Search Results (64)

In Japan, strawberries are produced in the off-season (June to November) in cool regions; however, the high temperatures and strong sunlight limit fruit production. Dark septate endophytic fungi (DSEs) support growth and flower bud formation of plants grown in environments unsuitable for plant growth. In this study, we investigated the effects of DSE on dry matter production and flower bud formation in strawberry plants grown in the summer and autumn. The seeds were sown in soil mixed with DSE on 5 February 2024. The DSEs used were Cladophialophora chaetospira SK51 (S) and Cc. MNB12 (M), and Veronaeopsis simplex Y34 (Y). Plants were planted in a plastic house on April 18. The total dry weight was significantly increased by DSEs. This is because S and Y-cultured plants did not show a significant decrease in leaf emergence under high temperatures, unlike those grown with M; however, its leaf area was larger than that of the control. This resulted in a larger leaf area for receiving light and higher cumulative light reception and light-use efficiency. Although the DSEs increased cumulative fruit yield, the harvest period was limited to July because of the extreme summer heat. In addition, there was no difference in the budding date or flowering date between the treatments. These results suggest that DSEs improve light use efficiency, thereby increasing total dry matter weight and contributing to increased fruit yield in summer-autumn cultivation. Full article

Cercophora species, typically known as saprobes or coprophiles, have occasionally been isolated from healthy roots and have recently been recognized as endophytes. Their dark-pigmented structures suggest adaptation traits similar to dark septate endophytes, although their symbiotic potential remains unclear. This study isolated and characterized Cercophora sp. NPKC241 from mung bean roots grown under artificial drought in soils with different fertilization histories, using PCR-based DNA sequencing and morphological observation. Its effects on legume growth were subsequently evaluated through pot inoculation experiments under drought. These experiments focused on mung bean, a species known to exhibit significant reductions in chlorophyll content and yield under drought conditions. Among 29 isolates, Cercophora sp. consistently promoted legume growth. In mung bean, it increased shoot and root mass, chlorophyll content, and root elongation under both optimal and water-limited conditions. Under drought, inoculated plants showed approximately threefold higher chlorophyll levels, two- to threefold greater biomass, and roots approximately 5 cm longer than the control, indicating mitigation of drought-induced physiological decline. These findings suggest that Cercophora sp. can act as a beneficial root-associated fungus, enhancing legume performance under drought. Future studies will further explore this interaction by underlying physiological mechanisms and the field-level application potential. Full article

With continuous increases in nitrogen (N) deposition in the future, its impacts on terrestrial ecosystems are attracting growing concern. Arbuscular mycorrhiza (AM) fungi play a crucial role in shaping both soil microbial and plant communities. AM fungi play a crucial role in shaping the soil microbial and plant communities, yet their patterns of influence under increased N deposition scenarios remain unclear, particularly in desert ecosystems. Therefore, we conducted a field experiment simulating increased N deposition and AM fungal suppression to assess the effects of increased N deposition and AM fungi on soil microbial communities, employing phospholipid fatty acid (PLFA) biomarker technology in the Gurbantunggut Desert of Xinjiang. We found that increased N deposition promoted soil microbial biomass, including AM fungi, fungi, Actinomycetes (Act), Gram-positive bacteria (G⁺), Gram-negative bacteria (G⁻), and Dark Septate Endophyte (DSE). AM fungal suppression significantly increased the content of soil Act and G⁺. There were clearly and significantly interactive effects of increased N deposition and AM fungi on soil microbial contents. Both increased N deposition and AM fungi caused significant changes in soil microbial community structure. Random forest analysis revealed that soil nitrate N (NO₃⁻-N), Soil Organic Carbon (SOC), and pH were main factors influencing soil microorganisms; soil AM fungi, G⁺, and Act significantly affected plant Shannon diversity; soil G⁻, Act, and fungi posed significant effects on plant community biomass. Finally, the structure equation model results indicated that soil fungi, especially AM fungi, were the main soil microorganisms altering the plant community diversity and biomass under increased N deposition. This study reveals the crucial role of AM fungi in regulating soil microbial responses to increased N deposition, providing experimental evidence for understanding how N deposition affects plant communities through soil microorganisms. Full article

Noccaea species (formerly Thlaspi) are Brassicaceae plants renowned for their capacity to hyperaccumulate zinc (Zn), cadmium (Cd), and nickel (Ni), which has made them model systems in studies of metal tolerance, phytoremediation, and plant adaptation to extreme environments. While their physiological and genetic responses to metal stress are relatively well characterised, the extent to which these traits influence microbiome composition and function remains largely unexplored. These species possess compact genomes shaped by ancient whole-genome duplications and rearrangements, and such genomic traits may influence microbial recruitment through changes in secondary metabolism, elemental composition, and tissue architecture. Here, we synthesise the current findings on how genome size, metal hyperaccumulation, structural adaptations, and glucosinolate diversity affect microbial communities in Noccaea roots and leaves. We review evidence from bioimaging, molecular profiling, and physiological studies, highlighting interactions with bacteria and fungi adapted to metalliferous soils. At present, the leaf microbiome of Noccaea species remains underexplored. Analyses of root microbiome, however, reveal a consistent taxonomic core dominated by Actinobacteria and Proteobacteria among bacterial communities and Ascomycetes, predominantly Dothideomycetes and Leotiomycetes among fungi. Collectively, these findings suggest that metal-adapted microbes provide several plant-beneficial functions, including metal detoxification, nutrient cycling, growth promotion, and enhanced metal extraction in association with dark septate endophytes. By contrast, the status of mycorrhizal associations in Noccaea remains debated and unresolved, although evidence points to functional colonisation by selected fungal taxa. These insights indicate that multiple plant traits interact to shape microbiome assembly and activity in Noccaea species. Understanding these dynamics offers new perspectives on plant–microbe co-adaptation, ecological resilience, and the optimisation of microbiome-assisted strategies for sustainable phytoremediation. Full article

Wheat domestication and selection for aboveground traits may have influenced belowground traits, reducing genetic diversity critical for adaptation to stress such as drought. However, the impacts on root system architecture and root–endophytic fungal interactions remain unclear. This study evaluated variation in root traits and associations with arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) among nine diploid Aegilops tauschii accessions (wild progenitor), one tetraploid Triticum turgidum cv. ‘Langdon’ (LNG), and one hexaploid Triticum aestivum cv. ‘Norin 61’ (N61). Root traits and fungal colonization varied significantly among genotypes. All Ae. tauschii accessions showed superior root development and lower DSE colonization compared to LNG and N61. AMF colonization was highest in accessions AT76 and KU-2126 (54% and 53%, respectively), while N61 exhibited the highest specific root length (SRL) and DSE colonization. AMF positively correlated with most root traits (except SRL), while DSE showed the opposite trend. Although Ae. tauschii accessions shared broadly favorable root traits, variation in their fungal interactions were more pronounced. A clustering heatmap incorporating both root and biotic traits clustered the genotypes into four groups, clearly separating the Ae. tauschii accessions into two clusters based on their root characteristics and root-fungal associations. These results highlight the hidden interspecific and intraspecific variations in Ae. tauschii and its potential as a genetic resource for optimizing root–endophytic fungal interactions, and improving wheat resilience to biotic and abiotic stress in a changing climate. Full article

Dark septate endophytes (DSEs) are commonly found in saline environments, such as the Flooding Pampas (Argentina), where the forage grass Chloris gayana has been introduced. This study evaluated the effect of salinity on the DSE fungus Exserohilum rostratum, isolated from C. gayana, and its contribution to the grass’s salinity tolerance. Two greenhouse experiments were conducted under three salinity levels (0, 40, and 80 meq Na·L⁻¹), with and without fungal inoculation. Fungal growth, root colonization, functional traits, plant biomass, chemical composition, and salinity tolerance indices were assessed. The fungus tolerated salinity and colonized roots, showing qualitative evidence of enzyme production and phosphate solubilization. In both experiments, shoot and root biomass decreased with increasing salinity. Inoculation significantly enhanced shoot biomass only under non-saline conditions in the first experiment, whereas in the second experiment no inoculation effect was observed on shoots. For roots, no effect of inoculation occurred in the first experiment, but a positive interaction between salinity and inoculation was recorded in the second experiment, where moderate salinity increased root biomass in inoculated plants. The K/Na and Ca/Na ratios decreased under salinity regardless of inoculation, indicating limited influence on ionic balance. These results suggest that although E. rostratum tolerates salinity and expresses functional traits, its ability to enhance plant performance under stress is context-dependent and restricted to specific conditions. Full article

This study investigates the potential role of Acrocalymma dark septate endophytic (DSE) fungi in promoting the growth of Solanum lycopersicum (tomato). Recognized as important symbionts that enhance plant growth and resilience under stress, particularly Acrocalymma species, DSE fungi were the focus of this investigation. Specifically, four stains isolated from gramineous plant roots (Acrocalymma sp. E00677, Acrocalymma vagum E00690, Acrocalymma chuxiongense E01299A, and Acrocalymma chuxiongense E01299B) were examined. Morphological characteristics were observed using three different media, confirming typical DSE traits such as dark pigmentation and septate hyphae. Phylogenetic analysis using six genetic markers (ITS, LSU, SSU, tef1, rpb2, and tub2) placed the strains within the Acrocalymma genus. Co-culture test and physiological index measurements showed that all strains significantly enhanced root development, as evidenced by an increased root-to-shoot ratio and a higher number of lateral roots. Additionally, the Acrocalymma DSE strains elevated chlorophyll a, chlorophyll b, and total chlorophyll content, suggesting improved photosynthetic efficiency. Anthocyanin levels were also increased in the tomato leaves, indicating enhanced antioxidative defense mechanisms. Among these strains, Acrocalymma vagum E00690 exhibited the most substantial effect on root activity. The widespread presence of 325 Acrocalymma isolates from 25 countries underscores its broad ecological adaptability. These findings suggest that Acrocalymma DSE fungi positively influence tomato growth, with potential implications for improving plant resilience under environmental stress. This study highlights the importance of further exploring DSEs, particularly Acrocalymma fungi, to better understand their ecological roles in agricultural practices, particularly in tomato cultivation. Full article

Increased precipitation and nitrogen (N) deposition critically influence ecological processes and stability in desert ecosystems. Studying how the soil microbial community responds to these climatic changes will improve our understanding of the impacts of climate changes on arid environments. Therefore, we conducted a field experiment in the Gurbantunggut Desert, applying phospholipid fatty acid (PLFA) analysis to assess the responses of soil microbial community to climate change. We found that in years with normal precipitation, increased precipitation promoted soil bacterial growth, whereas in drought years, increased N deposition promoted soil bacterial growth more effectively. Although soil microbial diversity did not change significantly overall, it decreased with increasing N deposition. Random forest analysis and linear regression analysis indicated that soil pH and microbial biomass carbon (MBC) were the main drivers for the changes in soil microbial community. Structural equation modeling (SEM) further revealed that increased precipitation increased soil Gram-positive bacteria (G⁺) by raising soil MBC, while decreasing soil Actinomycetes (Act), fungi, and Dark Septate Endophyte (DSE). In contrast, increased N deposition affected soil microbial community by altering soil pH and MBC. Our results highlight the synergistic effects of increased precipitation and N deposition on soil microbial community structure. Further research should pay more attention to the effects of climate changes on soil microbial communities with long-term monitoring to confirm our findings across different ecosystems. Full article

NaCl is the main cause of natural soil salinization. Exploring dark septate endophytes (DSEs) with NaCl tolerance provides information for ecological remediation in saline soil areas. In this study, six DSE strains (Didymella macrostoma (Dm), Paraboeremia selaginellae (Ps), Paraphoma pye (Pp), Paraphoma aquatica (Pa), Acrocalymma ampeli (Aa), and Exophiala xenobiotica (Ex)) isolated from the root sections of Anemone tomentosa were subjected to in vitro NaCl stress experiments and inoculation tests. The results showed that six DSE strains can grow on solid media with different NaCl concentrations (0, 0.2, 0.4, 0.6, 0.8, and 1.0 M) and increase the antioxidant enzyme activities and soluble protein contents to adapt to a salt stress environment. Among these strains, the Pp strain exhibited the greatest biomass accumulation under high NaCl concentrations (1.0 M), indicating greater NaCl tolerance compared to the other five strains. In addition, in the pot experiment, all six DSE strains were able to successfully establish a symbiotic relationship with A. tomentosa, and the Pp strain also showed significant growth-promoting effects on seedlings. In summary, the Pp strain is identified as having strong NaCl tolerance and a significant growth-promoting impact, indicating that it has potential applications as a NaCl-tolerant microbial agent and can be used for bioremediation in saline soils. This research contributes to the basic material and theoretical basis for joint plant–microbe combined remediation in areas prone to soil salinization. Full article

Short-term observations suggest that environmental changes affect the diversity and composition of soil fungi, significantly influencing forest resilience, plant diversity, and soil processes. However, time-series experiments should be supplemented with geobiological archives to capture the long-term effects of environmental changes on fungi–soil–plant interactions, particularly in undersampled, floristically diverse tropical forests. We recently conducted trnL-P6 amplicon sequencing to generate a sedimentary ancient DNA (sedaDNA) record of the regional catchment vegetation of the tropical waterbody Lake Towuti (Sulawesi, Indonesia), spanning over one million years (Myr) of the lake’s developmental history. In this study, we performed 18SV9 amplicon sequencing to create a parallel paleofungal record to (a) infer the composition, origins, and functional guilds of paleofungal community members and (b) determine the extent to which downcore changes in fungal community composition reflect the late Pleistocene evolution of the Lake Towuti catchment. We identified at least 52 members of Ascomycota (predominantly Dothiodeomycetes, Eurotiomycetes, and Leotiomycetes) and 12 members of Basidiomycota (primarily Agaricales and Polyporales). Spearman correlation analysis of the relative changes in fungal community composition, geochemical parameters, and paleovegetation assemblages revealed that the overwhelming majority consisted of soil organic matter and wood-decaying saprobes, except for a necrotrophic phytopathogenic association between Mycosphaerellaceae (Cadophora) and wetland herbs (Alocasia) in more-than-1-Myr-old silts and peats deposited in a pre-lake landscape, dominated by small rivers, wetlands, and peat swamps. During the lacustrine stage, vegetation that used to grow on ultramafic catchment soils during extended periods of inferred drying showed associations with dark septate endophytes (Ploettnerulaceae and Didymellaceae) that can produce large quantities of siderophores to solubilize mineral-bound ferrous iron, releasing bioavailable ferrous iron needed for several processes in plants, including photosynthesis. Our study showed that sedaDNA metabarcoding paired with the analysis of geochemical parameters yielded plausible insights into fungal-plant-soil interactions, and inferred changes in the paleohydrology and catchment evolution of tropical Lake Towuti, spanning more than one Myr of deposition. Full article

The establishment of artificial grassland is a good pathway for resolving serious social and economic problems in the Qinghai–Tibet Plateau. Some beneficial indigenous microbes may be used to improve productivity in artificial grassland. The genome of the indigenous dark septate fungus, Exophiala tremulae CICC2537, was sequenced and assembled at the chromosome level using the PacBio sequencing platform, with the assistance of the Hi-C technique for scaffolding, and its 3D genome structures were investigated. The genome size of E. tremulae is 51.903848 Mb, and it contains eight chromosomes. A total of 12,277 protein-coding genes were predicted, and 11,932 genes (97.19%) were annotated. As for the distribution of exon and intron number and the distribution of gene GC and CDS GC, E. tremulae showed similar distribution patterns to the other investigated members of the genus Exophiala. The analysis of carbohydrate-active enzymes showed that E. tremulae possesses the greatest number of enzymes with auxiliary activities and the lowest number of enzymes with carbohydrate-binding modules among the investigated fungi. The total number of candidate effector proteins was 3337, out of which cytoplasmic and apoplastic effector proteins made up 3100 and 163, respectively. The whole genome of E. tremulae contained 40 compartment As and 76 compartment Bs, and there was no significant difference in GC content in its compartment As and Bs. The whole genome of E. tremulae was predicted to contain 155 topologically associating domains (TADs), and their average length was 250,000 bp, but there were no significant differences in the numbers of genes and the GC content per bin localized within the boundaries and interiors of TADs. Comparative genome analysis showed that E. tremulae diverged from Exophiala mesophila about 34.1 (30.0–39.1) Myr ago, and from Exophiala calicioides about 85.6 (76.1–90.6) Myr ago. Compared with all the investigated fungi, the numbers of contraction and expansion gene families in the E. tremulae genome were 13 and 89, respectively, and the numbers of contraction and expansion genes were 14 and 670, respectively. Our work provides a basis for the use of the dark septate fungus in alpine artificial grassland and further research into its symbiosis mechanisms, which may improve the growth of plant species used in the Qinghai–Tibet Plateau. Full article

Arbuscular Mycorrhizal Fungi (AMF) play a key role in enduring stresses in desert ecosystems, as they enhance the moisture and nutrient supply to desert plants. An investigation was carried out to detect the existence of AMF in the root regions of five perennial native desert grasses of Kuwait (Cenchrus ciliaris L., Cenchrus setigerus Vahl, Lasiurus scindicus Henrard, Pennisetum divisum (Forssk.) Henr., and Panicum turgidum Forssk.) in comparison with a non-native grass (Panicum virgatum L.). The native plants, C. setigerus and P. divisum had the highest colonization (100%) with vesicles, followed by P. turgidum (90%). The colonization of arbuscules was highest in the non-native grass, P. virgatum (60%), followed by C. setigerus (50%). Phylogenetic analysis for molecular identification to determine the genetic diversity of the AMF community in association with the native plant roots of the two dominant desert species, i.e., L. scindicus and P. turgidum, against P. virgatum, revealed a rich diversity. The AMF, Claroideoglomus lamellosum, and Rhizophagus sp. were identified from L. scindicus roots, Rhizophagus iranicus from P. turgidum roots, and Claroideoglomus lamellosum, from the non-native grass, P. virgatum, with almost 98–100% sequence similarity, indicating a significant difference between the mycorrhizal species in the nativity of grasses. This research confirms the diversity of AMF associated with native desert plants and emphasizes their symbiosis and host specificity. Thus, this study provides insight into AMF community structures, functions, and profiling, allowing us to understand their ecological and economic impacts, and ultimately implement strategies for sustainable biodiversity, productivity, and ecosystem management. Full article

(1) Background: Endophytic fungi play an important role in plant growth and stress resistance. The presence of a special fungal taxon such as the dark septate endophytic (DSE) fungi in alpine environments is particularly important for plant resistance to environmental stresses. However, the composition of root endophytic fungi in different environments and between different host plants has not been well studied. (2) Results: A total of 408 culturable endophytic fungi were isolated from the roots of Saussurea involucrata and Rhodiola crenulata which were collected in 5 plots from the Tianshan and Karakoram Mountains of the Xinjiang region, belonging to 91 species, 54 genera, 31 families, and 3 phyla based on the morphological characteristics and molecular sequence. Among them, DSE fungi were the dominant group, accounting for 52.94%, and Leptodontidium orchidicola was the dominant species. In addition, we also compared the composition and diversity of root endophytic fungi from different plants and different sites, with emphasis on special fungal taxa such as DSE. (3) Conclusions: The composition and diversity of cultural endophytic fungi are significantly different in the two alpine medicinal plant species and across various locations. Some fungi showed the preferences of the host or environment. The endophytic fungal resources, especially DSE, were very rich in the two alpine medicinal plants, indicating that these fungi may play a crucial role in the ecological adaptation of host plants in harsh environments. Full article

Dark septate endophytes (DSE) may facilitate plant growth and stress tolerance in stressful ecosystems. However, little is known about the response of medicinal plants to DSE, especially under heavy metal stress. This study aimed to investigate how DSE affects the growth of Dendranthema morifolium in medicinal plants under cadmium (Cd) stress. In this investigation, the sterile and non-sterile inoculations were carried out to evaluate the effect of three DSE strains on D. morifolium stressed with Cd. For the root, DSE15 sterile or non-sterile inoculation resulted in enhanced root biomass, root volume, the Cd content of roots, and the indoleacetic acid (IAA) levels in D. morifolium under Cd stress. DSE7 non-sterile inoculation significantly enhanced the Cd content of roots at 1 and 5 mg Cd/kg soil. Regarding impact stems and leaves, under sterile conditions, DSE7 and DSE15 effectively regulated the shoot biomass, plant height, chlorophyll level, and superoxide dismutase (SOD) content. Under sterile conditions, DSE15 positively influenced shoot biomass and plant height, while DSE7 had no significant effect on them when subjected to Cd stress. For effects on flowers under non-sterile conditions, DSE7 and DSE15 significantly increased the flower biomass under Cd stress, while DSE7 reduced the Cd transfer coefficient of flowers at 1 and 5 mg Cd/kg soil. Importantly, at 1 mg Cd/kg soil, DSE7 and DSE15 non-sterile inoculations promoted the 1, 5-dicaffeoylquinic acid content by 18.29% and 21.70%. The interaction between DSE and soil factors revealed that DSE species had significant effects on soil organic carbon and available nitrogen in D. morifolium non-sterile soil. The DSE15 inoculation enhanced soil organic carbon content, while the inoculation of DSE7 and DSE15 reduced soil available nitrogen content under Cd stress. These results contribute to a better understanding of DSE-plant interactions in habitats contaminated by heavy metals and demonstrate the potential utility of DSE strains for cultivating medicinal plants. Full article