Search Results (31)

Valued above all others, the white truffle species (Tuber magnatum Picco) is highly dependent on the forest ecosystem and its underground biology. Despite its economic importance, knowledge of its biology and mycorrhizal symbioses remains limited; moreover, natural yields have sharply declined, and cultivation efforts have produced inconsistent results. This study evaluated various forest and mycorrhizal inoculation techniques to promote T. magnatum mycelium development in three Tuscan sites converted to truffle cultivation, using qPCR analysis. Alongside conventional practices like irrigation, mulching, and tillage, an experimental method with a sterile, spore-inoculated soil barrier was tested to improve host root establishment, enhance mycorrhization, and maintain long-term symbiosis for healthy truffle ecosystems. Soil analyses nine months after planting Quercus robur L. seedlings showed significant differences in Tuber magnatum mycelium abundance across sites and treatments. The MA treatment—mycorrhized seedlings combined with a sterile, inoculated substrate and separation diaphragm—produced the highest mycelial levels, underscoring the importance of initial mycorrhization and soil manipulation. These findings provide valuable insights for optimizing forest management and improving truffle cultivation by enhancing mycelial development, a key step toward increasing truffle production. Full article

The success of truffle cultivation is especially dependent on the quality of truffle-mycorrhized seedlings, which are typically produced in nurseries under aseptic conditions to avoid root colonization by undesired ectomycorrhizal fungi. However, such practices may also eliminate beneficial microorganisms that could support truffle symbiosis and improve seedling quality. In this study, twelve endophytic bacterial and fungal strains, isolated from the Tuber melanosporum environment (gleba tissue, mycorrhizae and truffle brûlé), were tested for their effect on T. melanosporum mycorrhization levels in inoculated Quercus ilex seedlings under nursery conditions. Co-inoculation with a strain of Agrobacterium tumefaciens significantly enhanced root colonization by T. melanosporum, supporting its potential role as mycorrhizal helper bacterium. In contrast, a strain of Trichoderma harzianum negatively affected mycorrhization. The remaining strains did not show significant effects on seedling mycorrhization or seedling growth. Our findings support the hypothesis that specific bacterial strains associated with truffles can act as mycorrhizal helper bacteria, highlighting the potential for co-inoculation strategies to enhance quality of truffle-inoculated seedlings in nurseries. However, further research is needed to gain a deeper understanding of the interactions within the mycorrhizosphere that could contribute to improving nursery seedling quality. Full article

Flavonoids serve as crucial plant antioxidants in drought tolerance, yet their antioxidant regulatory mechanisms within mycorrhizal plants remain unclear. In this study, using a two-factor design, trifoliate orange (Poncirus trifoliata (L.) Raf.) seedlings in the four-to-five-leaf stage were either inoculated with Funneliformis mosseae or not, and subjected to well-watered (70–75% of field maximum water-holding capacity) or drought stress (50–55% field maximum water-holding capacity) conditions for 10 weeks. Plant growth performance, photosynthetic physiology, leaf flavonoid content and their antioxidant capacity, reactive oxygen species levels, and activities and gene expression of key flavonoid biosynthesis enzymes were analyzed. Although drought stress significantly reduced root colonization and soil hyphal length, inoculation with F. mosseae consistently enhanced the biomass of leaves, stems, and roots, as well as root surface area and diameter, irrespective of soil moisture. Despite drought suppressing photosynthesis in mycorrhizal plants, F. mosseae substantially improved photosynthetic capacity (measured via gas exchange) and optimized photochemical efficiency (assessed by chlorophyll fluorescence) while reducing non-photochemical quenching (heat dissipation). Inoculation with F. mosseae elevated the total flavonoid content in leaves by 46.67% (well-watered) and 14.04% (drought), accompanied by significantly enhanced activities of key synthases such as phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), 4-coumarate:coA ligase (4CL), and cinnamate 4-hydroxylase (C4H), with increases ranging from 16.90 to 117.42% under drought. Quantitative real-time PCR revealed that both mycorrhization and drought upregulated the expression of PtPAL1, PtCHI, and Pt4CL genes, with soil moisture critically modulating mycorrhizal regulatory effects. In vitro assays showed that flavonoid extracts scavenged radicals at rates of 30.07–41.60% in hydroxyl radical (•OH), 71.89–78.06% in superoxide radical anion (O₂^•−), and 49.97–74.75% in 2,2-diphenyl-1-picrylhydrazyl (DPPH). Mycorrhizal symbiosis enhanced the antioxidant capacity of flavonoids, resulting in higher scavenging rates of •OH (19.07%), O₂^•− (5.00%), and DPPH (31.81%) under drought. Inoculated plants displayed reduced hydrogen peroxide (19.77%), O₂^•− (23.90%), and malondialdehyde (17.36%) levels. This study concludes that mycorrhizae promote the level of total flavonoids in trifoliate orange by accelerating the flavonoid biosynthesis pathway, hence reducing oxidative damage under drought. Full article

The synthesis and symbiotic mechanisms of truffle ectomycorrhizae have attracted considerable scientific interest in recent decades. Although previous research has successfully identified the symbiotic partners of truffles (Tuber spp.) and characterized their mature morphological features, the dynamic processes involved in truffle ectomycorrhizal formation remain insufficiently understood. In this study, we established an ectomycorrhizal synthesis system using Castanea mollissima seedlings inoculated with Tuber sinense spore suspensions under controlled greenhouse conditions, followed by an eight-month observation period. To systematically characterize and model the morphological changes during ectomycorrhizal development, we employed an innovative approach integrating resin sectioning with confocal microscopy. Ectomycorrhizal formation was initially observed two months post inoculation, with a colonization rate reaching 24.4 ± 5.3% by the third month. The ectomycorrhizae displayed a distinct color progression from light brown through ochre and finally dark brown, typically manifesting either monopodial or branched structures. Early developmental stages (2–3 months) were characterized by a thin mycelial membrane enveloping the root surface, accompanied by limited hyphal penetration into the root system. By the eighth month, the colonization rate stabilized at 45.2 ± 8.6%, with enhanced organization and density of the fungal mantle and extended Hartig nets reaching the periphery of outer cortical cells. The continuous growth and differentiation of mycorrhizal root tips generated repetitive root architectures, significantly enhancing symbiotic efficiency. These findings provide critical insights into the morphological development and symbiotic effectiveness of truffle ectomycorrhizae while establishing a methodological framework for investigating ectomycorrhizal associations in other economically significant plant–fungal systems. Full article

Soil salinization is a growing global concern in many ecosystems. Although ectomycorrhizal fungi have been shown to alleviate the effects of salinity in some tree species, uncertainties persist concerning their effectiveness when plants are exposed to different salinity levels that are commonly present in salt-affected soils. Quercus dentata seedlings either non-inoculated (mycorrhizal control) or inoculated with the ectomycorrhizal fungus Laccaria bicolor were then treated with three NaCl concentrations (0, 0.4%, and 0.8%). The physiological, stoichiometric, and growth characteristics of the plants were examined. NaCl significantly affected seedling growth and physiology. However, the impact of L. bicolor on Q. dentata seedlings could shift in response to varying salt concentrations. Under moderate salinity, inoculation of L. bicolor increased root biomass by 4.55% and leaf chlorophyll concentrations by 46.8%, and decreased leaf Na⁺ concentrations and the Na⁺/K⁺ ratios. Under high salinity, L. bicolor decreased leaf water content and fluorescence parameters, and increased leaf Na⁺ concentrations. The effect of ectomycorrhizal fungus L. bicolor on Q. dentata seedlings was dependent on NaCl concentration, and our results indicate that the use of L. bicolor in afforestation efforts with Q. dentata would only be effective under relatively low soil salinity levels. Full article

An indigenous consortium of arbuscular mycorrhizal fungi (AMF) from the Figuig oasis in southern Morocco, comprising Rhizophagus sp., Funneliformis sp., Acaulospora sp., Sclerocystis sp., and Scutellospora sp., was evaluated for its effects on the growth and sensitivity of Phoenix dactylifera L. variety (cv. Boufeggous Gharas) to Fusarium oxysporum f. sp. Albedinis (Foa), the causal agent of Bayoud disease. Despite its high fruit quality and local appreciation, the Boufeggous Gharas variety is highly susceptible to Foa and is currently at risk of extinction, underscoring the urgent need for its sustainable management. The results demonstrated that Boufeggous Gharas seedlings inoculated with a consortium of indigenous AMF showed significantly improved shoot and root length, leaf number, and biomass as compared to non-mycorrhized seedlings. In contrast, Foa-infected seedlings showed significantly reduced growth, with a 46.6% decrease in shoot height and a 50.4% reduction in root length compared to non-infected seedlings. Interestingly, AMF inoculation mitigated this sensitivity to Foa, significantly restoring growth parameters. Seedlings treated with AMF + Foa showed a 51% increase in shoot height and a 61% improvement in root length, along with over 100% gains in shoot and root biomass compared to seedlings infected solely with Foa. This study provides the first evidence of integrating AMF into sustainable date palm cultivation practices to mitigate the impacts of biotic stresses, thereby promoting the preservation and valorization of vulnerable date palm varieties. The protective effects of AMF are attributed to improved nutrient uptake, enhanced root architecture, and systemic resistance induced by AMF colonization. Full article

Arbuscular mycorrhizal fungi (AMF) and vermicompost can be efficient in enhancing the accumulation of metabolites, whereas there are no reports about their effects on antioxidant bioactive molecules and Sun Protection Factor (SPF) in Anadenanthera colubrina, a species used in cosmetic formulations. We hypothesized that the combination of AMF inoculation and vermicompost supplementation would synergistically optimize the production of these compounds and improve the antioxidant capacity and SPF of the plant leaves. A completely randomized experiment was set up in a factorial design with three mycorrhizal inoculation treatments (control, Acaulospora longula, and Gigaspora albida) and two substrate proportions (soil alone and soil with 10% vermicompost). After 126 days, the leaves were harvested to evaluate the content of primary metabolites, phenolics, antioxidant capacity, and SPF. Vermicompost did not synergize with AMF to enhance biomolecule synthesis in A. colubrina; instead, it neutralized the mycorrhizal effects. However, plants grown in soil supplemented with vermicompost showed an increase in metabolite and SPF accumulation compared to those grown solely in soil. Seedlings colonized by G. albida and grown in soil also exhibited enhanced anabolism. Therefore, this is the first report in the literature regarding the mitigating effect of vermicompost application on the SPF of mycorrhizal plants. Future studies should consider analyzing these factors in field conditions to attest the need of these agricultural tools. Full article

Tricholoma matsutake is one of the edible ectomycorrhizal fungi with great economic and ecological values. Artificially mycorrhized seedlings inoculated with T. matsutake strains from Finland and Japan have been widely reported. However, few reports on the morphological characteristics of mycorrhizae synthesized from the Chinese T. matsutake strain are available to date. Here, we find that the T. matsutake strain YN1 from Yunnan province, China, can form well-developed ectomycorrhizae in symbiosis with both exotic (Pinus elliottii) and Chinese native (Pinus armandii) species. The symbiotic structures of ectomycorrhizae included obvious mantle sheaths and Hartig nets visible under a microscope. The ectomycorrhizae appeared earlier in a larger quantity in P. elliottii than in P. armandii in the culture-plate symbiotic system. The ectomycorrhizae obviously promoted the growth of potted P. armandii and P. elliottii, accompanied by the formation of shiro-like structures. Our results provide references for the effective management of ectomycorrhizae synthesis in both P. armandii and P. elliottii seedlings to form shiro-like structures, and also provide a new perspective for the afforestation and mushroom cultivation research on T. matsutake. Full article

Oidiodendron maius G.L. Barron is a recognized fungal species capable of forming ericoid mycorrhiza with various positive effects on host plants; therefore, newly found and previously uncharacterized O. maius strains may be valuable for heather plants’ controlled mycorrhization. Characteristics of the O. maius F3860 strain were studied, i.e., mycelium growth on various nutrient media and the ability to secrete auxins and enzymes. O. maius F3860 grew rapidly on malt extract agar and potato dextrose agar. It was also able to grow on nutrient media suitable for heather plant cultivation. The presence of the flavonoids rutin and quercetin increased the mycelium growth rate compared to the control, starting from the 8th to the 13th days of cultivation. The ability to secrete auxins was confirmed with bioassay and thin-layer chromatography, and their content, as well as phytase activity, was estimated spectrophotometrically. Both in nutrient media with tryptophan and without it, O. maius F3860 secreted about 6 μg IAA/mL growth medium. O. maius F3860 possessed extracellular phytase, protease, and phenol oxidase activities. The investigation indicates O. maius F3860’s promise for heather seedling inoculation as an approach to increase their fitness. Full article

Large areas become unsuitable for full-fledged life after mining activity. To improve the state of environmental safety of post-industrial landscapes and the rational use of disturbed territories, a Decision Support System (DSS) should be created. This system should also contain proposals for restoring the soil cover and plant communities that are proposed in this article. The purpose of this study is to determine the influence of arbuscular mycorrhizal fungi on the process of vegetation formation in the post-industrial landscape of a sulfur quarry. During reclamation works in human-made ecotopes, vegetation has already formed there in a certain way due to natural succession processes. We assessed the level of vegetation self-restoration and, on the basis of the obtained data, the need and direction of phytoreclamation in relation to specific ecotopes. The set of restoration of soil cover and plant communities makes it possible to solve the problem of reusing post-industrial landscapes. The positive effect of the treatment of seedlings with a spore remedy of arbuscular, mycorrhizal fungi on the studied breeds’ height increase was observed. In the process of the revitalization of disturbed landscapes through the mycorrhization of planting material, there is a tendency to restore and increase phytodiversity at the floristic and coenotic levels. Full article

The drought sensitivity of the pedunculate oak (Quercus robur L.) poses a threat to its survival in light of climate change. Mycorrhizal fungi, which orchestrate biogeochemical cycles and particularly have an impact on the plant’s defense mechanisms and metabolism of carbon, nitrogen, and phosphorus, are among the microbes that play a significant role in the mitigation of the effects of climate change on trees. The study’s main objectives were to determine whether ectomycorrhizal (ECM) fungi alleviate the effects of drought stress in pedunculate oak and to investigate their priming properties. The effects of two levels of drought (mild and severe, corresponding to 60% and 30% of field capacity, respectively) on the biochemical response of pedunculate oak were examined in the presence and absence of ectomycorrhizal fungi. To examine whether the ectomycorrhizal fungi modulate the drought tolerance of pedunculate oak, levels of plant hormones and polyamines were quantified using UPLC-TQS and HPLC-FD techniques in addition to gas exchange measurements and the main osmolyte amounts (glycine betaine-GB and proline-PRO) which were determined spectrophotometrically. Droughts increased the accumulation of osmolytes, such as proline and glycine betaine, as well as higher polyamines (spermidine and spermine) levels and decreased putrescine levels in both, mycorrhized and non-mycorrhized oak seedlings. In addition to amplifying the response of oak to severe drought in terms of inducible proline and abscisic acid (ABA) levels, inoculation with ECM fungi significantly increased the constitutive levels of glycine betaine, spermine, and spermidine regardless of drought stress. This study found that compared to non-mycorrhized oak seedlings, unstressed ECM-inoculated oak seedlings had higher levels of salicylic (SA) and abscisic acid (ABA) but not jasmonic acid (JA), indicating a priming mechanism of ECM is conveyed via these plant hormones. According to a PCA analysis, the effect of drought was linked to the variability of parameters along the PC1 axe, such as osmolytes PRO, GB, polyamines, and plant hormones such as JA, JA-Ile, SAG, and SGE, whereas mycorrhization was more closely associated with the parameters gathered around the PC2 axe (SA, ODPA, ABA, and E). These findings highlight the beneficial function of the ectomycorrhizal fungi, in particular Scleroderma citrinum, in reducing the effects of drought stress in pedunculate oak. Full article

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

Yield and different nut parameters were measured for two growing seasons on mature (28–29 years) trees of 11 pecan cultivars grown in an experimental orchard located in the Puglia Region, Southeastern Italy. ‘Shoshoni’ and ‘Shawnee’ pecan seedlings were inoculated with three truffle species (Tuber borchii—known as the ‘whitish truffle’, T. aestivum—called the ‘summer truffle’, and T. melanosporum—the common ‘Black truffle’) and investigated for six months. The level of ectomycorrhizal colonization was assessed 6 and 12 months after inoculation. Results indicated that ‘Wichita’, ‘Shoshoni’, and ‘Pawnee’ performed well in the pedoclimatic conditions of the area with a yield higher than 20 kg/tree and a kernel dry weight of ≅3 g. These preliminary yield results suggested that some pecan cultivars could deserve consideration for cultivation in the Puglia Region, whereas others with low yield and a stronger alternate bearing should not be considered. Plant height, number of leaves, chlorophyll content (expressed as a SPAD unit) and stem diameter partially indicated the increase in ecological fitness in truffles-inoculated plants. Successful mycorrhization indicated ‘Shoshoni’ and ‘Shawnee’ as suitable to establish ectomycorrhizal symbiosis with T. aestivum, T. borchii, and T. melanosporum cultivation under Puglia climatic conditions. The results also showed that the applied protocol was adequate to obtain healthy mycorrhized seedlings appropriate for commercialization and plantation for truffles production on pecan in the future. Full article

The physiological and biochemical responses of pedunculate oaks (Quercus robur L.) to heat stress (HS) and mycorrhization (individually as well in combination) were estimated. One-year-old Q. robur seedlings were grown under controlled conditions in a pot experiment, inoculated with a commercial inoculum of ectomycorrhizal (ECM) fungi, and subjected to 72 h of heat stress (40 °C/30 °C day/night temperature, relative humidity 80%, photoperiod 16/8 h) in a climate chamber, and they were compared with seedlings that were grown at room temperature (RT). An in-depth analysis of certain well-known stress-related metrics such as proline, total phenolics, FRAP, ABTS, non-protein thiols, and lipid peroxidation revealed that mycorrhized oak seedlings were more resistant to heat stress (HS) than non-mycorrhized oaks. Additionally, levels of specific polyamines, total phenolics, flavonoids, and condensed tannins as well as osmotica (proline and glycine betaine) content were measured and compared between four treatments: plants inoculated with ectomycorrhizal fungi exposed to heat stress (ECM-HS) and those grown only at RT (ECM-RT) versus non-mycorrhized controls exposed to heat stress (NM-HS) and those grown only at room temperature (NM-RT). In ectomycorrhiza inoculated oak seedlings, heat stress led to not only a rise in proline, total phenols, FRAP, ABTS, non-protein thiols, and lipid peroxidation but a notable decrease in glycine betaine and flavonoids. Amounts of three main polyamines (putrescine, spermine, and spermidine) were quantified by using high-performance liquid chromatography coupled with fluorescent detection (HPLC/FLD) after derivatization with dansyl-chloride. Heat stress significantly increased putrescine levels in non-mycorrhized oak seedlings but had no effect on spermidine or spermine levels, whereas heat stress significantly increased all inspected polyamine levels in oak seedlings inoculated with ectomycorrhizal inoculum. Spermidine (SPD) and spermine (SPM) contents were significantly higher in ECM-inoculated plants during heat stress (approximately 940 and 630 nmol g⁻¹ DW, respectively), whereas these compounds were present in smaller amounts in non-mycorrhized oak seedlings (between 510 and 550 nmol g⁻¹ DW for Spd and between 350 and 450 nmol g⁻¹ DW for Spm). These findings supported the priming and biofertilizer roles of ectomycorrhizal fungi in the mitigation of heat stress in pedunculate oaks by modification of polyamines, phenolics, and osmotica content. Full article

A new Choiromyces species was discovered at local wild mushroom markets in Songpan County, Sichuan, southwest China where it has been considered as a Chinese white truffle. Based on both morphological and phylogenetic analyses, the collection was described as Choiromyces sichuanensis sp. nov. This study confirms the occurrence of members of Choiromyces in China. In addition, the mycorrhizal synthesis via spore inoculation between C. sichuanensis and Pinus armandii or two Picea species of Pi. likiangensis and Pi. crassifolia was attempted in a greenhouse. Both morphoanatomical and molecular analyses evidenced well-developed mycorrhization between C. sichuanensis and P. armandii, but not in Picea seedlings. Our current study provides data about the species diversity and mycorrhizal research of this genus for further studies. In addition, a successful mycorrhization between C. sichuanensis and selected tree species, irrespective of Pinus genus or other plant species, would broaden the set of species for a successful mycorrhization in greenhouse conditions and potential outplanting for cultivation purposes. Full article