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Soil salinization, especially in arid and semi-arid regions, is one of the major abiotic stresses that affect plant growth. To mediate and boost plant tolerance against this abiotic stress, arbuscular mycorrhizal fungi (AMF) symbiosis is commonly thought to be an effective tool. So, the main purpose of this study was to estimate the role of AMF (applied as a consortium of Claroideoglomus etunicatum, Funneliformis mosseae, Rhizophagus fasciculatum, and R. intraradices species) symbiosis in mitigating deleterious salt stress effects on the growth parameters (shoot length (SL), root length (RL), shoot dry weight (SDW), root dry weight (RDW), root surface area (RSA), total root length (TRL), root volume (RV), root diameter (RD), number of nodes and leaves) of Cenchrus ciliaris L. plants through improved accumulations of photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll), proline and phenolic compounds. The results of this experiment revealed that the roots of C. ciliaris plants were colonized by AMF under all the applied salinity levels (0, 75, 150, 225, and 300 mM NaCl). However, the rate of colonization was negatively affected by increasing salinity as depicted by the varied colonization structures (mycelium, vesicles, arbuscules and spores) which were highest under non-saline conditions. This association of AMF induced an increase in the growth parameters of the plant which were reduced by salinity stress. The improved shoot/root indices are likely due to enhanced photosynthetic activities as the AMF-treated plants showed increased accumulation of pigments (chlorophyll a, chlorophyll b and total chlorophyll), under saline as well as non-saline conditions, compared to non-AMF (N-AMF) plants. Furthermore, the AMF-treated plants also exhibited enhanced accumulation of proline and phenolic compounds. These accumulated metabolites act as protective measures under salinity stress, hence explaining the improved photosynthetic and growth parameters of the plants. These results suggest that AMF could be a good tool for the restoration of salt-affected habitats. However, more research is needed to check the true efficacy of different AMF inoculants under field conditions. [ABSTRACT FROM AUTHOR]

Biochar derived from poultry manure increases nutrient availability and promotes plant growth. This study investigated the effect of biochar with mycorrhizal and/or plant growth-promoting rhizobacteria on soil fertility, chemical properties, oil, and seed yield of Black Cumin (Nigella sativa L.) plants. A split-plot design with three replicates was employed, with biochar derived from poultry litter (BC) applied at rates of 0, 5, and 10 t ha−1, with beneficial microbes such as arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) affecting the growth of Black Cumin plants, and some soil properties, such as pH, electrical conductivity (EC), soil organic matter (SOM) and fertility index (FI), showing significant differences (p ≤ 0.05) among biochar and/or bio-fertilizer treatments. All biochar treatments with or without bio-fertilizers significantly increased pH, EC, OM and FI in comparison to the control treatment. The results demonstrated that applying biochar at the highest rate (10 t ha−1) increased fresh and dry capsule weights by 94.51% and 63.34%, respectively, compared to the control treatment (C). These values were significantly increased by 53.05 and 18.37%, compared to untreated plants when combined with AMF and PGPR. Furthermore, when biochar was applied in conjunction with both AMF and PGPR, fresh and dry capsule weights saw significant increases of 208.84% and 91.18%, respectively, compared to the untreated control treatment. The interaction between biochar, AMF, and PGPR significantly improved plant growth, yield, soil properties, and the fixed and volatile oil content of Black Cumin. These findings suggest that the combined application of biochar, AMF, and PGPR enhances nutrient availability and uptake, leading to improved growth and higher yields in Black Cumin plants, resulting in increased yield production. [ABSTRACT FROM AUTHOR]

Background: Arbuscular mycorrhizal fungi (AMF) form mutualistic partnerships with approximately 80% of plant species. AMF, and their diversity, play a fundamental role in plant growth, driving plant diversity, and global carbon cycles. Knowing whether AMF are sexual or asexual has fundamental consequences for how they can be used in agricultural applications. Evidence for and against sexuality in the model AMF, Rhizophagus irregularis, has been proposed. The discovery of a putative mating-type locus (MAT locus) in R. irregularis, and the previously suggested recombination among nuclei of a dikaryon R. irregularis isolate, potentially suggested sexuality. Unless undergoing frequent sexual reproduction, evolution of MAT-locus diversity is expected to be very low. Additionally, in sexual species, MAT-locus evolution is decoupled from the evolution of arbitrary genome-wide loci. Results: We studied MAT-locus diversity of R. irregularis. This was then compared to diversification in a phosphate transporter gene (PTG), that is not involved in sex, and to genome-wide divergence, defined by 47,378 single nucleotide polymorphisms. Strikingly, we found unexpectedly high MAT-locus diversity indicating that either it is not involved in sex, or that AMF are highly active in sex. However, a strongly congruent evolutionary history of the MAT-locus, PTG and genome-wide arbitrary loci allows us to reject both the hypothesis that the MAT-locus is involved in mating and that the R. irregularis lineage is sexual. Conclusion: Our finding shapes the approach to developing more effective AMF strains and is highly informative as it suggests that introduced strains applied in agriculture will not exchange DNA with native populations. [ABSTRACT FROM AUTHOR]

Mangroves, despite thriving at the fringes of habitat tolerance in coastal regions, stand out as one of the world's most highly productive ecosystems. This study delves into the remarkable symbiotic relationship between mangroves and arbuscular mycorrhizal fungi (AMF). Specifically, it assesses seasonal diversity in six true mangrove species and four associated species, situated in Henry's Island, Bakkhali, India. Spore density and root colonization were examined across different seasons. The highest spore density was observed in Heritiera fomes (a timber-producing mangrove) during the post-monsoon season, followed by pre-monsoon and monsoon periods. Root colonization was notably prominent in Ceriops tagal (Indian mangrove), Bruguira gymnorrhiza (Oriental mangrove), and Sonneratia alba (flowering evergreen mangrove) during both pre- and postmonsoon seasons. This study unveiled a rich fungal diversity, with a total of 60 AMF species belonging to 13 genera. Among these, the genus Glomus emerged as the dominant group, with species such as G. deserticola along with another genus Rhizophagus intraradics displaying widespread distribution. Notably, Glomus consistently ranked as the most prevalent genus throughout the year, indicating its remarkable adaptability and strong dispersal capacity in both true and associate mangrove plant species. This research sheds light on the seasonal dynamics of AMF associations in mangrove ecosystems, emphasizing the significance of Glomus as a key player in this symbiotic relationship. These findings contribute to our understanding of the ecological intricacies within mangrove habitats and highlight the adaptability of certain AMF genera to varying environmental conditions. [ABSTRACT FROM AUTHOR]

Dry evergreen Afromontane forests (DAF) once covered most of the Ethiopian highlands. Currently, they are found as a few patches. DAF restoration is a national forest restoration priority in Ethiopia. It has also been identified to be among global ecosystem restoration priorities. There are sufficient data to show DAF restoration from the soil seed bank or seed rain is hardly possible. Planting trees from multiple provenances is important to restore climate-resilient DAF. Therefore, DAF restoration cannot be achieved through natural regeneration alone and must be accomplished by planting characteristic DAF tree species. The poor soil moisture and nutrient conditions in Ethiopia's dry highlands result in low native tree seedling survival and growth. Hence, proper preparation of the planting sites and after-planting seedling care for at least two years is a reliable mechanism for achieving successful survival and growth. Along with seedling care after planting, four additional mechanisms discussed in this review (i.e. the use of nurse trees/shrubs, design of nursery practices, inoculation with arbuscular mycorrhizal fungi, and application of biochar) have also been shown to be useful. However, they cannot substitute for proper planting site preparation and post-planting seedling care. The complementary use of these five mechanisms could further enhance success. However, there are more questions than answers regarding the effectiveness of the five mechanisms discussed. We hope this review will motivate researchers to engage further to answer some of the important questions regarding restoration success. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) are widespread obligate symbionts of plants. This dynamic symbiosis plays a large role in successful plant performance, given that AMF help to ameliorate plant responses to abiotic and biotic stressors. Although the importance of this symbiosis is clear, less is known about what may be driving this symbiosis, the plant's need for nutrients or the excess of plant photosynthate being transferred to the AMF, information critical to assess the functionality of this relationship. Characterizing the AMF community along a natural plant productivity gradient is a first step in understanding how this symbiosis may vary across the landscape. We surveyed the AMF community diversity at 12 sites along a plant productivity gradient driven by soil nitrogen availability. We found that AMF diversity in soil environmental DNA significantly increased along with the growth of the host plants Acerrubrum and A. saccharum., a widespread tree genus. These increases also coincided with a natural soil inorganic N availability gradient. We hypothesize photosynthate from the increased tree growth is being allocated to the belowground AMF community, leading to an increase in diversity. These findings contribute to understanding this complex symbiosis through the lens of AMF turnover and suggest that a more diverse AMF community is associated with increased host–plant performance. [ABSTRACT FROM AUTHOR]

Recent agricultural research has prioritized the development of environmentally friendly management strategies to ensure food security, among which the application of biostimulants such as brown algae extracts, arbuscular mycorrhizal fungi (AMF), and their combination are included. The experimental protocol was based on the factorial combination of two planting times (4 May and 1 June) and seven biostimulant treatments (three brown algae species, Cystoseria tamariscifolia—C.t.; Fucus vesiculosus—F.v.; Padina pavonica—P.p.; arbuscular mycorrhizal fungi—AMF; C.t. + AMF; F.v. + AMF; P.p. + AMF) plus an untreated control. The earlier transplant resulted in a higher yield, due to the higher number of fruits per plant, and a higher plant fresh and dry biomass. The treatments with P.p. and F.v. extracts and the combination P.p. + AMF led to the highest yields (56.7 t ha−1), mainly due to the highest fruit number per plant. The earlier planting time led to higher values of dry residue, soluble solids, firmness, and colour component 'a'. The highest values of fruit dry residue were recorded under the F.v. and P.p. extracts, and the combinations F.v. + AMF and P.p. + AMF, the highest soluble solid content with P.p. treatment, and firmness under P.p. + AMF. The highest levels of 'L' and 'a' fruit colour components were obtained under the P.p. extract treatment, of 'b' upon the application of P.p. and F.v. extract, and AMF + P.p. and AMF + F.v. The later planting time led to significantly higher values of the antioxidant parameters, as did the application of the P.p. extract and P.p. + AMF. CAT activity was more intense corresponding to the later tomato crop cycle, P.p. extract, and AMF + P.p. Overall, our study highlights the potential of biostimulants, particularly brown algae extracts and their combination with AMF, to improve tomato yield, antioxidant properties, and biochemical activities. [ABSTRACT FROM AUTHOR]

Background: Salinity stress remains a chronic threat to pulses productivity in India. Arbuscular mycorrhizal (AM) fungi play a major role which influences plant growth, nutrient uptake and contributes to ecosystem processes under salt stress. The present study aims, to demonstrate the impact of Glomus mosseae (Gm), on physio-biochemical attributes of mungbean exposed to salinity. Methods: Two highly tolerant, two moderately susceptible and two highly susceptible mungbean lines were subjected to salinity stress alone and in presence of Gm under greenhouse. Result: Results revealed that Gm alleviates the salinity stress related alterations by improving the nutrient uptake and by balancing the ratio between K:Na, which impact directly the osmoregulation of the plants. Mycorrhiza inoculation also increased the proline content (23%), water-use efficiency (38%) and activity of different antioxidant enzymes in a significant manner providing efficient protection against salinity stress. All these positive impacts of Gm were duly reflected in a significant increase in grain yield (more than 2 fold increase) in mungbean. Interestingly, salt-induced retarded growth and decline in other biochemical parameters in susceptible lines recorded remarkable recovery following Gm inoculation. [ABSTRACT FROM AUTHOR]

Panax notoginseng is a highly valued perennial medicinal herb in China and is widely used in clinical treatments. The main purpose of this study was to elucidate the changes in the composition of P. notoginseng saponins (PNSs), which are the main bioactive substances, triggered by arbuscular mycorrhizal fungi (AMF) via ultrahigh-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (UPLC–ESI–MS/MS). A total of 202 putative terpenoid metabolites were detected, of which 150 triterpene glycosides were identified, accounting for 74.26% of the total. Correlation analysis, principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS–DA) of the metabolites revealed that the samples treated with AMF (group Ce) could be clearly separated from the CK samples. In total, 49 differential terpene metabolites were identified between the Ce and CK groups, of which 38 and 11 metabolites were upregulated and downregulated, respectively, and most of the upregulated differentially abundant metabolites were mainly triterpene glycosides. The relative abundances of the two major notoginsenosides (MNs), ginsenosides Rd and Re, and 13 rare notoginsenosides (RNs), significantly increased. The differential saponins, especially RNs, were more easily clustered into one branch and had a high positive correlation. It could be concluded that the biosynthesis and accumulation of some RNs share the same pathways as those triggered by AMF. This study provides a new way to obtain more notoginsenoside resources, particularly RNs, and sheds new light on the scientization and rationalization of the use of AMF agents in the ecological planting of medicinal plants. [ABSTRACT FROM AUTHOR]

The relationship between biodiversity and ecosystem functioning strengthens with ecosystem age. However, the interplay between the plant diversity - ecosystem functioning relationship and Glomeromycotinian arbuscular mycorrhizal fungi (AMF) community assembly has not yet been scrutinized in this context, despite AMF's role in plant survival and niche exploration. We study the development of AMF communities by disentangling soil- and plant-driven effects from calendar year effects. Within a long-term grassland biodiversity experiment, the pre-existing plant communities of varying plant diversity were re-established as split plots with combinations of common plant and soil histories: split plots with neither common plant nor soil history, with only soil but no plant history, and with both common plant and soil history. We found that bulk soil AMF communities were primarily shaped by common soil history, and additional common plant history had little effect. Further, the steepness of AMF diversity and plant diversity relationship did not strengthen over time, but AMF community evenness increased with common history. Specialisation of AMF towards plant species was low throughout, giving no indication of AMF communities specialising or diversifying over time. The potential of bulk soil AMF as mediators of variation in plant and microbial biomass over time and hence as drivers of biodiversity and ecosystem relationships was low. Our results suggest that soil processes may be key for the build-up of plant community-specific mycorrhizal communities with likely feedback effects on ecosystem productivity, but the plant-available mycorrhizal pool in bulk soil itself does not explain the strengthening of biodiversity and ecosystem relationships over time. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is a vital nutrient element that is essential for plant growth and development, and arbuscular mycorrhizal fungi (AMF) can significantly enhance P absorption. The phosphate transporter protein 1 (PHT1) family mediates the uptake of P in plants. However, the PHT1 gene has not yet been characterized in Salvia miltiorrhiza. In this study, to gain insight into the functional divergence of PHT1 genes, nine SmPHT1 genes were identified in the S. miltiorrhiza genome database via bioinformatics tools. Phylogenetic analysis revealed that the PHT1 proteins of S. miltiorrhiza, Arabidopsis thaliana, and Oryza sativa could be divided into three groups. PHT1 in the same clade has a similar gene structure and motif, suggesting that the features of each clade are relatively conserved. Further tissue expression analysis revealed that SmPHT1 was expressed mainly in the roots and stems. In addition, phenotypic changes, P content, and PHT1 gene expression were analyzed in S. miltiorrhiza plants inoculated with AMF under different P conditions (0 mM, 0.1 mM, and 10 mM). P stress and AMF significantly affected the growth and P accumulation of S. miltiorrhiza. SmPHT1;6 was strongly expressed in the roots colonized by AMF, implying that SmPHT1;6 was a specific AMF-inducible PHT1. Taken together, these results provide new insights into the functional divergence and genetic redundancy of the PHT1 genes in response to P stress and AMF symbiosis in S. miltiorrhiza. [ABSTRACT FROM AUTHOR]

The effect of inoculation of a combination of the arbuscular mycorrhizal fungus of Glomus and Acaulospora on micropropagated banana plantlets cultivar Raja from Bali during the acclimatization phase was investigated. The experiment was conducted at the Experimental Station of the Faculty of Agriculture, Udayana University, Denpasar, Bali, Indonesia, over the period of March to June 2022. The objective of this research was to evaluate the impact of various doses of mycorrhizae on the growth of tissue culture banana plantlets that had undergone acclimatization for a period of six weeks. A total of five different doses of mycorrhiza were applied to the acclimatized plantlets, namely M0=without mycorrhiza and M5=5g mycorrhiza.kg-1, M10=10 g mycorrhiza.kg-1, M15=15 g mycorrhiza.kg-1, M20=20 g mycorrhiza.kg-1. A significant effect was discovered at M15; however, compared to M20, M20 gave better results for root length and fresh weight of the above-ground part, indicating the best dose was 20 g mycorrhiza kg-1. This study concluded that mycorrhiza has a very significant role in supporting the growth of micro propagated banana plantlets at post-acclimatization. Variables observed, such as the average number of leaves, stem diameter, above-ground plant fresh and dry weight, and root fresh and dry weight, increased with the application of AMF (Glomus and Acaulospora). [ABSTRACT FROM AUTHOR]

Summary: Most plants form root hyphal relationships with mycorrhizal fungi, especially arbuscular mycorrhizal fungi (AMF). These associations are known to positively impact plant biomass and competitive ability. However, less is known about how mycorrhizas impact other ecological interactions, such as those mediated by pollinators.We performed a meta‐regression of studies that manipulated AMF and measured traits related to pollination, including floral display size, rewards, visitation, and reproduction, extracting 63 studies with 423 effects.On average, the presence of mycorrhizas was associated with positive effects on floral traits. Specifically, we found impacts of AMF on floral display size, pollinator visitation and reproduction, and a positive but nonsignificant impact on rewards. Studies manipulating mycorrhizas with fungicide tended to report contrasting results, possibly because fungicide destroys both beneficial and pathogenic microbes.Our study highlights the potential for relationships with mycorrhizal fungi to play an important, yet underrecognized role in plant–pollinator interactions. With heightened awareness of the need for a more sustainable agricultural industry, mycorrhizal fungi may offer the opportunity to reduce reliance on inorganic fertilizers. At the same time, fungicides are now ubiquitous in agricultural systems. Our study demonstrates indirect ways in which plant‐belowground fungal partnerships could manifest in plant–pollinator interactions. [ABSTRACT FROM AUTHOR]

Toona ciliata var. pubescens, known as "Chinese mahogany", has high commercial value and is classified as a level II priority protected wild plant in China. However, due to overexploitation and its poor natural regeneration capacity, natural T. ciliata var. pubescens forests show varying degrees of decline in habitat adaptability. Arbuscular mycorrhizal fungi (AMF) symbiosis presents a potential strategy to enhance its regeneration. In this study, T. ciliata var. pubescens seedlings were inoculated with Septoglomus viscosum, followed by RNA-Seq analysis to compare gene expression differences between AMF-inoculated (AMI) and non-mycorrhizal (NM) treatments three months post-inoculation. A total of 16,163 differentially expressed genes (DEGs) were upregulated by AMF colonization, constituting 96.46% of the total DEGs. Specifically, 14,420 DEGs were exclusively expressed in the AMI treatment, while 35 DEGs were completely silenced. Most of the upregulated DEGs were located on the cell membrane, nucleus, and cytoskeleton and functioned in protein binding, S-adenosylmethionine-dependent methyltransferase activity, and lipid binding during cellular/macromolecule/protein localization, intracellular/protein transport, the cell cycle, and signal transduction. Additionally, lots of key genes related to oxidative stress responses, nutrient transport, and small GTPase-mediated signal transduction were found to be upregulated. These results suggest that AMF inoculation may enhance root cell growth by activating genes involved in nutrient uptake, stress responses, signal transduction, and substance transportation. This study elucidates the molecular mechanisms underlying the growth promotion of T. ciliata var. pubescens through AMF symbiosis, laying a foundation for the future application of AMF in its natural forest regeneration. [ABSTRACT FROM AUTHOR]

At the southeastern periphery of the Tibetan Plateau, the subalpine ecosystem hosts grasses as some of the most substantial species. However, the community and function of arbuscular mycorrhizal fungi (AMF) around the rhizospheres of grasses in the subalpine zone are still poorly understood. In the present study, 28 soils and 11 species of dominant grasses collected from four microhabitats (shrubland, grassland, woodland, and forest) in the subalpine zone of northwestern Yunnan, China, were used to investigate the AMF community by Illumina MiSeq high-throughput sequencing technology as well as nutrient contents. Among the four microhabitats, the maximum soil nutrient levels around the rhizospheres of grasses were observed in woodland. The nitrogen, phosphorus, and potassium concentrations in Dactylis glomerata shoots were significantly higher than those in the other 10 grass species. The AMF diversity of grassland in summer was substantially greater than that of the other three microhabitats (p < 0.05). Discrepancies were observed within a given plant species across microhabitats; for example, in summer, the nitrogen concentration in the shoot of Iris tectorum in woodland was significantly higher than that in both forest and shrubland (p < 0.05). A total of eight genera were detected in the AMF communities, which were dominated by Glomus, with a relative abundance of 45.4%–94.4% in summer and 60.5%–84.3% in winter. Moreover, the abundance of Glomus was significantly positively correlated with the content of alkali-hydrolyzable nitrogen in soil and nitrogen in grasses according to the Mantel test. As a critical nutrient element in soil, nitrogen is beneficial for plant growth. Thus, these results provide a better understanding of the resilience of soil AMF community and the ecological adaptability of grasses in the subalpine ecosystems of northwestern Yunnan. [ABSTRACT FROM AUTHOR]

The invasive plant Wedelia trilobata benefits in various aspects, such as nutrient absorption and environmental adaptability, by establishing a close symbiotic relationship with arbuscular mycorrhizal fungi (AMF). However, our understanding of whether AMF can benefit W. trilobata by influencing its metabolic profile remains limited. In this study, Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was conducted to analyze the metabolites of W. trilobata under AMF inoculation. Metabolomic analysis identified 119 differentially expressed metabolites (DEMs) between the groups inoculated with AMF and those not inoculated with AMF. Compared to plants with no AMF inoculation, plants inoculated with AMF showed upregulation in the relative expression of 69 metabolites and downregulation in the relative expression of 50 metabolites. AMF significantly increased levels of various primary and secondary metabolites in plants, including amino acids, organic acids, plant hormones, flavonoids, and others, with amino acids being the most abundant among the identified substances. The identified DEMs mapped 53 metabolic pathways, with 7 pathways strongly influenced by AMF, particularly the phenylalanine metabolism pathway. Moreover, we also observed a high colonization level of AMF in the roots of W. trilobata, significantly promoting the shoot growth of this plant. These changes in metabolites and metabolic pathways significantly affect multiple physiological and biochemical processes in plants, such as free radical scavenging, osmotic regulation, cell structure stability, and material synthesis. In summary, AMF reprogrammed the metabolic pathways of W. trilobata, leading to changes in both primary and secondary metabolomes, thereby benefiting the growth of W. trilobata and enhancing its ability to respond to various biotic and abiotic stressors. These findings elucidate the molecular regulatory role of AMF in the invasive plant W. trilobata and provide new insights into the study of its competitive and stress resistance mechanisms. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) and rhizobium play a significant role in plant symbiosis. However, their influence on the rhizosphere soil microbiome associated with nutrient acquisition and soil health is not well defined in the drylands of Montana (MT), USA. This study investigated the effect of microbial inoculants as seed treatment on pea yield, nutrient uptake, potential microbial functions, and rhizosphere soil microbial communities using high-throughput sequencing of 16S and ITS rRNA genes. The experiment was conducted under two contrasting dryland conditions with four treatments: control, single inoculation with AMF or Rhizobium, and dual inoculations of AMF and Rhizobium (AMF+Rhizobium). Our findings revealed that microbial inoculation efficacy was site-specific. AMF+Rhizobium synergistically increased grain yield at Sidney dryland field site (DFS) 2, while at Froid site, DFS 1, AMF improved plant resilience to acidic soil but contributed a marginal yield under non-nutrient limiting conditions. Across dryland sites, the plants' microbial dependency on AMF+Rhizobium (12%) was higher than single inoculations of AMF (8%) or Rhizobium (4%) alone. Variations in microbial community structure and composition indicate a site-specific response to AMF and AMF+Rhizobium inoculants. Overall, site-specific factors significantly influenced plant nutrient uptake, microbial community dynamics, and functional potential. It underscores the need for tailored management strategies that consider site-specific characteristics to optimize benefits from microbial inoculation. [ABSTRACT FROM AUTHOR]

Panax notoginseng is a highly valued perennial medicinal herb plant in Yunnan Province, China, and the taproots are the main medicinal parts that are rich in active substances of P. notoginseng saponins. The main purpose of this study is to uncover the physiological and molecular mechanism of Panax notoginseng saponin accumulation triggered by methyl jasmonate (MeJA) under arbuscular mycorrhizal fungi (AMF) by determining physiological indices, high-throughput sequencing and correlation analysis. Physiological results showed that the biomass and saponin contents of P. notoginseng, the concentrations of jasmonic acids (JAs) and the key enzyme activities involved in notoginsenoside biosynthesis significantly increased under AMF or MeJA, but the interactive treatment of AMF and MeJA weakened the effect of AMF, suggesting that a high concentration of endogenous JA have inhibitory effect. Transcriptome sequencing results indicated that differential expressed genes (DEGs) involved in notoginsenoside and JA biosynthesis were significantly enriched in response to AMF induction, e.g., upregulated genes of diphosphocytidyl-2-C-methyl-derythritol kinases (ISPEs), cytochrome P450 monooxygenases (CYP450s)_and glycosyltransferases (GTs), while treatments AMF-MeJA and salicylhydroxamic acid (SHAM) decreased the abundance of these DEGs. Interestingly, a high correlation presented between any two of saponin contents, key enzyme activities and expression levels of DEGs. Taken together, the inoculation of AMF can improve the growth and saponin accumulation of P. notoginseng by strengthening the activities of key enzymes and the expression levels of encoding genes, in which the JA regulatory pathway is a key link. This study provides references for implementing ecological planting of P. notoginseng, improving saponin accumulation and illustrating the biosynthesis mechanism. [ABSTRACT FROM AUTHOR]

Biostimulants and bioinoculants offer the potential to enhance nutrient use efficiency within agricultural cropping systems and thus reduce the amount of mineral fertilizers needed to support crop growth. Considerable uncertainty, however, exists about their efficacy under different management regimes. The present field-based study investigated the effects of phosphorus (P) solubilizing bacteria (PSB) and mycorrhizal (AMF) inoculants in the presence of a range of mineral-based P fertilizers, including triple superphosphate (TSP), struvite and rock phosphate (RP), on the growth, yield, and P uptake of barley (Hordeum vulgare L.). Two consecutive field experiments performed in a low P soil (Eutric Cambisol) revealed that the bioinoculants (PSB and AMF) promoted plant P uptake and grain yield. Moreover, in comparison to P fertilizers lacking bio-inoculants, the application of external P sources combined with bio-inoculants led to significant increases in leaf P concentration, total P uptake, plant dry matter, grain P concentration, and crop yield. Grain yield significantly correlated with P uptake by roots and above-ground parts (i.e. stems, leaves, and spikes) as well as grain P concentration in both seasons. It is concluded that bioinoculants can help improve sustainable P use ultimately leading to greater sustainability of cropping systems and resilience in soil P cycling. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) can penetrate plant root cortical cells, establish a symbiosis with most land plant species, and form branched structures (known as arbuscules) for nutrient exchange. Plants have evolved a complete plant-AMF symbiosis system to sustain their growth and development under various types of abiotic stress. Here, we highlight recent studies of AM symbiosis and the regulation of symbiosis process. The roles of mycorrhizal symbiosis and host plant interactions in enhancing drought resistance, increasing mineral nutrient uptake, regulating hormone synthesis, improving salt resistance, and alleviating heavy metal stress were also discussed. Overall, studies of AM symbiosis and a variety of abiotic stresses will aid applications of AMF in sustainable agriculture and can improve plant production and environmental safety. [ABSTRACT FROM AUTHOR]

Drought is a major threat to food security worldwide. Recently, the root–soil interface has emerged as a major site of hydraulic resistance during water stress. Here, we review the impact of soil drying on whole-plant hydraulics and discuss mechanisms by which plants can adapt by modifying the properties of the rhizosphere either directly or through interactions with the soil microbiome. [ABSTRACT FROM AUTHOR]

The effects of planting ryegrass combined with sludge addition and arbuscular mycorrhizal fungi (AMF) inoculation on organic carbon accumulation in reclaimed mine substrates (RMS) were investigated. A 6-year field experiment was carried out; in the 0–15-cm edaphic layer, a mixed matrix was constructed according to the ratio of fly ash to coal gangue to sludge=1∶6∶3 , with 0.5 kg/m2 of AMF inoculated and ryegrass sowed annually. The particle size, carbon fraction, enzyme activity, AMF-related protein and ryegrass rhizosphere effect of RMS aggregates were monitored regularly. The cumulative contribution of the above factors to organic carbon in RMS was quantitatively explored by path analysis. After reclamation, the texture of reclamation matrix in mining area was improved, the stability of aggregates augmented significantly with the proportion of large aggregates increased gradually. Organic carbon in RMS increased by 1.96 times to 38.12 g/kg ; the contents of total N and available P increased significantly year by year, mainly concentrated in aggregates. Path analysis showed that the underground biomass of ryegrass and 0.5–2-mm aggregates were the two factors with the strongest direct positive effect on organic carbon accumulation in RMS. In addition, available phosphatase and easily extractable glomalin affected the process through complex interaction with each other. A combination of ryegrass-AMF-sludge on a reclamation mining field could improve the quality of RMS through aggregates by promoting the process of soil formation, and ryegrass root growth conducive to organic carbon accumulation. [ABSTRACT FROM AUTHOR]

Aims: Incorporation of flower strips is an agricultural measure to increase aboveground biodiversity and ecosystem services. Although soil communities are key components of terrestrial biodiversity and drive important ecosystem services, their abundance, diversity, and composition in flower strips remain largely unexplored. Here, we shed light on earthworms and soil microorganisms in flower strips. Methods: We sowed a grassy field margin vegetation as well as two annual and two perennial flower strip mixtures in fully randomized plots of 9 × 28 m in three different types of soil in Germany. Two years following sowing, we determined earthworm communities using chemical extraction and investigated the soil microbiome using real-time PCR (archaea, bacteria, fungi, and soil-N-cycling genes) and amplicon sequencing (bacteria and fungi). Results: Different plant mixtures (i.e. field margin, annual and perennial flower strips) harbored distinct earthworm and soil microbial communities. Earthworm density and biomass declined or remained unaffected in annual flower strips but increased in perennial flower strips as compared to the field margins. Arbuscular mycorrhizal fungi showed greater diversity and relative abundance in non-tilled (i.e. field margin and perennial flower strips) than in tilled plant mixtures (i.e. annual flower strips). Conclusions: We attribute changes in earthworm and microbial communities mainly to the effect of tillage and plant diversity. Overall, we suggest that perennial flower strips serve as refugia. Future studies should compare soil biota in perennial flower strips to those in adjacent fields and investigate whether the promotion of soil communities extends into adjacent fields ('spillover'). [ABSTRACT FROM AUTHOR]

Summary: Plants interact with arbuscular mycorrhizal fungi (AMF) and in doing so, change transcript levels of many miRNAs and their targets. However, the identity of an Argonaute (AGO) that modulates this interaction remains unknown, including in Nicotiana attenuata.We examined how the silencing of NaAGO1/2/4/7/and 10 by RNAi influenced plant‐competitive ability under low‐P conditions when they interact with AMF. Furthermore, the roles of seven miRNAs, predicted to regulate signaling and phosphate homeostasis, were evaluated by transient overexpression.Only NaAGO7 silencing by RNAi (irAGO7) significantly reduced the competitive ability under P‐limited conditions, without changes in leaf or root development, or juvenile‐to‐adult phase transitions. In plants growing competitively in the glasshouse, irAGO7 roots were over‐colonized with AMF, but they accumulated significantly less phosphate and the expression of their AMF‐specific transporters was deregulated. Furthermore, the AMF‐induced miRNA levels were inversely regulated with the abundance of their target transcripts. miRNA overexpression consistently decreased plant fitness, with four of seven‐tested miRNAs reducing mycorrhization rates, and two increasing mycorrhization rates. Overexpression of Na‐miR473 and Na‐miRNA‐PN59 downregulated targets in GA, ethylene, and fatty acid metabolism pathways.We infer that AGO7 optimizes competitive ability and colonization by regulating miRNA levels and signaling pathways during a plant's interaction with AMF. [ABSTRACT FROM AUTHOR]

Mountain ranges have been previously suggested to act as natural barriers to plant invasion due to extreme environmental conditions. However, how arbuscular mycorrhizal fungi (AMF) affect invasion into these systems has been less explored. Here, we investigated how changes in AMF communities affect the performance of Galinsoga quadriradiata in mountain ranges. We performed a greenhouse experiment to study the impact of inoculations of AMF from different elevations on the performance and reproduction of invaders and how competition with native plants changes the effects of invader–AMF interactions. We found strong evidence for a nuanced role of AMF associations in the invasion trajectory of G. quadriradiata, with facilitative effects at low elevations and inhibitory effects at high elevations. Galinsoga quadriradiata performed best when grown with inoculum collected from the same elevation but performed worst when grown with inoculum collected from beyond its currently invaded range, suggesting that AMF communities can help deter invasion at high elevations. Finally, the invasive plants grown alone experienced negative effects from AMF, while those grown in competition experienced positive effects, regardless of the AMF source. This suggests that G. quadriradiata lowers its partnerships with AMF in stressful environments unless native plants are present, in which case it overpowers native plants to obtain AMF support during invasion. Finally, our results indicate that invader–AMF interactions can inhibit invasive range expansion at high elevations, and biotic interactions, in addition to harsh environmental conditions, make high-elevation mountain ranges natural barriers against continued invasion. [ABSTRACT FROM AUTHOR]

Soil salinization is detrimental to crop growth, agricultural yields, and environmental protection. Echinochloa frumentacea (Roxb.) Link is a pioneer species for the alteration of saline–alkali lands. In this paper, we examined the effects of intercropping between E. frumentacea and leguminous forages on saline land improvement in the saline–alkali soil of the Hetao-Ningxia Plain, China. We found that intercropping increased the diversity and richness of the arbuscular mycorrhizal fungi (AMF) community in the rhizosphere soil of E. frumentacea. Glomus was the dominant genus in the saline–alkali soil of the Hetao-Ningxia Plain, where Glomeraceae, VTX00067, VTX000193, and VTX000165 were the dominant species. Intercropping improved the activities of soil urease, sucrase, alkaline phosphatase, and catalase. The hay yields of E. frumentacea were correlated positively with soil enzyme activities, Chao1 index, and ACE index, and negatively with total water-soluble salt content. Together, intercropping between E. frumentacea and leguminous forages enhances AMF diversity and soil enzyme activities, which provides an agricultural practice for improving sustainability of the agro-ecosystem in saline–alkali areas. [ABSTRACT FROM AUTHOR]

Date palm, an important crop in Morocco and many other arid regions around the world, faces significant challenges from wind, water shortages, and salinization, which contribute to vegetation loss and soil degradation in the harsh environmental conditions of oasis ecosystems with low soil fertility. Protecting and regenerating these degraded lands is crucial for sustainable agriculture and improving the dryland ecosystem. Arbuscular mycorrhizal fungi (AMF) comprise a vital element in this dynamic within the microflora of the soil rhizosphere. This study evaluated the potential in mycorrhizal soil and identified AMF in date palm rhizospheres in eight locations within the Figuig oasis (southeastern Morocco). This study found that Extension and Zenaga had more mycorrhizal propagules than other locations. Replanted maize (Zea mays L.) in these soils exhibited higher mycorrhization rates (91–93%) compared to that in other locations, with the Lamaiz site registering the lowest rate (39%). The phosphorus content was negatively correlated with the AMF spore frequency, intensity, and density, while a positive correlation was detected between the soil pH and the AMF spore frequency and density. The morphological identification of spores revealed Glomus as the predominant species, along with Acaulospora and Sclerocystis. This study represents an initial step toward the potential application of these fungi in environmental conservation and sustainable agriculture in arid regions. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) have been presumed to ameliorate crop tolerance to drought. Here, we review the role of AMF in maintaining water supply to plants from drying soils and the underlying biophysical mechanisms. We used a soil–plant hydraulic model to illustrate the impact of several AMF mechanisms on plant responses to edaphic drought. The AMF enhance the soil's capability to transport water and extend the effective root length, thereby attenuating the drop in matric potential at the root surface during soil drying. The synthesized evidence and the corresponding simulations demonstrate that symbiosis with AMF postpones the stress onset limit, which is defined as the disproportionality between transpiration rates and leaf water potentials, during soil drying. The symbiosis can thus help crops survive extended intervals of limited water availability. We also provide our perspective on future research needs and call for reconciling the dynamic changes in soil and root hydraulics in order to better understand the role of AMF in plant water relations in the face of climate changes. [ABSTRACT FROM AUTHOR]

Over the last few decades, argan trees (Argania spinosa L.) skeels have faced harsh ecological conditions and anthropogenic pressure, leading to a dramatic decline in surface and density of cultivation. Nowadays, most techniques used to regenerate argan trees have failed. Arbuscular mycorrhizal fungi (AMF) are root symbionts that increase plant resistance to biotic and abiotic stresses during transplantation. The exploration of these symbiotic fungi from different soils of argan stands is the starting point for the selection and production of high-performance organisms adapted to the reforestation sites. The objective of this study is to investigate the composition of the AMF community associated with the argan tree rhizosphere. Forty adult argan trees were sampled in eight forest sites representative of the distribution and genetic diversity of argan forest stands. Five sub-samples of rhizospheric soil were taken around each tree. Our results revealed the presence of different AMF structures (i.e., hyphae, vesicles/and arbuscules) in root samples. Based on morphological characterization, six genera of AMF spores were identified with a dominance of the genera Septoglomus (34%). In addition, soil organic matter and phosphorus concentrations showed a highly significant correlation with AMF spore density. The chi-square test showed a highly significant dependence of the distribution of genera on the site conditions of forest stands. These AMF could be tested and used during the inoculation of argan seedlings in forest nurseries for the success of restoration and reforestation programs, as well as for the development and sustainable improvement of this agroforestry system. [ABSTRACT FROM AUTHOR]

Summary: Fungi are crucial for soil organic carbon (SOC) formation, especially for the more persistent mineral‐associated organic C (MAOC) pool. Yet, evidence for this often overlooks arbuscular mycorrhizal fungi (AMF) communities and how their composition and traits impact SOC accumulation.We grew sudangrass with AMF communities representing different traits conserved at the family level: competitors, from the Gigasporaceae family; ruderals, from the Glomeraceae family; or both families combined. We labeled sudangrass with 13C‐CO2 to assess AMF contributions to SOC, impacts on SOC priming, and fungal biomass persistence in MAOC.Single‐family AMF communities decreased total SOC by 13.8%, likely due to fungal priming. Despite net SOC losses, all AMF communities contributed fungal C to soil but only the Glomeraceae community initially contributed to MAOC. After a month of decomposition, both the Glomeraceae and mixed‐family communities contributed to MAOC formation. Plant phosphorus uptake, but not hyphal chemistry, was positively related to AMF soil C and MAOC accumulation.Arbuscular mycorrhizal fungi contribution to MAOC is dependent on the specific traits of the AMF community and related to phosphorus uptake. These findings provide insight into how variations in AMF community composition and traits, and thus processes like environmental filtering of AMF, may impact SOC accumulation. [ABSTRACT FROM AUTHOR]

Summary: Plant root systems rely on a functionally diverse range of arbuscular mycorrhizal fungi to, among other benefits, extend their nutrient foraging. Extended nutrient foraging is likely of greatest importance to coarse‐rooted plants, yet few studies have examined the link between root traits and arbuscular mycorrhizal fungal community composition. Here, we examine the relationship between root diameter and the composition of arbuscular mycorrhizal fungal communities in a range of native and exotic plant species.We characterized the arbuscular mycorrhizal fungal communities of 30 co‐occurring native and exotic montane grassland/shrubland plant species in New Zealand.We found that plant root diameter and native/exotic status both strongly correlated with arbuscular mycorrhizal fungal community composition. Coarse‐rooted plants had a lower diversity of mycorrhizal fungi compared with fine‐rooted plants and associated less with generalist fungal partners. Exotic plants had a lower diversity of fungi and fewer associations with nondominant families of arbuscular mycorrhizal fungi compared with native plants.These observational patterns suggest that plants may differentially associate with fungal partners based on their root traits, with coarse‐rooted plants being more specific in their associations. Furthermore, exotic plants may associate with dominant arbuscular mycorrhizal fungal taxa as a strategy in invasion. [ABSTRACT FROM AUTHOR]

In soil, arbuscular mycorrhizal fungi (AMF) meet the roots of both host and presumed nonhost plants, but the interactional mechanisms of AMF with and functional relevance for nonhost plants is little known. Here we show AMF can colonize an individually grown nonhost plant, Arabidopsis thaliana, and suppress the growth of Arabidopsis and two nonhost Brassica crops. This inhibitory effect increased with increasing AMF inoculum density, and was independent of AMF species or nutrient availability. 13C isotope labeling and physiological analyses revealed no significant carbon‒phosphorus exchange between Arabidopsis and AMF, indicating a lack of nutritional function in this interaction. AMF colonization activated the danger‐associated peptide Pep‐PEPR signaling pathway, and caused clear defense responses in Arabidopsis. The impairment of Pep‐PEPR signaling in nonhost plants greatly compromised AMF‐triggered defensive responses and photosynthesis suppression, leading to higher colonization rates and reduced growth suppression upon AMF inoculation. Pretreatment with Pep peptide decreased AMF colonization, and largely substituted for AMF‐induced growth suppression in nonhosts, confirming that the Pep‐PEPR pathway is a key participant in resistance to AMF colonization and in mediating growth suppression of nonhost plants. This work greatly increases our knowledge about the functional relevance of AMF and their mechanisms of interactions with nonhost plants. Summary Statement: There is no significant carbon and phosphorus exchange between AMF and colonized nonhost plant Arabidopsis thaliana. AMF activated the danger‐associated peptide Pep‐PEPR signaling pathway, which acted as a key participant in resistance to AMF colonization and in mediating growth suppression of nonhost plants. [ABSTRACT FROM AUTHOR]

Twisted disease is one of the problems in shallot cultivation. The application of the biological agents Bacillus velezensis and arbuscular mycorrhizal fungi is an alternative to overcome disease problems in shallot plantings. The purpose of this study was to determine the effect of the application of B. velezensis and Arbuscular Mycorrhizal Fungi on the growth and health of shallot. The research was conducted in Gotakan, Panjatan, Kulon Progo, and the Phytopathology Laboratory, Department of Plant Protection, Faculty of Agriculture, Universitas Gadjah Mada, Yogyakarta. Shallot treatments with the application of biological agents were carried out either individually by soaking the bulbs in B. velezensis suspension before planting, coating the bulbs using Arbuscular Mycorrhizal Fungus (Rhizophagus intraradices) with a carrier medium of kaolin flour before planting, and a combination of spraying the B. velezensis suspension on plants at two-week intervals during the growth period and coating the bulbs before planting with R. intraradices. The results of the study showed that the shallot-applied single application of B. velezensis reduced the intensity and incidence of twisted disease by 2.51% and 37.6%, respectively. The combination treatment of B. velezensis and R. intraradices was able to increase the resistance of bulbs to postharvest pathogen Fusarium solani infection, with infected bulbs and areas of 0.70% and 0.71 cm², respectively. [ABSTRACT FROM AUTHOR]

Symbiotic microorganisms such as arbuscular mycorrhizal fungi (AMF) and rhizobia (Rh) both promote host plant N acquisition, but whether and how the combination affects host plant nitrogen (N) assimilation remains unclear. To clarify the role of AMF and rhizobia on N assimilation in white clover (Trifolium repens), the effect of single or combined inoculation with an arbuscular mycorrhizal fungus Paraglomus occultum and a rhizobium Rhizobium trifolii on plant growth, photosynthesis, leaf N and amino acid contents, and the activities of N assimilation-related enzymes were analyzed in white clover under potted conditions. The results obtained were as follows: (1) The plant height, stolon length, leaf number, shoot biomass, total biomass, chlorophyll b and total chlorophyll contents, steady-state light quantum efficiency, and leaf N contents of white clover were significantly increased by single inoculation with Paraglomus occultum, single Rhizobium trifolii, and combined inoculations of Paraglomus occultum and Rhizobium trifolii, along with the order of combined inoculations of Paraglomus occultum and Rhizobium trifolii > single Paraglomus occultum > single Rhizobium trifolii > non-inoculation control. (2) Combined inoculations of Paraglomus occultum and Rhizobium trifolii significantly increased the contents of various amino acids including alanine, arginine, asparagine, aspartate, glutamine, glutamic acid and histidine in leaves of white clover, and distinctly improved the activities of nitroreductase, nitrite reductase, glutamine synthetase, glutamate synthetase, glutamate dehydrogenase, asparagine synthetase, and aspartate aminotransferase. In addition, the introduction of Rhizobium trifolii significantly promoted the colonization of Paraglomus occultum to roots of white clover, suggesting the partnership between the two. Therefore, it is concluded that combined inoculations of AMF and rhizobia promote N assimilation, generate more amino acids, and further promote the growth of white clover by activating the activities of N assimilation-related enzymes. It is further demonstrated that AMF and rhizobia have synergistic effects on promoting N assimilation of white clover. [ABSTRACT FROM AUTHOR]

Purpose The reuse of treated wastewater (TWW) in agriculture may affect the growth of plants. The goal of this study is to investigate the potential use of TWW in irrigating Lily in presence of Arbuscular Mycorrhizal Fungi (AMF) in a closed soilless system. Method In the first experiment, plants were irrigated with a mixture of 3 part nutrient solution: 1 part treated wastewater (3NS:1TWW) supplemented with 50, 125, 160 or 200 mg L-1 Ca to determine the optimal Ca concentration supplement that would give the highest plant growth. In the second experiment, the plants were irrigated with a nutrient solution or a mixture of 3 part nutrient solution: 1part treated wastewater (3NS:1TWW) supplemented with 160 mg L-1 Ca in the presence or absence of AMF. Results The results indicated that the plants receiving the higher concentrations of Ca (160 or 200 mg L-1) showed better growth performance. The results showed that the plants receiving (3NS:1TWW) had a significantly higher dry weight of adventitious roots and fresh weight of the flower bud than those receiving nutrient solution. The flower bud was longer in presence of AMF. The highest shoot fresh weight was recorded for non-AMF plants receiving 3NS:1TWW, and the least shoot fresh weight. Conclusion The most efficient solution is to supplement the 3NS:1TWW irrigation solution with 160 mg Ca L-1 to reduce the salinity effects of TWW. Moreover, it is recommended to inoculate the roots of the Asiatic lily plants with AMF to achieve the longest flower. [ABSTRACT FROM AUTHOR]

Multiple facets of cutting-edge mycorrhizal research: 11th International Conference on Mycorrhiza (ICOM 11), Beijing, China, 1-5 August 2022 AM, arbuscular mycorrhizal; EM, ectomycorrhizal. gl Mycorrhizas and global change ICOM 11 facilitated an interesting discussion on how mycorrhizal fungi are affected by and respond to global change. Interestingly, almost all non-AM forming plants that specifically retain a portion of this gene set have been shown to host other kinds of intracellular symbioses such as intracellular bacteria, orchid mycorrhizas, or ericoid-like mycorrhizas (Radhakrishnan I et al i ., [8]). Keywords: 11th International Conference on Mycorrhiza (ICOM 11); arbuscular mycorrhizal fungi (AMF); ectomycorrhizal fungi (EMF); global change; hyphosphere; Meeting report; mycorrhizas EN 11th International Conference on Mycorrhiza (ICOM 11) arbuscular mycorrhizal fungi (AMF) ectomycorrhizal fungi (EMF) global change hyphosphere Meeting report mycorrhizas 1771 1774 4 05/02/23 20230601 NES 230601 Mycorrhizal fungi form mutualistic relationships with most plants on Earth (Steidinger I et al i ., [13]) and play key roles in plant health and development. [Extracted from the article]

Arbuscular mycorrhizal fungi (AMF) are effective natural alternatives to assist plants in improving crop productivity and immunity against pests and diseases. However, a comprehensive idea of the variables under which they show optimum activity, especially concerning particular soil, climate, geography, and crop characteristics, has yet to be adequately standardized. Since paddy is the staple food for half of the world's population, such standardization is highly significant globally. Research concerning determinants affecting AMF functioning in rice is limited. However, the identified variables include external variables such as abiotic, biotic, and anthropogenic factors and internal variables such as plant and AMF characteristics. Among the abiotic factors, edaphic factors like soil pH, phosphorus availability, and soil moisture significantly affect AMF functioning in rice. In addition, anthropogenic influences such as land use patterns, flooding, and fertilizer regimes also affect AMF communities in rice agroecosystems. The principal objective of the review was to analyse the existing literature on AMF concerning such variables generally and to assess the specific research requirements on variables affecting AMF in rice. The ultimate goal is to identify research gaps for applying AMF as a natural alternative in the sustainable agriculture of paddy with optimum AMF symbiosis enhancing rice productivity. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) symbiosis has been shown to improve the ability to obtain nutrients and resist adverse environmental conditions. However, there are few studies on the functions of AMF in the absorption and accumulation of boron (B). Moreover, it is still unclear whether the root colonization rates of AMF are limited by B deficiency. In this study, Camellia oleifera seedlings were planted in normal and boron-deficient substrates, and the seedlings were inoculated with Funneliformis mosseae or left uninoculated. The growth and physiological indices of C. oleifera seedlings were determined. The results of this experiment indicate that AMF inoculation increased the plant biomass, B content, B accumulation, and antioxidant enzyme activity in both normal and boron-deficient C. oleifera seedlings. Furthermore, boron deficiency resulted in a decrease in the AMF root colonization efficiency and the inhibition of C. oleifera seedlings' growth and physiological activity. These findings suggest that AMF inoculation could improve the resistance to B-deficiency stress. Additionally, the colonization efficiency of AMF was adversely affected by B deficiency; thus, AMF play a cooperative role with B in the growth and physiological functions of plants. The results provide a theoretical basis for taking measures to solve B-deficiency stress in C. oleifera and other plants' cultivation. [ABSTRACT FROM AUTHOR]

In farmland ecosystems, phosphorus and water have crucial roles. To elucidate the effects of phosphorus concentration and water management on arbuscular mycorrhizal fungi (AMF), field experiments were conducted in a farmland ecosystem (China). We examined the effects of different treatments, including drought and normal phosphorus, normal water and normal phosphorus, drought and low phosphorus, and normal water and low phosphorus, on the AM fungal biomass, diversity, and community. Results showed great differences in the AMF under different water and phosphorus concentrations. When under a suitable drought treatment, the AMF became more abundant and more conducive to plant growth. The abundance of AMF varied with different phosphorus treatments, and the abundance of AMF in low-phosphorus treatments was higher, which is more suitable for plant growth. In conclusion, as water and phosphorus concentrations change, the community structure of AMF constantly changes. Only under the appropriate water and phosphorus concentration processing can AMF play its role well. Understanding the influence of different phosphorus concentrations and the moisture contents of AMF can play a role in the agricultural production of AMF, and it can also provide improved theoretical support. [ABSTRACT FROM AUTHOR]

Two concurrent nursery experiments were conducted following a randomized complete block design (RCBD) aimed at screening the effectiveness of arbuscular mycorrhizal fungi (AMF) and nitrogenfixing bacteria (NFB) in promoting growth and survival of narra seedlings grown in Ni and Au mined-out soils. Seedlings were inoculated with either MYKORICH®, MYKOVAM®, newMycorrhiza (newMYC), newNitrogen-fixing bacteria (newNFB) and combined newMYC and newNFB or not inoculated (control). Narra seedlings were inoculated with uniform amounts of microbial biofertilizers and were grown for a month to ensure root infection. After 30 days, the uninoculated (control) and inoculated seedlings were transferred into polybags filled with mined-out soils mixed with compost (1:1; v%/v%) and were applied with 10 g complete (14:14:14NPK) fertilizer per seedling. After six months of observation, results demonstrated notable and significant effects to the incremental growth in height, stem diameter, plant dry weight and root-to-shoot ratio of narra seedlings in response to the applied microbial biofertilizers. MYKORICH®, newMYC, newNFB and the combined newMYC and newNFB are recommended microbial biofertilizers for narra seedlings used for rehabilitating Ni and Au mined-out sites. Furthermore, combined newMYC + newNFB and MYKORICH® yielded the highest quality seedling index while MYKORICH® gave the highest biovolume index, for seedlings grown in both Ni and Au mined-out soils. The assumption that adding NFB to the already NFBloving narra species enhances its capability to absorb more nutrients and adapt in heavy metal contaminated soils was proven in this study which makes it a potential host-plant in the bioremediation and rehabilitation of Ni and Au mined-out areas in Claver and Placer (Surigao del Norte), respectively. [ABSTRACT FROM AUTHOR]

Remediation of mercury (Hg)-contaminated soil by mycorrhizal technology has drawn increasing attention because of its environmental friendliness. However, the lack of systematic investigations on arbuscular mycorrhizal fungi (AMF) community composition in Hg-polluted soil is an obstacle for AMF biotechnological applications. In this study, the AMF communities within rhizosphere soils from seven sites from three typical Hg mining areas were sequenced using an Illumina MiSeq platform. A total of 297 AMF operational taxonomic units (OTUs) were detected in the Hg mining area, of which Glomeraceae was the dominant family (66.96%, 175 OTUs). AMF diversity was significantly associated with soil total Hg content and water content in the Hg mining area. Soil total Hg showed a negative correlation with AMF richness and diversity. In addition, the soil properties including total nitrogen, available nitrogen, total potassium, total phosphorus, available phosphorus, and pH also affected AMF diversity. Paraglomeraceae was found to be negatively correlated to Hg stress. The wide distribution of Glomeraceae in Hg-contaminated soil makes it a potential candidate for mycorrhizal remediation. [ABSTRACT FROM AUTHOR]

Mycorrhizal fungi can increase the effectiveness of a mineral fertilizer top dressing, positively affecting sweet pepper yield and quality. For this reason, an experiment was carried out between 2014 and 2016 to study the effect of top dressing doses and the inoculation of the root system with mycorrhizal fungi on the growth and yield of sweet pepper and the content of nutrients and macro- and microelements in the fruits. Root inoculation with Arbuscular Mycorrhizal Fungi (AMF) and mineral fertilizer doses were used as experimental factors with the following combinations: (1) mycorrhization: control (without AMF); AMF applied to the plant root zone during seedling production; AMF applied to the plant root zone after seedlings were transferred to pots; (2) top dressing doses: basic dose (100%); 50% of the basic dose; 25% of the basic dose. The sweet pepper fruits were harvested during physiological maturity. AMF inoculation of the root zone resulted in high sweet pepper yields of good quality. In particular, mycorrhizal fungi applied to the root system during seedling production positively affected the pepper yield and biometric characteristics, with fruits of the thickest pericarp and the largest mass. In the experimental units with AMF, the reduction in the top dressing fertilizer dose by 50% and 75% did not cause a statistically significant decrease in the yield of peppers and did not result in a deterioration of the biometric characteristics of the plants and fruits or a reduction in the biological value of the fruits. Despite the reduction in top dressing dose by 50% and 75%, AMF contributed to the accumulation of similar amounts of phosphorus in the sweet pepper fruits. The top dressing dose of 50% applied during seedling production to the experimental units with mycorrhizal fungi resulted in a significant increase in the content of potassium, calcium, and magnesium. A significant increase in the amount of sodium in the fruits was noted in the experimental units with mycorrhizal fungi applied to the roots when the seedlings were transferred to pots. To summarize, the application of mycorrhizal fungi to the pepper root zone during seedling production is recommended because it has a positive effect on the yield and its quality. In the unit with mycorrhiza, a lower dose of mineral fertilizers did not result in a significant decrease in the yield of pepper fruits. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) can form symbiosis with many plants and the effect of AMF on phytoremediation of heavy metal has been a hot topic. But the effects of AMF on pollutants and microbes in rhizosphere and non-rhizosphere soil are still scarce. Therefore, the effects of AMF on plant growth, Pb translocation, and bacteria community in rhizosphere and non-rhizosphere soils spiked with Pb were investigated. It was found that AMF could significantly increase the uptake of Pb by Paspalum notatum, and Pb content was about 11 to 197 times higher in the root than that in the leaves. Besides, concentration of soil exchangeable Pb was significantly reduced after plant cultivation, and application of AMF increased the reduction (the exchangeable Pb concentrations of Pb300M and Pb3000M in the rhizosphere were 26.3% and 23.6% lower than that of Pb300 and Pb3000, respectively). The reduction was generally higher in the rhizosphere soil than that in the non-rhizosphere soil. The amount of Pb uptake by plants only accounted for a small part (4.9–21.7%) of the soil decreased exchangeable Pb, irrespective of AMF application, and most of the original exchangeable Pb was transformed into stabilized forms. Although bacteria community exhibited some differences between rhizosphere and non-rhizosphere soils, PCoA analysis indicated that both AMF and Pb were stronger impact factors affecting the beta-diversity of soil bacteria community than rhizosphere. The results of this study can help to clarify the impacts of AMF on phytoremediation of heavy metal. [ABSTRACT FROM AUTHOR]

A pot experiment was performed to investigate the effect of phytoremediation (CK, using tall fescue), fungi remediation (GV, using Glomus versiforme), bacterial remediation (PS, using Pseudomonas fluorescens Ps2-6), and microbial-phytoremediation (GVPS, using three species) on removing polycyclic aromatic hydrocarbons (PAHs) and the microbial diversity in soils. Inoculation with G. versiforme and P. fluorescens could increase the biomass of tall fescue and the accumulation of phenanthrene (PHE) and pyrene (PYR) in plants. Among them, the highest PHE and PYR removal efficiencies and highest biomass of tall fescue were observed in the GVPS treatment and the microbial diversity in contaminated soil was changed, the result revealed that Proteobacteria and Ascomycota were the dominant bacterial phylum and fungal phylum in all treatments, while more Proteobacteria were detected in GVPS treatment. At the genus level, the abundance of Sphingomonas (3.17%), Pseudomonas (2.05%), and Fusarium (8.65%) treated with GVPS increased compared with other treatments. These pieces of evidence contribute to a better understanding of the mechanisms involved in the combined microbial-phytoremediation strategies for PAHs-contaminated soils, especially the effects of microbial-phytoremediation on rhizosphere microbial diversity. Inoculation with G. versiforme and P. fluorescens could increase PHE and PYR removal efficiencies, the biomass of tall fescue, microbial diversity, and the abundance of Proteobacteria, Sphingomonas, Pseudomonas, and Fusarium in (PHE + PYR)-contaminated soils. [ABSTRACT FROM AUTHOR]

The biogeographic region of Argentinean Puna mainly extends at elevations higher than 3,000 m within the Andean Plateau and hosts diverse ecological communities highly adapted to extreme aridity and low temperatures. Soils of Puna are typically poorly evolved and geomorphology is shaped by drainage networks, resulting in highly vegetated endorheic basins and hypersaline basins known as salar or salt flats. Local communities rely on soil fertility for agricultural practices and on pastures for livestock rearing. From this perspective, investigating the scarcely explored microbiological diversity of these soils as indicators of ecosystems functioning might help to predict the fragility of these harsh environments. In this study we collected soil samples from 28 points, following a nested design within three different macrohabitats, i.e., Puna grassland, hypersaline salar and family-run crop fields. Total fungi and arbuscular mycorrhizal fungi (AMF) occurrence were analyzed using eDNA sequencing. In addition, the significance of soil salinity and organic matter content as significant predictors of AMF occurrence, was assessed through Generalized Linear Mixed Modeling. We also investigated whether intensive grazing by cattle and lama in Puna grasslands may reduce the presence of AMF in these highly disturbed soils, driving or not major ecological changes, but no consistent results were found, suggesting that more specific experiments and further investigations may address the question more specifically. Finally, to predict the suitability for AMF in the different macro-habitats, Species Distribution Modeling (SDM) was performed within an environmental coherent area comprising both the phytogeographic regions of Puna and Altoandino. We modeled AMF distribution with a maximum entropy approach, including bioclimatic and edaphic predictors and obtaining maps of environmental suitability for AMF within the predicted areas. To assess the impact of farming on AMF occurrence, we set a new series of models excluding the cultivated Chaupi Rodeo samples. Overall, SDM predicted a lower suitability for AMF in hypersaline salar areas, while grassland habitats and a wider temperature seasonality range appear to be factors significantly related to AMF enrichment, suggesting a main role of seasonal dynamics in shaping AMF communities. The highest abundance of AMF was observed in Vicia faba crop fields, while potato fields yielded a very low AMF occurrence. The models excluding the cultivated Chaupi Rodeo samples highlighted that if these cultivated areas had theoretically remained unmanaged habitats of Puna and Altoandino, then large-scale soil features and local bioclimatic constraints would likely support a lower suitability for AMF. Using SDM we evidenced the influence of bioclimatic, edaphic and anthropic predictors in shaping AMF occurrence and highlighted the relevance of considering human activities to accurately predict AMF distribution. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Arbuscular mycorrhizal fungi (AMF) are known to improve plant stress tolerance by regulating proline accumulation, and nitric oxide (NO) plays an important signaling role in proline metabolism. Environmental nitrogen (N) affects AMF colonization and its contribution to host plants resistance to stress conditions. However, the relationship between proline metabolism and NO in mycorrhizal rice and the effect of N application on symbiont proline metabolism under low temperature have not been established. Pot culture experiments with different temperature, N and exogenous NO donor treatments were conducted with non-mycorrhizal and mycorrhizal rice. The results showed that AMF enhanced rice proline accumulation under lowtemperature stress and decreased glutamate (Glu) and ornithine (Orn) concentrations significantly. In comparison with non-mycorrhizal rice, AMF colonization significantly decreased the Glu concentration, but had little effect on the Orn concentration under low-temperature stress, accompanied by increasing expression of OsP5CS2, OsOAT and OsProDH1. Exogenous application of NO increased proline concentration both under normal and low temperature, which exhibited a higher increase in mycorrhizal rice. NO also triggered the expression of key genes in the Glu and Orn pathways of proline synthesis as well as proline degradation. Higher N application decreased the AMF colonization, and AMF showed greater promotion of proline metabolism at low N levels under low temperature stress by regulating the Glu synthetic pathway. Meanwhile, AMF increased rice nitrate reductase (NR) and nitric oxide synthase (NOS) activities and then enhanced NO accumulation under low N levels. Consequently, it could be hypothesized that one of the mechanisms by which AMF improves plant resistance to low-temperature stress is the accumulation of proline via enhancement of the Glu and Orn synthetic pathways, with the involvement of the signaling molecule NO. However, the contribution of AMF to rice proline accumulation under low-temperature stress was attenuated by high N application. [ABSTRACT FROM AUTHOR]

Hormonal regulation and symbiotic relationships provide benefits for plants to overcome stress conditions. The aim of this study was to elucidate the effects of arbuscular mycorrhizal fungal (AMF) inoculum, methyl jasmonate (MeJA), and saline-alkali effects on the growth and physiology of tall fescue (Festuca elata "Crossfire II"). Treatments included AMF-inoculation, and non-AMF inoculation, four MeJA application concentrations (0, 50, 100, and 200 mg/L), and two saline-alkali levels (0 and 200 mmol/L). The results showed that AMF inoculation significantly enhanced saline-alkali resistance of the plants, and the beneficial effects were increased by MeJA at a concentration of 50 mg/L (50 MeJA) and decreased by MeJA at a concentration both of 100 (100 MeJA) and 200 mg/L (200 MeJA). AMF inoculation plants when treated with 50 MeJA accumulated significantly more biomass, had greater proline and total phenolic concentration, and lower malondialdehyde (MDA) concentration than plants only treated either with AMF or 50 MeJA. However, no significant differences in growth or physiological characteristics were observed between AMF and non-AMF plants when treated either with 100 or 200 MeJA. All of these results suggest that the interaction between a certain concentration of MeJA and AMF can significantly increase saline-alkali resistance of the tall fescue by regulating the biomass, proline, total phenolic, and MDA. Our findings provide new information on the effect of biological and chemical priming treatments on plant performance under saline-alkali stress. [ABSTRACT FROM AUTHOR]

The use of microbial biostimulants such as plant growth-promoting rhizobacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) has gained popularity in recent years as a sustainable approach to boost yield as well as the quality of produce. The beneficial effects of microbial biostimulants have been reported numerous times. However, information is missing concerning quantitative assessment of the overall impact of microbial biostimulants on the yield and quality of vegetable crops. Here we provide for the first time a comprehensive, semi-systematic review of the effects of microbial biostimulants allowed by Regulation (EU) 2019/1009, including microorganisms belonging to the AMF (phylum Glomeromycota), or to Azospirillum, Azotobacter and Rhizobium genera, on vegetable crops' quality and yield, with rigorous inclusion and exclusion criteria based on the PRISMA method. We identified, selected and critically evaluated all the relevant research studies from 2010 onward in order to provide a critical appraisal of the most recent findings related to these EU-allowed microbial biostimulants and their effects on vegetable crops' quality and yield. Moreover, we highlighted which vegetable crops received more beneficial effects from specific microbial biostimulants and the protocols employed for plant inoculation. Our study is intended to draw more attention from the scientific community to this important instrument to produce nutrient-dense vegetables in a sustainable manner. Finally, our semi-systematic review provides important microbial biostimulant application guidelines and gives extension specialists and vegetable growers insights into achieving an additional benefit from microbial biostimulant application. [ABSTRACT FROM AUTHOR]