Enhancing Sesame ( Sesamum indicum L.) Yield and Drought Tolerance through Reduced Phosphorus Fertilizer Combined with Funneliformis mosseae and Humic Acid Under Varying Irrigation Regimes

Sesame (Sesamum indicum L.), a vital oilseed crop valued for its oil quality and drought tolerance, faces yield and quality challenges in arid regions like southern Iran, where farmers contend with water scarcity and high fertilizer costs. A two-year field study (2023–2024) in semi-arid Esfahan province evaluated the synergistic effects of phosphorus (P), Funneliformis mosseae (AMF), and humic acid on sesame cv. Dashtestan under drought stress, hypothesizing that reduced P with AMF and humic acid would enhance yield and oil quality via improved nutrient uptake compared to conventional treatments. Using a split-plot design with three replications, treatments comprised three irrigation regimes (I1: 40% soil moisture depletion, I2: 60%, I3: 80%) and seven fertilizer treatments (F1: control, F2: 100% P, F3: AMF, F4: humic acid, F5: 50% P + AMF, F6: 50% P + humic acid, F7: 50% P + AMF + humic acid). Combined treatments (F5, F6, F7) outperformed F1–F4, validating the hypothesized improvements with F5 achieving a seed yield increase with 62% (exceeding the 30-50% range) and oil yield with 85.5% (aligning with or surpassing expected synergies). These treatments enhanced oil quality, improving linoleic acid (up to 43.5%), oleic acid (41.2%), palmitic acid (9.0%), stearic acid (5.8%), lignan content (3600 mg kg−1, +80%), and antioxidant capacity (28.5 µmol L−1, +185%) under drought. Integrated nutrient management with reduced P, AMF, and humic acid offers a sustainable strategy for optimizing sesame yield and oil quality in water-scarce regions, reducing chemical inputs while boosting economic value for farmers.

A simulation of the environment inhabited by arbuscular mycorrhizal (AM) fungi could provide clues as to how to cultivate these obligate biotrophs axenically. Host intraradical and rhizospheric environments, root extracts and exudates in particular, would be crucial for AM fungi to complete their life cycles. In this study, we analyzed and compared the effects of root exudates (RE) and root extracts (RET) of white clover (Trifolium repens) on the asymbiotic growth of the AM fungus Funneliformis mosseae in vitro, and furtherly analyzed the chemical components of different RET with the LC-MS/MS technique in order to establish an asymbiotic cultivation system for this important and hardly domesticated AM fungus. RET is superior to RE in stimulating spore germination, hyphal elongation and branching, and secondary spore formation (p < 0.05). RET-induced effects were dependent on phosphate supplement levels, and the RET obtained following the treatment with low levels of phosphorus significantly promoted hyphal growth and sporulation (p < 0.05). A few newly formed secondary spores showed limited colonization of white clover roots. The low phosphorus-induced effects could be ascribed to the metabolic adjustment (mainly lipids and organic acids) of white clover roots under low phosphate conditions. Our findings demonstrate that the low phosphate-induced RET boosts the asymbiotic growth of AM fungus, and thus offers an alternative way to fulfill the life cycle of AM fungi asymbiotically.

The role of sesame oil in human nutrition is clear and water limitation decreases production and oil yield of sesame. This study was conducted to evaluate the effects of seed treatment and irrigation regimes on sesame yield, yield component and oil percentage. A split-plot arrangement was used in a randomized complete block design with three replications. Main-plot consisted of four irrigation regimes (50, 60, 70 and 80% soil moisture depletions of available water) and sub-plot consisted of two seed treatments (osmopriming with solution -2 bar PEG and untreated seed as control). The studied characteristics were number of days from planting to emergence, 50% flowering, capsule formation, physiological ripening, plan height, LAI, number of capsule per plant, number of seed per capsule, 1000-grain weight, grain yield, biological yield, harvest index and oil yield. The results showed that irrigation regime had no significant effect on number of days from planting to seed emergence, 50% flowering, number of seed per capsule, seed weight and biological yield. Seed treatment had significant effect on all studied traits except number of days from planting to 50% flowering, seed per capsule, seed weight, biological yield and harvest index. Also, interaction between irrigation regimes and priming was significant on 1000-grain weight and oil yield. The highest grain and oil yield obtained from 50% soil moisture depletions and the lowest obtained from 80% soil moisture depletions. The highest grain and oil yield obtained from osmopreming and the lowest grain and oil yield was obtained under control (unprimed). The 50% soil moisture depletions with osmopriming had the highest seed weight and oil yield while irrigation regime 80% soil moisture depletions with control had the lowest oil yield. Based on overall results, osmopriming with -2 bar PEG under70% was the most suitable treatment.

ZnO nanoparticles (NPs) are widely used in many applications, such as plastics, ceramics, glass, cement, rubber, lubricants, paints, pigments, batteries, fire retardants, catalysts, and anti-microbial agents. They directly or indirectly enter aquatic and terrestrial environments through application, accidental release, contaminated soil/sediments, or atmospheric fallouts. When present in excess, ZnO NPs can induce phytotoxicity and reduce plant growth and yields. ZnO NPs can also cause Zn accumulation in edible parts of food crops, and then subsequently enter human bodies and pose a significant health risk. Arbuscular mycorrhizae are ubiquitous symbiotic associations in nature formed between arbuscular mycorrhizal (AM) fungi and most higher plants in terrestrial ecosystems. In addition to their well-known contribution to plant nutrient acquisition and growth, AM fungi can improve plant tolerance to various environmental stresses, but mycorrhizal effects vary with environmental conditions such as phosphorus status in both soil and plants. AM fungi have been shown to alleviate the negative effects of ZnO NPs and zinc accumulation in plants, however, the role of phosphorus fertilization has been neglected. A greenhouse pot culture experiment was conducted using maize as the test plant inoculated with or without AM fungus Funneliformis mosseae. Four levels of phosphorus (0, 20, 50 or 100 mg·kg-1) and two levels of ZnO NPs (0 or 500 mg·kg-1) were applied to pots. Shoots and roots were harvested separately after two months of growth. Mycorrhizal infection, plant biomass, P and Zn concentrations and uptake in plants, and soil DTPA-extractable zinc and pH were determined. The results showed that ZnO NPs did not significantly affect the growth of maize, but inhibited root mycorrhizal infection and plant phosphorus uptake, and led to the accumulation of zinc in plants. ZnO NPs and high phosphorus supply decreased root mycorrhizal infection, but AM inoculation significantly promoted plant growth under all phosphorus supply levels. Phosphorus application and AM inoculation increased soil pH, but reduced the bioavailability of Zn derived from ZnO NPs, decreased the translocation and accumulation of zinc in maize shoots, and thus produced beneficial effects on plants. In general, AM inoculation showed positive mycorrhizal effect, especially under low phosphorus conditions and addition of ZnO NPs. Our results showed for the first time that both AM fungi and phosphate fertilizer could help to mitigate soil pollution and the ecological and health risks posed by ZnO NPs.

The use of arbuscular mycorrhizal (AM) fungi is considered as an effective approach to enhance plants’ growth; nevertheless, its efficacy may vary with the type of inoculum and its application method. The present study, for the first time, investigates the effects of different mycorrhizal species applied through different methods on morpho-physiological growth, root system architecture, nutrient uptake, and root exudates of maize. Four AM fungi species viz., Claroideoglomus etunicatum (C.E), Rhizophagus intraradices (R.I), Funneliformis mosseae (F.M), and Diversispora versiformis (D.V) were applied to maize through seed coating, soil application, or seed coating+ soil application. A control without AM fungi was maintained for comparison. All the thirteen treatments were arranged in completely randomized design with three replications. Application of C.E, R.I, F.M, and D.V through different methods triggered the growth performance of maize by improving morpho-physiological characteristics and root morphology, modulating AM fungi colonization, enhancing the nutrient (N, P, K) uptake, and reducing the root exudates (oxalic, malonic, fumaric, malic, citric, and T-aconitic) compared with control. Among the different mycorrhizal species, F.M applied particularly through seed coating+ soil application was more effective in regulating maize growth as compared with C.E, R.I, or D.V species owing to better root system, higher root colonization, and greater nutrient uptake in this treatment. Interestingly, seed coating of F.M recorded statistically similar or higher shoot and root growth attributes compared with soil application particularly at 30 days after sowing. In crux, F.M applied through seed coating + soil application performed better than that of other mycorrhizal species. The obtained results also suggest that seed coating can be a cheap, viable, and efficient delivery system of AM fungi particularly for large scale application, as AM fungi seed coating had faster and greater effect on maize growth compared with soil application during early growth stages.

Contribution of biochar and arbuscular mycorrhizal fungi to sustainable cultivation of sunflower under semi-arid environment

Artemisia annua L. is a medicinal plant appreciated for the production of artemisinin, a molecule used for malaria treatment. However, the natural concentration of artemisinin in planta is low. Plant nutrition, in particular phosphorus, and arbuscular mycorrhizal (AM) fungi can affect both plant biomass and secondary metabolite production. In this work, A. annua plants were ino- culated or not with the AM fungus Funneliformis mosseae BEG12 and cultivated for 2 months in controlled conditions at three different phosphatic (P) concentrations (32, 96, and 288 µM). Plant growth parameters, leaf photosynthetic pigment concentrations, artemisinin production, and mineral uptake were evaluated. The different P levels significantly affected the plant shoot growth, AM fungal colonization, and mineral acquisition. High P levels negatively influenced mycorrhizal colonization. The artemisinin concentration was inversely correlated to the P level in the substrate. The fungus mainly affected root growth and nutrient uptake and significantly lowered leaf artemisinin concentration. In conclusion, P nutrition can influence plant biomass production and the lowest phosphate level led to the highest artemisinin concentration, irrespective of the plant mineral uptake. Plant responses to AM fungi can be modulated by cost–benefit ratios of the mutualistic exchange between the partners and soil nutrient availability.

It is widely accepted that the symbiotic arbuscular mycorrhizal fungi (AMF) play a key role in sustainable production systems in rice cultivation and they readily form a symbiotic relationship with these fungi. Four species consortium of AMF, Funneliformis mosseae, Rhizophagus intraradices, Clariodeoglomus etunicatum and Glomus aggregatum, produced through in vitro production system and formulated with organic biostimulants viz. humic acids and sea weed extract were tested in this experiment, both for direct seeded and transplanted paddy, under anaerobic cultivation system. AMF inoculated fields produced significantly higher yield than non-inoculated field. AMF inoculants formulated with a blend of humic acids and seaweed extract produced significantly higher grain yield than the inoculants formulated with humic acids alone, in both the cultivation systems. Effect of AMF inoculation was highly pronounced in transplanted paddy than direct seeded paddy, resulted in highest grain yield, highest grain weight, better grain filling rate and highest tiller production. It can be concluded that AMF inoculants can be potentially used for rice cultivation under anaerobic water management system, both for direct seeded and transplanted paddy and the nature of biostimulants used in the formulation also play a key role in the efficacy of AMF inoculants. Our findings contribute to the growing global consensus that mycorrhizal inoculants could play a role in sustainable rice production systems of the future, when used appropriately.

Study the effects of inoculation with two arbuscular mycorrhizal (AM) fungi, Gm (Glomus mosseae T.H. Nicolson & Gerd.)Gerd & Trappe) and Gi (Glomus intraradices N.C. Schenck & G.S. Sm.) on the herb yield, essential oil (EO) content and nutrient acquisition of basil (Ocimum basilicum L.) under drought stress conditions,The experiment conducted with 9 treatments and 4 replications. Drought stress treatments were applied by increasing the irrigation intervals from 4 days to 8 and 12 days. The root colonization, dry matter yield, oil content, oil yield and nutrients uptake decreased as the irrigation intervals increased. The AM fungi inoculation significantly increased the dry matter yield, oil content, oil yield and uptake of N, K, Zn, Fe and Cu as compared to Nm (non-mycorrhizal) plants in both well-watered and drought stressed condition. Analysis of essential oil by GC and GC/MS showed that Linalool, (E)-β-ocimene, eugenol and (Z, E)-farnesol, main components of oil, had no significant variation by drought stress or AM fungi inoculation. The effect of AM fungi inoculation on herb yield, oil content, oil yield and nutrient acquisition was more significant with G. mosseae than G. intraradices. Results suggest that inoculation of AM fungi could be a feasible procedure to increase growth, yield and essential oil production under water deficit conditions.

Mycorrhizal effectiveness in Citrus macrophylla at low phosphorus fertilization

ABSTRACTPresent investigation studied plant water relations and soil physical properties through AM fungi (Glomus mosseae) to mitigate drought stress in Himalayan acid Alfisol having low water retentivity. Experimentation was carried out at Palampur, India during 2009–2011 in okra–pea cropping system in randomized block design (RBD) replicated thrice with 14 treatments comprising arbuscular mycorrhizal (AM) fungi, varying phosphorus nutrition and irrigation regimes at 40 and 80% available water holding capacity. Integrated use of AM fungi at varying phosphorus (P) levels and irrigation regimes led to significantly higher relative leaf water content (3% each) in okra and pea besides significantly higher xylem water potential (27%) in pea over non-AM fungi counterparts. AM fungi enhanced water-use-efficiency in okra (5–17%) and pea (12–35%) over non–AM fungi counterparts. AM fungi also improved water holding capacity (5–6%) and mean weight diameter of soil particles (4–9%) over non–AM fungi counterparts; but, had nominal or no effect on bulk density. Mycorrhizal plants maintained higher tissue water content imparting greater drought resistance to plants over non–mycorrhizal plants at moisture stress. It is inferred that integrated application of AM fungi and P at varying irrigation regimes improved the plant water relations vis-à-vis drought resistance, crop productivity, WUE, soil aggregation and water holding capacity in okra–pea sequence in Himalayan acid Alfisol.

Functional compatibility in cucumber mycorrhizas in terms of plant and fungal growth, and foliar nutrient composition from all possible combinations of six cucumber varieties and three species of arbuscular mycorrhizal (AM) fungi was evaluated. Measurements of foliar nutrient composition included N, P, K, Mg, Ca, Na, Fe, Zn, Mn and Cu. Growth of AM fungi was measured in terms of root colonisation, as examined with microscopy and the AM fungus biomarker fatty acid 16:1ω5 from both phospholipids and neutral lipids. Different responses of plant growth and foliar nutrient profiles were observed for the different AM symbioses examined. The AM fungus Claroideoglomus claroideum caused growth depression in association with four out of six cucumber varieties; Rhizophagus irregularis caused growth promotion in one of six cucumber varieties; whereas Funneliformis mosseae had no effect on the growth performance of any of the cucumber varieties examined. All three AM fungi markedly altered host plant shoot nutrient composition, with the strongest contrast observed between cucumber-R.irregularis symbioses and non-mycorrhizal cucumber plants, independent of cucumber variety. On the other hand, AM fungal growth in roots differed between the three AM fungi, but was unaffected by host genotype. Strong build-up of storage lipids was observed for R.irregularis, which was more moderate in the two other AM fungi. In conclusion, strong differential responses of cucumber varieties to inoculation with different AM fungi in terms of growth and shoot nutrient composition revealed high functional diversity in AM symbioses in cucumber plants.

Climate change is increasing drought events and decreasing water availability. Tomato is commonly transplanted to an open field after seedling production in a nursery, requiring large volumes of water. Arbuscular mycorrhizal (AM) fungi help plants cope with drought stress; however, their effects depend on plant genotype and environmental conditions. In this study, we assessed the interactions among different tomato seedling genotypes and two AM fungi, Funneliformis mosseae and Rhizophagus intraradices, under two water regimes, full and reduced. Our results showed that F. mosseae was more effective than R. intraradices in the mitigation of drought stress both in old and modern genotypes. However, seedlings inoculated with R. intraradices recorded the highest values of leaf area. ‘Pearson’ and ‘Everton’ genotypes inoculated with F. mosseae recorded the highest values of root, leaf, and total dry weights under reduced and full irrigation regimes, respectively. In addition, ‘Pearson’ and ‘H3402’ genotypes inoculated with F. mosseae under a reduced irrigation regime displayed high values of water use efficiency. Our results highlight the importance of using AM fungi to mitigate drought stress in nursery production of tomato seedlings. However, the development of ad hoc AM fungal formulations, which consider genotype x AM fungi interactions, is fundamental for achieving the best agronomic performances.

Water scarcity and climate variability threaten citrus production in semi-arid regions, requiring strategies to improve drought resilience. This study evaluated the physiological and hormonal responses of two citrus cultivars, alemow (Citrus macrophylla Wester) and 'Cleopatra' mandarin (Citrus reshni Hort. Ex Tanaka), inoculated with arbuscular mycorrhizal (AM) fungi (Rhizophagus irregularis + Funneliformis mosseae) and subjected to drought stress imposed by progressive soil drying (water withholding) and quantified by volumetric soil water content (θv) classes: >0.20 cm3 cm-3 (well-watered), 0.05-0.20 cm3 cm-3 (moderate drought), and <0.05 cm3 cm-3 (severe drought). Gas exchange, plant water status, and abscisic acid (ABA) dynamics were monitored to assess cultivar-specific effects of AM symbiosis. Under well-watered conditions, +AM plants exhibited higher photosynthetic rates than non-inoculated plants, with a stronger response in Macrophylla. During drought, contrasting patterns emerged: +AM Macrophylla maintained higher stomatal conductance and photosynthesis, with foliar ABA increasing only under severe stress, suggesting that non-hormonal mechanisms support gas exchange. In Cleopatra, AM inoculation was associated with higher root-derived ABA and earlier stomatal closure, suggesting a more conservative water-use strategy under soil drying conditions; however, the benefits were limited to moderate stress and decreased beyond a stomatal conductance threshold. These findings reveal that AM symbiosis enhances drought resilience through contrasting mechanisms: hydraulic stabilization predominates in Macrophylla, whereas hormonal (ABA-mediated) regulation drives the response in Cleopatra. This cultivar-dependent modulation highlights the importance of developing AM-based strategies adapted to each cultivar for effective citrus drought management. Combining AM inoculation with irrigation-saving practices could improve water productivity and support climate-smart citrus production.

Arbuscular mycorrhizal fungi (AMF) improve plant growth and may be useful in maintaining and even restoring soil. However, data on the latter function are sparse and only indirect, which is especially true for conventional management conditions with adequate nutrient availability. Our study focused on utilizing the prevalent AMF species, Funneliformis mosseae, to enhance Glycine max production, while also exploring its partly explored impact on soil aggregation. Working in greenhouse conditions, we examined whether, in a nutrient-sufficient environment, AMF would improve crop biomass accumulation and nutrition, as well as the stability of soil aggregates (SAS). We also looked for a synergistic effect of dual inoculation using AMF and symbiotic rhizobium. Plants were or were not inoculated with AMF or Bradyrhizobium japonicum in a two-factorial design. AMF inoculation increased soybean biomass, but AMF inoculation had no impact on P and N input to the shoots. Mycorrhiza did not affect either glomalin abundance or SAS. All the impacts were, however, independent from rhizobial inoculation, which was ineffective in this nutrient-available environment. Our assay suggests that arbuscular mycorrhiza may have a positive effect on soybean growth even under conventional management with adequate nutrition. The positive effects of AMF on soybean growth, together with the fact that AMF generally do not thrive in good nutrient availability, should be taken into account when planning mineral fertilization levels.