Arbuscular Mycorrhizal Fungi Spores Research Articles

Characterization of arbuscular mycorrhizal fungal species associating with Zea mays

Taxonomic identification of arbuscular mycorrhizal (AM) fungal spores extracted directly from the field is sometimes difficult because spores are often degraded or parasitized by other organisms. Single-spore inoculation of a suitable host plant allows for establishing monosporic cultures of AM fungi. This study aimed to propagate AM fungal spores isolated from maize soil using single spores for morphological characterization. First, trap cultures were established to trigger the sporulation of AM fungal species. Second, trap cultures were established with individual morphotypes by picking up only one spore under a dissecting microscope and transferring it to a small triangle of sterilized filter paper, which was then carefully inoculated below a root from germinated sorghum seeds in each pot and covered with a sterile substrate. All pots were placed in sunbags and maintained in a plant growth room for 120 days. Spores obtained from single spore trap cultures from each treatment, maize after oats (MO), maize after maize (MM), maize after peas (MP), and maize after soybean (MS), were extracted using the sieving method. Healthy spores were selected for morphological analysis. Direct PCR was conducted by crushing spores in RNAlater and applying three sets of primer pairs: ITS1 × ITS4, NS31 × AML2, and SSUmcf and LSUmBr. Nucleotide sequences obtained from Sanger sequencing were aligned on MEGA X. The phylogenetic tree showed that the closest neighbors of the propagated AM fungal species belonged to the genera Claroideoglomus, Funneliformis, Gigaspora, Paraglomus, and Rhizophagus. The morphological characteristics were compared to the descriptive features of described species posted on the INVAM website, and they included Acaulospora cavernata, Diversispora spurca, Funneliformis geosporus, Funneliformis mosseae, Gigaspora clarus, Gigaspora margarita, Glomus macrosporum, Paraglomus occultum, and Rhizophagus intraradices. These findings can provide a great contribution to crop productivity and sustainable management of the agricultural ecosystem. Also, the isolate analyzed could be grouped into efficient promoters of growth and mycorrhization of maize independent of their geographical location.

Inoculation of Native Arbuscular Mycorrhizae and Bacillus subtilis Can Improve Growth in Vegetable Crops.

Arbuscular mycorrhizal fungi (AMF) and some rhizobacteria are known as plant growth-promoting microorganism (PGPM) as they play significant roles in improving soil fertility structure, plant nutrition, growth, and health. However, little is known about the PGPM potential of AMF and rhizobacteria native to the Rift Valley and highland regions of Ethiopia. Hence, this study aimed to investigate the PGPM effect of single and co-inoculation of AMF and the Bacillus subtilis ALCR46 strain, on tomato (Lycopersicum esculentum L.), onion (Allium cepa L.), and squash (Cucurbita pepo L.) plants. The experimental setup was a randomized complete block design with three replications of the following treatments: (i) inoculation with a consortium of AMF, (ii) co-inoculation with a consortium of AMF and the Bacillus subtilis, (iii) inoculation with Rhizophagus clarus, (iv) co-inoculation with R. clarus and B. subtilis, (v) inoculation with B. subtilis, (vi) plants without inoculation (negative control), and (vii) plants treated with chemical fertilizer (positive control). Plants were maintained in a greenhouse for 60 days, and after harvest, plant growth parameters, percentage of AMF root colonization, and spore number were analyzed. The result shows that the growth of crops significantly increased by co-inoculation with the consortium of AMF and B. subtilis. AMF spore density and root colonization rate were also increased in co-inoculated plants. Highest root colonization, spore number, and mycorrhizal dependency were observed in A. cepa. Our results suggest that there is a synergistic effect between the AMF and B. subtilis ALCR46, and between AMF inoculants. However, the application of present findings under field conditions is required to be confirmed by further studies.

Can Arbuscular Mycorrhizal Fungi Enhance Crop Productivity and Quality in Hydroponics? A Meta-Analysis

Finding environmentally friendly solutions for crop growth and productivity has been gaining more attention recently. This meta-analysis aims to understand the combined application of arbuscular mycorrhizal fungi (AMF) and hydroponic systems compared to AMF in conventional (soil) systems. The analysis of up-to-date studies revealed that the root colonization, calculated as the proportion of colonized root segments relative to the total root length, by AMF in conventional (soil-based) culture exceeded hydroponic (or soilless) culture systems by 16.8%. The mean root colonization by AMF was determined to be 52.3% in hydroponic systems and 61.1% in conventional systems. Within hydroponic systems, the root colonization ranged from 2% to 20% after 10 days of inoculation, and notably, it exceeded 50% after 30 to 65 days, depending on the growing substrate and species. Under hydroponics, AMF application had a higher (compared to none-inoculated) positive effect on crop biomass and yield than fruit and leaf quality (antioxidants, phenols, and sugars) as well as leaf nutrients. However, AMF do not always have the potential to improve crop growth, quality and productivity in hydroponics. Among the studies analyzed in this review, approximately 34% (no effect: 29%; negative: 5%) reported no discernible positive effect on biomass or yield, 37% (no effect: 16%; negative: 21%) on fruit or leaf quality, and 60% (no effect: 47%; negative: 13%) on nutrient levels within plant tissues. To improve the performance of AMF in hydroponic systems, the meta-analysis recommended maintaining phosphorus levels in the nutrient solution within the range of 0.15 to 15.5 mg L−1 as elevated levels (40–75 mg L−1) were found to significantly reduce AMF colonization. Additionally, it was observed that certain hydroponic techniques, such as the presence of air bubbles generated by air pumps in floating hydroponic systems (Deep Flow technique) and continuous circulation of the nutrient solution (Ebb and Flow systems), may create dynamic conditions that could potentially hinder the introduction of AMF spores into hydroponic systems and potentially compromise the integrity of the spores and hyphae.

OsEXO70L2 is required for large lateral root formation and arbuscular mycorrhiza establishment in rice

As a major subunit of the exocyst complex, members of the EXO70 family have mainly been shown to play roles in cell polarity and morphogenesis in Arabidopsis, but their roles in plant endosymbiosis, such as with arbuscular mycorrhizal fungi (AMF), have rarely been reported. Here, using knockout and overexpression lines, we show that OsEXO70L2, which encodes a divergent EXO70 protein in rice, controls the number of primary roots and is essential for large lateral root formation. Furthermore, the OsEXO70L2 mutant sr1 displayed rare internal AMF hyphae and no arbuscules. We also found that AMF sporulation can occur in roots despite low colonization and that AMF colonization and sporulation are modulated by photoperiod and co-culture with clover. Finally, genes related to auxin homeostasis were found to be affected in the OsEXO70L2 knockout or overexpression lines, suggesting that auxin is at least partly responsible for the phenotypes. This study provides new perspectives on the role of the exocyst complex during root development and AM in rice.

A Morpho-Biochemical and functional comparison of Arbuscular Mycorrhizal Fungal spores cultured in two distinct conditions

A Morpho-Biochemical and functional comparison of Arbuscular Mycorrhizal Fungal spores cultured in two distinct conditions

Bacteria Associated with Spores of Arbuscular Mycorrhizal Fungi Improve the Effectiveness of Fungal Inocula for Red Raspberry Biotization

Intensive crop production leads to the disruption of the symbiosis between plants and their associated microorganisms, resulting in suboptimal plant productivity and lower yield quality. Therefore, it is necessary to improve existing methods and explore modern, environmentally friendly approaches to crop production. One of these methods is biotization, which involves the inoculation of plants with appropriately selected symbiotic microorganisms which play a beneficial role in plant adaptation to the environment. In this study, we tested the possibility of using a multi-microorganismal inoculum composed of arbuscular mycorrhizal fungi (AMF) and AMF spore-associated bacteria for biotization of the red raspberry. Bacteria were isolated from the spores of AMF, and their plant growth-promoting properties were tested. AMF inocula were supplemented with selected bacterial strains to investigate their effect on the growth and vitality of the raspberry. The investigations were carried out in the laboratory and on a semi-industrial scale in a polytunnel where commercial production of seedlings is carried out. In the semi-industrial experiment, we tested the growth parameters of plants and physiological response of the plant to temporary water shortage. We isolated over fifty strains of bacteria associated with spores of AMF. Only part of them showed plant growth-promoting properties, and six of these (belonging to the Paenibacillus genus) were used for the inoculum. AMF inoculation and co-inoculation of AMF and bacteria isolated from AMF spores improved plant growth and vitality in both experimental setups. Plant dry weight was improved by 70%, and selected chlorophyll fluorescence parameters (the contribution of light to primary photochemistry and fraction of reaction centre chlorophyll per chlorophyll of the antennae) were increased. The inoculum improved carbon assimilation, photosynthetic rate, stomatal conductance and transpiration after temporary water shortage. Raspberry biotization with AMF and bacteria associated with spores has potential applications in horticulture where ecological methods based on plant microorganism interaction are in demand.

Spores of arbuscular mycorrhizal fungi host surprisingly diverse communities of endobacteria.

Arbuscular mycorrhizal fungi (AMF) are ubiquitous plant root symbionts, which can house two endobacteria: Ca. Moeniiplasma glomeromycotorum (CaMg) and Ca. Glomeribacter gigasporarum (CaGg). However, little is known about their distribution and population structure in natural AMF populations and whether AMF can harbour other endobacteria. We isolated AMF from two environments and conducted detailed analyses of endobacterial communities associated with surface-sterilised AMF spores. Consistent with the previous reports, we found that CaMg were extremely abundant (80%) and CaGg were extremely rare (2%) in both environments. Unexpectedly, we discovered an additional and previously unknown level of bacterial diversity within AMF spores, which extended beyond the known endosymbionts, with bacteria belonging to 10 other phyla detected across our spore data set. Detailed analysis revealed that: CaGg were not limited in distribution to the Gigasporaceaefamily of AMF, as previously thought; CaMg population structure was driven by AMF host genotype; and a significant inverse correlation existed between the diversity of CaMg and diversity of all other endobacteria. Based on these data, we generate novel testable hypotheses regarding the function of CaMg in AMF biology by proposing that they might act as conditional mutualists of AMF.

A survey on the composition and occurrence frequency of arbuscular mycorrhizal fungi in rhizospheric soils and roots of vegetables grown in Ho Chi Minh city

The study aimed to determine the presence and composition of arbuscular mycorrhizal fungi (AMF) in the rhizospheric soils and roots of vegetable plants (14 species of leafy vegetables) grown in Hoc Mon, Cu Chi, and Binh Chanh districts, Ho Chi Minh city. The results of the isolation of AMF spores based on the wet sieving method showed the presence of AMF in the rhizospheric soils of vegetables with an average spore density of 87.6 spores/50 g of soil. For the symbiotic ratio of AMF to the root tissues, there was no symbiosis in 4 vegetable crops, including amaranth, mustard green, leaf mustard, and bok choy. Still, there was symbiosis in the remaining 10 plants, with an average symbiotic rate of 6.6%. Identification of AMF spores based on the morphological characteristics recorded in all the soil samples appeared spore phenotypes of 5 fungal genera including Glomus, Acaulospora, Gigaspora, Scutellospora, and Sclerocystis. However, 3 morphological types were not yet identified. From the obtained results, two genera, Glomus and Acaulospora, have the highest frequency at 43.9 and 39.6%, respectively.

Root-mycorrhizae species and variety pairing matters: A study case with arbuscular mycorrhizal fungi communities and Vitis vinifera varieties in the southern Brazil

Vitis vinifera varieties can change the arbuscular mycorrhizal fungi (AMF) community structure in their rhizosphere. Our aim here was to present a quantitative analysis of the AMF species associated with V. vinifera varieties from Cabernet, Merlot, and Sauvignon groups in a subtropical Cambisol, Southern Brazil. Eight V. vinifera varieties were selected for the field experiment from September 2019 to June 2021. For each studied variety, we established five rectangular plots (60.0 × 14.0 m) using a randomized block design with seven blocks. We found seven main groups considering the dissimilarities of AMF spores: i) Entrophospora claroidea in the root zone of C. Eidos and C. Volos (both varieties from the Cabernet group); ii) Funneliformis mosseae in the root zone of Fleurtai; iii) Racocetra coralloidea in the root zone of Merlot Khantus; iv) Scutellospora calospora in the root zone of M. Khorus; v) Quatunica erytrophus in the root zone of Sauvignon Kretos; vi) Glomus coremioides in the root zone of S. Rytos; and vii) Acaulospora tuberculata in the root zone of Soreli. The results of our study highlighted the importance of considering V. vinifera varieties as potential hosts for specific AMF species by creating an AMF-host pairing specificity to improve root colonisation and plant yield in their own advantage. Thus, field experiments considering V. vinifera varieties into agrosystems for vine production contribute to our understanding of the AMF symbiosis in subtropical soils.

Host plants directly determine the α diversity of rhizosphere arbuscular mycorrhizal fungal communities in the National Tropical Fruit Tree Field Genebank

Arbuscular mycorrhizal fungi (AMF) typically exhibit reduced diversity in nutrient-rich soils. However, whether the influence of host plants on AMF within the rhizosphere is direct or indirect through the alteration of soil nutrient levels has yet to be determined. This study explored the diversity and colonization of AMF in the National Tropical Fruit Tree Genebank, where chemical fertilizers are used to preserve minor tropical fruit germplasms. We aimed to understand the direct and indirect effects of host plants on AMF community dynamics, sporulation, and colonization. By analyzing fine roots and rhizosphere soil from 12 tropical fruit trees, we assessed mycorrhizal colonization indices, soil nutrients, AMF spore density, and community structure. Despite their low colonization density and arbuscular abundance, all the tree roots harbored AMF, with spore densities ranging from 24.00 to 204.80 spores/100 g of dry soil. High-throughput sequencing identified 207 AMF virtual taxa (VTs) from 60 soil samples, with dominant taxa, including early-evolved Paraglomus fungi and ruderal AMF, being minimally affected by soil nutrient levels. Interestingly, there was no correlation between α diversity and spore density. Structural equation modeling (SEM) indicated that host plant evolutionary divergence time (ET) directly influenced AMF α diversity indices and indirectly impacted spore density via soil nutrients. However, neither ETs nor soil nutrients significantly affected the AMF community structure, with only arbuscular abundance showing a negative correlation with ET. This research underscores the intricate relationship between host plants and AMF in genebanks, offering insights for effective AMF resource management and informed conservation practices.Graphical

Arbuscular Mycorrhizal Fungi (AMF) diversity and population in UPV Nature Trail, Miagao, Iloilo, Philippines

Abstract. De Asis EPT, Demetillo FMM, Paguntalan DP. 2023. Arbuscular Mycorrhizal Fungi (AMF) diversity and population in UPV Nature Trail, Miagao, Iloilo, Philippines. Biodiversitas 24: 6692-6703. Arbuscular Mycorrhizal Fungi (AMF) are soil microorganisms that form the most prevalent mutualistic associations with plant species. Studies revealed its global distribution in various terrestrial habitats, but available local literature remains few. This study investigated AMF diversity in the University of the Philippines Visayas (UPV) Nature Trail, Miagao, Iloilo, Philippines. AMF spores were isolated using wet sieving, decanting, and centrifugation. A total of 2815 individual spores were documented, with 114 distinct morphospecies representing 16 genera, nine families, and four orders classified. Glomus clarum, Acaulospora sp.7, and Scutellospora pellucida tallied the highest abundance across all points. Scutellospora pellucida (FOC=83.3%) recorded the highest species richness, followed by Ambispora sp. (FOC=77.78%), then Acaulospora mellea and Glomus australe (FOC=72.22%). Overall, Shannon-Weiner diversity index (H=3.6019) and Simpson diversity index (D=0.0420) revealed a very high AMF diversity in the trail, while the Pielou evenness index (J=0.7605) suggested a semi-balanced number of individuals among each morphospecies. A more abundant, even, and diverse, albeit not statistically significant, AMF community was recorded in forested areas compared to non-forested areas of the trail. Results generally suggest that the AMF community is diverse and abundant regardless of the location, ecosystem type, and faunal association.

Strigolactone GR24-mediated mitigation of phosphorus deficiency through mycorrhization in aerobic rice

Strigolactones (SLs) are a new class of plant hormones that play a significant role in regulating various aspects of plant growth promotion, stress tolerance and influence the rhizospheric microbiome. GR24 is a synthetic SL analog used in scientific research to understand the effects of SL on plants and to act as a plant growth promoter. This study aimed to conduct hormonal seed priming at different concentrations of GR24 (0.1, 0.5, 1.0, 5.0 and 10.0 µM with and without arbuscular mycorrhizal fungi (AMF) inoculation in selected aerobic rice varieties (CR Dhan 201, CR Dhan 204, CR Dhan 205, and CR Dhan 207), Kasalath-IC459373 (P-tolerant check), and IR-36 (P-susceptible check) under phosphorus (P)-deficient conditions to understand the enhancement of growth and priming effects in mycorrhization. Our findings showed that seed priming with 5.0 µM SL GR24 enhanced the performance of mycorrhization in CR Dhan 205 (88.91 %), followed by CR Dhan 204 and 207, and AMF sporulation in CR Dhan 201 (31.98 spores / 10 gm soil) and CR Dhan 207 (30.29 spores / 10 g soil), as well as rice growth. The study showed that the highly responsive variety CR Dhan 207 followed by CR Dhan 204, 205, 201, and Kasalath IC459373 showed higher P uptake than the control, and AMF treated with 5.0 µM SL GR24 varieties CR Dhan 205 followed by CR Dhan 207 and 204 showed the best performance in plant growth, chlorophyll content, and soil functional properties, such as acid and alkaline phosphatase activity, soil microbial biomass carbon (MBC), dehydrogenase activity (DHA), and fluorescein diacetate activity (FDA). Overall, AMF intervention with SL GR24 significantly increased plant growth, soil enzyme activity, and uptake of P compared to the control. Under P-deficient conditions, seed priming with 5.0 µM strigolactone GR24 and AMF inoculum significantly increased selected aerobic rice growth, P uptake, and soil enzyme activities. Application of SLs formulations with AMF inoculum in selected aerobic rice varieties, CR Dhan 207, CR Dhan 204, and CR Dhan 205, will play an important role in mycorrhization, growth, and enhancement of P utilization under P- nutrient deficient conditions.

Density and Phenotypic Diversity of Arbuscular Mycorrhizal Fungi in a Revegetated Tailing Storage Facility in Ghana

Arbuscular Mycorrhizal fungi (AMF) aid the establishment of vegetation on stressed soils as they contribute to soil ecological functions as well as improvement in plant growth. Understanding the mycorrhizal diversity and density within an area is an important step in harnessing the immense benefits of mycorrhiza. This study assessed the diversity and density of AMF in a revegetated tailing storage facility in Ghana. A balanced hierarchical sampling scheme with 4 stages and 72 sampling points was used over four sampling periods. Seventeen AMF spore types from nine genera (Acaulospora, Claroideoglomus, Diversispora, Gigaspora, Glomus, Racocetra, Rhizophagus, Septoglomus and Scutellospora) and five families (Acaulosporaceae, Claroideoglomeraceae, Diversisporaceae, Gigasporaceae and Glomeraceae) were isolated and identified from the samples. The density of spores varied between 24 and 817; 21 and 303; 21 and 321; and 24 and 875 spores 100 g-1 dry tailing solids respectively for the four sampled periods. The spore densities for the control samples also varied between 85 and 307; 65 and 248; 90 and 321 and 70 and 287 spores 100 g-1 dry soil for the respective sampling periods. Recorded spore densities varied significantly within sampling locations (p = 0.000) and between sampling periods (p = 0.000). The density and diversity of the AMF found in this study were relatively high and may have contributed significantly to the revegetation of the storage facility. These findings are important pointers for the adoption of mycorrhization in vegetation establishment and ultimately rehabilitation of decommissioned tailings storage facilities in Ghana. Further studies should however be done to determine how the various vegetation types found on the TSF affect AMF diversity and density.

Developing novel techniques for efficient Arbuscular Mycorrhizal Fungi (AMF) Inoculum Production

The demand for AMF propagules has experienced a surge as a result of their capability to amplify growth and nutrient uptake. This demand has triggered the adoption of contemporary propagule cultivation techniques, as conventional AMF propagation methods often involve extensive labor and time requirements, creating difficulties for large-scale production. The adoption of bioreactors, for example, has become one of the most promising approaches for the substantial cultivation of AMF propagules. Bioreactors offer a promising approach for the large-scale production of AMF propagules, which boost nutrient absorption and plant development. They provide superior yield, cost-effectiveness, and scalability in contrast to conventional methods. Synthetic substrates also provide a regulated environment that enhances optimal growth and development. They can be adjusted to satisfy specific nutrient specifications and promote consistent spore production. Synthetic substrates enable researchers to manipulate concentration and timing, thereby increasing spore yields and preserving non-destructive yield. This approach enables the iterative extraction of spores from the same batch. The prioritization of nutrient composition optimization in bioreactors is crucial for supporting AMF propagule growth and reproduction in future research. For instance, understanding AMF's distinct nutrient requirements can lead to media that is nutrient-rich, increased yields of propagules, and improved interactions with plants. Furthermore, developments in synthetic substrate technology can produce substrates that replicate natural soil environments. This study focused on innovative materials and additives can amplify substrate fertility and stability. Likewise, the careful concentration and timing of application when optimizing growth regulators can have a substantial impact on the production of AMF spores. These advancements can contribute to the sustainable production of AMF propagules, thereby offering advantages to agriculture and ecological restoration initiatives.

Kajian Fungi Mikoriza Arbuskula dan Populasi Bakteri pada Mikorhizosfer Semai Mahoni (Swietenia macrophylla King.) dalam Pot Organik

The mycorrhizosphere is the zone of soil influenced by roots colonized by mycorrhizal fungi and contains many microorganisms. This study aims to analyze mycorrhizal and bacterial populations in the mycorrhizosphere of ​​mahogany (Swietenia macrophylla King.) seedlings growing in silica sand post-mining media by using organic pot as container growth media. The experimental design used was a Completely Randomized Design (CRD) consisting of two treatments, namely the composition and size of organic pot materials. The results showed that the composition of the organic pot could affect the presence of AMF spores. The organic pots composition of 50% newspaper, 35% compost, and 15% cocopeat showed the best results for the development of AMF spores and bacterial colonies, the development of AMF spores and bacterial colony populations in growing media was better than the development of AMF spores and bacterial colonies in organic pots. There are seven different morphological characters of bacterial colonies which are dominated by round, thready, flat, and white.
 Keywords: arbuscular mycorrhizal fungi (AMF), bacteria, correlation, mahagony, mycorrhizosphere

Soil Physicochemical Characteristics and Spore Density of Indigenous Arbuscular Mycorrhizal Fungi (AMF) in Different Vegetation Patches of a Marginal Upland in Central Philippines

To show the importance of plant-microbe association in stressed tropical landscapes, the study evaluated the physicochemical characteristics and indigenous arbuscular mycorrhizal fungi (AMF) spore density in selected vegetation patches of marginal upland soils in Central Philippines. Five quadrats were used in the study, namely Andropogon aciculatus (control plot), Imperata cylindrica, Chromolaena odorata, Melastoma malabathricum and mixed vegetation patch. Results showed that soils in the studied vegetation patches had different physicochemical characteristics and AMF spore density. Although all patches had clay soil texture and comparable water-holding capacity, mixed vegetation patch had moderate compaction (1.33 g cm-3) and higher porosity (50.31%) compared with the other patches, which had extreme compaction (1.37-1.65 g cm-3) and lower porosity (37.74-48.76%). In terms of chemical properties, soils in different patches had moderate (5.69) to strongly acidic pH (5.13), moderate organic matter (2.69-2.91%) levels, low P (2.67-3.94 ppm) content and above critical K levels (0.2-1.2 cmol+ kg-1). Results also revealed that C. odorata patch had the highest spore density count (11.33 spores 100 g-1), followed by mixed vegetation (9 spores 100 g-1), M. malabathricum (8.33 spores 100 g-1), and A. aciculatus patch having the lowest spore density count (4 spores 100 g-1). The significant spore density variability was attributed to the differences in soil’s physicochemical characteristics among the different vegetation patches and AMF host specificity. Spores detection, therefore, indicated AMF presence and helped the adaptation mechanism of the natural vegetation in this degraded upland.

Diversity and Distribution of Arbuscular Mycorrhizal Fungi in Selected Medicinal Plants

Background: Tha Arbuscular Mycorrhizal Fungi (AMF) association previously known as VAM belongs to an ancient fungal group known as Glomeromycota. In this study five commonly used medicinal plants viz., Eclipta prostrata, Mentha arvensis, Elettaria cardamomum, Bacopa monneri and Mimosa pudica were investigated for AMF colonization in the form of arbuscules, vesicles and hyphae from their roots and their rhizospheric soil was isolated for AMF spores. Majorly two genera of AMF dominated the rhizospheric soil of the plants investigated which were Acaulospora and Glomus. Altogether 12 AMF spores were isolated from the rhizospheric environment of the plants and they belonged to six different genera of AMF. Methods: In this field-laboratory investigation during 2022-23, different localities of Banaras Hindu University was surveyed. 5 different plants were selected for investigation on the diversity and distribution of AMF colonisation found in their rhizospheric soil. Result: Our investigation on the diversity and distribution of AMF of few selected plants from BHU have allowed us to isolate and morphologically identify 12 different species of AMF from 6 different genera. The geographical distribution of the collected species was discussed. The present work will be a complementary contribution to the comprehensive study of the identification and utility of AMF in plant growth and sust.

Diversity of Arbuscular Mycorrhizal fungi under different agroforestry practices in the drylands of Southern Ethiopia

The conversion of an agroforestry based agricultural system to a monocropping farming system influences the distribution and composition of arbuscular mycorrhizal fungi (AMF). The aim of this paper was to analyze AMF species diversity, spore density, and root colonization across different agroforestry practices (AFP) in southern Ethiopia. Soil and root samples were collected from homegarden, cropland, woodlot, and trees on soil and water conservation-based AFP. AMF spores were extracted from the soil and species diversity was evaluated using morphological analysis and root colonization from root samples. The AMF spore density, root colonization and composition were significantly different among the AFP (P < 0.05). In this study, 43 AMF morphotypes belonging to eleven genera were found, dominated by Acaulospora (32.56%), followed by Claroideoglomus (18.60%). Home gardens had the highest spore density (7641.5 spore100 g− 1 dry soil) and the lowest was recorded in croplands (683.6 spore100 g− 1 dry soil). Woodlot had the highest root colonization (54.75%), followed by homegarden (48.25%). The highest isolation frequency (63.63%) was recorded for Acaulospora scrobiculata. The distribution of AMF species and diversity were significantly related to soil total nitrogen and organic carbon. The homegarden and woodlot AFP were suitable for soil AMF reserve and conservation.

The effect of indigenous Arbuscular mycorrhizal fungi (AMF) on phyto-accumulation in Carica papaya hybrids

Papaya (Carica papaya L.) is a climacteric fruit with a resilient and distinctive aroma. The consumption of the fruit is global due to its high nutritive and medicinal values. However, there has been low production of quality papaya fruits due to unavailability of crucial mineral elements in the soils. The current study therefore, focuses on the effect of indigenous arbuscular mycorrhizal fungi (AMF) as a biofertilizer on the quality of papaya fruits. In order to verify AMF effectiveness on papaya fruits, four treatments were used: AMF inoculum only, composted farm yard manure (FYM) only, combination of AMF inoculum and compost FYM and control where only soil and sand media were used at a ratio of 1:1. Jomo Kenyatta University of Agriculture and Technology (JKUAT) and Malkia papaya hybrids were used. The papaya seeds from JKUAT and Malkia papaya hybrids were sown in trays and transplanted at 3 leaves stage into 5 litre pots within a green house. The AMF spores were bulked using sorghum plants to obtain the AMF inoculum. The treatments were added into the soil media of the papaya plantlets at a ratio of 1:3, every 4 weeks after first transplanting until they were 20 weeks old. They were then transplanted to 100 litre containers, where completely randomized design was used and replication of six papaya plants for each treatment and hybrid. Watering, weeding and cooling the green house with water fumes was carried out when necessary; as the papaya plants grew until the fruits attained physiological maturity. The fruits were separately harvested and ripened to a predetermined stage. They were then analysed for moisture content, crude fibre, minerals (nitrogen, phosphorous, potassium, magnesium, calcium, iron and zinc), ascorbic acid, total carotenoids and total polyphenols. Data obtained was subjected to two-way ANOVA at p ≤ 0.05 significance level; means were separated using Tukey's HSD test in Genstat's 15th edition. JKUAT hybrid with AMF inoculum treatment had 3.07%crude fibre and 8.42mg/100g phosphorous content while JKUAT hybrid with both AMF inoculum and manure treatments had 4.9 % crude fibre and 9.88 mg/100g phosphorous content. Malkia and JKUAT hybrids with compost FYM treatment had potassium content of 98.31mg/100g and 109.4 mg/100g respectively while the controls had 31.58 mg/100g and 35.32mg/100g respectively. Incorporating soil media with manure and AMF inoculum improved the nutritive quality of papaya fruits and this was contingent on papaya hybrids. Key words: biofertilizer, inoculum, mineral elements, nutritive quality, physiological maturity

Responses of arbuscular mycorrhizal fungal morphological traits and the diversity of spore-associated bacteria to simulated nitrogen deposition and drought in a Cunninghamia lanceolata plantation soil

Arbuscular mycorrhizal (AM) fungi play an important role in plant nutrient absorption and stress resistance. AM fungal spore-associated bacteria are essential for mycorrhizal colonization, but their responses to environmental changes remain largely unknown. We collected surface soil samples from a Chinese fir plantation in both summer and winter to investigate the responses of AM fungal morphological traits and spore-associated bacterial communities to simulated nitrogen deposition (40 kg N·hm-2·a-1 addition) and drought (-50% precipitation exclusion). Our results showed that nitrogen addition and precipitation exclusion significantly affected AM fungal spore density and extraradical hyphal length, respectively. AM fungal intraradical colonization rate, extraradical hyphal length and spore density were significantly differed between the two seasons. Compared to control (no nitrogen addition and no precipitation exclusion treatment), both nitrogen addition and precipitation exclusion significantly reduced spore density in winter, while precipitation exclusion alone and the combined nitrogen addition and precipitation exclusion significantly increased extraradical hyphal length in summer. The dominant spore-associated bacterial phyla were Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, and Planctomycetes. Nitrogen addition and precipitation exclusion did not affect the diversity of spore-associated bacteria. However, the combined nitrogen addition and precipitation exclusion treatment altered the composition of the bacterial community, with significant variations between the two seasons. The spore-associated bacterial diversity was significantly higher and community variability (or turnover) was lower during summer than winter. Soil total nitrogen, nitrate nitrogen and dissolved organic carbon were important factors influencing the bacterial community composition. In all, the effects of nitrogen addition and precipitation exclusion on the morphological traits of AM fungi are seasonally dependent. The combination of nitrogen addition and precipitation exclusion has a significant impact on AM fungal spore-associated bacterial community structure.