Characterization of Dark Septate Endophytic Fungi and Improve the Performance of Liquorice Under Organic Residue Treatment

Comparative analysis of mycorrhizal communities associated with Struthiopteris spicant (L.) Weiss across Europe and North America

Introduction

Ferns constitute the second largest group of vascular plants. Previous studies have shown that the diversity and composition of fern communities are influenced by resource availability and water stress, among other factors. However, little is known about the influence of these environmental factors on their biotic interactions, especially regarding the relationship between mycorrhizal fungi and ferns. The present study compares the mycorrhizal communities associated with 36 populations of Struthiopteris spicant L. Weiss across Europe and North America. This species exhibits a great tolerance to variations in light, nutrient, and pH conditions, and it can survive with and without mycorrhizae.

Methods

With the aim of determining which environmental factors impact the composition and abundance of the root-associated fungal communities in this species, we used an ITS-focused metabarcoding approach to identify the mycorrhizal fungi present and analyzed the influence of climatic and edaphic variables at global and regional scales.

Results and discussion

We encountered striking differences in the relative abundance of arbuscular mycorrhizal fungi (AMF) between S. spicant populations at both spatial levels. We recorded a total of 902 fungal ASVs, but only 2- 4% of the total fungal diversity was observed in each individual, revealing that each fern had a unique fungal community. Light availability and the interactive action of pH and soil nitrogen concentration showed a positive influence on AMF relative abundance, explaining 89% of the variance. However, environmental factors could only explain 4- 8% of the variability in AMF community composition, indicating that it might be determined by stochastic processes. These results support the hypothesis that ferns may be more independent of mycorrhization than other plant groups and interact with fungi in a more opportunistic manner.

Distinct fungal communities affecting opposite galanthamine accumulation patterns in two Lycoris species

Lycoris radiata is the main source of galanthamine, a clinical drug used in Alzheimer's disease; however, the galanthamine content in L. radiata is low. Lycoris aurea is another Lycoris species with high galanthamine content. Fungal endophytes can enhance plant secondary metabolite accumulation; thus, we compared the fungal communities in these two Lycoris species to identify certain fungal taxa in L. aurea capable of enhancing galanthamine accumulation. Several fungal endophytes, which were enriched in, exclusively isolated from L. aurea, or showed significant correlations with galanthamine, were demonstrated to enhance the accumulation of only galanthamine but no other Amaryllidaceae alkaloids (AAs) in L. radiata. These fungal endophytes mainly upregulated the downstream genes in the biosynthesis pathways of AAs in L. radiata, suggesting that they may allocate more precursors for galanthamine biosynthesis. This study demonstrated that fungal endophytes from L. aurea with higher galanthamine content can specifically enhance the accumulation of this medicinal alkaloid in other Lycoris species, thereby increasing the galanthamine source and reducing galanthamine separation and purification costs. This study broadens our understanding of the complex interactions between plant secondary metabolites and fungal endophytes.

Effects of plants-associated microbiota on cultivation and quality of Chinese herbal medicines

Microbial resource influences the life activities of medicinal plants from several perspectives. Endophytes, rhizosphere microorganisms, and other environmental microorganisms play essential roles in medicinal plant growth and development, plant yield, and clinical efficacy. The microbiota can influence the biosynthesis of active compounds in medicinal plants by stimulating specific metabolic pathways. They induce host plants to improve their resistance to environmental stresses by accumulating secondary metabolites. Microorganisms can interact with their host plants to produce long-term, targeted selection results and improve their ability to adapt to the environment. Due to the interdependence and interaction between microorganisms and medicinal plants, Chinese herbal medicines (CHMs) quality is closely related to the associated microorganisms. This review summarizes the relationship between medicinal plants and their associated microorganisms, including their species, distribution, life activities, and metabolites. Microorganisms can aid in quality control, improve the efficacy of medicinal plants, and provide markers for identifying the origin and storage time of CHMs. Therefore, a comprehensive understanding of the relationship between microorganisms and medicinal plants will help to control the quality of CHMs from different perspectives.

Roles of endophytic fungi in medicinal plant abiotic stress response and TCM quality development

Medicinal plants, as medicinal materials and important drug components, have been used in traditional and folk medicine for ages. However, being sessile organisms, they are seriously affected by extreme environmental conditions and abiotic stresses such as salt, heavy metal, temperature, and water stresses. Medicinal plants usually produce specific secondary metabolites to survive such stresses, and these metabolites can often be used for treating human diseases. Recently, medicinal plants have been found to partner with endophytic fungi to form a long-term, stable, and win-win symbiotic relationship. Endophytic fungi can promote secondary metabolite accumulation in medicinal plants. The close relationship can improve host plant resistance to the abiotic stresses of soil salinity, drought, and extreme temperatures. Their symbiosis also sheds light on plant growth and active compound production. Here, we show that endophytic fungi can improve the host medicinal plant resistance to abiotic stress by regulating active compounds, reducing oxidative stress, and regulating the cell ion balance. We also identify the deficiencies and burning issues of available studies and present promising research topics for the future. This review provides guidance for endophytic fungi research to improve the ability of medicinal plants to resist abiotic stress. It also suggests ideas and methods for active compound accumulation in medicinal plants and medicinal material development during the response to abiotic stress.

Long-term push-pull cropping system shifts soil and maize-root microbiome diversity paving way to resilient farming system

BACKGROUND

The soil biota consists of a complex assembly of microbial communities and other organisms that vary significantly across farming systems, impacting soil health and plant productivity. Despite its importance, there has been limited exploration of how different cropping systems influence soil and plant root microbiomes. In this study, we investigated soil physicochemical properties, along with soil and maize-root microbiomes, in an agroecological cereal-legume companion cropping system known as push-pull technology (PPT). This system has been used in agriculture for over two decades for insect-pest management, soil health improvement, and weed control in sub-Saharan Africa. We compared the results with those obtained from maize-monoculture (Mono) cropping system.

RESULTS

The PPT cropping system changed the composition and diversity of soil and maize-root microbial communities, and led to notable improvements in soil physicochemical characteristics compared to that of the Mono cropping system. Distinct bacterial and fungal genera played a crucial role in influencing the variation in microbial diversity within these cropping systems. The relative abundance of fungal genera Trichoderma, Mortierella, and Bionectria and bacterial genera Streptomyces, RB41, and Nitrospira were more enriched in PPT. These microbial communities are associated with essential ecosystem services such as plant protection, decomposition, carbon utilization, bioinsecticides production, nitrogen fixation, nematode suppression, phytohormone production, and bioremediation. Conversely, pathogenic associated bacterial genus including Bryobacter were more enriched in Mono-root. Additionally, the Mono system exhibited a high relative abundance of fungal genera such as Gibberella, Neocosmospora, and Aspergillus, which are linked to plant diseases and food contamination. Significant differences were observed in the relative abundance of the inferred metabiome functional protein pathways including syringate degradation, L-methionine biosynthesis I, and inosine 5'-phosphate degradation.

CONCLUSION

Push-pull cropping system positively influences soil and maize-root microbiomes and enhances soil physicochemical properties. This highlights its potential for agricultural and environmental sustainability. These findings contribute to our understanding of the diverse ecosystem services offered by this cropping system where it is practiced regarding the system's resilience and functional redundancy. Future research should focus on whether PPT affects the soil and maize-root microbial communities through the release of plant metabolites from the intercrop root exudates or through the alteration of the soil's nutritional status, which affects microbial enzymatic activities.

Colonization dynamic and distribution of the endophytic fungus Microdochium bolleyi in plants measured by qPCR

Microdochium bolleyi is a fungal endophyte of cereals and grasses proposed as an ideal model organism for studying plant-endophyte interactions. A qPCR-based diagnostic assay was developed to detect M. bolleyi in wheat and Brachypodium distachyon tissues using the species-specific primers MbqITS derived from the ITS of the ribosomal gene. Specificity was tested against 20 fungal organisms associated with barley and wheat. Colonization dynamics, endophyte distribution in the plant, and potential of the seed transmission were analyzed in the wheat and model plant B. distachyon. The colonization of plants by endophyte starts from the germinating seed, where the seed coats are first strongly colonized, then the endophyte spreads to the adjacent parts, crown, roots near the crown, and basal parts of the stem. While in the lower distal parts of roots, the concentration of M. bolleyi DNA did not change significantly in successive samplings (30, 60, 90, 120, and 150 days after inoculation), there was a significant increase over time in the roots 1 cm under crown, crowns and stem bases. The endophyte reaches the higher parts of the base (2-4 cm above the crown) 90 days after sowing in wheat and 150 days in B. distachyon. The endophyte does not reach both host species' leaves, peduncles, and ears. Regarding the potential for seed transmission, endophyte was not detected in harvested grains of plants with heavily colonized roots. Plants grown from seeds derived from parental plants heavily colonized by endophyte did not exhibit any presence of the endophyte, so transmission by seeds was not confirmed. The course of colonization dynamics and distribution in the plant was similar for both hosts tested, with two differences: the base of the wheat stem was colonized earlier, but B. distachyon was occupied more intensively and abundantly than wheat. Thus, the designed species-specific primers could detect and quantify the endophyte in planta.

Why Are There So Few Basidiomycota and Basal Fungi as Endophytes? A Review

A review of selected studies on fungal endophytes confirms the paucity of Basidiomycota and basal fungi, with almost 90% attributed to Ascomycota. Reasons for the low number of Basidiomycota and basal fungi, including the Chytridiomycota, Mucoromycota, and Mortierellomycota, are advanced, including isolation procedure and media, incubation period and the slow growth of basidiomycetes, the identification of non-sporulating isolates, endophyte competition, and fungus-host interactions. We compare the detection of endophytes through culture-dependent methods and culture-independent methods, the role of fungi on senescence of the host plant, and next-generation studies.

Dark septate endophyte inoculation enhances antioxidant activity in Astragalus membranaceus var. mongholicus under heat stress

The influence of dark septate endophytic (DSE) on the antioxidant activity of Astragalus membranaceus var. mongholicus under heat stress was investigated. A. membranaceus plants, with or without DSE inoculation, were grown at 28°C for 8 weeks in a greenhouse and subsequently subjected to heat stress conditions (42°C) in an artificial climate chamber. DSE inoculation significantly decreased the malondialdehyde (MDA) content during the initial three days of heat stress. The activities of superoxide dismutase (SOD) and peroxidase (POD) of A. membranaceus leaves were significantly enhanced by DSE inoculation under heat stress, with SOD activities being 63-81% higher than in other treatments. The glutathione (GSH) and putrescine (Put) contents accumulated significantly on the third day under heat stress with DSE inoculation. Additionally, the contents of soluble sugars and proline (Pro) exhibited significant increases on the seventh day of heat stress and were 33-55% and 81-83% higher than in other treatments, respectively. Three-way ANOVA shows that DSE inoculation under heat stress exerted a significant impact on MDA. Multivariate linear regression and structural equality modelling (SEM) further show that the interaction among these antioxidants significantly decreased MDA content and maintained the normal function of cell membranes. In conclusion, DSE inoculation enhanced the heat tolerance of A. membranaceus by boosting its antioxidant capacity and reducing MDA production. This study highlights the potential of utilizing DSE as a strategy to enhance plant heat tolerance.

Genotype-Controlled Vertical Transmission Exerts Selective Pressure on Community Assembly of Salvia miltiorrhiza

The plant's endophytic fungi play an important role in promoting host development and metabolism. Studies have shown that the factors affecting the assembly of the endophyte community mainly include host genotype, vertical transmission, and soil origin. However, we do not know the role of vertically transmitted endohytic fungi influences on the host-plant's endophytic community assembly. Salvia miltiorrhiza from three production areas were used as research objects; we constructed three production area genotypes of S. miltiorrhiza regenerated seedlings simultaneously. Based on high-throughput sequencing, we analyzed the effects of genotype, soil origin, and vertical transmission on endophytic fungal communities. The results show that the community of soil origins significantly affected the endophytic fungal community in the regenerated seedlings of S. miltiorrhiza. The influence of genotype on community composition occurs through a specific mechanism. Genotype may selectively screen certain communities into the seed, thereby exerting selection pressure on the community composition process of offspring. As the number of offspring increases gradually, the microbiota, controlled by genotype and transmitted vertically, stabilizes, ultimately resulting in a significant effect of genotype on community composition.Furthermore, we observed that the taxa influencing the active ingredients are also selected as the vertically transmitted community. Moreover, the absence of an initial vertically transmitted community in S. miltiorrhiza makes it more vulnerable to infection by pathogenic fungi. Therefore, it is crucial to investigate and comprehend the selection model of the vertically transmitted community under varying genotypes and soil conditions. This research holds significant implications for enhancing the quality and yield of medicinal plants and economic crops.

Effects of Phosphorus-dissolving Dark Septate Endophytes on the Growth of Blueberry

Dark septate endophytes (DSEs) are widely distributed and improve plant growth. DSEs secrete large amounts of enzymes to mineralize insoluble phosphorus in soil and convert it into soluble phosphorus, promoting plant uptake of phosphorus. However, the effects of DSEs with phosphate-solubilizing ability on host plants need further study. In this study, phosphorus-dissolving DSEs were screened for growth-promoting effects. We isolated, identified and characterized three DSE species (Thozetella neonivea, Pezicula ericae and Hyaloscyphaceae sp.) showing phosphate-solubilizing ability. The impact of single, dual or triple inoculation of DSEs on blueberry plant characteristics was studied. Their effects on colonization intensity, seedling biomass, nutrients in plants and soil, and activities of plant resistance enzymes and soil enzymes were markedly upregulated relative to the control (P < 0.05). The available phosphorus and acid phosphatase levels in different combinations were significantly increased. These findings indicate that the application of the three DSEs may be valuable in facilitating the cultivation of blueberry with a higher biomass and improved plant quality.

Effect of natural weed and Siratro cover crop on soil fungal diversity in a banana cropping system in southwestern China

Introduction

Natural weed cover and a legume cover crop were examined to determine if they could impact soil fungal diversity as an indicator of soil quality in banana production.

Methods

Banana in Yunnan Province, China, was grown under three treatments: conventional tillage (bare soil), natural weed cover (primarily goosegrass (Eleusine indica (L.) Gaerth)), or a cover crop (Siratro (Macroptilium atropurpureum (DC.) Urb.)). Analysis of the soil fungal communities between 2017 and 2020 was done by Illumina Miseq high-throughput sequencing.

Results

Most significant effects were in the intercropping area for the treatments, whereas it was rarely observed in the furrow planted with banana. Based on the Shannon and Simpson diversity indices, soil fungal diversity in the intercropping area significantly decreased following planting banana in 2017 with all three treatments. However, both the Shannon and Simpson diversity indices showed that there were significant increases in fungal soil diversity in 2019 and 2020 with natural weed cover or Siratro compared to bare soil. At the end of the experiment, significant increases in fungal genera with Siratro compared to bare soil were observed with Mortierella, Acremonium, Plectophaerella, Metarhizium and Acrocalymma, and significant decreases were observed with Fusicolla, Myrothecium, Exserohilum, Micropsalliota and Nigrospora. Siratro resulted in higher stability of the soil fungal microbiome by increasing the modularity and the proportion of negative co-occurrences compared to bare soil. For fungal guilds, Siratro significantly increased saprotrophs_symbiotrophs in 2019 and 2020 and significantly decreased pathogens_saprotrophs in 2020 compared to bare soil.

Discussion

Using Siratro as a cover crop in the intercropping area of banana helped maintain soil fungal diversity, which would be beneficial for soil health with more symbiotrophs and less pathogens in the soil. However, further research is needed to determine the long-term impact of weed or Siratro cover crop on the fungal soil ecosystem and growth of banana.

Effects of Dark Septate Endophytes on the Performance and Soil Microbia of Lycium ruthenicum Under Drought Stress

In the current study, we explored the effects of dark septate endophytes (DSE) (Neocamarosporium phragmitis, Alternaria chlamydospore, and Microascus alveolaris) on the performance and rhizosphere soil microbial composition of Lycium ruthenicum Murr under drought stress. Differences in plant growth and physiological indexes, soil parameters, and microbial composition under different treatments were studied. Three DSE species could form good symbiotic relationships with L. ruthenicum plants, and the symbionts depended on DSE species and water availability. Inoculation of DSE had the greatest benefit on host plants under drought conditions. In particular, N. phragmitis and A. chlamydospore had a significant positive influence on the biomass, morphological and physiological indexes of host plants. Additionally, the content of arbuscular mycorrhiza (AM) fungi, gram-negative bacteria, and actinomycetes in the soil was significantly elevated after DSE inoculation in the absence of water. Based on a variance decomposition analysis, DSE was the most important factor affecting the growth and physiological parameters of host plants, and DSE inoculation combined with water conditions significantly affected the contents of soil microbial communities. Structural equation model (SEM) analysis showed that the positive effects of DSE on L. ruthenicum varied with DSE species and plant parameters under different water conditions. These results are helpful to understand the ecological function of DSE and its potential application in the cultivation of L. ruthenicum plants in drylands.

Insights into the beneficial roles of dark septate endophytes in plants under challenging environment: resilience to biotic and abiotic stresses

Dark septate endophytes (DSE) exert a plethora of effects in regulating plant growth, signalling and stress tolerance. The advent of metagenomics has led to the identification of various species of DSE to be associated with plant organs. They are known to modulate growth, nutrient uptake, phytohormone biosynthesis and production of active bioconstituents in several plants. The interactions between the DSE and host plants are mostly mutualistic but they can also be neutral or exhibit negative interactions. The DSE has beneficial role in removal/sequestration of toxic heavy metals from various environmental sites. Here, we discuss the beneficial role of DSE in enhancing plant tolerance to heavy metal stress, drought conditions, high salinity and protection from various plant pathogens. Furthermore, the underlying mechanism of stress resilience facilitated by DSE-plant interaction has also been discussed. The article also provides insights to some important future perspectives associated with DSE-mediated phytoremediation and reclamation of polluted land worldwide thus facilitating sustainable agriculture.

Do mycorrhizae increase plant growth and pollutant removal in stormwater biofilters?

Mycorrhizae can improve plant growth and drought tolerance by enhancing plant uptake of nutrients and water, which are important targets for biofilters, a common stormwater treatment system. This study evaluated the role of mycorrhizal inoculation on plant growth, photosynthetic efficiency and pollutant removal in two Australian plant species grown in stormwater biofilters. During the establishment period and column study, Ficinia nodosa showed over 80% mycorrhizal colonization, leading to a doubling of shoot and root biomass compared to the control, while Carex appressa showed less than 26% mycorrhizal colonization and no effect on shoot and root biomass. Columns planted with mycorrhizal-inoculated F. nodosa had 5% higher removal of total phosphorus and 10% higher removal of total nitrogen (Figure 5), phosphate (Figure 6), and cadmium (Table 3). Mycorrhizal colonization did not appear to affect plant stress during drought as indicated by similar photosynthetic efficiencies within species. Our results indicate that mycorrhizal inoculation can be highly successful in biofilters while increasing plant growth and nutrient removal, opening opportunities to further study the role of mycorrhizae in enhancing plant drought tolerance and pollutant removal in existing biofiltration systems.

Inoculation With Ectomycorrhizal Fungi and Dark Septate Endophytes Contributes to the Resistance of Pinus spp. to Pine Wilt Disease

Pine wilt disease (PWD) is a deadly disease to pines (Pinus spp.) worldwide. The occurrence of PWD can reduce the relative abundance of root ectomycorrhizal fungi (ECMF) and dark septate endophytes (DSE). However, the effects of exogenous ECMF/DSE inoculation on the rhizosphere microbial community structure of Pinus tabulaeformis infected by pine wood nematode (PWN) is little known. Here, we tested how ECMF/DSE may improve resistance to PWD by quantifying microbial carbon biomass and soil enzymatic activity among different treatments at 6 and 9 months after PWN infection. Denaturing gradient gel electrophoresis (DGGE) was used to study the microbial community structure at 3, 6, and 9 months after PWN infection in the rhizosphere of P. tabulaeformis seedlings inoculated with ECMF/DSE. The results showed that exogenous ECMF/DSE inoculation reduced the disease severity caused by PWN infection. After PWN infection, the rhizosphere microbial carbon of seedlings inoculated with Amanita vaginata, Suillus bovinus, Gaeumannomyces cylindrosporus, and Paraphoma chrysanthemicola was 38.16, 49.67, 42.11, and 96.05% higher than that of the control group, respectively. Inoculation of ECMF/DSE inhibited the decrease of rhizosphere microbial biomass caused by PWN infection. The richness and diversity of P. tabulaeformis rhizosphere fungi at 9 months were reduced by PWN infection but partially recovered by the exogenous fungi (ECMF/DSE) inoculation except for P. chrysanthemicola, which indicates a role of ECMF/DSE in maintaining stability of the microbial community. Inoculation with ECMF/DSE increased the beneficial bacterial (Thauera sp., Mesorhizobium sp., etc.) and fungal groups (Tomentella ellisii, Wilcoxina mikolae, etc.) of in the rhizosphere. In summary, exogenous ECMF/DSE inoculation could increase P. tabulaeformis resistance to PWD probably by improving the rhizosphere microenvironment.

Dark Septate Endophytes Isolated From Wild Licorice Roots Grown in the Desert Regions of Northwest China Enhance the Growth of Host Plants Under Water Deficit Stress

This study aimed to explore dark septate endophytes (DSE) that may improve the cultivation of medicinal plants in arid ecosystems. We isolated and identified eight DSE species (Acremonium nepalense, Acrocalymma vagum, Alternaria chartarum, Alternaria chlamydospora, Alternaria longissima, Darksidea alpha, Paraphoma chrysanthemicola, and Preussia terricola) colonizing the roots of wild licorice (Glycyrrhiza uralensis) in the desert areas of northwest China. Moreover, we investigated the osmotic stress tolerance of the DSE using pure culture, along with the performance of licorice plants inoculated with the DSE under drought stress in a growth chamber, respectively. Here, five species were first reported in desert habitats. The osmotic-stress tolerance of DSE species was highly variable, A. chlamydospora and P. terricola increased the total biomass and root biomass of the host plant. All DSE except A. vagum and P. chrysanthemicola increased the glycyrrhizic acid content; all DSE except A. chartarum increased the glycyrrhizin content under drought stress. DSE × watering regimen improved the glycyrrhizic acid content, soil organic matter, and available nitrogen. Structural equation model analysis showed that DSE × watering regimen positively affected soil organic matter, and total biomass, root length, glycyrrhizic acid, and glycyrrhizin (Shapotou site); and positively affected soil organic matter, available phosphorus, and glycyrrhizin (Minqin site); and positively affected the root length (Anxi site). DSE from the Shapotou site accounted for 8.0, 13.0, and 11.3% of the variations in total biomass, root biomass, and active ingredient content; DSE from the Minqin site accounted for 6.6 and 8.3% of the variations in total biomass and root biomass; DSE from the Anxi site accounted for 4.2 and 10.7% of the variations in total biomass and root biomass. DSE × watering regimen displayed a general synergistic effect on plant growth and active ingredient contents. These findings suggested that the DSE-plant interactions were affected by both DSE species and DSE originating habitats. As A. chlamydospora and P. terricola positively affected the total biomass, root biomass, and active ingredient content of host plants under drought stress, they may have important uses as promoters for the cultivation of licorice in dryland agriculture.

Insights into the mechanism of the effects of rhizosphere microorganisms on the quality of authentic Angelica sinensis under different soil microenvironments

BACKGROUND

Angelica sinensis (Oliv.) Diels (A. sinensis) is a Chinese herb grown in different geographical locations. It contains numerous active components with therapeutic value. Rhizosphere microbiomes affect various aspects of plant performance, such as nutrient acquisition, growth and development and plant diseases resistance. So far, few studies have investigated how the microbiome effects level of active components of A. sinensis. This study investigated whether changes in rhizosphere microbial communities and metabolites of A. sinensis vary with the soil microenvironment. Soils from the two main A. sinensis-producing areas, Gansu and Yunnan Province, were used to conduct pot experiments. The soil samples were divided into two parts, one part was sterilized and the other was unsterilized planting with the seedling variety of Gansu danggui 90-01. All seedlings were allowed to grow for 180 days. At the end of the experiment, radix A. sinensis were collected and used to characterize growth targets and chemical compositions. Rhizosphere soils were subjected to microbial analyses.

RESULTS

Changes in metabolic profiles and rhizosphere microbial communities of A. sinensis grown under different soil microenvironments were similar. The GN (Gansu non-sterilized), YN (Yunnan non-sterilized), GS (Gansu sterilized), and YS (Yunnan sterilized) groups were significantly separated. Notably, antagonistic bacteria such as Sphingomonas, Pseudomonas, Lysobacter, Pseudoxanthomonas, etc. were significantly (p < 0.05) enriched in Gansu soil compared with Yunnan soil. Moreover, senkyunolide I and ligustilide dimers which were enriched in GS group were strongly positively correlated with Pseudomonas parafulva; organic acids (including chlorogenic acid, dicaffeoylquinic acid and 5-feruloylquinic acid) and their ester coniferyl ferulate which were enriched in YS Group were positively associated with Gemmatimonadetes bacterium WY71 and Mucilaginibater sp., respectively.

CONCLUSIONS

The soil microenvironment influences growth and level/type of active components in A. sinensis. Further studies should explore the functional features of quality-related bacteria, identify the key response genes and clarify the interactions between genes and soil environments. This will reveal the mechanisms that determine the quality formation of genuine A. sinensis.

Rethinking Crop Nutrition in Times of Modern Microbiology: Innovative Biofertilizer Technologies

Global population growth poses a threat to food security in an era of increased ecosystem degradation, climate change, soil erosion, and biodiversity loss. In this context, harnessing naturally-occurring processes such as those provided by soil and plant-associated microorganisms presents a promising strategy to reduce dependency on agrochemicals. Biofertilizers are living microbes that enhance plant nutrition by either by mobilizing or increasing nutrient availability in soils. Various microbial taxa including beneficial bacteria and fungi are currently used as biofertilizers, as they successfully colonize the rhizosphere, rhizoplane or root interior. Despite their great potential to improve soil fertility, biofertilizers have yet to replace conventional chemical fertilizers in commercial agriculture. In the last 10 years, multi-omics studies have made a significant step forward in understanding the drivers, roles, processes, and mechanisms in the plant microbiome. However, translating this knowledge on microbiome functions in order to capitalize on plant nutrition in agroecosystems still remains a challenge. Here, we address the key factors limiting successful field applications of biofertilizers and suggest potential solutions based on emerging strategies for product development. Finally, we discuss the importance of biosafety guidelines and propose new avenues of research for biofertilizer development.

Simultaneous gas expansion and nitrogen doping strategy to prepare licorice root residues-derived nitrogen doped porous carbon for supercapacitors

Licorice root residues-derived nitrogen doped porous carbon (NP-LRC) have been prepared via a simultaneous gas expansion, activation and nitrogen doping strategy, which exhibits high specific capacitance and excellent long-term stability.

Brassica oleracea var. acephala (kale) improvement by biological activity of root endophytic fungi

Brassica oleracea var. acephala (kale) is a cruciferous vegetable widely cultivated for its leaves and flower buds in Atlantic Europe and the Mediterranean area, being a food of great interest as a "superfood" today. Little has been studied about the diversity of endophytic fungi in the Brassica genus, and there are no studies regarding kale. In this study, we made a survey of the diversity of endophytic fungi present in the roots of six different Galician kale local populations. In addition, we investigated whether the presence of endophytes in the roots was beneficial to the plants in terms of growth, cold tolerance, or resistance to bacteria and insects. The fungal isolates obtained belonged to 33 different taxa. Among those, a Fusarium sp. and Pleosporales sp. A between Setophoma and Edenia (called as Setophoma/Edenia) were present in many plants of all five local populations, being possible components of a core kale microbiome. For the first time, several interactions between endophytic fungus and Brassica plants are described and is proved how different interactions are beneficial for the plant. Fusarium sp. and Pleosporales sp. B close to Pyrenophora (called as Pyrenophora) promoted plant growth and increased cold tolerance. On the other hand, isolates of Trichoderma sp., Pleosporales sp. C close to Phialocephala (called as Phialocephala), Fusarium sp., Curvularia sp., Setophoma/Edenia and Acrocalymma sp. were able to activate plant systemic resistance against the bacterial pathogen Xanthomonas campestris. We also observed that Fusarium sp., Curvularia sp. and Setophoma/Edenia confered resistance against Mamestra brassicae larvae.

Effects of Dark Septate Endophytes Strain A024 on Damping-off Biocontrol, Plant Growth and the Rhizosphere Soil Enviroment of Pinus sylvestris var. mongolica Annual Seedlings

Dark septate endophytes (DSEs) exert a vital role in promoting plant growth, improving mineral absorption, biological disease control, and enhancing plant stress resistance. The effects of dark septate endophyte strain, Phialocephala bamuru A024 on damping-off biocontrol, plant development, nutrients within the rhizosphere soil, as well as bacterial communities in the annual seedlings of P. sylvestris var. Mongolica were studied. According to our findings, following P. bamuru A024 inoculation, the damping-off disease morbidity decreased significantly compared with control, some physiological indices such as β-1,3-glucanase, chitinase enzyme activity as well as a soluble protein and proline content in P. sylvestris var. mongolica were elevated under R. solani stress. After inoculation with P. bamuru A024, the biomass in seedlings, nutrients in soil, root structure index, together with activities of soil enzymes were remarkably up-regulated relative to control (p < 0.05). As suggested by the results of high-throughput sequencing, the microbial structure in the rhizosphere soil of the P. sylvestris var. mongolica showed significant differences (p < 0.05) after P. bamuru A024 inoculation compared to control treatment and the rhizosphere soil bacterial community structure after DSE A024 inoculation was positively correlated to the main soil nutrition indices.

Plant performance of enhancing licorice with dual inoculating dark septate endophytes and Trichoderma viride mediated via effects on root development

BACKGROUND

This study aimed to assess whether licorice (Glycyrrhiza uralensis) can benefit from dual inoculation by Trichoderma viride and dark septate endophytes (DSE) isolated from other medicinal plants.

METHODS

First, we isolated and identified three DSE (Paraboeremia putaminum, Scytalidium lignicola, and Phoma herbarum) and Trichoderma viride from medicinal plants growing in farmland of China. Second, we investigated the influences of these three DSE on the performance of licorice at different T. viride densities (1 × 106, 1 × 107, and 1 × 108 CFU/mL) under sterilised condition in a growth chamber.

RESULTS

Three DSE strains could colonize the roots of licorice, and they established a positive symbiosis with host plants depending on DSE species and T. viride densities. Inoculation of P. putaminum increased the root biomass, length, surface area, and root:shoot ratio. S. lignicola increased the root length, diameter and surface area and decreased the root:shoot ratio. P. herbarum increased the root biomass and surface area. T. viride increased the root biomass, length, and surface area. Structural equation model (SEM) analysis showed that DSE associated with T. viride augmented plant biomass and height, shoot branching, and root surface area. Variations in root morphology and biomass were attributed to differences in DSE species and T. viride density among treatments. P. putaminum or P. herbarum with low- or medium T. viride density and S. lignicola with low- or high T. viride density improved licorice root morphology and biomass.

CONCLUSIONS

DSE isolated from other medicinal plants enhanced the root growth of licorice plants under different densities T. viride conditions and may also be used to promote the cultivation of medicinal plants.

Plant Growth and Soil Microbial Impacts of Enhancing Licorice With Inoculating Dark Septate Endophytes Under Drought Stress

This study mainly aimed to investigate the effects of dark septate endophytes (DSE) (Acrocalymma vagum, Paraboeremia putaminum, and Fusarium acuminatum) on the growth and microbial community composition in the rhizosphere soil of a medicinal plant, licorice (Glycyrrhiza uralensis), grown in the non-sterile soil under drought stress. The results showed that three DSE strains could effectively colonize the plant roots and form a strain-dependent symbiosis with licorice. Although drought stress declined the growth of licorice plants, these decreases were partly recovered by DSE inoculation. Specifically, the inoculation of A. vagum and P. putaminum significantly increased the biomass and glycyrrhizin content, whereas A. vagum and F. acuminatum increased glycyrrhizic acid content of host plants under drought stress. However, the inoculation of F. acuminatum showed significant negative effects on the shoot, root, and total biomass of licorice plants. In addition, the effects of DSE inoculation on the morphological, photosynthetic, and antioxidant parameters of licorice plants, and mineral nutrient and microbial community composition in the rhizosphere soil were dependent on the DSE species as well as water regime. Interestingly, DSE inoculation significantly increased AM fungi content under drought stress. In addition, DSE associated with water had a significant positive influence on soil organic matter, available phosphorus (P), AM fungi, leaf number, soluble protein, SOD activity, total root length, root branch, and glycyrrhizic acid content. Based on the results of variance partitioning analysis, 17.0, 34.0, 14.9, 40.1, 28.2, and 18.0% variations in shoot morphology, root morphology, plant biomass, active ingredient, photosynthetic parameters, and antioxidant parameters, respectively, were attributable to the presence of certain soil microorganisms. These findings suggest the possibility that DSE inoculation improved the root development and nutrient absorption of host plants, altered the soil microbiota, and might also contribute to plant growth and survival under drought conditions. As A. vagum exhibited positive effects on the plant biomass, morphological and physiological parameters, and active ingredient content in licorice plants under drought stress, it was considered to be the best fungus for licorice cultivation. These results contribute to the understanding of the ecological function of DSE fungi in dryland agriculture.