, contributing to a 10% decline in the world’s total arable lands and threatening food productivity and the sustainability of agriculture. About 76 million hectares of productive land are estimated to have been affected by human-induced salinization such as extreme salt deposits in soil, which are mainly caused by the actions of humans. For instance, continued irrigation and the frequent use of chemical fertilizers need to be understood. To ensure food availability, it is essential to improve upon traditional farming methods using current technologies to facilitate the reclamation of saline-affected arable lands to achieve high and sustainable food production. This review details current innovative strategies such as the modification of metabolic pathways, manipulation of antioxidant pathways, genetic engineering, RNA interference technology, engineered nanoparticles, arbuscular mycorrhizal fungi (AMF), organic amendments, and trace elements for improving saline marginal lands. These strategies were identified to have contributed to the improvement of plants salinity tolerance in diverse ways. For instance, the accumulation of plant metabolites such as amino acids, sugars, polyols, organic acids, saponins, anthocyanins, polyphenols, and tannins detoxify plants and play crucial roles in mitigating the detrimental effects of oxidative damage posed by salinity stress. Multiple plant miRNAs encoding the up- and down-regulation of single- and multi-ion transporters have been engineered in plant species to enhance salt tolerance. Nanomaterials and plant root system colonized by arbuscular mycorrhizal increase water uptake, photosynthetic efficiency, and biomass allocation in plants exposed to saline stress by excluding 65 percent of the Na+ uptake and enhancing K+ uptake by 84.21 percent. Organic amendments and trace elements reduced salinity concentrations by 22 percent and improved growth by up to 84 percent in maize subjected to salinity stress. This study also discusses how researchers can use these strategies to improve plants growth, development, and survival in saline soil conditions to enhance the productivity and sustainability of agriculture. The strategies discussed in this study have also proven to be promising approaches for developing salinity stress tolerance strategies for plants to increase agricultural productivity and sustainability.