Arbuscular Mycorrhizal Fungi Genera Research Articles

Winter forage crops influence soil properties through establishing different arbuscular mycorrhizal fungi communities in paddy field

Winter planting is promising for improving the utilization rate of fallow paddy fields in southern China by establishing arbuscular mycorrhizal fungi (AMF) communities. However, the effects of different winter forage crops on AMF community construction remain unknown. The AMF community establishment of different winter planting forage crops were conducted in oat, rye, Chinese milk vetch, and ryegrass, with winter fallow as a control. The AMF colonization rate, soil AMF spore density, community structure and diversity, and soil physicochemical properties were determined. The results showed that the total nitrogen and available nitrogen in winter Chinese milk vetch were 11.11% and 16.92% higher than those in winter fallow (P < 0.05). After planting winter forage crops, the AMF spore density in winter oat, rye, Chinese milk vetch, and ryegrass soil were 127.90%, 64.37%, 59.91%, and 73.62% higher than that before planting, respectively (P < 0.05). Claroideoglomus was the dominant AMF genus in the soil of winter planting oat, rye, and ryegrass. The average membership function value of winter Chinese milk vetch was the highest, indicating that it had the best comprehensive effect on soil physicochemical properties, AMF community structure and diversity, and fresh forage yield. Winter forage crops could increase the spore pool of soil AMF and improve the soil AMF community structure and diversity. Winter Chinese milk vetch in paddy field had the best comprehensive effect on soil physicochemical properties and soil AMF community according to the comprehensive evaluation. These findings provide a theoretical basis for sustainable development and utilization of the southern rice paddy ecosystem.

Root Endophyte-Manipulated Alteration in Rhizodeposits Stimulates Claroideoglomus in the Rhizosphere to Enhance Drought Resistance in Peanut.

Drought dramatically affects plant growth and yield. A previous study indicated that endophytic fungus Phomopsis liquidambaris can improve the drought resistance of peanuts, which is related with the root arbuscular mycorrhizal fungi (AMF) community; however, how root endophytes mediate AMF assembly to affect plant drought resistance remains unclear. Here, we explored the mechanism by which endophytic fungus recruits AMF symbiotic partners via rhizodeposits to improve host drought resistance. The results showed that Ph. liquidambaris enhanced peanut drought resistance by enriching the AMF genus Claroideoglomus of the rhizosphere. Furthermore, metabolomic analysis indicated that Ph. liquidambaris significantly promoted isoformononetin and salicylic acid (SA) synthesis in rhizodeposits, which were correlated with the increase in Claroideoglomus abundance following Ph. liquidambaris inoculation. Coinoculation experiments confirmed that isoformononetin and SA could enrich Claroideoglomus etunicatum in the rhizosphere, thereby improving the drought resistance. This study highlights the crucial role of fungal consortia in plant stress resistance.

Effects of organic contaminants on arbuscular mycorrhiza formation: A meta-analysis

Arbuscular mycorrhizal fungi (AMF) function mostly depends on their colonization to roots. However, it has not been systematically clear how arbuscular mycorrhiza (AM) formation is affected by organic contaminants. In this study, a meta-analysis was performed to estimate the effects of three groups of organic contaminants (polycyclic aromatic hydrocarbons (PAHs), crude oil, and pesticide) in soil on mycorrhizal colonization rates (MCRs) from various moderators, such as AMF (genus, species, and inoculation mode), contaminant (level, type, and source), and experimental conditions (plant type, duration, and soil sterilization). Our results showed that all MCRs (total, vesicular, arbuscular and hyphal) significantly decreased under the stresses of three contaminants. Generally, pesticide caused larger decrease in all MCRs than PAHs and crude soil except for vesicular MCRs. Mixed AMF showed larger decrease in the total and vesicular MCRs than single AM fungus, but contrary trends in the arbuscular and hyphal MCRs. Moreover, man-made contaminant seemed to produce larger negative effects on the total, vesicular, and arbuscular MCRs than industry contaminant. The inhibitive effects of three contaminants on the total and vesicular MCRs increased with increasing experimental duration, and were larger in the non-sterilized soil than in the sterilized soil. Hyphal and spore growth were also inhibited by three contaminants in most cases. Hyphal length and spore number of single AM fungus were lower than those of mixed AMF, and pesticide produced larger inhibition on the hyphal length and spore number than PAHs and crude oil. Similar trend was found in the non-sterilized soil relative to the sterilized soil. This study indicated that AM formation and AM structure were negatively affected by three organic contaminants, whereas the inhibitive degrees varied with AMF, organic contaminant and experimental conditions.

ARBUSCULAR MYCORRHIZAL SYMBIOSIS OF VIOLA BAOSHANENSIS AT BAOSHAN PB/ZN MINE IN CHINA

Despite great potential for arbuscular mycorrhizal fungi (AMF) in restoration of heavy metals (HMs) polluted lands, limited information is available about the arbuscular mycorrhizal (AM) symbiosis of naturally-occurring hyperaccumulators. A preliminary survey was conducted to investigate the AM symbiosis of Viola baoshanensis, a Cadmium (Cd) hyperaccumulator, growing at an abandoned mine. Shoot/root ratios of 1.78 for Cd, and 2.57 for zinc (Zn) indicate that these two metals were preferentially transported from roots to shoots, whereas the ratio of 0.32 for lead (Pb) shows that most Pb was stored in roots. High level of colonization was found in the roots of V. baoshanensis with relative mycorrhizal root length of 69.1%, relative arbuscular richness of 46.9% and relative vesicular richness of 1.7%. Fifteen AMF species were identified from the root zone soil of V. baoshanensis. The dominant AMF genus was Glomus, and the most abundant species were Glomus ambisporum and Claroideglomus etunicatum.

Diazotrophic organisms and arbuscular mycorrhizal fungi in the establishment of cassava plants

Cassava is an important food base and an excellent alternative source of carbohydrates, especially in developing countries. As it is an easy-to-manage crop, it can be grown in small areas and does not require high soil fertility. This culture has a symbiotic relationship with arbuscular mycorrhizal fungi (AMF), which expand the extent of the roots by the projection of their hyphae, which favors the absorption of water and nutrients from the soil and with nitrogen-fixing bacteria. The objective of this work was to evaluate the interaction of nitrogen-fixing bacteria with arbuscular mycorrhizal fungi at the initial stage of cassava culture. The following parameters were evaluated: the day of sprouting, plant height, root length, plant volume, colonization rate of mycorrhizal fungi and the genera of arbuscular mycorrhizal fungi. Plants inoculated with AMF and diazotrophic bacteria presented the lowest day of sprouting, the highest plant height and longer root length. Mycorrhizal interactions with and without inoculation with nitrogen-fixing bacteria were classified, and mycorrhizal fungi of the genera Acaulospora, Diversispora, Glomus and Gigaspora were classified.

Arbuscular mycorrhizal fungi enhance active ingredients of medicinal plants: a quantitative analysis

Medicinal plants are invaluable resources for mankind and play a crucial role in combating diseases. Arbuscular mycorrhizal fungi (AMF) are widely recognized for enhancing the production of medicinal active ingredients in medicinal plants. However, there is still a lack of comprehensive understanding regarding the quantitative effects of AMF on the accumulation of medicinal active ingredients. Here we conducted a comprehensive global analysis using 233 paired observations to investigate the impact of AMF inoculation on the accumulation of medicinal active ingredients. This study revealed that AMF inoculation significantly increased the contents of medicinal active ingredients by 27%, with a particularly notable enhancement observed in flavonoids (68%) and terpenoids (53%). Furthermore, the response of medicinal active ingredients in belowground organs (32%) to AMF was more pronounced than that in aboveground organs (18%). Notably, the AMF genus Rhizophagus exhibited the strongest effect in improving the contents of medicinal active ingredients, resulting in an increase of over 50% in both aboveground and belowground organs. Additionally, the promotion of medicinal active ingredients by AMF was attributed to improvements in physiological factors, such as chlorophyll, stomatal conductance and net photosynthetic rate. Collectively, this research substantially advanced our comprehension of the pivotal role of AMF in improving the medicinal active ingredients of plants and provided valuable insights into the potential mechanisms driving these enhancements.

Effectiveness of multiple culture of arbuscular mycorrhizal fungi (AMF) from the rhizosphere of cocoa on host plant Pueraria javanica

The utilization of single Arbuscular Mycorrhizal Fungi (AMF) is constrained by the propagation of the single spore and usually depends on the host plant. This study aims to examine the effectiveness of single culture propagation of several genera of AMF from the rhizosphere of cocoa and the concentration of NPK on the host Pueraria javanica. The study was designed with a completely randomized design with two factors. The first factor was the genus FMA which consisted of Acaulospora sp1 (M1), Acaulospora sp2 (M2), Glomus sp1 (M3), Glomus sp2 (M4), Glomus sp3 (M5). The second factor was that the concentration of liquid fertilizer was five levels: control (P0), 0.5g/l water (P1), 1.0g/l water (P2), 1.5g/l water (P3), 2.0g/l water (P4), and repeated four times. Parameters observed: root infection, spore number, main stem length, root length. The study showed that the highest number of spores resulted from the interaction of Acaulospora sp1 with 0.5g/l NPK. The most extended stem and root lengths were produced at 1.0g/l NPK with Acaulospora sp2, 27.40 cm, and 2.0 g NPK fertilizer with Acaulospora sp2, which had a root length of 8.8 cm. The highest colonization rate was found in plants not given NPK and infected with Glomus sp1. This study showed that the Pueraria Javanica plant is a suitable plant to be used as a host plant for the development of spore types Acaulospora and Glomous in single culture.

Mycorrhizae enhance reactive minerals but reduce mineral-associated carbon.

Soil organic carbon (C) is the largest active C pool of Earth's surface and is thus vital in sustaining terrestrial productivity and climate stability. Arbuscular mycorrhizal fungi (AMF) form symbioses with most terrestrial plants and critically modulate soil C dynamics. Yet, it remains unclear whether and how AMF-root associations (i.e., mycorrhizae) interact with soil minerals to affect soil C cycling. Here we showed that the presence of both roots and AMF increased soil dissolved organic C and reactive Fe minerals, as well as litter decomposition and soil CO2 emissions. However, it reduced mineral-associated C. Also, high-resolution nanoscale secondary ion mass spectrometry images showed the existence of a thin coating (0.5-1.0 μm thick) of 56 Fe16 O- (Fe minerals) on the surface of 12 C14 N- (fungal biomass), illustrating the close physical association between fungal hyphae and soil Fe minerals. In addition, AMF genera were divergently related to reactive Fe minerals, with Glomus being positively but Paraglomus and Acaulospora negatively correlated with reactive Fe minerals. Moreover, the presence of roots and AMF, particularly when combined with litter addition, enhanced the abundances of several critical soil bacterial genera that are associated with the formation of reactive minerals in soils. A conceptual framework was further proposed to illustrate how AMF-root associations impact soil C cycling in the rhizosphere. Briefly, root exudates and the inoculated AMF not only stimulated the decomposition of litter and SOC and promoted the production of CO2 emission, but also drove soil C persistence by unlocking mineral elements and promoting the formation of reactive minerals. Together, these findings provide new insights into the mechanisms that underlie the formation of reactive minerals and have significant implications for understanding and managing soil C persistence.

Association of mycoheterotrophic Gentianaceae with specific Glomus lineages.

Some plant species took an alternative evolutionary pathway in which they lost their photosynthetic capacity to depend exclusively on carbon supplied by arbuscular mycorrhizal fungi (AMF) in an association called mycoheterotrophy. Among them is Voyriella parviflora, a species of the family Gentianaceae, which is found in tropical regions such as the Amazon basin. Here, we assessed the identity of AMF symbionts associated with this species. DNA was isolated from eight Gentianaceae specimens and from litter and surrounding roots of photosynthetic plants. The atp1 gene was amplified by Sanger sequencing to determine the taxonomic affiliation of the mycoheterotrophic plants. A 280bp region of the 18S rRNA gene of AMF was amplified with primers NS31/AML2 by high-throughput sequencing. The mycoheterotrophic specimens were assigned to V. parviflora with a bootstrap support of 72%. Glomus was the most abundant AMF genus, both in the mycoheterotrophic plants and in the litter and roots of photosynthetic plants. In addition, a few Glomus genotypes were abundantly enriched in the mycoheterotrophic plants, with only a few specimens colonized by Gigaspora, Acaulospora, and Scutellospora in a low proportion. These genotypes formed a cluster within a larger clade, suggesting that V. parviflora shows a preferential association with a narrow Glomus lineage which is not phylogenetically close to a previously identified V. parviflora's associated lineage. Furthermore, detecting fungi from other families suggests that V. parviflora is colonized by other genera, although with low frequency. These findings provide new insights into the association between AMF and mycoheterotrophic species and highlight the importance of considering trap culture-independent approaches in understanding this symbiosis.

Arbuscular Mycorrhizal Fungi Response on Soil Phosphorus Utilization and Enzymes Activities in Aerobic Rice under Phosphorus-Deficient Conditions.

The prominence of arbuscular mycorrhizal fungi (AMF) in sustainable rice production has long been recognized. However, there is little information about AMF response in aerobic rice cultivation under phosphorus (P)-deficient conditions. The aim of this experiment was to compare and determine the preeminent AMF effects on rice mycorrhizal colonization, responsiveness, P utilization, and different growth-promoting traits under P-deficient conditions. Different AMF genera viz. (Funneliformis sp., Rhizophagus sp., Glomus sp., Acaulospora sp., and Claroideoglomus sp.) in four different aerobic rice varieties developed by ICAR-NRRI, India (CR Dhan 201, CR Dhan 204, CR Dhan 205, and CR Dhan 207) were investigated using the check P-susceptible variety (IR 36) and the P-tolerant variety (Kasalath IC459373). Data analyzed through linear modeling approaches and bivariate associations found that AMF colonization was highly correlated with soil enzymes, particularly fluorescein diacetate (FDA) and plant P uptake. The microbial biomass carbon (MBC) and FDA content were significantly changed among rice varieties treated with AMF compared to uninoculated control. Out of four different rice varieties, CR Dhan 207 inoculated with AMF showed higher plant P uptake compared to other varieties. In all the rice varieties, AMF colonization had higher correlation coefficients with soil enzymes (FDA), MBC, and plant P uptake than uninoculated control. The present study indicates that AMF intervention in aerobic rice cultivation under P-deficient conditions significantly increased plant P uptake, soil enzymes activities and plant growth promotion. Thus, the information gathered from this study will help us to develop a viable AMF package for sustainable aerobic rice cultivation.

Abundance and distribution of arbuscular mycorrhizal fungi associated with oil-yielding plants.

Due to their role in nutrient transmission, arbuscular mycorrhizal fungi (AMF) are widespread plant root symbionts. They may improve plant production by altering plant community structure and function. Therefore, a study was conducted in the state of Haryana to analyze the distribution pattern, diversity, and association of different AMF species with oil-yielding plants. The results of the study revealed the percentage of root colonization, sporulation, and diversity of fungal species associated with the selected 30 oil-yielding plants. The percentage root colonization ranged from 0% to 100%, the highest in Helianthus annuus (100.00 ± 0.00) and Zea mays (100.00 ± 0.00) and the least in Citrus aurantium (11.87 ± 1.43). At the same time, there was no root colonization in the Brassicaceae family. The number of AMF spores present in 50 g of soil samples varied from 17.41 ± 5.28 to 497.2 ± 8.38, with maximum spore population in Glycine max (497.2 ± 8.38) and minimum in Brassica napus (17.41 ± 5.28). Besides, the presence of several species of different genera of AMF was reported in all the studied oil-yielding plants, that is, 60 AMF belonging to six genera viz. Acaulospora, Entrophospora, Glomus, Gigaspora, Sclerocystis, and Scutellospora were observed. Overall, this study will promote AMF usage in oil-yielding plants.

Identifikasi Fungi Mikoriza Arbuskula (FMA) pada Mangga Lokal Indramayu

Mango (Mangifera indica L.) is one of Indonesia's leading horticultural commodities. The island of Java is the national center for mango production. Mango production in West Java is one of the largest in Indonesia. The Indramayu region is the largest mango production center in West Java. Demand for this commodity is increasing, especially exports, while mango production in the last five years has fluctuated. The way to maintain optimal and sustainable mango production is by using fertilization. One of the fertilization efforts that can be done is with Arbuscular Mycorrhizal Fungi (AMF). The presence of AMF in host plants can help the uptake of nutrients, especially phosphorus which is very important in growth, especially in the generative phase of plants. However, not all AMF can be symbiotic with plants. Therefore, it is necessary to explore and identify AMF for its utilization. This study aimed to obtain information on the diversity of AMF in local mangoes from Indramayu. This research was conducted in Jatibarang District, Indramayu with a research time of 12 months and started after the rainy season. The results showed that two AMF genera were found in the local mango rhizosphere of Indramayu, namely the genus Glomus and Acaulospora. The number of AMF spores found per 20 g of soil was 37.67 in Lobener Village, 31.67 in Jatisawit Village, and 42.33 in Krasak Village. AMF colonization in Lobener Village was 34.44%, Jatisawit Village 23.33%, and Krasak Village 33.33%.

The root-associated arbuscular mycorrhizal fungal assemblages of exotic alien plants are simplified in invaded distribution ranges, but dominant species are retained: A trans-continental perspective.

Arbuscular mycorrhizal fungi (AMF) provide crucial support for the establishment of plants in novel environments. We hypothesized that the OTU/genus richness and diversity of soil- and root-associated AMF associated with alien plant species in their exotic ranges are lower than those in their native ranges. We examined the root-associated and soil-dwelling AMF of 11 invasive plant species in their native and exotic ranges in the United States and Europe by DNA sequencing of the ITS2 locus. Examined root-associated AMF assemblages were simplified, which manifested as the loss of several AMF genera in the exotic ranges of the plants. These fungal assemblages were also characterized by greater dominance and simplification of the fungal assemblages. The dominant fungal genera were present regardless of whether their host plants were in their native or exotic ranges. Interestingly, both the native and invaded soils hosted diverse local AMF assemblages. Therefore, alien plant invasions were not limited to soils with low AMF diversity. Some AMF taxa could be context-dependent passengers rather than drivers of alien plant invasions. Further studies should identify functions of AMF missing or less abundant in roots of plants growing in exotic ranges.

Effect of water stress and mixed types of the genus Arbuscular Mycorrhizal Fungi from cocoa roots on spore propagation and root colonization used corn as the host

Biofertilizer with Arbuscular Mycorrhizal Fungi (AMF) as the inoculants is needed in organic cocoa cultivation on smallholder plantations in Indonesia. AMF biofertilizer requires a sufficient number of spore inoculants, so it is necessary to multiply isolated spores. Research objective was determining the effect of water stress and mixed types of AMF genus from cocoa roots on spore propagation and root colonization used corn as the host plant. The study used a 2-factors randomized block design and 3 replications. The first factor was water stress consisting of 3 levels (without water stress as a control, soil moisture content 100% of field capacity; light water stress, soil moisture content 70% of field capacity; and heavy water stress, soil moisture content 40% of field capacity), while the second factor was mixed types of AMF genus also consisting of 3 levels (inoculant of genus Glomus only, mixed inoculants of the genus Glomus + Acaulospora, and mixed inoculants of the genus Glomus + Scutelospora. Result of research showed, the interaction of water stress and mixed types of the AMF genus had no significantly affect on the number of spores reproduced, root colonization and host plant growth. The best way of propagation of AMF spores was by heavy water stress treatment with a soil moisture content of 40% of field capacity producing 6,713.40 spores or an increase of 13,326.82%. Mixed inoculants of the genus Glomus + Scutelospora gave the highest number of spores after propagation (6,263.40 pieces) or an increase of 12,427.77%.

Arbuscular mycorrhizal fungi community linkages to soil nutrient availability across contrasting agroecosystems

Perennial grain crops have been proposed as a groundbreaking tactic to establish sustainable agroecosystems, as their growth habit and no-till management likely invoke multifunctionality such as improvement of soil structure as well as increases in nutrient retention and carbon (C) sequestration. Arbuscular mycorrhizal fungi (AMF) are multifunctional symbioses, which are ecologically important for over 80% terrestrial plants that form root associations with these fungi. Our study examined AMF diversity and community composition in annual and perennial grain crops; with and without nitrogen (N) fertilizer addition at two field sites within the Canadian prairies (Breton and Edmonton). AMF diversity and community composition were significantly different between the two study sites. This was attributed to the contrasting cropping management histories of the sites; previous long-term land use in Edmonton was annual cropping, whereas Breton was perennial forage crop. AMF community composition was not different between annual versus perennial grain cropping on both the bulk soil and rhizosphere (roots). Overall, the addition of N fertilizer did not change AMF diversity and community compositions but increased the abundance of Archaeospora. The most predominant genus in these temperate agroecosystems was Paraglomus, while Archaeospora and Claroideoglomus were observed in the roots compartment but unfrequently and specifically at the Edmonton site. Interestingly, Archaeospora and Paraglomus were significantly correlated with changes in particulate organic matter C, while Claroideoglomus had a positive correlation with ammonium concentration. Results revealed functional associations between key soil properties and certain AMF genera, which showed to be site specific.

Acaulospora as the Dominant Arbuscular Mycorrhizal Fungi in Organic Lowland Rice Paddies Improves Phosphorus Availability in Soils

Flooding in rainfed lowlands greatly impairs the mutualistic relationship between indigenous arbuscular mycorrhizal fungi (AMF) and rice. In flooded soils, root colonization by AMF is arrested, but some AMF genera, defined as the core AMF, remain present. However, the core AMF in rainfed lowlands and their symbiotic roles remain unknown. Here, we showed that Acaulospora fungi were the core AMF in rice seedling roots of the Sangyod Muang Phatthalung (SMP) landrace rice variety grown in non-flooded and flooded paddy soils. Subsequently, indigenous Acaulospora spores were propagated by trap cultures using maize as the host plants. Therefore, to clarify the roles of cultured Acaulospora spores in a symbiotic partnership, the model japonica rice variety Nipponbare was grown in sterile soil inoculated with Acaulospora spores, and recolonized with a native microbial filtrate from the organic rice paddy soil. Our data demonstrated that the inoculation of Acaulospora spores in well-drained soil under a nutrient-sufficient condition for six weeks enabled 70 percent of the rice roots to be colonized by the fungi, leading to higher phosphate (Pi) accumulation in the mycorrhizal roots. Unexpectedly, the growth of rice seedlings was significantly suppressed by inoculation while photosynthetic parameters such as fractions of incoming light energy and relative chlorophyll content were unaltered. In the soil, the Acaulospora fungi increased soil phosphorus (P) availability by enhancing the secretion of acid phosphatase in the mycorrhizal roots. The findings of this work elucidate the symbiotic roles of the dominant Acaulospora fungi from lowland rice paddies.

Host-Specific Effects of Arbuscular Mycorrhizal Fungi on Two Caragana Species in Desert Grassland.

Arbuscular mycorrhizal fungi (AMF), which form symbioses with most land plants, could benefit their hosts and potentially play important roles in revegetation of degraded lands. However, their application in revegetation of desert grasslands still faces challenges and uncertainties due to the unclear specificity of AMF-plant interactions. Here, Caragana korshinskii and Caragana microphylla were inoculated with either conspecific (home) or heterospecific (away) AM fungal communities from the rhizosphere of three common plant species (C. korshinskii, C. microphylla and Hedysarum laeve) in Kubuqi Desert, China. AMF communities of the inocula and their home and away effects on growth and nutrition status of two Caragana species were examined. Results showed that AMF communities of the three inocula from C. korshinskii, H. laeve and C. microphylla were significantly different, and were characterized by high abundance of Diversispora, Archaeospora, and Glomus, respectively. The shoot biomass, photosynthetic rate, foliar N and P contents of C. korshinskii only significantly increased under home AMF inoculation by 167.10%, 73.55%, 9.24%, and 23.87%, respectively. However, no significant effects of AMF on C. microphylla growth were found, regardless of home or away AMF. Positive correlations between C. korshinskii biomass and the abundance of AMF genus Diversispora were found. Our study showed strong home advantage of using native AMF community to enhance C. korshinskii growth in the desert and presented a potentially efficient way to use native AMF in restoration practices.

Molecular Diversity of Arbuscular Mycorrhizal Fungi (AMF) Associated with Carissa edulis, an Endangered Plant Species along Lake Victoria Basin of Kenya

Carissa edulis is a tropical plant belonging to the family Apocynaceae. The species is widely used in the preparation of various herbal medicines. Earlier works in Kenya show that an aqueous extract from the roots of C. edulis has remarkable anti-herpes simplex virus. Due to its medicinal value, the species has been overexploited in its natural range and requires conservation interventions. Studies show that the species has beneficial relationships with arbuscular mycorrhizal fungi (AMF) that can enhance restoration of its population; however, no study has been undertaken to document the diversity of these AMF species. This study evaluated the genetic diversity of AMF associated with the roots of C. edulis within Lake Victoria basin ecosystem of Kenya. A cross-sectional, laboratory-based prospective study was carried out from roots of C. edulis collected from six sites within the ecosystem. Root samples were collected from 6 points (replicates) per site. AMF was assessed through morphological characterization and sequencing of small subunit of ribosomal DNA. Morphological identification identified four genera of AMF (Gigaspora, Acaulospora, Scutellospora, and Glomus) with no significant difference among the sites. Molecular analysis also revealed presence of four genera, but only two (Glomus and Acaulospora) were common for both the analyses with Glomus as the most predominant genera. In all the sites, there were large numbers of spores both in soil and in the roots confirming the association between C. edulis and AMF.

Temperature and precipitation significantly influence the interactions between arbuscular mycorrhizal fungi and diazotrophs in karst ecosystems

Arbuscular mycorrhizal fungi (AMF) and diazotrophs have the potential for nutrient transfer and biological nitrogen fixation in ecosystems, respectively. However, their response to vegetation restoration remains unclear, especially under varying temperature and precipitation levels in karst ecosystems. This study aimed to understand the effects of three climatic levels within four natural and managed vegetation restoration types on the diversity and community composition of AMF and diazotrophs. The interactive effects of temperature, precipitation, and vegetation types affected AMF diversity, while diazotroph diversity was not affected. Under conditions of natural vegetation restoration, there was an increase in AMF diversity in response to increasing temperature and precipitation. AMF richness was higher in shrubland and mature forest than in cropland when temperatures were over 20 ℃ and precipitation was high. Thus, in terms of diversity, AMF were more responsive to changes in climatic conditions and vegetation recovery than diazotrophs. Both AMF and diazotroph community compositions were affected by temperature and vegetation type. The relative abundances of AMF groups (e.g., Gigaspora, Glomus, and Septoglomus) and diazotroph taxa (e.g., Frankia) increased at temperatures above 18 ℃. The relative abundances of the AMF genus Glomus and the diazotroph genus Bradyrhizobium in shrubland and mature forest were higher than those in cropland, while abundances of the AMF genus Septoglomus and diazotroph genus Anabaena increased in cropland. Network complexity increased with increasing temperature and precipitation between AMF and diazotroph taxa. Glomus and Bradyrhizobium showed the most links with other groups, confirming that the dominant genera perform well in the co-occurrence network. These results suggested high hydrothermal regions resist rapid nutrient decomposition by strengthening the interactions between AMF and diazotrophs, especially between the abundant groups Glomus and Bradyrhizobium. Management to increase AMF and diazotroph abundance during vegetation recovery in high climate level may stimulate nutrient absorption and transport.

Clary Sage Cultivation and Mycorrhizal Inoculation Influence the Rhizosphere Fungal Community of an Aged Trace-Element Polluted Soil.

Soil fungal communities play a central role in natural systems and agroecosystems. As such, they have attracted significant research interest. However, the fungal microbiota of aromatic plants, such as clary sage (Salvia sclarea L.), remain unexplored. This is especially the case in trace element (TE)-polluted conditions and within the framework of phytomanagement approaches. The presence of high concentrations of TEs in soils can negatively affect not only microbial diversity and community composition but also plant establishment and growth. Hence, the objective of this study is to investigate the soil fungal and arbuscular mycorrhizal fungi (AMF) community composition and their changes over time in TE-polluted soils in the vicinity of a former lead smelter and under the cultivation of clary sage. We used Illumina MiSeq amplicon sequencing to evaluate the effects of in situ clary sage cultivation over two successive years, combined or not with exogenous AMF inoculation, on the rhizospheric soil and root fungal communities. We obtained 1239 and 569 fungal amplicon sequence variants (ASV), respectively, in the rhizospheric soil and roots of S. sclarea under TE-polluted conditions. Remarkably, 69 AMF species were detected at our experimental site, belonging to 12 AMF genera. Furthermore, the inoculation treatment significantly shaped the fungal communities in soil and increased the number of AMF ASVs in clary sage roots. In addition, clary sage cultivation over successive years could be one of the explanatory parameters for the inter-annual variation in both fungal and AMF communities in the soil and root biotopes. Our data provide new insights on fungal and AMF communities in the rhizospheric soil and roots of an aromatic plant, clary sage, grown in TE-polluted agricultural soil.