Arbuscular Mycorrhizal Fungi Species Research Articles

Quantification of Arbuscular Mycorrhizal Fungi Colonization Rate in the Study of Invasive Alien Plants.

Arbuscular mycorrhizal fungi (AMF) are widely distributed soil fungi in ecosystems and can form symbiotic associations (mycorrhizae) with the roots of most terrestrial plants. Plants provide carbon sources to AMF through mycorrhizal associations, while AMF hyphae can expand the range of nutrient absorption by roots and promote plant nutrient uptake. There are many different species of AMF, and the symbiotic relationships between different species of AMF and different plants vary. Invasive plants can enrich AMF species with better symbiotic capabilities through root exudates, promoting their growth and thereby increasing their colonization in invasive plant roots. At the same time, invasive plants can also disrupt the symbiotic relationship between AMF and native plants, affecting the local plant community, which is one of the mechanisms for successful plant invasion. The colonization rate of AMF in the roots of invasive and native plants indirectly reflects the role of AMF in the process of invasive plant invasion. In this method, collected plant roots can be processed directly or saved in a fixative for later batch processing. Through decolorization, acidification, staining, and destaining treatment of roots, the hyphae, spores, and arbuscular structures of AMF in the root system can be clearly observed. This method can be completed in a basic laboratory to observe and calculate the colonization rate of AMF in the root systems of invasive plants.

Rhizoglomus variabile and Nanoglomus plukenetiae, Native to Peru, Promote Coffee Growth in Western Amazonia.

Coffee (Coffea arabica) is among the world's most economically important crops. Coffee was shown to be highly dependent on arbuscular mycorrhizal fungi (AMF) in traditionally managed coffee plantations in the tropics. The objective of this study was to assess AMF species richness in coffee plantations of four provinces in Perú, to isolate AMF isolates native to these provinces, and to test the effects of selected indigenous AMF strains on coffee growth. AMF species were identified by morphological tools on the genus level, and if possible further to the species level. Two native species, Rhizoglomus variabile and Nanoglomus plukenetiae, recently described from the Peruvian mountain ranges, were successfully cultured in the greenhouse on host plants. In two independent experiments, both species were assessed for their ability to colonize coffee seedlings and improve coffee growth over 135 days. A total of 35 AMF morphospecies were identified from 12 plantations. The two inoculated species effectively colonized coffee roots, which resulted in 3.0-8.6 times higher shoot, root and total biomass, when compared to the non-mycorrhizal controls. R. variabile was superior to N. plukenetiae in all measured parameters, increasing shoot, root, and total biomass dry weight by 4.7, 8.6 and 5.5 times, respectively. The dual inoculation of both species, however, did not further improve plant growth, when compared to single-species inoculations. The colonization of coffee by either R. variabile or N. plukenetiae strongly enhances coffee plant growth. R. variabile, in particular, offers enormous potential for improving coffee establishment and productivity. Assessment of further AMF species, including species from other AMF families should be considered for optimization of coffee growth promotion, both alone and in combination with R. variabile.

Long-term N addition reduced the diversity of arbuscular mycorrhizal fungi and understory herbs of a Korean pine plantation in northern China

With the development of agriculture and industry, the increase in nitrogen (N) deposition has caused widespread concern among scientists. Although emission reduction policies have slowed N releases in Europe and North America, the threat to biodiversity cannot be ignored. Arbuscular mycorrhizal (AM) fungi play an important role in the establishment and maintenance of plant communities in forest ecosystems, and both their distribution and diversity have vital ecological functions. Therefore, we analyzed the effects of long-term N addition on AM fungi and understory herbaceous plants in a Korean pine plantation in northern China. The soil properties, community structure, and diversity of AM fungi and understory herbaceous plants were detected at different concentrations of NH4NO3 (0, 20, 40, 80 kg N ha−1 year−1) after 7 years. The results showed that long-term N deposition decreased soil pH, increased soil ammonium content, and caused significant fluctuations in P elements. N deposition improved the stability of soil aggregates by increasing the content of glomalin-related soil protein (GRSP) and changed the AM fungal community composition. The Glomus genus was more adaptable to the acidic soil treated with the highest N concentration. The species of AM fungi, understory herbaceous plants, and the biomass of fine roots were decreased under long-term N deposition. The fine root biomass was reduced by 78.6% in the highest N concentration treatment. In summary, we concluded that long-term N deposition could alter soil pH, the distribution of N, P elements, and the soil aggregate fractions, and reduce AM fungal and understory herb diversity. The importance of AM fungi in maintaining forest ecosystem diversity was verified under long-term N deposition.

Natural grass coverage enriches arbuscular mycorrhizal fungal communities in subtropical citrus orchards through the regulation of Glomus on a regional scale

Arbuscular mycorrhizal (AM) fungi are ubiquitous soil fungi in orchard ecosystem, conferring a diverse array of benefits to citrus plants. However, how natural grass coverage, a common phenomenon in citrus orchards in southern China, shifts AM fungal communities in subtropical citrus orchards is far from being understood, especially on a regional scale, which impedes the understanding of the indigenous AM fungal adaptations. In this study, natural grass coverage rate, soil chemical properties, and soil AM fungal community in 80 sampling sites spanning 179, 700 km2 area in subtropical citrus orchards were investigated. The result of 18S rRNA gene high-throughput sequencing revealed that a total of eight AM fungal genera were identified and Glomus (90.15 %) was dominant genus in the community in citrus orchards. Natural grass coverage significantly increased soil organic matter (SOM), soil available phosphorus, and AM fungal alpha diversity, especially Glomus. Variation partitioning analysis revealed that grass coverage rate explained more variation in AM fungal alpha diversity than SOM. All the contrasting AM fungal species between different grass coverage rates and all the core AM fungal species belonged to Glomus. Null model analysis revealed that determinism played a slightly larger role in the assembly process of AM fungal communities than stochasticity with a distance-decay relationship. Moreover, natural grass coverage increased the relative importance of stochasticity in the community assembly. Taken together, these results suggest that maintaining natural grass coverage (naturally growing grass) is an effective nature-based solution for enriching AM fungal communities, which is essential for the sustainability of citrus production.

Arbuscular Mycorrhizal Fungi Colonization of Jatropha curcas Roots and Its Impact on Growth and Survival under Greenhouse-Induced Hydric Stress

Arbuscular mycorrhizal fungi (AMF) provide benefits to host plants by enhancing nutrition and overall fitness. In this study, AMF species were isolated from the soil rhizosphere of Jatropha curcas and were identified and evaluated for their potential in fostering the development of Jatropha seedlings within a controlled greenhouse environment. The first experiment assessed the interplay between hydric stress and AMF inoculation on mycorrhizal colonization. The next experiment examined the impact of quercetin on mycorrhizal colonization. Out of 204 glomerospores corresponding to 28 species spanning 10 genera, Acaulospora (14) and Scutellospora (5) were the most abundant taxa. Six new records of AMF for Costa Rica are reported. Mycorrhizal colonization was observed in 43.2% of Jatropha plants (34.7% by AMF typical hyphae; arbuscules 8.9%; coils 5.6%; and vesicles 5.4%). Significant survival effects due to AMF inoculation under hydric stress were observed. On day 85, non-mycorrhizal plants subjected to hydric stress showed a mere 30% survival rate, whereas their mycorrhizal counterparts under hydric stress exhibited survival rates of 80% and 100% with and without irrigation, respectively. Furthermore, plants with irrigation and mycorrhizas showed greater hydric stress tolerance and superior growth. The inoculated plants, irrespective of irrigation, demonstrated mycorrhizal colonization rates of 63% and 72%, respectively. Quercetin did not affect Jatropha’s growth, but there were differences in AMF root colonization. In summary, these findings accentuate the viability of a native consortium in augmenting Jatropha survival, warranting consideration as a potent biofertilizer within greenhouse settings. The AMF described can be used for Jatropha propagation programs.

Arbuscular mycorrhizal fungi with contrasting life-history strategies differently affect health-promoting compounds in field-grown tomato by changing arbuscule occurrence and mycorrhizal assemblages in roots

Contrasting life-history characteristics of arbuscular mycorrhizal (AM) fungal families may have important implications for mycorrhizal functioning. Nevertheless, the effect of inoculation with AM fungi having different life-history strategies on the quality parameters of tomato fruits was not investigated. In this study, fruit and sauce quality of two tomato varieties were evaluated in field conditions after inoculation with four AM fungal species belonging to Glomeraceae and Gigasporaceae. The functional relationship between AM fungal traits (i.e., root colonization structures, community diversity) and fruit quality parameters was analyzed. AM fungal inoculation increased total phenols (TPC) and lycopene concentration in fruits of both varieties (47% and 247%, respectively) and antioxidant activity in var. Rio Grande (85%). Gigasporaceae were more effective in increasing TPC and antioxidant activity compared to Glomeraceae in var. Rio Grande. Gigaspora gigantea outperformed Scutellospora pellucida in var. Pisanello for TPC, antioxidant activity, and lycopene. Inoculated strains of G. gigantea, S. pellucida, Funneliformis mosseae, and Sclerocystis sinuosa were molecularly retrieved within tomato roots. In both varieties, a functional relationship between occurrence of arbuscules in roots and fruit quality was found. In var. Rio Grande, the abundance of some native AM fungal taxa shaped the pattern of fruit quality parameters. Gigasporaceae might be of great relevance for the synthesis of health-promoting compounds in tomato and should be included in biostimulant programmes targeting the production of high-quality vegetables.

Arbuscular Mycorrhizal Fungi Associated with Maize (Zea mays L.) in the Formation and Stability of Aggregates in Two Types of Soil.

Knowledge of native Arbuscular Mycorrhizal Fungi (AMF) and their relationship with the edaphic characteristics where they live is important to establish the influence of allochthonous AMF, which were inoculated, on the development and stability of soil aggregates. The objectives of this research were to know the composition of native AMF species from two contrasting soils, and to establish the development and stability of aggregates in those soils with corn plants after inoculating them with allochthonous AMF. The experiment had three factors: Soil (two levels [S1 and S2]), HMA (three levels: without application [A0], with the application of Claroideoglomus claroideum [A1] and with the application of a consortium [A2]) and Fertilization (two levels (without fertilization [f0] and with fertilization [f1])). Twelve treatments were generated, with five replicates (60 experimental units [EU]). The EU consisted of a pot with a corn plant and the distribution was completely random. The results demonstrated that the Typic Ustifluvent presented nine species of native AMF, while the Typic Dystrustert had three; the native AMF in each soil influenced the activity of allochthonous AMF, such as their colonization and sporulation. Likewise, differences were found in the stability of macro-sized aggregates (0.5 to 2.0 mm).

Diversity of arbuscular mycorrhizal fungi in seleniferous soils and their role in plant growth promotion.

The present study aimed to investigate the molecular diversity of arbuscular mycorrhizal fungi (AMF) in natural seleniferous soils and their role in protecting plants from Se toxicity. The genomic DNA extracted from maize roots grown in seleniferous and non-seleniferous regions was amplified using AMF-specific primers by nested PCR. The 1.5kb amplicon spanning pSSU-ITS-pLSU of 18S rRNA of AMF was deciphered using the Illumina Miseq Next Generation Sequencing (NGS) technique. A total of 17 AMF species from the seleniferous region and 18 AMF species from the non-seleniferous region were identified. The number of reads of Glomus irregularis, G. custos, and G. intraradices was higher in seleniferous soil than in non-seleniferous soil, indicating their tolerance to Se. A consortium of Se-tolerant AMF inoculum was prepared and inoculated to maize plants, grown in natural seleniferous soils. AMF-inoculated plants had healthy growth with higher root, shoot, and grain biomass than non-AMF-inoculated plants. AMF inoculation leads to higher Se accumulation in roots but lesser Se accumulation in shoots and seeds of inoculated maize plants as compared to control plants. Present study results suggest that AMF species from seleniferous soils have the potential to be used as biofertilizers to improve plant growth and tolerate Se toxicity in seleniferous soils.

Maize, wheat, and soybean root traits depend upon soil phosphorus fertility and mycorrhizal status.

Strong effects of plant identity, soil nutrient availability or mycorrhizal fungi on root traits have been well documented, but their interactive influences on root traits are still poorly understood. Here, three crop species (maize, wheat and soybean) were grown under four phosphorus (P) addition levels (0, 20, 40 and 60mg P kg-1 dry soil), and plants were inoculated with or without five combined arbuscular mycorrhizal fungal (AMF) species. Plant biomass, nutrient contents, root traits (including total root length, average root diameter, specific root length and root tissue density) and plants' mycorrhizal responses were measured. Crop species, P level, AMF, and their interactions strongly affected plant biomass and root traits. P fertilization promoted plant growth but reduced mycorrhizal benefits on plant biomass and nutrient uptake. Root traits of maize were sensitive to P addition only under the non-mycorrhizal condition, whilst most root traits of soybean and wheat plants were responsive to mycorrhizal inoculation but not P addition. Mycorrhizal colonization reduced the root plasticity in response to P fertility for maize but not for wheat or soybean. This study highlights the importance of soil nutrient fertility and mycorrhizal symbiosis in influencing root traits.

Can cardiolipins be used as a biomarker for arbuscular mycorrhizal fungi?

Specific biomarker molecules are increasingly being used for detection and quantification in plant and soil samples of arbuscular mycorrhizal (AM) fungi, an important and widespread microbial guild heavily implicated in transfers of nutrients and carbon between plants and soils and in the maintenance of soil physico-chemical properties. Yet, concerns have previously been raised as to the validity of a range of previously used approaches (e.g., microscopy, AM-specific fatty acids, sterols, glomalin-like molecules, ribosomal DNA sequences), justifying further research into novel biomarkers for AM fungal abundance and/or functioning. Here, we focused on complex polar lipids contained in pure biomass of Rhizophagus irregularis and in nonmycorrhizal and mycorrhizal roots of chicory (Cichorium intybus), leek (Allium porrum), and big bluestem (Andropogon gerardii). The lipids were analyzed by shotgun lipidomics using a high-resolution hybrid mass spectrometer. Size range between 1350 and 1550Da was chosen for the detection of potential biomarkers among cardiolipins (1,3-bis(sn-3'-phosphatidyl)-sn-glycerols), a specific class of phospholipids. The analysis revealed a variety of molecular species, including cardiolipins containing one or two polyunsaturated fatty acids with 20 carbon atoms each, i.e., arachidonic and/or eicosapentaenoic acids, some of them apparently specific for the mycorrhizal samples. Although further verification using a greater variety of AM fungal species and samples from various soils/ecosystems/environmental conditions is needed, current results suggest the possibility to identify novel biochemical signatures specific for AM fungi within mycorrhizal roots. Whether they could be used for quantification of both root and soil colonization by the AM fungi merits further scrutiny.

Effects of Arbuscular Mycorrhizal Fungi on Growth and Nutrient Accumulation of Oat under Drought Conditions

Arbuscular mycorrhizal fungi (AMF) have established themselves as pivotal allies in the realm of plant physiology, renowned for their remarkable contributions to augmenting both growth and resilience against environmental stresses. In this study, we embarked on a comprehensive investigation into the discernible impact of two distinct AMF species on a widely planted oat cultivar, ‘Qingyan No. 1’, when subjected to the austere conditions of a drought. The experimental design included three distinct AMF treatments (inoculation with Rhiaophagus intraradices, Funneliformis mosseae, or not), and the three water treatments were 75% of field capacity (well watered), 50% of field capacity (moderate drought), and 30% of field capacity (severe drought). The obtained results showed that the rate of inoculation under 75% FC for both AMF species was over 74%. Drought stress limited the growth and osmotic regulation of the oat plants. However, AMF inoculation observably increased the above-ground biomass under 75% FC and increased the root biomass under 30% FC. AMF inoculation also increased the root traits under 75% FC and 50% FC. R. intraradices inoculation increased the above-ground soluble sugar and soluble protein concentrations, and both AMF species showed decreased malondialdehyde (MDA) concentrations in the roots. Furthermore, the pervasive influence of drought stress exerted a discernible stranglehold on nutrient uptake in the oat plants, profoundly impacting the distribution of nutrients within the shoots and roots. Regardless of the drought stress treatment, the inoculation with both AMF species increased the P concentrations in the roots and the K and Mg concentrations in the roots, and the inoculation with R. intraradices increased the Ca concentration in the whole oat plant. Under 75% FC, the N concentration of the whole oat plant was significantly reduced by both AMF species. However, under 50% FC and 30% FC, the N concentrations in the shoots inoculated with both AMF species were close to that of the non-inoculated shoots. In summary, AMF improved the osmotic regulation and nutrient absorption and distribution of oat plants under drought stress and thus promoted the growth and biomass accumulation of oat plants.

Arbuscular mycorrhizal fungi can reduce severity of fusariosis (Fusarium oxysporum) in cowpea plants (Vigna unguiculata (L.) Walp.)

Mycorrhizal symbiosis with arbuscular mycorrhizal fungi (AMF) provides plants with high nutrient absorption and non-nutritional benefits such as resistance to diseases. Fusariosis (Fusarium oxysporum) affects cowpea (Vigna unguiculata (L.) Walp.) production, which is a common culture in household farms in the northeast region of Brazil. The aim of this study was to evaluate the potential of native AMF from Maranhão Cerrado to provide resistance/non-nutritional benefits to cowpea plants infected with F. oxysporum f.sp. tracheiphilum. The bioassay was conducted using cowpea plants to assess their responses to different AMF species and F. oxysporum under controlled greenhouse conditions. Vegetative development of cowpeas (fresh and dry shoot and root mass, leaf number, and plant height) benefited from AMF symbiosis, especially with Claroideoglomus etunicatum and Acaulospora morrowiae. All AMF species reduced the severity score of the disease, confirming the potential use of mycorrhizal fungi species to reduce F. oxysporum damage in cowpea cultures.

Quantifying microbial communities in pot cultures of Arbuscular Mycorrhizal fungi: A comprehensive analysis

Substrate based inoculum production using traditional “Pot Culture” technique contains all AMF structures, and is highly infective and common method of AM fungal production and pure culture maintenance. Aim of the present study was to investigate the microorganisms associated (Bacteria, Fungi, Actinomycetes, Nitrogen fixers, P-solubilizers) with pot cultures of 10 AM fungal cultures like Acaulospora laevis, Gigaspora margarita, Funneliformis caledonius, Rhizophagus fasciculatus, Rhizophagus intraradices, Ambispora leptoticha, Glomus macrocarpum, Funneliformis mosseae, Glomus bagyarajii and Entrophospora etunicata (=Claroideoglomus etunicatum) through quantitative analysis. The highest bacterial population (37×107 and 35×107) were associated with pots of G. margarita and R. fasciculatus respectively. The highest fungal population was observed in pots of Glomus macrocarpum (87×105) and R. fasciculatus (82×105). The F. caledonius and R. fasciculatus pot cultures harboured the highest actinomycetes population. The highest N-fixing and phosphate solubilizing bacteria (92×104 and 54×104) were isolated from the pots of R. fasciculatus and G. margarita respectively. However, the highest dehydrogenase activity was observed in the sample collected from pots of R. fasciculatus. These findings highlight the distinct preferences and proliferation rates of different microbial groups in the pot cultures of different AM fungal species.

Biological Control of Three Fungal Diseases in Strawberry (Fragaria × ananassa) with Arbuscular Mycorrhizal Fungi

Similar to many other plant-based products, strawberries are susceptible to fungal diseases caused by various pathogen groups. In recent years, efforts have been made to combat these diseases using biological control methods, particularly the application of arbuscular mycorrhizal fungi (AMF). This study aimed to determine the effects of AMF (Funneliformis mosseae (Fm) and Gigaspora margarita (Gm)) on Rhizoctonia fragariae (Rf), Fusarium oxysporum (Fo), and Alternaria alternata (Aa), which are major pathogens for strawberry. The results showed that the effects of AMF on disease severity and plant growth varied depending on the pathogens involved. Rf caused the highest disease severity, followed by Fo and Aa, but all AMF treatments significantly reduced the disease severity compared to control treatments. The study also found that the specific AMF species and their combinations influenced plant growth responses under different pathogenic conditions. Different AMF treatments resulted in varying increases in plant fresh weight, dry weight, and length, depending on the pathogen. Moreover, the application of AMF led to increased levels of total phenolic content, antioxidant activity, and phosphorus content in pathogen-infected plants compared to control treatments. Fm was more efficient than Gm in increasing these biochemical parameters. The levels of root colonization by AMF were similar among different AMF treatments, but the effects on fungal spore density varied depending on the pathogen. Some AMF treatments increased fungal spore density, while others did not show significant differences. In conclusion, our research sheds light on the differential effects of AMF species on disease severity, plant growth, and biochemical parameters in strawberry plants facing diverse pathogens. These findings underscore the potential benefits of AMF in disease management, as they reduce disease severity and bolster plant growth and defense mechanisms.

Effects of combinations of arbuscular mycorrhizal fungal species on tomato growth and Fusarium wilt control

In this study, we investigated the effects of combinations of arbuscular mycorrhizal (AM) fungal species on tomato seedling growth and Fusarium wilt control. The study was conducted in greenhouse pot experiments using the tomato (Solanum lycopersicum) variety Fusan 88 and the fungi Funneliformis mosseae, Diversispora versiformis, Claroideoglomus etunicatum, and Rhizophagus intraradices as inoculants. The results showed higher mycorrhizal root colonization rates in all inoculation mixtures than in single-inoculum treatments, while growth-promotion effects differed significantly among AM fungal species and their combinations. Except for inoculation with F. mosseae alone, other inoculation treatments significantly promoted the growth of tomato seedlings. Of all fungal species, R. intraradices had the most significant effect on promoting seedling growth, as observed in all inoculum combinations containing this species. The greatest effect on seedling growth was observed for combined inoculation with D. versiformis + R. intraradices, which led to increases in above- and belowground biomass of 67.74 % and 100 %, respectively, compared to the control (CK), followed by C. etunicatum + R. intraradices, which led to increases in above- and belowground biomass of 61.29 % and 100 % compared to CK. Redundancy analyses showed that compared to the other three species, R. intraradices had more significant effects on promoting plant nitrogen, phosphorus, and potassium uptake and increasing above- and belowground dry weight. Mycorrhizalized seedlings were more resistant to Fusarium wilt and had lower malondialdehyde content and higher catalase, superoxide dismutase, and polyphenol oxidase activity in tomato plants. The lowest Fusarium wilt disease index value was 39.96 %, for mixed inoculation with F. mosseae + D. versiformis + C. etunicatum; this was 34.28 % lower than that of CK, and the control effect was 34.27 %, followed by inoculation with C. etunicatum + R. intraradices, which had a disease index value of 41.48 %, 31.78 % lower than that of CK, with a control effect value of 31.76 %. Therefore, we transplanted tomato seedlings inoculated with C. etunicatum + R. intraradices, which had both good growth-promotion and disease-resistance effects, to a greenhouse for sand culture under conditions of high water and fertilization. The mycorrhizal relationships developed in these plants at the seedling stage remained stable throughout the tomato reproductive period. The mycorrhizal seedlings had a significantly lower incidence of Fusarium wilt and lower disease index values, indicating better disease control than observed in non-mycorrhizal seedlings. The mycorrhizal plants produced fruits with a significantly higher soluble-sugar content and sugar:acid ratio (30.8 % and 42.3 % higher, respectively, than CK) and a significantly lower organic acid content (11.5 % lower than CK). Thus, mycorrhization significantly improved tomato plants’ growth, disease resistance, and fruit quality. These findings lay a foundation for the application of mycorrhizal fungi in tomato agriculture.

Temporal dynamics of wild herbaceous arbuscular mycorrhizal fungi under crop succession: Rice-bean-amaranth-okra-eggplant

Arbuscular mycorrhizal fungi (AMF) are ubiquitous symbionts that colonize approximately 80% of wild and cultivated plants, with the exception of a few botanical families such as Amarantaceae, Brassicaceae, Cyperaceae, and Chenopodiaceae, which mycorrhizae less or not at all. These symbioses are important because they improve the hydro-mineral nutrition of plants. During a succession of crops on a plot, it is possible to observe the diversity of AMF in the soil; this work fits into this framework. The experiment was carried out in pots in a completely randomized block design with 5 crops, including rice-beans-amaranth-okra-eggplant, repeated 5 times. The temporal dynamics of AMF were assessed during crop succession on the same soil. The results show a high species richness for rice, with 23 AMF species compared to 9 AMF species found on amaranth. Spore density and root colonization frequency show the same trend, respectively 5 to 38 spores per 100 g soil for rice compared to 3 to 10 spores per 100 g soil for amaranth. The colonization frequency ranged from 79 to 80% in rice and bean, while amaranth was only colonized to 13%. The introduction of amaranth during crop succession contributes to a decrease in species richness, spore density and AMF colonization frequency, in contrast to other crops.

Arbuscular mycorrhizae increase but vermicompost decrease the sun protection factor (SPF) in leaves of Hymenaea martiana Hayne seedlings

This study aimed to select the most efficient combination of arbuscular mycorrhizal fungi (AMF) and substrate to increase the photoprotective and in vitro antioxidant activities in Hymenaea martiana Hayne leaves. Hymenaea martiana seedlings were grown in soil with or without 10% vermicompost and inoculated with three AMF species: Acaulospora longula, Gigaspora albida, and Claroideoglomus etunicatum. Seedlings grown in soil without vermicompost or AMF inoculation served as controls. After 148 days of growth in a greenhouse, the photoprotective and antioxidant activities, and the production of some phenolics in the leaves were evaluated. Vermicompost supplementation reduced the photoprotective and antioxidant effects in extracts compared to the control. However regardless of the vermicompost treatment, mycorrhizal colonization resulted in a 40% increase in photoprotective activity compared to control; this enhancement was correlated with the increased concentration of proanthocyanidins in mycorrhizal plants. AMF inoculation improves the quality of H. martiana phytomass, dispensing the application of vermicompost in the cultivation substrate. This is the first report on the potential of AMF and vermicompost to increase the sun protection factor in H. martiana leaves.

Morphological and Molecular Characterizations of Arbuscular Mycorrhizal Fungi and Their Influence on Soil Physicochemical Properties and Plant Nutrition.

Pulses are considered a remarkable and stable source of nutrients, which are being presently extensively cultivated and consumed in different parts of the world. Pulses belong to the family Leguminosae and are a rich source of nutrients such as phosphorus (P) and nitrogen (N) for best growth via symbiotic relationship with bacteria and AMF (arbuscular mycorrhizal fungi). The aim of the current study was evaluating the influence of AMF diversity associated with various pulses (French bean, mung bean, kidney bean, peas, soybean, peanuts, and grams). Furthermore, AMF characterization was done using morphological features of spores and sequencing of the rDNA gene, which confirmed the existence of 10 different AMF taxa. Among the different genera, the genus Glomus was observed to be the most dominant with 30% species followed by Gigaspora (22%), Sclerocystis (12%), Acaulospora (8%), Rhizophagus and Septoglomus (7%), Diversispora (5%), and Claroideoglomus, Archaeospora, and Ambispora (3%). Furthermore, soil physicochemical analysis and percentage of AMF colonization results revealed the fact that the phosphorus content (inversely proportional to the AMF diversity) was a determining factor of AMF diversity. The highest amount of available phosphorus (62.825 mg kg-1) in the district Swabi resulted in a low rate of AMF colonization (6.66 ± 11.54%) with a comparatively higher rate of AMF colonization (50.66 ± 1.15%) found in the soil of the district Chitral having a low phosphorus content (17.3 ± 7.6 mg kg-1). Nutrient uptake by pulses including nitrogen (2.4 ± 1.3%), phosphorus (13.5 ± 7.6 mg kg -1), potassium (99.5 ± 25.8 mg kg -1), zinc (1.4 ± 0.5 mg kg -1), moisture (2.3 ± 1.3%), crude fats (5.6 ± 2.8%), ash (4 ± 1.2%), and proteins (13.6 ± 9.01%) determined the fact that AMF species diversity is positively correlated to the plant mineral nutrition. From the current study, it is concluded that AMF inoculation to the soil fields is beneficial to ensure the sustainability and productivity of pulse crops in diverse environmental conditions without polluting the soil.

Arbuscular Mycorrhizal Fungus Funneliformis mosseae Improves Soybean Growth Even in Soils with Good Nutrition

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

Electrical Conductivity and pH Are Two of the Main Factors Influencing the Composition of Arbuscular Mycorrhizal Fungal Communities in the Vegetation Succession Series of Songnen Saline-Alkali Grassland.

Arbuscular mycorrhizal fungi (AMF) are widely distributed microorganisms in the soil, playing an important role in vegetation succession, plant community diversity, and improving soil physicochemical properties. In this study, morphological identification and high-throughput sequencing technology were used to comprehensively analyze the AMF community composition and diversity at different succession stages of Songnen saline-alkali grassland. To determine the root colonization status of plants collected in the field, a colonization system was established using late-succession plants as host plants to verify the existence of mycorrhizal symbiosis and the matching phenomenon of AMF in Songnen saline-alkali grassland. The results indicated that both morphological methods and high-throughput sequencing technology showed that glomus was the dominant genus of AMF in Songnen saline grassland. Redundancy analysis (RDA) and linear regression analysis showed that electrical conductivity (EC) and pH were the main environmental factors affecting AMF species diversity and community structure in the succession sequence of Songnen saline grassland. In addition, the results of root colonization identification and the colonization system test in the field showed that AMF successfully colonized vegetation at different succession stages and had mycorrhizal symbiosis. The results of this study could help to understand the AMF community of Songnen saline-alkali grassland as well as provide a reference and basis for optimizing the AMF community structure of Songnen saline-alkali grassland through human intervention in the future and using mycorrhizal technology to restore and rebuild the degraded ecosystem of Songnen saline-alkali grassland.