Mycorrhiza最新文献

Developing management practices that enhance crop yield while maintaining soil health is the foremost objective of the regenerative agriculture movement. One avenue to achieving this goal is using biofertilizers and alternative soil amendments to supplement or replace agrochemicals. Here we report the results of a pairwise field trial of spring wheat (Triticum aestivum) wherein we investigated individual and combined impacts of inoculation with arbuscular mycorrhizal fungi (AMF) and a spent mushroom compost amendment (herein mushroom compost). The symbiotic relationship between AMF and plants has been demonstrated to benefit the yield and nutritional quality of many crops by enhancing access to mineral nutrients and water. Mushroom compost, consisting of the devitalized residual substrate following harvest of edible mushrooms, is a byproduct of the mushroom industry and is comprised of a variety of nutrient-rich organic material inputs. Therefore, the objective of this study was to (1) determine the effect to which AMF and mushroom compost individually impact wheat yield and nutritional quality, and (2) examine if these effects are synergistic or antagonistic when both amendments are applied together. We found that mushroom compost addition, regardless of AMF inoculation, enhanced grain yield by ~ 40%, but reduced AMF root colonization level by ~ 25-40%. Additionally, despite yield increases, mushroom compost addition reduced grain phosphorus (P), potassium (K), and magnesium (Mg) concentrations by ~ 10% and boron concentration by ~ 45%. In fact, grain P, K, and Mg concentrations were all correlated with mycorrhizal colonization level. These results suggest that while spent mushroom compost additions enhanced grain yield, this may have led to a mineral nutrient 'dilution effect' exacerbated by negative impacts on AMF colonization and community composition.

Arbuscular mycorrhizal fungi (AMF) form symbiotic associations with plant roots, enhancing water and nutrient absorption. Phosphate-solubilizing fungi (PSF) can solubilize and mineralize phosphorus, an essential nutrient with low bioavailability, and eventually interact with AMF. However, the understanding of how they interact in the hyphosphere, where root influence is absent, remains limited. Furthermore, the effect of PSF on the phosphatase activity of AMF, related to the P efficiency in acquisition and utilization, within the hyphosphere and mycorrhizosphere zones, remains unclear. Therefore, this study aimed to assess the effect of three different PSF (Talaromyces flavus, T. helicus, and T. diversus) exudates on extracellular acid phosphatases and alkaline phosphatases associated with intra- and extraradical AMF structures in the hyphosphere and mycorrhizosphere, in vitro. To achieve this aim, the AMF Rhizophagus intraradices was cultured with Ri T-DNA transformed carrot roots in a system using Petri dishes that mimicked the hyphosphere (with 2 sections: (a) with roots and AMF, and (b) with only AMF) and the mycorrhizosphere (with roots and AMF in the same place). Different concentrations of PSF exudates were placed in either the hyphosphere or the mycorrhizosphere, and at the end of the experiment (8 weeks), the phosphatase activity of the AMF was measured. This research highlights that the enzymatic activity of AMF is modulated by PSF exudates, depending on whether these exudates are present in the hyphosphere or the mycorrhizosphere. Exudates in the hyphosphere, where PSF are directly associated with AMF hyphae, have a more pronounced effect on AMF extraradical alkaline phosphatases than acid phosphatases, and promote symbiosis efficiency. In contrast, PSF exudates in the mycorrhizosphere had a neutral or negative effect on symbiosis efficiency, improving the extraradical alkaline phosphatases of AMF and the acid phosphatases of the roots. Also, the effect depends on the fungal identity. AMF act as mediators in this context, improving communication between the roots and the hyphosphere microbiome. When exploring the soil, the hyphae encounter compounds produced by microorganisms, thus establishing a complex network of interactions. These interactions enhance the symbiotic efficiency of AMF, modulating the host plant without direct contact. These results show that microbial interactions not only influence the efficiency of phosphorus transfer to plants but also have broader implications for soil health and fertility management.

Aucoumea klaineana is the most important timber species in Central Africa, naturally forming monodominant stands. While soil fungi are crucial for plant growth, their role in promoting monodominance or supporting suppressed, light-demanding trees remains underexplored. This study, the first to analyze the root mycobiota of A. klaineana, investigates fungal communities in monodominant stands and old-growth mixed forests in Gabon, and plantations in the DRC, sampling both canopy-reaching vs. suppressed individuals, using ITS2 rDNA and 18S rDNA high-throughput sequencing. We identified high fungal diversity in both regions but found no "core mycobiota" across stand types or tree social status (canopy-reaching vs. suppressed). Fungal communities varied significantly between stand types, emphasizing a context-dependent nature. Moreover, no distinct fungal communities characterize the mycobiota of suppressed trees. Our findings indicate that fungal associations, including mycorrhizal ones, are unlikely to be a driver of monodominance in A. klaineana. These results highlight the need to consider alternative processes, not related to fungal interactions, such as root grafting, in explaining the persistence of suppressed trees and the dynamics of monodominant stands of A. klaineana. Finally, this study illustrates the highly variable and diverse belowground communities associated with A. klaineana, whose functions and interactions could contribute to the sustainable management of this major timber tree species.

Arbuscular mycorrhizal fungi (AMF) establish symbiotic associations with most plants and play a crucial role in enhancing the quality of medicinal plants. Although AMF is widely applied to improve growth and pharmacological properties, their regulatory mechanisms in Polygala tenuifolia remain unclear. In this study, we systematically examined the effects of five AMF species on the growth and metabolism of P. tenuifolia through pot experiments, integrating phenotypic traits, physiological indices, and untargeted metabolomics. Among the tested fungi, Funneliformis mosseae significantly promoted plant growth and induced the highest accumulation of 3',6-disinapoylsucrose (DISS), a key bioactive metabolite. Metabolomic profiling revealed that AMF, particularly F. mosseae, reprogrammed root metabolism by modulating biosynthetic pathways related to unsaturated fatty acids, diterpenoids, and flavonoids. Correlation analysis revealed that DISS levels were strongly associated with AMF-induced growth promotion index (GPI), total chlorophyll, and flavonoid content, and closely linked to shifts in key metabolites within these pathways. These findings suggest that AMF enhance P. tenuifolia growth and medicinal quality through metabolic reprogramming. This study provides a theoretical basis for selecting efficient AMF species for precision cultivation of medicinal plants and lays the groundwork for future exploration of gene-level mechanisms driving quality formation in P. tenuifolia.

Cultivated strawberry dominates fruit production of the northern hemisphere and provide essential nutrients for human health. However, strawberry production has still a negative impact on agricultural soil and fruit quality does not always meet consumer expectations. Plant-microorganism interactions engineering involving arbuscular mycorrhizal fungi and rhizobacteria is known to alter plant's metabolic pathways and shape fruit quality (flavour and nutrient content). In our study, 21 Pseudomonas fluorescens strains were isolated from a two-year strawberry cultivation system and screened for their plant growth promoting activities. Four P. fluorescens were selected based on their activity and phylogenetic groups and inoculated in association or not with Rhizophagus irregularis DAOM 197198 on 3 different strawberry genotypes. The volatile profiles of the harvested strawberries were analysed by GC-MS. The abundance of hexanal, a compound used to extend shelf-life and reduce post-harvest diseases, was found more abundant in strawberry fruit from plants inoculated with the AMF R. irregularis than in non-Ri plants. The study showed that metabolite content of strawberries is significantly different between cultivars but exhibits a distinct and consistent pattern in response to P. fluorescens in association or not with the AMF R. irregularis. Our results suggest that the inoculation with P. fluorescens and R. irregularis improves strawberry quality and fine-tunes taste to consumer preference. Broadly, microbiome engineering has the potential to tailor fruit flavour to consumer taste while increasing nutritional benefits and food safety.

While the positive impact of arbuscular mycorrhizal fungi (AMF) on rice growth has been well documented, the specific mechanisms by which different AMF species regulate rice growth and the rhizosphere microecosystem are not fully understood. This research investigated two AMF species, Funneliformis mosseae (Fm) and Rhizophagus intraradices (Ri), to elucidate their effects on rice rhizosphere soil characteristics, microbial community structure, and rice yield. Field experiments showed that treatment with Fm resulted in significantly yields (26.96%) compared to Ri (21.19%). Although both AMF species significantly increased mycorrhizal colonization rates compared to the control (Fm: 78.23%, Ri: 70.13% at maturity), they induced distinct improvements in soil properties. Specifically, Fm significantly boosted soil enzyme activities, increasing urease and cellulase activities by 47.29% and 24.62%, respectively, compared to Ri, Conversely, Ri promoted the accumulation of soil available phosphorus (69.81% higher than Fm). Additionally, the two AMF strains influenced the rhizosphere microbial community through different regulatory mechanisms. Fm significantly enriched bacterial taxa related to carbon cycling, such as Chloroflexota and Actinomycetota. Ri not only significantly increased microbial α-diversity but also specifically enriched bacterial function groups related to sulfur cycling. Crucially, the two AMF species optimized interactions between AMF, rice plants, and rhizosphere microorganisms via different structural modifications. Under Fm, fungal community network modularity was significantly higher, while the bacterial network under Ri treatment exhibited stronger connectivity. This study elucidates the distinct mechanisms by which AMF species synergistically enhance rhizosphere soil microenvironmental quality and increase rice yield. These findings provide a theoretical basis for the sustainable management of rice fields and suggest new directions for developing environmentally friendly agricultural technologies.

Waitea circinata, an orchid-associated mycorrhizal fungus, was evaluated for the first time as a biological control agent against the root-knot nematode Meloidogyne javanica. The fungus was originally isolated from the roots of Epidendrum nocturnum, a rupicolous orchid to the Brazilian Cerrado. In vitro assays demonstrated that W. circinata parasitized nematode eggs, with parasitism rates of 13-15% and characteristic emergence of septate hyphae with right-angle branching. Microscopy revealed eggshell degradation, arrested embryogenesis, and juvenile deformation. A mycelial suspension (MSF) of the fungus increased juvenile (J2) mortality in a dose-dependent manner, suggesting the action of nematicidal metabolites. In greenhouse experiments, W. circinata significantly reduced the nematode reproduction factor (RF), with values dropping from above 5 in the control to below 1 at the highest concentrations. In addition, MSF application promoted plant growth, increasing root length, root mass, and shoot height. No phytotoxic effects were observed at any dose. Principal component analysis confirmed a negative correlation between nematode-related variables and plant development, reinforcing the dual action of W. circinata in nematode suppression and plant stimulation. These effects are likely mediated by a combination of mechanisms, including parasitism, enzyme activity, antibiosis, and the production of phytohormones. The results highlight W. circinata as a promising candidate for the sustainable management of plant-parasitic nematodes and the enhancement of crop performance.

Frequent drought events pose escalating threats to global ecosystems, driving vegetation degradation, biodiversity loss, while destabilizing ecosystem functions. Dark septate endophytes (DSE), which exhibit drought stress tolerance in vitro and have the potential to enhance plant drought tolerance in arid environments, represent a key microbial component possibly mitigating drought impacts. Therefore, this study focuses on the dominant drought-tolerant plant Anemone tomentosa (A. tomentosa) and its symbiotic DSE in the drought-prone Taihang Mountain area, aiming to reveal the community composition, spatial distribution and functions of DSE, explore their application potential in arid environments, and provide a basis for fully utilizing DSE resources to promote vegetation restoration and ecological reconstruction in arid regions. Root and soil samples of A. tomentosa were collected from six sampling sites in the Taihang Mountain area to systematically investigate DSE colonization, community composition, species diversity and their correlations with soil environmental factors across different sites. Then six DSE strains with high isolation frequencies were selected for the drought resistance study in pure cultures, and varying polyethylene glycol (PEG-6000) concentrations (0%, 15%, 25%, And 35%) were set to simulate drought stress. The results showed that the roots of A. tomentosa at all six sampling sites in the Taihang Mountain area were highly colonized by DSE, forming typical dark-colored septate hyphae And microsclerotia structures. A total of 20 DSE strains belonging to 14 genera were isolated and identified, and the community composition of DSE at different sampling sites differed significantly (P < 0.05). The results of redundancy analysis (RDA) showed that soil organic carbon and soil total phosphorus were the Main factors influencing the community composition of DSE. The growth of 5 frequently isolated DSE strains under pure culture conditions was not adversely affected by drought stress, except for Exophiala xenobiotica (Ex), and biomass accumulation increased significantly with increasing drought stress, which was related to the content of antioxidant enzymes, osmotic adjustment substances, membrane lipid peroxidases and melanin in the different fungi. In summary, A. tomentosa in Taihang Mountain has rich DSE species diversity, and the two can form a symbiotic relationship, thus enhancing the adaptability of A. tomentosa to the environment. Five DSE strains exhibited drought stress tolerance under in vitro culture conditions, which enriched the understanding of the ecological functions and adaptive mechanisms of DSE in arid environments and provided a basis for the development and application of drought-resistant and water-preserving microbial agents.

Early stages of the ectomycorrhizal symbiosis have rarely been studied on seedlings germinating in the field. By collecting lodgepole and ponderosa pine seedlings during their first growing season in recent clearcuts and burned areas, we were able to identify when colonization of pine roots first began, the rate at which ectomycorrhizal fungi colonized new germinants, and how this related to nitrogen nutrition and growth. Pine seedlings were first colonized in July, a month after germination was first observed. As the first seedlings became mycorrhizal, ectomycorrhizal lodgepole pine seedlings contained approximately 40% more nitrogen and > 60% greater biomass compared to uncolonized seedlings collected at the same time. Nitrogen content was 47% higher in mycorrhizal than nonmycorrhizal naturally-regenerating ponderosa pine seedlings. Ascomycetes, with a Pustularia sp. and Wilcoxina spp. most abundant, formed 80% of the ectomycorrhizae. Because all collected seedlings had ectomycorrhizae present on their roots by the end of the season, we concluded that inoculum of ectomycorrhizal fungi, especially of ruderal ascomycetes, was not limiting colonization of seedlings on these severely burned or recently clearcut sites. Our results are consistent with a role for ectomycorrhizal fungi in nitrogen acquisition, even within the first weeks after mycorrhiza formation; however, it is also possible that larger, more nitrogen-replete seedlings became colonized earlier than smaller seedlings. We saw no evidence of nitrogen loss by mycorrhizal pine seedlings as observed in previous studies.