Arbuscular Mycorrhizal Research Articles

Arbuscular mycorrhizal fungi and exogenous Ca2+ application synergistically enhance salt and alkali resistance in perennial ryegrass through diverse adaptive strategies

The challenge of soil salinization and alkalization, with its significant impact on crop productivity, has raised growing concerns with global population growth and enhanced environmental degradation. Although arbuscular mycorrhizal fungi (AMF) and calcium ions (Ca2+) are known to enhance plant resistance to stress, their combined effects on perennial ryegrass’ tolerance to salt and alkali stress and the underlying mechanisms remain poorly understood. This study aimed to elucidate the roles of AMF Rhizophagus irregularis and exogenous Ca2+ application in molecular and physiological responses to salt-alkali stress. AM symbiosis and exogenous Ca2+ application enhanced antioxidant enzyme activity and non-enzymatic components, promoting reactive oxygen species (ROS) scavenging and reducing lipid peroxidation while alleviating oxidative damage induced by salt-alkali stress. Furthermore, they enhanced osmotic balance by increasing soluble sugar content (Proportion of contribution of the osmotic adjustment were 34%~38% in shoots and 30%~37% in roots) under salt stress and organic acid content (Proportion of contribution of the osmotic adjustment were 32%~36% in shoots and 37%~42% in roots) under alkali stress. Changes in organic solute and inorganic cation-anion contents contributed to ion balance, while hormonal regulation played a role in these protective mechanisms. Moreover, the protective mechanisms involved activation of Ca2+-mediated signaling pathways, regulation of salt-alkali stress-related genes (including LpNHX1 and LpSOS1), increased ATPase activity, elevated ATP levels, enhanced Na+ extrusion, improved K+ absorption capacity, and a reduced Na+/K+ ratio, all contributing to the protection of photosynthetic pigments and the enhancement of photosynthetic efficiency. Ultimately, the combined application of exogenous Ca2+ and AMF synergistically alleviated the inhibitory effects of salt-alkali stress on perennial ryegrass growth. This finding suggested that exogenous Ca2+ may participate in the colonization of perennial ryegrass plants by R. irregularis, while AM symbiosis may activate Ca2+ pathways. Consequently, the combined treatment of AM and Ca2+ is beneficial for enhancing plant regulatory mechanisms and increasing crop yield under salt-alkali stress.

Essential oil phytochemistry and antifungal activity of lemongrass inoculated with arbuscular mycorrhizal fungi under different phosphorous levels

This study aimed to investigate the effect of inoculating Cymbopogon citratus (lemongrass) with arbuscular mycorrhizal fungi (AMF) Rhizophagus clarus and Claroideoglomus etunicatum under low and high phosphorus (P) levels on essential oil (EO) content, composition, and minimum inhibitory concentration (MIC) for four isolates of phytopathogenic fungi of the genus Fusarium. The EO content was obtained by the hydrodistillation process, followed by the evaluation of chemical constituents using gas chromatography coupled to mass spectrometry and MIC by microdilution in broth. The EO content increased 2.5-fold due to high P and inoculation with C. etunicatum compared with uninoculated under low P. Twenty-two compounds were identified in EO. The major components were citronellol, geraniol, citral, neral and geranial. The EO of lemongrass showed a MIC in the four phytopathogenic fungal isolates. Therefore, the secondary metabolites were influenced by P levels and AMF inoculation, increasing EO´s content (until 2.5-fold), chemical composition (citral, neral and geranial) and MIC.

Arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria promoted changes in plant metabolism and the volatile profile of Piper callosum Ruiz & Pav

Piper callosum Ruiz & Pav. is known in the Amazon as a paregoric elixir and exists as a shrub native to the Neotropics. In traditional medicine, the tea from its leaves is used to treat pain in the digestive tract, rheumatism, and muscular aches. This study aimed to evaluate the influence of arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) inoculation on the secondary metabolism of P. callosum. The plants were inoculated after 30 days of cultivation and kept in a greenhouse. Plant development parameters were monitored at 30-, 60-, and 90-days after inoculation (DAI) and indicated that AMF and PGPR favored plant growth throughout all stages of development. The leaf volatiles extracted by simultaneous distillation and extraction were analyzed by gas chromatography coupled with mass spectrometry and showed that phenylpropanoids and monoterpene hydrocarbons were predominant in all essential oils, revealing distinct abundance patterns across the different sampling points. The major volatile compounds identified were safrole, methyl eugenol, and β-pinene, and a reduction trend in their content was observed for safrole and methyl eugenol, especially at 90 DAI in both treatments. Principal component analysis revealed that germacrene D-4-ol and limonene were among the most influential in both treatments. Finally, the total phenolic content and the enzymatic activity of phenylalanine ammonia-lyase revealed different effect patterns for inoculation and time of evaluation on each treatment. All the data presented indicate that symbiotic inoculation can optimize the production of essential oil, which can improve the quality and productivity of P. callosum plants.

Glucoproteins in particulate and mineral-associated organic matter pools during grassland restoration

Glomalin related soil proteins (GRSP) produced by arbuscular mycorrhizal fungi are important stabilizing components of soil aggregates, and consequently helping to entrap organic matter and encapsulate it from microbial decomposition. Grasslands provide excellent opportunity to study GRSP effects because arbuscular mycorrhiza responsible for GRSP production is well development on roots of grasses. Fast GRSP production will accelerate soil organic carbon (SOC) accumulation, but the contribution of GRSP to particulate organic C (POC) and mineral-associated organic C (MAOC) pool remain unclear. We investigated GRSP content and thermal stability of POC and MAOC in topsoil (0–10 cm) as dependent on grassland restoration. SOC content had a nonlinear rise tendency with grassland restoration, and SOC changes were largely dependent on MAOC (>64 %). The POC content decreased by 58 %, while the MAOC content increased by 34 % after 40 years of restoration, microbial transformation of POC plays important role for MAOC formation. The GRSP content contributed 1.7 times more to MAOC (15 %) content than to POC (9 %), but the potential accumulation of GRSP in POC was higher than that in MAOC. The GRSP in the POC pool (less protected) is more sensitive to grassland restoration than in the MAOC pool (more protected). Thermally easily decomposable and refractory organic matter was quantified in POC and MAOC. Thermal stability of MAOC was higher than POC, and GRSP contribute to increase in SOC thermal stability. The GRSP content and thermal stability of POC pool gradually decreased with grassland restoration, reflecting production of more organic matter available for microorganisms and with fast turnover. In conclusion, we must account for the role of GRSP in maintaining SOC thermal stability, and the potential for GRSP sequestration during grassland restoration.

MicroRNA399s and strigolactones mediate systemic phosphate signaling between dodder‐connected host plants and control association of host plants with rhizosphere microbes

Summary A dodder (Cuscuta) often simultaneously parasitizes two or more adjacent hosts. Phosphate (Pi) deficiency is a common stress for plants, and plants often interact with soil microbes, including arbuscular mycorrhizal fungi (AMF), to cope with Pi stress. Little is known about whether dodder transmits Pi deficiency‐induced systemic signals between different hosts. In this study, dodder‐connected plant clusters, each composed of two tobacco (Nicotiana tabacum) plants connected by a dodder, were established, and in each cluster, one of the two tobacco plants was treated with Pi starvation. AMF colonization efficiency, rhizosphere bacterial community, and transcriptome were analyzed in the other dodder‐connected Pi‐replete tobacco plant to study the functions of interplant Pi signals. We found that dodder transfers Pi starvation‐induced systemic signals between host plants, resulting in enhanced AMF colonization, changes of rhizosphere bacterial communities, and alteration of transcriptomes in the roots of Pi‐replete plants. Importantly, genetic analyses indicated that microRNA399s (miR399s) and strigolactones suppress the systemic Pi signals and negatively affect AMF colonization in the Pi‐replete plants. These findings provide new insight into the ecological role of dodder in mediating host–host and host–microbe interactions and highlight the importance of strigolactone and miR399 pathways in systemic Pi signaling.

Increasing Phylogenetic Clustering of Arbuscular Mycorrhizal Fungal Communities in Roots Explains Enhanced Plant Growth and Phosphorus Uptake.

Temporal variation during the assembly of arbuscular mycorrhizal (AM) fungal communities within plant roots have been posited as critical drivers of the plant-fungal symbiotic outcomes. However, functional implications of these dynamics for the host plant remain poorly understood. We conducted a controlled pot experiment with Sorghum bicolor to investigate how temporal shifts in AM fungal community composition and phylogenetic diversity influence plant growth and phosphorus responses to the symbiosis. We characterised the root-colonising AM fungal communities across three time points and explored their community assembly processes by analysing their phylogenetic diversity and employing joint species distribution modelling with the Hierarchical Modelling of Species Communities (HMSC) framework. We found strong AM fungal turnover through time with a high phylogenetic signal, indicating recruitment of phylogenetically clustered AM fungal species in the host. This temporal phylogenetic clustering of communities coincided with marked increases in plant biomass and phosphorus responses to the AM fungal symbiosis, suggesting that host selection for specific fungi may be a key determinant of these benefits.

Enhanced soil carbon storage and arbuscular mycorrhizal fungal biomass in a long-term nutrient management under soybean-based cropping system.

To ensure the sustainability of crop production and ecosystem functioning, a thorough understanding of the mechanisms governing soil carbon (C) sequestration and soil health is essential. This study examined the effects of three nutrient management practices (organic, inorganic, and integrated) and two cropping systems (soybean-wheat and soybean-chickpea), on arbuscular mycorrhizal fungi (AMF) and soil C-sequestration in a long-term (12 years) field experiment. We measured the stocks of soil organic carbon, total glomalin-related soil protein, pertinent soil quality parameters such as microbial biomass carbon, and β-glucosidase activity along with AMF biomass [microscopic parameters and 16:1ω5cis phospholipid fatty acid (AM PLFA) and neutral lipid fatty acid (AM NLFA)]. It was observed that the measures of AMF biomass were positively correlated with the soil organic carbon stocks, total glomalin-related soil protein stocks, and soil quality parameters. Organic practice recorded significantly higher AMF spores, mycorrhizal colonization percentage, AM PLFA (2.58 nmol g-1 soil), AM NLFA (7.95 nmol g-1 soil), soil organic carbon stocks (15.78 Mg ha-1), total glomalin-related soil protein stocks (2.10 Mg ha-1), and soil quality parameters such as microbial biomass carbon, and β-glucosidase activity than inorganic and integrated practices. In comparison to soybean-chickpea, C-sequestration was higher in soybean-wheat. Principal component analysis validated the said results and differentiated soybean-wheat under organic practice from the rest of the treatments. In conclusion, our results suggest that organic management in conjunction with soybean-wheat crop rotation enhances AMF and can be recommended for improving soil quality and C sequestration without compromising crop yield.

Claroideglomus etunicatum enhances Pteris vittata L. arsenic resistance and accumulation by mediating the rapid reduction and transport of arsenic in roots

Arbuscular mycorrhizal fungi (AMF) have been widely shown to significantly promote the growth and recovery of Pteris vittata L. growth and repair under arsenic stress; however, little is known about the molecular mechanisms by which AMF mediate the efficient uptake of arsenic in this species. To understand how AMF mediate P. vittata arsenic metabolism under arsenic stress, we performed P. vittata root transcriptome analysis before and after Claroideglomus etunicatum (C. etunicatum) colonization. The results showed that after C. etunicatum colonization, P. vittata showed greater arsenic resistance and enrichment, and its dry weight and arsenic accumulation increased by 2.01–3.36 times. This response is attributed to the rapid reduction and upward translocation of arsenic. C. etunicatum enhances arsenic uptake by mediating the MIP, PHT, and NRT transporter families, while also increasing arsenic reduction (PvACR2 direct reduction and vesicular PvGSTF1 reduction). In addition, it downregulates the expression of ABC and P-type ATPase protein families, which inhibits the compartmentalization of arsenic in the roots and promotes its translocation to the leaves. This study revealed the mechanism of C. etunicatum-mediated arsenic hyperaccumulation in P. vittata, providing guidance for understanding the regulatory mechanism of P. vittata.

Garlic stalk waste and arbuscular mycorrhizae mitigate challenges in continuously monocropping eggplant obstacles by modulating physiochemical properties and fungal community structure.

Continuous vegetable production under plastic tunnels faces challenges like soil degradation, increased soil-borne pathogens, and diminished eggplant yield. These factors collectively threaten the long-term sustainability of food security by diminishing the productivity and resilience of agricultural soils. This research examined the use of raw garlic stalk (RGS) waste and arbuscular mycorrhizal fungi (AMF) as a sustainable solution for these issues in eggplant monoculture. We hypothesized that the combined application of RGS waste and AMF would improve soil physicochemical properties compared to untreated soil in eggplant monoculture. The combined use of RGS and AMF was expected to suppress soil-borne pathogens, increase the abundance of soil beneficial microorganisms and alter fungal community structure. The combined application of RGS and AMF will significantly enhance eggplant yield compared to untreated plots. This study aimed to determine whether AMF and RGS, individually or in combination, can ameliorate the adverse effects of monoculture on eggplant soil. We also investigated whether these treatments could enhance eggplant yield. The experiment was arranged in a completely randomized design with four treatments: AMF, RGS, and a combined treatment of AMF + RGS (ARGS), along with a control. Each treatment was replicated three times, Eggplant seedlings inoculated with AMF and treated with RGS amendments, both individually and combined. The effects on root traits, soil physicochemical properties, soil enzyme activity, and fungal community structure were investigated. RGS amendments and AMF inoculation improved root length, volume, and mycorrhizal colonization. The combined treatment showed the most significant improvement. RGS and AMF application increased soil nutrient availability (N, P, K) and organic matter content. Enzyme activities also increased with RGS and AMF treatments, with the combined application showing the highest activity. Soil electrical conductivity (EC) increased, while soil pH decreased with RGS and AMF amendments. Sequencing revealed a shift in the fungal community structure. Ascomycota abundance decreased, while Basidiomycota abundance increased with RGS and AMF application. The combined treatment reduced the abundance of pathogenic genera (Fusarium) and enriched beneficial taxa (Chaetomium, Coprinellus, Aspergillus). Pearson correlations supported the hypothesis that soil physicochemical properties influence fungal community composition. This study demonstrates the potential of co-applying RGS and AMF in continuous cropping systems. It enhances soil physicochemical properties, reduces soil-borne pathogens, and promotes beneficial microbial communities and eggplant yield. This combined approach offers a sustainable strategy to address the challenges associated with eggplant monoculture under plastic tunnels.

Cotton-mycorrhizal symbiosis: a comprehensive review of benefits for sustainable agriculture

Abstract Fertilizers and plant protection chemicals have played crucial role in modern agriculture. However, their excessive and imbalanced use over decades has resulted in the degradation and deterioration of soil health. The sustainability of agricultural systems largely depends on improving soil health. In this context, the arbuscular mycorrhizal fungi (AMF) association is a well-known interaction among plant microbial symbiotic associations that plays a multifunctional role in maintaining plant-soil health. More than 90% of terrestrial crop plants, including cultivated cotton, have a mutualistic symbiotic association with AMF. Symbiosis provides several benefits, such as the acquisition of mineral nutrients (primarily phosphorus), protection against biotic and abiotic stresses, and improved yield and fiber quality, contributing to the growth and development of the host plant. Under controlled conditions, the percent root length colonization of cotton was 50 to 70%, indicating the potential of AMF as a biological agent and plant growth promoter for sustainable cotton production. This review provides an updated and comprehensive overview of cotton-mycorrhizal symbiosis and its benefits.

Mycorrhization and chemical seed priming boost tomato stress tolerance by shifts of primary and defence metabolic pathways.

Priming modulates plant stress responses before the stress appears, increasing the ability of the primed plant to endure adverse conditions and thrive. In this context, we investigated the effect of biological (i.e., arbuscular mycorrhizal fungi, AMF) agents and natural compounds (i.e., salicylic acid applied alone or combined with chitosan) against water deficit and salinity on a commercial tomato genotype (cv. Moneymaker). Effects of seed treatments on AMF colonization were evaluated, demonstrating the possibility of using them in combination. Responses to water and salt stresses were analysed on primed plants alone or in combination with the AMF inoculum in soil. Trials were conducted on potted plants by subjecting them to water deficit or salt stress. The effectiveness of chemical seed treatments, both alone and in combination with post-germination AM fungal inoculation, was investigated using a multidisciplinary approach that included eco-physiology, biochemistry, transcriptomics, and untargeted metabolomics. Results showed that chemical seed treatment and AM symbiosis modified the tomato response to water deficit and salinity triggering a remodelling of both transcriptome and metabolome, which ultimately elicited the plant antioxidant and osmoprotective machinery. The plant physiological adaptation to both stress conditions improved, confirming the success of the adopted approaches in enhancing stress tolerance.

Fumigation Effect on the Mycorrhizal Status, the Mycorrhizal Diversity and the Roots System Development of Strawberry in Morocco

This study was undertaken to evaluate the fumigation effect on the mycorrhization status of strawberry roots, the diversity of indigenous arbuscular mycorrhizal fungi in the rhizosphere of strawberry and the roots system development of strawberry. Two parcels were taken randomly in the perimeter of Loukkos with fumigated one. For each parcel, samples of strawberry’s rhizosphere soil were taken regularly all over the cycle of culture. The mycorrhization parameters (mycorrhizal frequency, mycorrhizal intensity, arbuscular content, vesicular content and spores number) were calculated using Phillips and Hayman technique according to the scale of Trouvelot. An identification of spores was made according to the key International culture collection of Vesicular Arbuscular Mycorrhizal Fungi (INVAM). The frequency of the apparition of genera and species of spores at the sites were calculated. The roots system development was evaluated with the visual analogical scale (VAS: 0-100 mm). All the parameters were compared between the two parcels. Results showed that Mycorrhizal frequency, the number of spores and the roots system development between fumigated soil and non-fumigated one were respectively ((99.3 ± 2.8 vs. 100); (69 ± 12.3 vs. 137.5 ± 47.8); (23.8 ± 9.6 vs. 63.1 ± 21.6)). Six genera with nine species were identified and three undefined. Glomus genera were the dominant. In multivariate analysis, the roots system development was dependant to the fumigation status (yes/no), the vesicular content and the mycorrhization frequency. The roots system development was dependant to the fumigation status (yes/no) and spores number. As conclusion, this study suggests that the fumigation has a significant effect on the mycorrhization colonisation of roots, diversity of AMF and roots system development of strawberry.

Plant pests influence the movement of plant‐fixed carbon and fungal‐acquired nutrients through arbuscular mycorrhizal networks

Abstract Plants typically interact with multiple, co‐occurring symbionts, including arbuscular mycorrhizal (AM) fungi which can form networks, connecting neighbouring plants. A characteristic aspect of the mycorrhizal symbiosis is the bidirectional exchange of nutrients between host plants and fungal partners. Concurrent interactions with competing organisms such as aphids or potato cyst nematodes (PCN) can disrupt the carbon‐for‐nutrient exchange between plants and AM fungi. However, the role of mycorrhizal networks (MNs) in mediating these interactions remains unclear. Using isotope tracing in multi‐plant experimental systems, we investigated the movement of plant photosynthates and fungal‐acquired soil phosphorus through MNs and the interactive effects of PCN infection on this. We found evidence of preferential allocation of fungal‐acquired phosphorus to plants that were not infected by PCN compared with infected neighbours. Contrary to previous findings using single plants, we did not detect a PCN‐induced reduction in the amounts of plant carbon delivered to AM fungi in multi‐plant systems. However, the MN(s) moved plant‐fixed carbon away from PCN‐infected host plants, regardless of the PCN infection status of the neighbouring plant host. Our work highlights the responsiveness of MNs to interactions with below‐ground organisms. It also strengthens the argument for a more mycocentric view of AM–plant symbioses. Experimental designs of increasing ecological complexity are needed for a more comprehensive understanding of the carbon‐for‐nutrient dynamics in AM fungi–plant networks. This will, in turn, elucidate the role of AM fungi in terrestrial carbon cycling and their function in agricultural systems. Read the free Plain Language Summary for this article on the Journal blog.

Transcriptomic responses of Solanum tuberosum cv. Pirol to arbuscular mycorrhiza and potato virus Y (PVY) infection.

Arbuscular mycorrhizal fungi (AMF) serve as both plant symbionts and allies in resisting pathogens and environmental stresses. Mycorrhizal colonization of plant roots can influence the outcomes of plant-pathogen interactions by enhancing specific host defense mechanisms. The transcriptional responses induced by AMF in virus-infected plants remain largely unexplored. In the presented study, we employed a comprehensive transcriptomic approach and qPCR to investigate the molecular determinants underlying the interaction between AMF and potato virus Y (PVY) in Solanum tuberosum L. Our primary goal was to identify the symbiosis- and defense-related determinants activated in mycorrhizal potatoes facing PVY. Through a comparative analysis of mRNA transcriptomes in experimental treatments comprising healthy and PVY-infected potatoes colonized by two AMF species, Rhizophagus regularis or Funneliformis mosseae, we unveiled the overexpression of genes associated with mycorrhiza, including nutrient exchange, lipid transfer, and cell wall remodeling. Furthermore, we identified several differentially expressed genes upregulated in all mycorrhizal treatments that encoded pathogenesis-related proteins involved in plant immune responses, thus verifying the bioprotective role of AMF. We investigated the relationship between mycorrhiza levels and PVY levels in potato leaves and roots. We found accumulation of the virus in the leaves of mycorrhizal plants, but our studies additionally showed a reduced PVY content in potato roots colonized by AMF, which has not been previously demonstrated. Furthermore, we observed that a virus-dependent reduction in nutrient exchange could occur in mycorrhizal roots in the presence of PVY. These findings provide an insights into the interplay between virus and AMF.

Arbuscular Mycorrhizae Confers Salinity Tolerance to Medicago sativa L.

Alfalfa, a crop cultivated worldwide for use as livestock feed, exhibits great adaptability to various environmental conditions. This study evaluates the biomass production, lipid peroxidation, photosynthetic pigments and osmo-compatible response in Medicago sativa var CW660 mycorrhizae (AM) and non-mycorrhizae (NM) plants with Rhizophagus intraradices and when subjected to salinity (100 mM and 200 mM of NaCl). They were evaluated using the following morphological parameters: foliage fresh weight (FFW), foliage dry weight (FDW), root fresh weight (RFW), root dry weight (RDW), foliage length (FL) and root length (RL), chlorophylls a and b, proline and malondialdehyde (MDA) in AM and NM plants treated with different concentration of NaCl. The LFW and the LDW were higher in M plants. The RFW and the RDW increased in control AM plants, and under different saline treatments there were no differences between AM and NM in either parameter. FL increased in the control and at 100 mM of NaCl in M plants. Chlorophyll a decreased 27–30% and b decreased 1–50% in AM and NM plants at 200 mM NaCl. The proline level increased four times and promoted a defense in AM plants at 200 mM of NaCl. Lipid peroxidation decreased in AM plants by 10% at maximum salinity. M. sativa CW660 is sensitive to salinity stress, and inoculation with arbuscular mycorrhizal fungi (AMF) regulates its physiology and performance under such conditions, with osmotic protection and membrane protection.

Insight into the assembly process of angiosperms and arbuscular-mycorrhizal fungi in tropical wetland ecosystems

ABSTRACT Background The interaction between plants and mycorrhizal fungi is one of the most important and well-studied in ecology. However, the manner in which ecological communities of plants and arbuscular mycorrhizal (AM) fungi are structured by both deterministic and stochastic processes remains unclear. Aims To quantify the role of deterministic and stochastic assembly processes in both plant and arbuscular mycorrhizal (AM) fungal communities along with environmental filters in the assembly of communities in areas subject to flooding. Methods We studied phylogenetic relationships and diversity measures in plants and arbuscular mycorrhizal fungi in three tropical coastal wetland communities with contrasting landscapes and soil properties. Results We found that non-random processes were dominant in plant communities, while mycorrhizal communities appeared to be determined by stochastic processes. Clustering trends were predominant in plant communities in areas subject to flooding. Conclusion Environment filters and limiting similarity drive the plant community assembly, whereas ecological drift and/or dispersal limitations were determinants in the assembly of mycorrhizal communities. Environmental filters were found to be the main driver of plant community assembly in in areas subject to flooding.

Response surface methodology-based optimization of hairy roots cultures for in vitro AM production

Arbuscular mycorrhizal fungi can do wonders in promoting the crop growth as well maintaining soil health. In vitro root organ culture technology is an exciting avenue for AM biofertilizer production. This study aims to optimize the key influencing factors for enhancing the hairy root production used for in vitro AMF culturing using response surface methodology, a statistical and mathematical tool used for designing optimization studies. Study uses Rhizobium rhizogenes MTCC 2364 for transformation in carrot explant. Factors considered for optimization are concentration of gelling agent (phytagel), carbon source (sucrose) and pH of the Modified Strullu and Romand medium (MSR). Design Expert software uses second order polynomial regression equation for predicting the outcome of each experiment. Totally, 17 experiments were run following Box-Behnken design and average hairy root length and average side branch emergence were taken as response. ANOVA analysis reveals that the concentration of phytagel and sucrose had a strong influence on root length, while the phytagel and pH of the medium had a strong effect on side branch emergence. Overall, taking into account the both responses, concentration of phytagel had a significant impact on hairy root production. The maximum average hairy root length obtained was 1.12 cm and number of side branches emerged were 6.78 per day. Based on these results, the optimal parameters were MSR medium with 3gL-1 phytagel, 11gL-1 sucrose and a pH of 4 for boosting hairy root development. This study is a cost-effective approach and minimizes the time taken for establishing the hairy root technology.

Unveiling the Ecological and Pharmacological Perspectives of Lithophytic Life Form

Environmental extremes such as high temperature, cold, alkalinity, drought, and rocky substrate modulate plant growth and promulgate adaptive characteristics in plants. The same plants can be found inhabited in different life forms, namely epiphytic, lithophytic, terrestrial, halophytic, and psammophytic, based upon adaptive characteristics essential for their survival. Microorganisms residing on the surface or within rocks make a unique habitat referred to as “lithobiontic habitat,” which further facilitates weathering phenomena and accumulates water and nutrients from the ecosystem to form a lithobiontic ecological niche. Lithobionts are divided into two groups, namely epiliths and endoliths, based on their presence on rock surfaces. Lithophytes, the rock-inhabiting plants, thriving under extreme stress conditions adapted successfully and their extraordinarily challenging atmosphere encouraged them to make new forms of life. Many biotic and abiotic factors are responsible for dwelling in such environments. Lithophytes interact with their surroundings to obtain vital elements necessary for their metabolism and, because of natural selection, their morphology and physiology help them with better adaptation. Another factor that facilitates such adaptation in lithophytes is the association of a fungus with lithophytic roots to ensure nutrient supply for their survival and facilitate growth in extreme conditions. Arbuscular mycorrhizal (AM) root fungal associations commonly found among plants under stressed conditions help hosts adapt and promote plant life. In lithophytes, AM association aids in nutrient uptake from soil and facilitates plant survival under harsh conditions. The present review provides a comprehensive account of lithophytic life forms and covers different aspects of rock-dwelling plants concerning their historical background, classification, habitat, distribution in various families, root adaptive mechanisms, and phytopharmacological status. This review focused on plant species that can be considered among the most common representatives of lithophytes. This manuscript furnishes insights into different perspectives on the ecological and biological properties of the most common lithophytic species adapted to extreme rocky structures and explains their wide array of applications for pharmacological use.

Selection for agronomic traits in intermediate wheatgrass increases responsiveness to arbuscular mycorrhizal fungi

Societal Impact StatementAgricultural practices have had a negative impact on the physical, chemical, and biological components of soil. Perennial cropping systems that facilitate positive soil microbial interactions could not only rebuild soils but also sustain productivity through expected variations in environmental conditions. Here, we show the presence of arbuscular mycorrhizal (AM) fungi, soil symbionts that can improve host performance and soil health, increased the growth of intermediate wheatgrass, a novel perennial grain crop, in populations that have been increasingly bred for desirable agricultural characteristics. The right pairing of intermediate wheatgrass and a beneficial AM fungal community could lead to more sustainable agroecosystems.Summary Intermediate wheatgrass (IWG) is a novel perennial grain that can provide many soil health benefits in agroecosystems; however, little is known about how selection for agronomic traits has impacted interactions with soil biota. Here, we assess how the selection for agronomic traits in IWG has impacted its relationship with arbuscular mycorrhizal (AM) fungi. First, growth response to AM fungi was compared across five generations of IWG with varying degrees of selection. Second, variation in AM fungal responsiveness was compared among genets of IWG individuals within a more advanced generation. Finally, a meta‐analysis was performed on all published studies exploring AM fungal inocula effects on IWG performance to increase understanding of selection effects. AM fungal responsiveness increased with selection for agronomic traits, responsiveness varied among genets in the advanced generation, and a majority of genets performed better in the presence of AM fungi. The meta‐analysis supported the findings that AM fungal responsiveness has increased with selection in IWG. Further studies are needed to realize the combined potential soil health and sustainability benefits of IWG and AM fungi, including assessment of symbiotic benefits beyond biomass production, identification of IWG traits correlated with responsiveness, and characterization of AM fungal community response to IWG.

Isolation and characterization of non-rhizobial bacteria and arbuscular mycorrhizal fungi from legumes

This study investigates non-rhizobial endophytic bacteria in the root nodules of chickpea (Cicer arietinum L), faba bean (Vicia faba), and cowpea (Vigna unguiculata L. Walp), as well as arbuscular mycorrhizal fungi in the rhizospheric soil of chickpea and faba bean. Out of the 34 endophytic bacterial populations examined, 31 strains were identified as non-rhizobial based on nodulation tests. All strains were assessed for their plant growth-promoting (PGP) activities in vitro. The results revealed that most isolates exhibited multiple PGP activities, such as nitrogen fixation, indole-3-acetic acid (IAA) and ammonia (NH3) production, phosphate solubilization, and exopolysaccharide production. The most effective PGP bacteria were selected for 16S rRNA analysis. Additionally, a total of 36 species of native arbuscular mycorrhizal fungi (AMF) were identified. Acaulospora (100%) and Scutellospora (91.66%) were the most prevalent genera in Cicer arietinum L. and Vicia faba L. plants, respectively. Acaulospora also exhibited the highest spore density and relative abundance in both plants. Moreover, the root colonization of Cicer arietinum L. and Vicia faba L. plants by hyphae, vesicles, and arbuscules (HVA) was significant. The findings of this study provide valuable insights into non-rhizobial endophytic bacteria associated with legume root nodules and the diversity of AMF. These organisms have great potential for PGP and can be manipulated by co-inoculation with rhizobia to enhance their biofertilizer effectiveness. This manipulation is crucial for promoting sustainable agriculture, improving crop growth, and advancing biofertilizer technology.