Correlation in endophytic fungi community diversity and bioactive compounds of Sophora alopecuroides

Biochar-induced microbial and metabolic reprogramming enhances bioactive compound accumulation in Panax quinquefolius L

Panax quinquefolius L., with a history of over 300 years in traditional Chinese medicine, is notably rich in ginsenosides-its primary bioactive components. Although our previous study found that biochar application could enhance the content of ginsenoside Re, Rg and other contents in P. quinquefolius, its effect on the overall secondary metabolism of P. quinquefolius and its mechanism are still unclear. In this paper, the correlation between plant microbiome and secondary metabolites was studied from the perspective of plant rhizosphere microorganisms and endophytes, and the mechanism of biochar-induced metabolic reprogramming of P. quinquefolius was revealed. The results showed that biochar treatment significantly increased the accumulation of various substances in P. quinquefolius, including nucleosides, glycerophosphocholines, fatty acyls, steroidal glycosides, triterpenoids, and other bioactive compounds. Additionally, biochar treatment significantly enriched beneficial rhizosphere microorganisms such as Bacillus, Flavobacterium, and Devosia, while reducing the relative abundance of harmful fungi like Fusarium. Furthermore, it promoted endophytic Flavobacterium, Acaulospora, and Glomus, and suppressed pathogenic genera such as Plectosphaerella, Cladosporium, and Phaeosphaeria. These shifts in rhizosphere microbial community and endophytes structure and function were closely linked to the accumulation of secondary metabolites (e.g. ginsenosides Rg3, F2) in P. quinquefolius. Overall, our findings suggest that biochar may influence key endophytes and rhizosphere microorganisms to regulate the accumulation of secondary metabolites in P. quinquefolius. Therefore, this study provides valuable insights into the potential application of biochar in Chinese medicine agriculture.

Diversity of endophytic bacteria in Paris Polyphylla var. yunnanensis and their correlation with polyphyllin content

BACKGROUND

Paris polyphylla var. yunnanensis (PPY) is commonly used in traditional Chinese medicine formulas and folk families. Nearly more than 100 chemical substances with medicinal values have been reported in PPY, among which steroidal saponins are the main active components. Due to its long growth cycle, the resource of PPY has become too scarce, and the current production capacity of PPY is still far from meeting the market demand. Numerous studies have shown that endophytic bacteria not only promote the production of secondary metabolites in the host plant, but some of them are also able to produce the same secondary metabolites as the host. However, little is known about the endophytic bacteria associated with PPY in different geographic conditions and tissues. In order to compare the endophytic bacterial communities associated with PPY in different geographic conditions and plant tissues, the endophytic bacteria from roots, stems, and leaves of PPY collected from five locations were isolated, and the diversity, richness, and homogeneity of bacterial communities were analyzed, and the dominant genera correlation with polyphyllin content was further investigated.

RESULTS

A total of 268 endophytic bacterial strains were isolated and identified from PPY. The experimental results showed that the isolates belonged to 5 phyla, 7 classes, 14 orders and 39 genera of bacteria, of which the dominant order was Bacillariophyta and the dominant genera were Bacillus, Pseudomonas and Agrobacterium. In general, the differences in the distribution pattern and diversity of endophytic bacteria in PPY were characterized by the highest diversity and richness index of endophytic bacterial communities in Er yuan Qisheng (QS) and the highest evenness index in Dali Fengyi (FY). The diversity, richness and evenness of bacterial communities in terms of tissue state showed a hierarchical pattern of root > stem > leaf. The three optimal genera were positively correlated with polyphyllin content.

CONCLUSION

The distribution pattern and diversity of endophytic bacteria in PPY were influenced by tissue type and habitat. In addition, three endophytic bacteria (Pseudomonas, Bacllius and Agrobacterium) were positively correlated with the content of polyphylin.

A review on fungal endophytes of the family Fabaceae, their metabolic diversity and biological applications

Fabaceae is considered the third largest family of the plant kingdom, comprising of a large number of plants, belonging to 650 genera and 20,000 species of plants. Out of the various plant species that are reported in the family Fabaceae, many of the species have been reported to exhibit diverse pharmacological activities and are of economic importance to agriculturists and scientists across the globe. Studies over the last few decades have unraveled a lot of concrete information about different plants, ranging from the mutualistic interdependence of plants and microbes for their survival to the innumerable benefits of plants in the sectors of agriculture, food industry, medicine, and healthcare. The survival and effective maintenance of plant homeostasis is largely regulated by the diverse microbial population that co-exists in symbiotic relationships with plants. This endophytic microbial population can be either categorized as endophytic bacteria or endophytic fungi. The studies over the past decades have highlighted the crucial role of both endophytic bacteria and fungi in the growth and development of plants. This review explores the ameliorative roles of endophytic fungi in alleviating biotic and abiotic stresses in plants. Additionally, it highlights the vast diversity of secondary metabolites produced by these fungi and their potential applications. Secondary metabolites exhibit a wide range of biologically significant activities, including anticancer, antimicrobial, antimalarial, and nematicidal properties, which hold substantial importance in therapeutic and agricultural applications. Furthermore, the role of various endophytic fungi of the Fabaceae family has been shown in phytoremediation.

Differences in Metabolic Characteristics of Rhizosphere Fungal Community of Typical Arboreal, Shrubby and Herbaceous Species in Oasis of Arid Region

Populus euphratica, Tamarix ramosissima, and Sophora alopecuroides are, respectively, typical arboreal, shrubby, and herbaceous species in oases of arid regions. It is important to study the difference in metabolic characteristics of the rhizosphere fungal community of these plant species and their relationships with soil factors for the preservation of delicate arid oasis ecosystems with future environmental changes. In this study, we, respectively, collected 18 rhizosphere soil samples of P. euphratica, T. ramosissima, and S. alopecuroides to explore the difference in rhizosphere fungal metabolic characteristics of different plant life forms and their underlying driving factors. The results showed that (1) soil physicochemical properties (including soil water content, pH, etc.) were significantly different among different plant species (p < 0.05). (2) Rhizosphere fungal metabolic characteristics were significantly different between S. alopecuroides and T. ramosissima (ANOSIM, p < 0.05), which was mainly caused by the different utilization of carboxylic carbon. (3) The RDA showed that the main driving factors of the variations in rhizosphere fungal metabolic characteristics were different among different plant species. The main explanatory variables of the variations in the metabolic characteristics of the rhizosphere fungal community were carbon to nitrogen ratio (23%) and available potassium (17.4%) for P. euphratica, while soil organic carbon (23.1%), pH (8.6%), and total nitrogen (8.2%) for T. ramosissima, and soil clay content (36.6%) and soil organic carbon (12.6%) for S. alopecuroides. In conclusion, the variations in rhizosphere fungal metabolic characteristics in arid oases are dominantly affected by soil factors rather than plant life forms.

The diversity of endophytic fungi in Tartary buckwheat (Fagopyrum tataricum) and its correlation with flavonoids and phenotypic traits

Tartary buckwheat (Fagopyrum tataricum) is a significant medicinal crop, with flavonoids serving as a crucial measure of its quality. Presently, the artificial cultivation of Tartary buckwheat yields low results, and the quality varies across different origins. Therefore, it is imperative to identify an effective method to enhance the yield and quality of buckwheat. Endophytic fungi reside within plants and form a mutually beneficial symbiotic relationship, aiding plants in nutrient absorption, promoting host growth, and improving secondary metabolites akin to the host. In this study, high-throughput sequencing technology was employed to assess the diversity of endophytic fungi in Tartary buckwheat. Subsequently, a correlation analysis was performed between fungi and metabolites, revealing potential increases in flavonoid content due to endophytic fungi such as Bipolaris, Hymenula, and Colletotrichum. Additionally, a correlation analysis between fungi and phenotypic traits unveiled the potential influence of endophytic fungi such as Bipolaris, Buckleyzyma, and Trichosporon on the phenotypic traits of Tartary buckwheat. Notably, the endophytic fungi of the Bipolaris genus exhibited the potential to elevate the content of Tartary buckwheat metabolites and enhance crop growth. Consequently, this study successfully identified the resources of endophytic fungi in Tartary buckwheat, explored potential functional endophytic fungi, and laid a scientific foundation for future implementation of biological fertilizers in improving the quality and growth of Tartary buckwheat.

Community ecological succession of endophytic fungi associates with medicinal compound accumulation in Sophora alopecuroides

Endophytic fungi of medicinal plants are symbiotic with the host and play an important role in determining metabolites. To understand the relationship between the accumulation of Sophora alopecuroides' medicinal bioactive compounds and the ecological succession of endophytic fungi, here we collected samples from S. alopecuroides at four developmental stages (adult, flowering, podding, and mature) and different organs (roots, stems, leaves, and seeds) at the mature stage. We then used high-performance liquid chromatography-mass spectrometry and high-throughput sequencing on the internal transcribed spacer region to identify the medicinal compounds and endophytic fungal communities in each sample. The endophytic fungal community characteristics and accumulation of medicinally bioactive compounds of S. alopecuroides varied with the host's developmental stages and organs, with the highest total alkaloids content of 111.9 mg/g at the mature stage. Membership analysis and network connection analysis showed a total of 15 core endophytic fungi in different developmental stages and 16 core endophytic fungi in different organs at the mature stage. The unclassified Ascomycota, Aspergillus, and Alternaria were significantly and positively correlated with the medicinal compounds of S. alopecuroides at the mature stage (r > 0.6 or r < -0.6; P < 0.05). In this study, we identified key endophytic fungal resources that affect the content of medicinally bioactive compounds in S. alopecuroides. This discovery could lay the foundation for enhancing the yield of medicinally bioactive compounds in S. alopecuroides and the development and application of functional endophytic fungi.IMPORTANCESophora alopecuroides is a traditional Chinese herbal medicine. The major medicinal chemicals are considered to be quinolizidine alkaloids. Quinolizidine alkaloids have been widely used for the treatment of tumors, dysentery, and enteritis. Previous studies have found that endophytic fungi in S. alopecuroides can promote the accumulation of host quinolizidine alkaloids. However, the relationship between the accumulation of S. alopecuroides' medicinal bioactive compounds and the ecological succession of endophytic fungi remains unclear. In this study, we screened the key endophytic fungal resources affecting the content of medicinally bioactive compounds and laid the foundation for subsequent research on the mechanism by which endophytic fungi promote the accumulation of medicinally bioactive compounds in S. alopecuroides.

Diversity of Endophytes of Actinidia arguta in Different Seasons

The seasonal changes in environmental conditions can alter the growth states of host plants, thereby affecting the living environment of endophytes and forming different endophytic communities. This study employs Illumina MiSeq next-generation sequencing to analyze the 16SrRNA and ITS rDNA of endophytes in 24 samples of Actinidia arguta stem tissues across different seasons. The results revealed a high richness and diversity of endophytes in Actinidia arguta, with significant seasonal variations in microbial community richness. This study identified 897 genera across 36 phyla for bacteria and 251 genera across 8 phyla for fungi. Notably, 69 bacterial genera and 19 fungal genera significantly contributed to the differences in community structure across seasons. A distinctive feature of coexistence in the endophytic community, both specific and conservative across different seasons, was observed. The bacterial community in winter demonstrated significantly higher richness and diversity compared to the other seasons. Environmental factors likely influence the optimal timing for endophyte colonization. Solar radiation, temperature, precipitation, and relative humidity significantly impact the diversity of endophytic bacteria and fungi. In addition, seasonal variations show significant differences in the nutritional modes of fungal endophytes and the degradation, ligninolysis, and ureolysis functions of bacterial endophytes. This study elucidates the potential role of endophytes in assisting Actinidia arguta in adapting to seasonal changes and provides a theoretical basis for further exploration of functional microbial strains.

Succession of endophytic fungi and rhizosphere soil fungi and their correlation with secondary metabolites in Fagopyrum dibotrys

Golden buckwheat (Fagopyrum dibotrys, also known as F. acutatum) is a traditional edible herbal medicinal plant with a large number of secondary metabolites and is considered to be a source of therapeutic compounds. Different ecological environments have a significant impact on their compound content and medicinal effects. However, little is known about the interactions between soil physicochemical properties, the rhizosphere, endophytic fungal communities, and secondary metabolites in F. dibotrys. In this study, the rhizosphere soil and endophytic fungal communities of F. dibotrys in five different ecological regions in China were identified based on high-throughput sequencing methods. The correlations between soil physicochemical properties, active components (total saponins, total flavonoids, proanthocyanidin, and epicatechin), and endophytic and rhizosphere soil fungi of F. dibotrys were analyzed. The results showed that soil pH, soil N, OM, and P were significantly correlated with the active components of F. dibotrys. Among them, epicatechin, proanthocyanidin, and total saponins were significantly positively correlated with soil pH, while proanthocyanidin content was significantly positively correlated with STN, SAN, and OM in soil, and total flavone content was significantly positively correlated with P in soil. In soil microbes, Mortierella, Trechispora, Exophiala, Ascomycota_unclassified, Auricularia, Plectosphaerella, Mycena, Fungi_unclassified, Agaricomycetes_unclassified, Coprinellus, and Pseudaleuria were significantly related to key secondary metabolites of F. dibotrys. Diaporthe and Meripilaceae_unclassified were significantly related to key secondary metabolites in the rhizome. This study presents a new opportunity to deeply understand soil-plant-fungal symbioses and secondary metabolites in F. dibotrys, as well as provides a scientific basis for using biological fertilization strategies to improve the quality of F. dibotrys.

Diversity and correlation analysis of endophytes and metabolites of Panax quinquefolius L. in various tissues

BACKGROUND

Panax quinquefolius L. (American ginseng) is widely used in medicine due to its wealth of diverse pharmacological effects. Endophytes colonize within P. quinquefolius in multiple tissue types. However, the relationship between endophytes and the production of their active ingredients in different parts of the plant is not clear.

RESULTS

In this study, the relationship of endophytic diversity and the metabolites produced in different plant tissues of P. quinquefolius were analyzed using metagenomic and metabolomic approaches. The results showed relatively similar endophyte composition in roots and fibrils, but obvious differences between endophyte populations in stems and leaves. Species abundance analysis showed that at the phylum level, the dominant bacterial phylum was Cyanobacteria for roots, fibrils, stems and leaves, Ascomycota forroots and fibrils roots, and Basidiomycota for stems and leaves. LC-MS/MS technology was used to quantitatively analyze the metabolites in different tissues of P. quinquefolius. A total of 398 metabolites and 294 differential metaboliteswere identified, mainly organic acids, sugars, amino acids, polyphenols, and saponins. Most of the differential metabolites were enriched in metabolic pathways such as phenylpropane biosynthesis, flavonoid biosynthesis, citric acid cycle, and amino acid biosynthesis. Correlation analysis showed a positive and negative correlation between the endophytes and the differential metabolites. Conexibacter significantly enriched in root and fibril was significantly positively correlated with saponin differential metabolites, while cyberlindnera significantly enriched in stem and leaf was significantly negatively correlated with differential metabolites (p < 0.05).

CONCLUSION

The endophytic communities diversity were relatively similar in the roots and fibrils of P. quinquefolius, while there were greater differences between the stems and leaves. There was significant difference in metabolite content between different tissues of P. quinquefolius. Correlation analysis methods demonstrated a correlation between endophytes and differential metabolism.

The Endophytic Fungi Diversity, Community Structure, and Ecological Function Prediction of Sophora alopecuroides in Ningxia, China

Sophora alopecuroides L. has great medicinal and ecological value in northwestern China. The host and its microbiota are mutually symbiotic, collectively forming a holobiont, conferring beneficial effects to the plant. However, the analysis of diversity, mycobiota composition, and the ecological function of endophytic fungi in the holobiont of S. alopecuroides is relatively lacking. In this article, the fungal community profiling of roots, stems, leaves, and seeds of S. alopecuroides (at the fruit maturity stage) from Huamachi and Baofeng in Ningxia, China were investigated based on the ITS1 region, using high-throughput sequencing technology. As a result, a total of 751 operational taxonomic units (OTUs) were obtained and further classified into 9 phyla, 27 classes, 66 orders, 141 families, 245 genera, and 340 species. The roots had the highest fungal richness and diversity, while the stems had the highest evenness and pedigree diversity. There also was a significant difference in the richness of the endophytic fungal community between root and seed (p < 0.05). The organ was the main factor affecting the community structure of endophytic fungi in S. alopecuroides. The genera of unclassified Ascomycota, Tricholoma, Apiotrichum, Alternaria, and Aspergillus made up the vast majority of relative abundance, which were common in all four organs as well. The dominant and endemic genera and biomarkers of endophytic fungi in four organs of S. alopecuroides were different and exhibited organ specificity or tissue preference. The endophytic fungi of S. alopecuroides were mainly divided into 15 ecological function groups, among which saprotroph was absolutely dominant, followed by mixotrophic and pathotroph, and the symbiotroph was the least. With this study, we revealed the diversity and community structure and predicted the ecological function of the endophytic fungi of S. alopecuroides, which provided a theoretical reference for the further development and utilization of the endophytic fungi resources of S. alopecuroides.