Mycorrhiza最新文献

Most plants extend their zone of interaction with surrounding soils and plants via mycorrhizal hyphae, which in some cases can form common mycorrhizal networks with hyphal continuity to other neighbouring plants. These interactions can impact plant health and ecosystem function, yet the role of these radial plants in mycorrhizal interactions and subsequent plant performance remains underexplored. Here we investigated the influence of hyphal exploration and interaction with neighbouring mycorrhizal plants, plants that are weakly mycorrhizal, and a lack of neighbouring plants on the performance of Plantago lanceolata, a mycotrophic perennial herb common to many European grasslands, using mesh cores and the manipulation of neighbouring plant communities. Allowing growth of hyphae beyond the mesh core increased carbon capture above-ground and release below-ground as root exudates and resulted in the greater accumulation of elements relevant to plant health in P. lanceolata. However, contrary to expectations, the presence of mycorrhizal, or weakly mycorrhizal neighbours as well as an absence of neighbours did not significantly alter the benefits of hyphal networks to P. lanceolata. Our findings demonstrate that enabling the development of a fungal network beyond the immediate host rhizosphere significantly influences plant leaf elemental stoichiometry, enhances plant carbon capture, and increases the amount of carbon they release via their roots as exudates. Our experimental design also provides a simple set of controls to prevent attributing positive mycorrhizal effects to neighbouring plant connections.

Host plant identity is a primary determinant of ectomycorrhizal (ECM) fungal diversity and community composition, but the effect of host identity within congeneric species and whether this effect varies with environmental changes remain unclear. In this study, we used ITS rRNA amplicon sequencing to assess the diversity and community composition of ECM fungi in the roots of six phylogenetically distinct spruce (Picea) species grown in three common gardens with varying environmental conditions. Our results showed that, although ECM fungal richness and Shannon diversity were similar among spruce species at each site, their ECM fungal community composition differed. The differences in ECM fungal community composition between paired spruce species were not significant at the wettest site, but were significant at two dry sites, with the main difference observed between P. asperata and other spruce species (p < 0.05). The Mantel test indicated a weak positive correlation between ECM fungal community composition differences and the phylogenetic distance among host species. Preferred spruce/ECM fungal species varied across the three sites, with the lowest preference ratio observed at the wettest site. Additionally, Sebacina, Trichophaea, and Wilcoxina were the dominant genera in spruce roots. These results highlight the significant role of host identity within congeneric species in ECM fungal community assembly in relatively dry environment, enhancing our understanding of how congeneric plants influence ECM fungal diversity and community composition.

Common mycorrhizal networks of ectomycorrhizal (EcM) fungi could be of great benefit to trees growing in the shallow soils of Sub-Mediterranean Karst ecosystems, potentially playing a crucial role in the survival of trees in this harsh environment. The first step to confirm the existence of such networks is to assess the extent and nature of symbiont sharing in the mycelial community. To address this question, we incubated in-growth mesh bags under the native Ostrya carpinifolia and Quercus pubescens, and the non-native Pinus nigra, over two consecutive years. In Q. pubescens and P. nigra, but not in O. carpinifolia, mycelium production was significantly higher in the year with higher spring precipitation, indicating the influence of climatic conditions, but also the identity of the host tree. We observed a complex interaction between tree species and sampling year in structuring the composition and diversity of mycelial communities. Local environmental conditions contributed additionally and were responsible for 21.46% of the community variation between samples. Although ~ 70% of fungal operational taxonomic units were shared across the studied tree species, distinct community compositions emerged, emphasizing the role of host tree specificity. Q. pubescens exhibited greater stability in EcM richness between sampling years, whereas P. nigra showed lower EcM richness, likely due to limited availability of compatible fungi and reliance on introduced fungal partners. Additionally, differences in EcM fungal exploration strategies were observed. O. carpinifolia and Q. pubescens mainly hosted non-specific EcM fungi with short distance exploration types. In contrast, EcM fungi of P. nigra had higher spatial spread, and were predominantly conifer specific. Overall, our results emphasize the importance of host specificity, soil parameters, spatial proximity, and climatic variability for the structuring of mycelial communities in fragmented forests.

Glomalin-related soil protein (GRSP), a glycoprotein produced by arbuscular mycorrhizal fungi (AMF), plays a critical role in soil organic carbon (SOC) storage in forest ecosystems. However, the factors influencing its variability and contribution to SOC along forest elevation gradients remain poorly understood, limiting our ability to predict how soil carbon sequestration through GRSP will respond to future global warming. Therefore, this study explored the relationships among GRSP and SOC with climatic and edaphic factors along elevation gradients (666-3892 m) spanning diverse forest types in tropical rainforest, subtropical forest, and subalpine forest in Yunnan, Southwest China. Our findings revealed that AMF spore abundance declined, whereas AMF root colonization and GRSP concentrations increased with increasing elevation. GRSP showed a stronger positive correlation with AMF root colonization than with spore abundance, particularly in subtropical and subalpine forests where nutrient availability was higher. A significant positive relationship was observed between GRSP and SOC across all three forest sites, with the strongest association in subtropical forests. These results suggest that GRSP accumulation is sensitive to climate and nutrient cycling, emphasizing the role of AMF activity and GRSP as an AMF-derived compound in mediating SOC storage across elevation gradients, consequently contributing to climate change mitigation.

Soil contamination with polycyclic aromatic hydrocarbons (PAHs) represents a major environmental challenge and requires cost-effective and environmentally friendly remediation technologies. Phytoremediation, enhanced by arbuscular mycorrhizal fungi (AMF), is an effective and extensive technique for PAHs remediation, although, its application with non-vascular plants, is largely unexplored. This study investigates the role of the AMF Rhizophagus irregularis in the uptake and bioaccumulation of anthracene in the liverwort Lunularia cruciata under in vitro conditions. The thallus and the AMF were able to absorb and bioaccumulate anthracene in the cell wall and spores, hyphae and arbuscules respectively. Our results indicate that the liverwort-fungus system employs multiple phytoremediation mechanisms, including phytoaccumulation and phytostabilization. At intermediate contamination levels, the fungal symbiont enhanced contaminant accumulation in the plant, whereas at higher contamination levels, this effect diminished, suggesting a potential limitation in fungal-mediated uptake under extreme conditions. These findings highlight the potential of AMF symbiosis in liverworts for developing biological tools for PAHs remediation, emphasizing the dependence on pollutant concentration for the effectiveness of phytoremediation.

The mycoheterotrophic nutritional mode, characterized by the acquisition of fungal-derived carbon by plants, has long captivated botanists and mycologists. Recent stable isotope analyses of fungal pelotons isolated from roots have advanced our understanding of this nutritional strategy; however, concerns remain regarding potential isotopic biases, particularly ¹⁵N depletion during lysis or extraction. To address these concerns, we focused on Gastrodia pubilabiata, a fully mycoheterotrophic orchid that associates with saprotrophic fungi. This species offers an ideal system to test whether peloton tissues reliably reflect fungal isotope signatures, as its mycorrhizal roots occasionally occur in direct contact with the fruiting bodies of its fungal partner. We measured δ¹³C and δ¹⁵N values in the aboveground tissues of G. pubilabiata, pelotons extracted from its roots, and fruiting bodies of the associated wood-decaying fungus Cyanotrama gypsea, along with neighboring autotrophic reference plants. The stable isotope analysis revealed that δ¹³C values were nearly identical between pelotons and fruiting bodies, while δ¹⁵N values were slightly higher in pelotons, indicating that peloton-derived isotopic data reliably reflect the fungal source. Moreover, the ¹³C and ¹⁵N enrichment observed in the orchid relative to the fungal fractions was broadly consistent with expected trophic-level fractionation, suggesting a predator-prey-like mode of nutrient transfer. Taken together, these findings support the validity of recently developed isotope-based approaches using extracted pelotons to represent fungal isotopic signatures, at least within this system.

Plants have evolved symbioses with mycorrhizal and endophytic fungi that are essential for their growth and survival. While most plants associate with a single guild of mycorrhizal fungi, a select group termed "dual-mycorrhizal plants" associate with both arbuscular mycorrhizal and ectomycorrhizal fungi. Although a shift from predominance of arbuscular mycorrhizal to ectomycorrhizal colonization with plant development has been demonstrated on other dual-mycorrhizal hosts, it is not known how mycorrhizal colonization shifts with plant age in Populus species. We performed a controlled growth experiment with natural field-sourced inocula to test for age-dependent shifts in fungal colonization rates and for host-specific patterns of colonization in two species of Populus (P. tremuloides and P. trichocarpa). We found that only P. trichocarpa displayed dual-mycorrhizal colonization, while P. tremuloides associated with ectomycorrhizal fungi, but not arbuscular mycorrhizal fungi. Both guilds of mycorrhizal fungi increased in abundance with plant age, while root endophytic fungal colonization decreased. Many of the early-colonizing endophytic fungi that we documented have strong saprotrophic capabilities, which may be an important trait for fast colonization. Dark septate endophytes were more abundant than either guild of mycorrhizal fungi, and are likely to be functionally important members of the Populus root fungal community. Our findings represent a novel pattern in the development of dual-mycorrhizal colonization and illustrate that Populus species vary in their association with arbuscular mycorrhizal fungi. Our results also highlight the importance of dark septate endophyte colonization dynamics on dual-mycorrhizal plants.

Plants interact closely with arbuscular mycorrhizal (AM) fungi. They allocate photosynthates to AM fungi in exchange for nutrients, thereby influencing plant fitness. Although plant phenotypes result from multiple traits constrained by trade-offs, the effects of AM fungi on plants are often studied using one trait. Plant response to AM fungi therefore needs to be analysed using multiple traits. Four Asteraceae species were inoculated with ten AM fungal strains using a factorial design in the greenhouse. The effect of AM fungal inoculation and their taxonomic identity on plants vegetative and reproductive traits were assessed. The predictability of the effects was evaluated based on AM fungal phylogenetic relatedness. The effect of the inoculation depended on the trait considered. Compared with the non-inoculated control, biomass allocation to roots decreased, while allocations to shoots or reproduction increased depending on the AM fungi or the plant. Significant differences were observed among AM fungi inoculates used, whether looking at separate traits, trade-offs between vegetative or reproductive growth, and the trait syndrome. In Centaurea cyanus, changes in plant phenotype were associated with the phylogenetic distance between AM fungi. These results underline the importance of using multi-trait approaches to understand AM fungal effects on plant phenotype. In accordance with the holobiont concept, the outcomes of this interaction depended on both the host plant and the AM fungus involved. It contributes to a better understanding of the biological effectors shaping the reaction norm (i.e., the range of phenotypic variation of a given host genotype) within the plant holobiont.

Nutrient exchanges are a key feature of arbuscular mycorrhizal (AM) symbiosis. Grapevine (Vitis vinifera), one of the most economically important crops worldwide, relies heavily on AM symbiosis for its growth and development. Since the phylloxera crisis, cultivated grapevines are obtained by grafting a Vitis vinifera scion onto a rootstock. In this study, we investigated the responses of the rootstock "Riparia Gloire de Montpellier" to mycorrhizal root colonization under three distinct phosphate (P) levels. We explored regulatory aspects of plant P nutrition by comparing the transcriptome profiling of non-colonized roots and roots colonized by the AM fungus Rhizophagus irregularis DAOM197198. We have shown that P availability significantly influences gene expression in both the AM fungus and the grapevine. Our transcriptomic study shed light on the molecular mechanisms that prevail during the AM symbiosis of a perennial woody plant species, with available P affecting several functional classes of proteins. The nine genes coding for Pht1 transporters in the R. irregularis genome were either down-regulated (RiPT1 and RiPT2) or up-regulated by the high-P treatment (RiPT8 and RiPT11), up-regulated by the low-P treatment (RiPT5), and regulated in a P-dose-dependent manner (RiPT9 and RiPT10). Expression of two of the three identified AM-induced Pht1, VvPT4 and VvPT8, was enhanced under mycorrhizal conditions, but finely tuned by the P treatment. To immunolocalize VvPT4 and VvPT8, we developed an innovative root-clearing protocol specifically designed for woody plants. This technological advancement has made it possible to visualize only VvPT4 at the periarbuscular membrane of mature arbuscules, its expression being strongly influenced by differences in P availability.