Arbuscular Mycorrhizal Research Articles

Arbuscular mycorrhizal fungi equalize differences in plant fitness and facilitate plant species coexistence through niche differentiation.

Mycorrhizal fungi are essential to the establishment of the vast majority of plant species but are often conceptualized with contradictory roles in plant community assembly. On the one hand, host-specific mycorrhizal fungi may allow a plant to be competitively dominant by enhancing growth. On the other hand, host-specific mycorrhizal fungi with different functional capabilities may increase nutrient niche partitioning, allowing plant species to coexist. Here, to resolve the balance of these two contradictory forces, we used a controlled greenhouse study to manipulate the presence of two main types of mycorrhizal fungus, ectomycorrhizal fungi and arbuscular mycorrhizal fungi, and used a range of conspecific and heterospecific competitor densities to investigate the role of mycorrhizal fungi in plant competition and coexistence. We find that the presence of arbuscular mycorrhizal fungi equalizes fitness differences between plants and stabilizes competition to create conditions for host species coexistence. Our results show how below-ground mutualisms can shift outcomes of plant competition and that a holistic view of plant communities that incorporates their mycorrhizal partners is important in predicting plant community dynamics.

Mycorrhizal fungi in Annona muricata L. rhizosphere in two agricultural production systems in Nayarit, Mexico

Mycorrhizal symbiosis is the association between the roots of several plant species and soil fungi of the Glomeromycotina subphylum. This symbiosis plays a crucial role in plant growth, development, and defense; therefore, understanding the abundance and diversity of arbuscular mycorrhizal fungi (AMF) species associated with plants of economic importance is of utmost concern. The objective of this study was to compare the abundance and composition of AMF communities in two Annona muricata cultivation sites, and in propagated soil, under different agricultural practices. The first cultivation site is under technified management with periodic fertilization and irrigation (TS), while the second cultivation site is under agroecological management without fertilization, irrigation, and with the presence of livestock (non-technified site; NTS). The extracted spores from the collected samples and the trap cultures were taxonomically identified based on their morphology. 13 species associated with A. muricata belonging to seven genera were identified in soil samples. The most abundant species were Funneliformis geosporum, Acaulospora kentinensis and Rhizophagus intraradices with a relative abundance of 45.9, 19.0 and 15.8%, respectively. In the propagation substrates, only 69% of the AMF species found in the field were identified. 11 species of AMF were found in the site with non-technified agronomic management, while only five species were found in the technified site.

Changing plant phosphorus acquisition strategies in relation to altered soil phosphorus fractions after wetland drainage

Abstract Plant phosphorus (P) acquisition strategy is considered to be an intrinsic driver behind plant succession. However, variations in plant P acquisition strategies in connection to soil P fraction changes after wetland drainage remain unclear. To address this issue, here we conducted a study in six distinct wetlands that experienced long‐term (>20 years) artificial drainage, with the adjacent waterlogged wetlands as a control. We analysed plant community composition, biomass and soil P fractions, and identified three plant P acquisition strategies based on soil acid phosphatase activity, plant P resorption efficiency, and soil arbuscular mycorrhizal fungi (AMF) content. We found that soil calcium‐bound P (PCa) and enzyme‐extractable P (Penzyme) were key factors influencing plant P acquisition. Soil PCa correlated negatively with acid phosphatase activity but positively with AMF content. Soil Penzyme negatively impacted P resorption efficiency. The wetlands were categorised into three types based on the change in plant richness and composition, with each exhibiting distinct plant P acquisition strategies. These changes in strategies after drainage corresponded with shifts in soil P fractions. Overall, our study highlights the role of soil P fractions in explaining plant P acquisition strategies after wetland drainage, suggesting P regulations on plant succession and ecosystem services. Read the free Plain Language Summary for this article on the Journal blog.

Cover crop grazing length impacts on soil health and crop productivity in US Coastal Plain soils

AbstractIntroducing integrated crop‐livestock systems into row crop production promotes income diversification and potential soil health benefits through cover crop grazing on degraded soils of the southeastern United States, but effects of these practices on crop yields and soil health in Coastal Plain soils are not well established. A 4‐year study was performed to evaluate the effects of grazing a multi‐species winter cover crop on soil health and crop yields under mid‐February, mid‐March, and mid‐April cattle removal dates and a non‐grazed control within an annual cotton (Gossypium hirsutum L.) and peanut crop rotation (Arachis hypogaea L.). Chemical soil health indicators (soil organic carbon and permanganate oxidizable carbon), physical soil health indicators (water‐stable aggregates and penetration resistance), biological soil health indicators (microbial biomass carbon, soil respiration, and arbuscular mycorrhizal fungi colonization), crop yield, and cover crop biomass were evaluated. Cover crop biomass at termination was reduced by 3660, 5250, and 5610 kg ha−1 for the mid‐February, mid‐March, and mid‐April cattle removal treatments compared to the non‐grazed control. No grazing treatment effects were observed for biological soil properties. Soil organic carbon was higher in the non‐grazed treatment than the mid‐April grazing treatment across 0‐ to 30‐cm depth. Penetration resistance across 0‐ to 50‐cm depth and water‐stable aggregates at the 0‐ to 30‐cm depth were both negatively impacted by increased grazing period lengths. Results from this study suggest that longer cover crop grazing periods have little effect on biological and chemical soil health indicators in the short term but can negatively impact some physical soil health indicators.

Mycorrhizal and non-mycorrhizal perennial ryegrass roots exhibit differential regulation of lipid and Ca2+ signaling pathways in response to low and high temperature stresses

Lipids and Ca2+ are involved as intermediate messengers in temperature-sensing signaling pathways. Arbuscular mycorrhizal (AM) symbiosis is a mutualistic symbiosis between fungi and terrestrial plants that helps host plants cope with adverse environmental conditions. Nonetheless, the regulatory mechanisms of lipid- and Ca2+-mediated signaling pathways in mycorrhizal plants under cold and heat stress have not been determined. The present work focused on investigating the lipid- and Ca2+-mediated signaling pathways in arbuscular mycorrhizal (AM) and non-mycorrhizal (NM) roots under temperature stress and determining the role of Ca2+ levels in AM symbiosis and temperature stress tolerance in perennial ryegrass (Lolium perenne L.) Compared with NM plants, AM symbiosis increased phosphatidic acid (PA) and Ca2+ signaling in the roots of perennial ryegrass, increasing the expression of genes associated with low temperature (LT) stress, including LpICE1, LpCBF3, LpCOR27, LpCOR47, LpIRI, and LpAFP, and high temperature (HT) stress, including LpHSFC1b, LpHSFC2b, LpsHSP17.8, LpHSP22, LpHSP70, and LpHSP90, under LT and HT conditions. These effects result in modulated antioxidant enzyme activities, reduced lipid peroxidation, and suppressed growth inhibition caused by LT and HT stresses. Furthermore, exogenous Ca2+ application enhanced AM symbiosis, leading to the upregulation of Ca2+ signaling pathway genes in roots and ultimately promoting the growth of perennial ryegrass under LT and HT stresses. These findings shed light on lipid and Ca2+ signal transduction in AM-associated plants under LT and HT stresses, emphasizing that Ca2+ enhances cold and heat tolerance in mycorrhizal plants.

Genome-wide transcriptome and gene family analysis reveal candidate genes associated with potassium uptake of maize colonized by arbuscular mycorrhizal fungi

BackgroundPotassium (K) is an essential nutrient for plant growth and development. Maize (Zea mays) is a widely planted crops in the world and requires a huge amount of K fertilizer. Arbuscular mycorrhizal fungi (AMF) are closely related to the K uptake of maize. Genetic improvement of maize K utilization efficiency will require elucidating the molecular mechanisms of maize K uptake through the mycorrhizal pathway. Here, we employed transcriptome and gene family analysis to elucidate the mechanism influencing the K uptake and utilization efficiency of mycorrhizal maize.Methods and resultsThe transcriptomes of maize were studied with and without AMF inoculation and under different K conditions. AM symbiosis increased the K concentration and dry weight of maize plants. RNA sequencing revealed that genes associated with the activity of the apoplast and nutrient reservoir were significantly enriched in mycorrhizal roots under low-K conditions but not under high-K conditions. Weighted gene correlation network analysis revealed that three modules were strongly correlated with K content. Twenty-one hub genes enriched in pathways associated with glycerophospholipid metabolism, glycerolipid metabolism, starch and sucrose metabolism, and anthocyanin biosynthesis were further identified. In general, these hub genes were upregulated in AMF-colonized roots under low-K conditions. Additionally, the members of 14 gene families associated with K obtain were identified (ARF: 38, ILK: 4, RBOH: 12, RUPO: 20, MAPKK: 89, CBL: 14, CIPK: 44, CPK: 40, PIN: 10, MYB: 174, NPF: 79, KT: 19, HAK/HKT/KUP: 38, and CPA: 8) from maize. The transcript levels of these genes showed that 92 genes (ARF:6, CBL:5, CIPK:13, CPK:2, HAK/HKT/KUP:7, PIN:2, MYB:26, NPF:16, RBOH:1, MAPKK:12 and RUPO:2) were upregulated with AM symbiosis under low-K conditions.ConclusionsThis study indicated that AMF increase the resistance of maize to low-K stress by regulating K uptake at the gene transcription level. Our findings provide a genome-level resource for the functional assignment of genes regulated by K treatment and AM symbiosis in K uptake-related gene families in maize. This may contribute to elucidate the molecular mechanisms of maize response to low K stress with AMF inoculation, and provided a theoretical basis for AMF application in the crop field.

Role of Arbuscular Mycorrhizal Fungi in Alleviating Salinity Stress and Improving Physiological Parameters of Wheat (Triticum aestivum L.): A Review

Salinity stress poses a significant threat to global wheat production, impacting crop yield and food security. In recent years, Arbuscular Mycorrhizal Fungi (AMF) have gained attention as potential bioinoculants capable of mitigating salinity-induced stress and improving plant physiological parameters. This review provides a comprehensive examination of the role of AMF in alleviating salinity stress and enhancing physiological parameters in wheat (Triticum aestivum L.). Through a systematic analysis of relevant literature, we explore the mechanisms underlying the beneficial interactions between AMF and wheat under saline conditions. Key findings from various studies demonstrate that AMF colonization enhances wheat growth, nutrient uptake, and antioxidant enzyme activities, while reducing the adverse effects of salinity stress. However, challenges such as variability in AMF effectiveness and compatibility with modern agricultural practices persist. Future research directions should focus on refining AMF inoculation techniques and developing strains with enhanced salt tolerance to maximize their potential in sustainable agriculture. Overall, this review underscores the promising role of AMF in revolutionizing wheat cultivation in saline environments, offering insights for enhancing crop productivity and resilience to salinity stress.

Indole-3-acetic acid-producing Pantoea strain MTP 17 and Glomus mosseae synergistically improve the growth, yield and bacoside content of Bacopa monnieri

The present study aimed to evaluate the performance of Indole-3-acetic acid-producing bacteria (IPB) and arbuscular mycorrhizal fungi (AMF) in compatible form for early establishment and higher growth, yield, and secondary metabolite content of vegetatively propagated Bacopa monnieri plants. Four species of Glomus, viz., G. mosseae (Gm), G. aggregatum (Ga), G. fasciculatum (Gf), G. intraradices (Gi), and two Indole-3-acetic acid-producing bacteria (IPB), Bacillus mojavensis (Bm), and Pantoea sp. (Pt) were evaluated individually and in combinations in a pot experiment. Various plant growth parameters like height, biomass, NPK uptake, mycorrhizal colonization, bacterial population in the rhizosphere, phosphatase activity, and bacoside-A content were determined and found to vary with different treatments. Among all the treatments, plants inoculated with Gm + Pt performed better than any other treatment or un-inoculated control. The performance of the consortium of Gm + Pt was further validated in a field experiment on the same parameters. A clear synergistic interaction between Gm and Pt was observed as Pt enhanced rooting and subsequently improved the colonization and spore population of Gm. On the other hand, the presence of Gm improved the population of Pt in the rhizosphere. The presence of both microbes improved the bacoside-A yields in B. monnieri. The results of this experiment indicate the compatibility and synergy between G. mosseae and Pantoea sp. and suggest using this microbial consortium for plant propagation and growth enhancement while improving soil biological health.

Progressing beyond colonization strategies to understand arbuscular mycorrhizal fungal life history.

Knowledge of differential life-history strategies in arbuscular mycorrhizal (AM) fungi is relevant for understanding the ecology of this group and its potential role in sustainable agriculture and carbon sequestration. At present, AM fungal life-history theories often focus on differential investment into intra- vs extraradical structures among AM fungal taxa, and its implications for plant benefits. With this Viewpoint we aim to expand these theories by integrating a mycocentric economics- and resource-based life-history framework. As in plants, AM fungal carbon and nutrient demands are stoichiometrically coupled, though uptake of these elements is spatially decoupled. Consequently, investment in morphological structures for carbon vs nutrient uptake is not in competition. We argue that understanding the ecology and evolution of AM fungal life-history trade-offs requires increased focus on variation among structures foraging for the same element, that is within intra- or extraradical structures (in our view a 'horizontal' axis), not just between them ('vertical' axis). Here, we elaborate on this argument and propose a range of plausible life-history trade-offs that could lead to the evolution of strategies in AM fungi, providing testable hypotheses and creating opportunities to explain AM fungal co-existence, and the context-dependent effects of AM fungi on plant growth and soil carbon dynamics.

Arbuscular mycorrhizal fungi improve the disease resistance of Lycium barbarum to root rot by activating phenylpropane metabolism.

Root rot is one of the common diseases of Lycium barbarum. Pathogens can cause devastating disasters to plants after infecting host plants. This study investigated the effect of arbuscular mycorrhizal fungi (AMF) Rhizophagus intraradices inoculation on phenylpropane metabolism in L. barbarum and evaluated its resistance to root rot. The experiment was set up with AMF inoculation treatments (inoculated or not) and root rot pathogen-Fusarium solani inoculation treatments (inoculated or not). The results showed that AMF was able to form a symbiosis with the root system of L. barbarum, thereby promoting plant growth significantly and increasing plants' resistance to disease stress. The plant height of AMF-colonized L. barbarum increased by 24.83% compared to non-inoculated diseased plants. After inoculation with AMF, the plant defense response induced by pathogen infection was stronger. When the enzyme activity of the leaves reached the maximum after the onset of mycorrhizal L. barbarum, phenylalanine ammonia-lyase, cinnamic acid-4-hydroxylase, and 4-coumaric acid-CoA ligase increased by 3.67%, 31.47%, and 13.61%, respectively, compared with the non-inoculated diseased plants. The products related to the lignin pathway and flavonoid pathway downstream of phenylpropane metabolism such as lignin and flavonoids were also significantly increased by 141.65% and 44.61% compared to nonmycorrhizal diseased plants. The activities of chitinase and β-1,3-glucanase increased by 36.00% and 57.96%, respectively. The contents of salicylic acid and jasmonic acid were also 17.7% and 31.63% higher than those of nonmycorrhizal plants in the early stage of plant growth, respectively. The results indicated that AMF significantly promoted plant growth and enhanced disease resistance by increasing enzyme activities and the production of lignin and flavonoids.

Biochar and arbuscular mycorrhizal fungi promote rapid-cycling Brassica napus growth under cadmium stress

Purpose: To explore the mechanisms of tolerance of Brassica napus to ultra-high concentration cadmium pollution and the synergistic effects of biochar (BC) and Arbuscular mycorrhizal fungi (AMF) on plant growth under cadmium (Cd) stress. Results: The application of 5 % BC and inoculation with 10 g AMF significantly promoted the growth and development of B. napus. The combined application of BC and AMF (BC1A and BC2A) was better than the single application. At the Cd 200 mg/kg level, BC1A increased the fresh weight and Cd content of the above-ground parts of B. napus by 35.5 % and decreased by 21.20 %. The SOD and POD activities increased by 30.63 % and 73.37 %. The MDA and H2O2 contents decreased by 40.8 % and 69.99 %, soluble sugar content increased by 37.96 %. At the Cd 300 mg/kg level, BC1A increased the fresh weight and Cd content of the above-ground parts of B. napus by 32.8 % and decreased by 15.99 %. The SOD and POD activities increased by 39.06 % and 93.56 %. The MDA and H2O2 contents decreased by 28.39 % and 72.45 %, and the soluble sugar content increased by 21.16 %. Overall, both BC and AMF treatments alone or in combination (BC1A) were able to alleviate Cd stress and promote plant growth, with the combination of biochar and AMF being the most effective. Furthermore, transcriptome analyses indicated that BC may improve cadmium resistance in B. napus by significantly up-regulating the expression of genes related to peroxidase, photosynthesis, and plant MAPK signaling pathways. AMF may alleviate the toxicity of Cd stress on B. napus by up-regulating the expression of genes related to peroxisomes, phytohormone signaling, and carotenoid biosynthesis. The results of the study will provide support for ecological restoration technology in extremely heavy metal-polluted environments and provide some reference for the application and popularization of BC and AMF conjugation technology.

The interactive effect of tree mycorrhizal type, mycorrhizal type mixture and tree diversity shapes rooting zone soil fungal communities in temperate forest ecosystems

Abstract The underlying processes of plant‐microbe associations particularly their interactions with their mycorrhizal fungal partners have been extensively studied. However, considerably less is known about the consequences of tree‐tree interactions on rooting zone soil microbiota when tree species of different mycorrhizal type (myco‐type) grow together as mono and mixed myco‐type mixtures along a tree diversity gradient. Using the MyDiv tree diversity experiment, where arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) trees and their mixtures were planted in monocultures, two‐species and four‐species mixture plots, we investigated the interplay of target tree myco‐type, myco‐type mixture, tree diversity and rooting zone compartment (target tree dominated and its interaction zones with neighbour trees) on the rooting zone soil mycobiota employing meta‐barcoding of the ITS2 rDNA fragment of the fungal internal transcribed spacer (ITS). Our results revealed significant individual and interaction effects of tree myco‐type, myco‐type mixture and tree diversity but not rooting zone compartment on the fungal taxonomic and functional alpha and beta diversity. This implies intermingling of roots of target and neighbouring tree species there by reducing the target tree species effect in its rooting zone. As tree diversity increases, we found convergence of the fungal community in general, where the fungal community dissimilarity varies depending on the co‐existing tree species myco‐type and tree species diversity. Furthermore, the fungal community composition in the two and four species mixtures were consistently influenced by soil pH, whereas in the mixed multi‐species stands basal respiration, N, PO4−, NO3− were found to be equally important unlike in AM and EcM multi‐species stands. Comparative analysis of the fungal taxa specialisation between mono and mixed myco‐type multi‐species stands revealed that the mixed myco‐type plots shared 23.5% (AM) and 19.7% (EcM) of the generalist fungal communities However, the percentage of specialised fungal community in mixed myco‐type plots (13.2%) was significantly higher as compared to EcM (9.5%), and significantly lower (9%) as compared to AM (11.7%) plots, resulting in myco‐type and myco‐type mixture specific fungal communities and functional guild patterns Our results provide novel insights on the significance of tree species and its co‐existing trees preferred mycorrhizal association in shaping the target tree rooting zone soil mycobiome along a tree diversity gradient. Furthermore, it highlights the significance of generalist and specialist fungal communities in mono and mixed myco‐type stands in modulating tree‐tree interaction, tree species co‐existence and regulating soil properties and ecosystem functions. Read the free Plain Language Summary for this article on the Journal blog.

Long-Term Manuring Enhanced Compositional Stability of Glomalin-Related Soil Proteins through Arbuscular Mycorrhizal Fungi Regulation

Glomalin-related soil proteins (GRSP) play a crucial role in strengthening soil structure and increasing carbon (C) storage. However, the chemical stability of GRSP and related arbuscular mycorrhizal fungi (AMF) community response to fertilization remains unclear. This study investigated C and nitrogen (N) contents, three-dimensional fluorescence characteristics in GRSP, and AMF properties based on a field experiment that was subjected to 29 years of various fertilizations. The experiment included treatments with no fertilizer (CK), chemical fertilizer (NPK), manure (M), and manure combined with NPK (NPKM) treatments. Results showed that GRSP contained 37–49% C and 6–9% N, respectively. Compared with CK and NPK, the C and N proportions in GRSP significantly increased under M and NPKM. Using the parallel factor model, four fluorescent components of GRSP were identified: one fulvic acid-like component (C2), one tyrosine-like component (C4), and two humic acid-like components (C1, C3). Under M and NPKM, the fluorescent intensity of C2 and C4 decreased, while the humification index (HIX) increased relative to CK and NPK, indicating that organic fertilization could enhance the stability of GRSP. The C and N proportion in GRSP positively associated with soil organic C (SOC), total N (TN), available phosphorus (AP), AMF biomass, and diversity, while C2 and C4 showed negative associations. Structural equation modeling further revealed that manure-induced changes in pH, SOC, TN, and AP increased AMF biomass and diversity, thereby altering GRSP composition and stability. This study provides valuable insights into the compositional traits of GRSP, contributing to sustainable soil management and C sequestration in agroecosystems.

The Effects of Bio-Fertilizer by Arbuscular Mycorrhizal Fungi and Phosphate Solubilizing Bacteria on the Growth and Productivity of Barley under Deficit of Water Irrigation Conditions

Bio-fertilizers are the most important and effective method used to reduce the quantities of chemical fertilizers consumed and reduce dependence on them in agricultural production to avoid their harmful effects on the environment and public health as well as reduce the cost of agricultural production in light of increasing pollution and under adverse conditions for production and climate change. A bio-fertilizer depends primarily on the use of beneficial microorganisms such as arbuscular mycorrhizal fungi (AMF) to improve the uptake of nutrients, improve plant growth, productivity, and grain yield. Crop production faces many challenges, and drought is one of the majority of the significant factors limiting crop production worldwide, especially in semi-arid regions. The objective of this study was to evaluate the effects of AMF and phosphate solubilizing bacteria (PSB), plus three rates of the recommended dose of phosphorus (RDP) fertilizer on yield, yield components, and nutrients uptake, in addition to evaluating the beneficial effects of these combinations to develop Phosphorus (P) management under three levels of irrigation water, i.e., three irrigations (normal or well-watered), two irrigations (moderate drought), and one irrigation (severe drought) on barley (Hordeum vulgare L.). The results showed that the treatment with AMF bio-fertilizer yielded the highest values of plant height, spike length, spike weight, number of grains/spike, 1000-grain weight, grain yield, straw yield, biological yield, and harvest index. Moreover, the grain and straw uptake of nitrogen (N), P, and potassium (K) (kg ha−1) in the two seasons under the three levels of irrigation, respectively, were superior followed by the inoculation by PSB. While the treatment without bio-fertilizer yielded the lowest values of these traits of barley, the treatment with bio-fertilizer yielded the increased percentage of the grain yield by 17.27%, 17.33% with applying AMF, and 10.31%, 10.40% with treatment by PSB. Treatment with AMF or PSB (Phosphorien), plus rates of phosphorus fertilizer under conditions of irrigation water shortage, whether irrigation was performed once or twice, led to an increase in grain yield and other characteristics compared to the same fertilization rates without inoculation. The results of this study showed that the use of bio-fertilizers led to an increase in plant tolerance to drought stress, and this was demonstrated by an increase in various traits with the use of treatments that include bio-fertilizers. Therefore, it is suggested to inoculate the seeds with AMF or PSB plus adding phosphate fertilizers at the recommended dose under drought conditions.

Mitigating nitrogen loss in paddy field microcosms through indigenous arbuscular mycorrhizal fungi assemblage

AbstractWhether farmers should consider the role of arbuscular mycorrhizal fungi (AMF) in agriculture is a hotly debated topic. We aimed to investigate the role of indigenous AMF in reducing nitrogen (N) loss from paddy fields via runoff, leaching, NH3 volatilization, and N2O emission. We conducted a pot experiment employing a mycorrhiza‐defective rice mutant (non‐mycorrhizal) as the control, grown in soil containing indigenous AMF. The corresponding AMF treatment used the progenitor of this mutant with the same soil. The plants were fertilized with nitrogen, phosphorus and potassium 6 weeks after sowing. The root colonization was 23% in mycorrhizal rice, and no typical AMF structures were observed in the roots of non‐mycorrhizal rice. Our findings indicated that the mycorrhizal system exhibited lower N concentrations of runoff and leachate further compounded by reduced fluxes of N2O and NH3. This led to 14% decrease (mycorrhizal rice 111 kg N ha−1; the non‐mycorrhizal rice: 129 kg N ha−1) in cumulative N loss within 3 days post‐fertilization. While this AMF effect was consistent across the four tested N loss pathways, differences were observed between NH4+‐N and NO3−‐N in the runoff pathway. Notably, our results revealed no evidence of trade‐offs in AMF effect on N loss among the tested pathways. Additionally, mycorrhizal rice had larger shoots and roots than their non‐mycorrhizal counterparts. Our study underscores the potential benefits of indigenous AMF in paddy fields for mitigating water pollution and reducing greenhouse gas emission.

The effectiveness of combination of arbuscular mycorrhizal fungi and compost ameliorant on sengon growth in former coal mine soil

Abstract Mining activities give a negative impact to the soil which become the ex-coal mine soil. The soil has a solid soil structure and low nutrient content so is not suitable for planting. The problems need to be improved by being treated with biological agents from soil microorganisms such as Arbuscular Mycorrhizal Fungi (AMF). The provision of AMF on ex-coal mine soil with the addition of ameliorant compost can be one strategy that can be used. AMF can help increase plant growth and help the process of absorption of phosphate (P) by plants. Compost from goat manure can help the association between AMF and plant roots, also being a source of nutrients that are free from chemicals. The plants which suitable for this association are sengon. Sengon commonly used to help revegetation of ex-mining soil because it is able to withstand various conditions of overgrown soil. This study aims to determine the effect of the addition of a combination of AMF and compost on the growth of sengon plants in the soil of ex-coal mines. Observations were made weekly until the age of three months, the best results were the results at the end of the observation. The results showed that the AMF dose and the addition of compost had an effect on percent AMF colonization, increasing plant height, dry weight of plant roots increasing plant stem diameter, and number of leaves.

The crosstalk interaction of ethylene, gibberellins, and arbuscular mycorrhiza improves growth in salinized tomato plants by modulating the hormonal balance

Ethylene (ET) and gibberellins (GAs) play key roles in controlling the biotic and abiotic interactions between plants and environment. To gain insights about the role of ET and GAs interactions in the mycorrization and response to salinity of tomato (Solanum lycopersicum L.) plants, the ET-insensitive (Never-ripe, Nr), and the ET-overproducer (Epinastic, Epi) mutants and their wild type cv. Micro-Tom (MT), were inoculated or not with the arbuscular mycorrhizal fungi (AMF) Rhizophagus irregularis and exposed to control (0 mM NaCl) and salinity (100 mM NaCl) conditions, with and without gibberellic acid (10−6 M GA3) application during four weeks. Exogenous GA3 enhanced plant growth irrespective of the genotype, AMF, and salinity conditions, while an additional effect on growth by AMF was only found in the ET-overproducer (Epi) mutant under control and salinity conditions. Epi almost doubled the AMF colonization level under both conditions but was the most affected by salinity and GA3 application compared to MT and Nr. In contrast, Nr registered the lowest AMF colonization level, but GA3 produced a positive effect, particularly under salinity, with the highest leaf growth recovery. Foliar GA3 application increased the endogenous concentration of GA1, GA3, and total GAs, more intensively in AMF-Epi plants, where induced levels of the ET-precursor ACC were also found. Interestingly, GA4 which is associated with AMF colonization, registered the strongest genotype x GA x AMF × salinity interactions. The different growth responses in relation to those interactions are discussed.

Leveraging the complex interplay between arbuscular mycorrhizal fungi, seasonal dynamics, and genotypic diversity to optimize maize productivity in semi-arid agroecosystems

Maize production under low-input agricultural systems in semi-arid areas of Sub-Saharan Africa faces significant challenges, primarily stemming from the synergistic impacts of climate variability and suboptimal agronomic practices. Harnessing soil microbiota, particularly arbuscular mycorrhizal fungi (AMF), represents a pivotal strategy for bolstering low-input systems. However, their functional utility is contingent upon their compatibility with the prevailing environmental conditions and biotic interactions. This study examines the influence of two distinct AMF inoculants on the growth and yield attributes of diverse maize genotypes across varying seasons within semi-arid regions of Kenya. We hypothesized that AMF inoculants exhibit differential adaptability to varying environmental sites and seasons, and their interaction will enhance the provision of key ecosystem services important for maize production. Field experiments were conducted in three semi-arid Counties (Tharaka-Nithi, Embu, and Kitui) during the 2019/2020 cropping seasons. A randomized complete block design with three replications and three treatments was adopted. Treatments consisted of Rhizatech (a commercial AMF inoculant), a consortium of AMF isolates (Rhizophagus irregularis and Funneliformis mosseae), and a non-inoculated control. In season one, notable interaction effects were observed for both site × maize genotype (p = 0.0007) and site × AMF inoculation (p < 0.0001), whereby Duma 43 genotype had the highest yield in Embu (11.93 t ha−1) and Kitui (11.76 t ha−1) counties, and Rhizatech and consortium inoculation consistently led to elevated grain yields across all three genotypes in Kitui, surpassing non-inoculated controls. AMF inoculation notably augmented phosphorus (P) uptake, with Rhizatech demonstrating a 79.7 % increase and consortium showing a 38.7 % increase in shoot P content compared to control plants in season 1. These findings highlight the complex interplay between AMF effectiveness, seasonal variations, and maize diversity. Further research is needed to elucidate the underlying mechanisms driving these seasonal shifts, allowing for optimized AMF inoculation strategies for improved maize performance under diverse conditions.

The Effect of Mycorrhiza and Plant Growth-Promoting Rhizobacteria Supplementation on Zea mays saccharata Sturt. Growth and Productivity Grown on Low Nutrients Soil

Marginal land has low nutrient content (nitrogen, phosphorus, potassium). Addressing nutrient deficiencies on marginal land requires a strategic approach. Biological fertilizers like Arbuscular Mycorrhizal Fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) enhance nutrient availability through symbiotic interactions. In addition, organic fertilizers such as compost could provide organic matter and improve soil structure to increase plant growth and productivity. Combining these three fertilizers with the addition of low doses of NPK fertilizer can increase the growth and productivity of maize crops on sub-marginal land. This study aims to determine the effect of AMF, consortium of PGPR, and a low dose of NPK on the growth and productivity of maize and soil nutrients on sub-marginal land by measuring plant growth up to 8 WAP (week after planting) (parameters: plant height, stem diameter, number of leaves, leaf area, chlorophyll content, stomatal density) and productivity (parameters: cob length, cob weight with husk, fresh weight, dry weight) and levels of N, P, and K elements at 8 WAP in the soil after planting. All treatments showed an increase in the level of N and K elements, while the P element showed a decrease compared to the control (soil without treatment). Moreover, each parameter did not show a significant difference, but the P2 (Compost + PGPR consortium + AMF + 50% of NPK) treatment showed the best growth and productivity. Overall, the data showed the utilization of PGPR and AMF combination was able to reduce the usage of chemical fertilizer by 50%.

Combined inoculation of arbuscular mycorrhiza fungi with Meso‐rhizobium improves nutrient uptake, growth performance, and moisture stress tolerance of chickpea (Cicer arietinum L.)

AbstractBiofertilizers can be better alternatives to chemical fertilizers to enhance plant nutrition and productivity as they improve the soil fertility and crop productivity in an eco‐friendly and cost‐effective manner. A pot experiment was conducted between December 2018 and March 2019 in southern Ethiopia to evaluate the combined inoculation of arbuscular mycorrhizal fungi (AMF) and Meso‐rhizobium (MR) on biomass yield, nutrient uptake, and moisture stress tolerance of chickpea (Cicer arietinum L.) (variety: Habru). The experiment was executed as a factorial arrangement using a completely randomized design with three replications. The treatments were control (non‐fertilized), sole AM fungi inoculation, AM fungi inoculation with phosphorus fertilizer (20 kg P ha−1) and MR, and sole inorganic fertilizers (20 kg P;10 kg N ha−1) at four different moisture levels (optimum throughout the growing season, stressed at vegetative, flowering, and seed filling stages). The results demonstrated that biomass yields were limited by moisture stress, especially at vegetative and flowering stages of chickpea. Sole and co‐application of AMF with MR and inorganic P increased biomass yields on average by 19%, 39%, and 33% under water stress conditions, respectively, compared to the non‐inoculated control. The application of AMF with MR and inorganic P also significantly increased nodulation, AMF colonization, and nutrient uptake, but these effects were dependent on soil moisture status. In conclusion, there are potential advantages to be gained from sole and combined AMF application with rhizobium to improve growth and productivity of chickpea through enhanced nutrient and water uptake, though the results of this pot experiment should be validated through field trials.