Skip to main content
Download PDF

Diversity, antibacterial and phytotoxic activities of intestinal fungi from Epitheca bimaculata

BMC Microbiology volume 25, Article number: 249 (2025) Cite this article

Abstract

Insect gut fungi, as specialized microorganisms, are a significant source of bioactive compounds. However, there is currently no systematic research on the diversity of gut fungi in Epitheca bimaculata and their bioactive secondary metabolites. A total of 54 strains of gut fungi were isolated and purified from the gut of E. bimaculata using 12 different isolation media. The identification results revealed that these fungal strains were distributed across seven classes (Agaricomycetes, Cystobasidiomycetes, Eurotiomycetes, Dothideomycetes, Sordariomycetes, Saccharomycetes, and Zygomycetes) in 17 genera. The dominant genera were Irpex, Cladosporium, Penicillium, Mucor, and Talaromyces, with isolation frequencies of 14.81%, 12.96%, 12.96%, 11.11%, and 9.25%, respectively. Antibacterial tests showed that six strains extracts exhibited inhibitory activity against at least one of the tested bacteria (Staphylococcus aureus, Micrococcus tetragenus, Escherichia coli, and Pseudomonas syringae pv. actinidiae). Phytotoxic tests indicated that strains QTU-39, QTU-22, QTU-9, QTU-41, QTU-37, QTU-28, and QTU-25 showed strong phytotoxic activity against Echinochloa crusgalli with the inhibition rate of exceeding 93.5%. Seven monomer compounds, including citrinin (1), emodin (2), citreorosein (3), 8-hydroxy-6-methyl-9-oxo-9 H-xanthene-1-carboxylic acid methyl ester (4), ergosterol (5), rubratoxin B (6), and erythrol (7), and two compounds, including flufuran (8) and 4-N-butylpyridine-2-carboxylic acid (9) were isolated from Penicillium sp. QTU-25 and Pestalotiopsis sp. QTU-28, respectively. Among these, compound 1 exhibited strong antibacterial activity against four pathogenic bacteria (S. aureus, M. tetragenus, E. coli, and P. syringae pv. actinidiae), with the IZD of 20.0, 18.0, 22.3, 24.1 mm, which were equal to those of positive gentamicin sulfate with the IZD of 25.7, 22.7, 27.6, 24.6 mm, respectively. Compound 9 also exhibited strong antibacterial activity against S. aureus, M. tetragenus, E. coli, and P. syringae pv. actinidiae, with the IZD of 14.3, 17.3, 13.3, and 21.1 mm, respectively. Furthermore, compounds 1 and 6 exhibited strong phytotoxic activity against E. crusgalli and Abutilon theophrasti with an inhibition rate of 97.4% and 87.4% at a concentration of 100 µg/mL, respectively. In conclusion, the fungi isolated from the gut of E. bimaculata exhibited significant microbial diversity, representing a promising natural source of antibacterial and herbicidal compounds.

Peer Review reports

Introduction

Insects, among the oldest living organisms, have a 479 million-year evolutionary history [1]. They are one of the most diverse groups and significantly influence natural and agricultural systems [2, 3]. Most insects are long-term hosts of microorganisms, which are often beneficial and even essential to the insect hosts [4]. Microbial communities can vary among different insect species and even among different life stages of the same insect species [5, 6]. For example, new microbial species from beetles, bees, and fruit flies were isolated and expanded the diversity of known microbial species [7,8,9,10]. Therefore, the diversity of insects drives the diversity of insect-associated microorganisms.

Diverse insect-associated microorganisms can regulate host immunity, assist in defense against predators, and protect against pathogenic infections by synthesizing a variety of bioactive metabolites [11,12,13]. Insect intestinal fungi, as part of the broader insect-associated microbiome, are particularly notable for their ability to produce a wide array of metabolites with unique chemical structures and potential biological activities [14]. Recent studies have shown that these fungi have yielded various novel compounds with antimicrobial, antiviral, and antitumor activities, offering valuable resources for the discovery of new drug molecules [15,16,17,18]. In addition to their medicinal potential, these bioactive metabolites have significant applications in agriculture, particularly as sources for new agricultural antibiotics or herbicides. With weeds causing substantial crop yield losses globally—ranging from 30 to 45%, and in extreme cases, up to 90% [19, 20], the urgent need for new herbicides is evident. In this context, insect intestinal fungi have emerged as a promising source of novel compounds with potent herbicidal activity [21, 22].

Dragonflies, one of the oldest insects, have existed on Earth for over 300 million years [23]. They host a rich diversity of gut microorganisms, forming complex symbiotic relationships with these microbes [24, 25]. Previous research has confirmed that fungi associated with dragonflies exhibit various bioactivities. For instance, fungi isolated from the gut of Crocothemis servilia have shown various antibacterial activities [14]. This study aims to analyze the diversity of fungi in the gut of Epitheca bimaculata and investigate their antibacterial and herbicidal activities. Additionally, secondary metabolites from selected target strain will be isolated and tested for bioactivity. The goal is to explore the potential applications of these insect gut fungi in both medicine and agriculture.

Materials and methods

Sample collection and microbial isolations

The larvae of E. bimaculata were collected from the Yalu River Wetland (Dandong city, China) in March 2022. The larvae of E. bimaculata were starved for 24 h. In a sterile workbench, they were disinfected by soaking in 75% alcohol for 3 min, rinsed 3 times with sterile water, and dried with sterile filter paper. The abdomen of E. bimaculata was carefully opened with forceps and a dissection needle to extract the gut. The extracted gut was placed in a mortar containing 0.5 mL of sterile water, with a few grains of quartz sand added to aid in thorough grinding, resulting in a gut homogenate of E. bimaculata. The gut homogenate was serially diluted to 10− 1, 10− 2, and 10− 3 times. Then, 100 µL of each dilution was evenly spread on plates which had 12 media (Table S1) and containing 1% ampicillin and streptomycin. The plates were left to absorb the homogenate, and each set was repeated three times. The plates were then inverted and incubated at 28 °C for 14 days. During the incubation period, the plates were observed daily for colony growth. When colonies appeared, hyphae were picked from the colony edges and transferred to new PDA plates for 3–4 days to obtain single fungal strains. Finally, the obtained single fungal strains were preserved in PDA slant tubes and stored in a refrigerator at 4 °C.

DNA extraction and PCR amplification

DNA sequencing was performed according to the previous methods with some modified [26]. Fungi were transferred into PDA medium and cultured at 28℃ in Constant Temperature Incubator Shakers for 3–4 days. Fresh fungal mycelium was used for genomic DNA extraction, following the manufacturer’s instructions for the DNeasy Plant Minikit (TIANGEN). The internal transcriptional spacer (ITS) of fungal ribosomal DNA was amplified using the forward primer ITS1 (5’-TCCGTAGGTGAACCTGCGG-3’) and the reverse primer ITS4 (5’-TCCTCCGCTTATTGATATGC-3’) [27]. The purity of the DNA was checked using 1% agarose gel electrophoresis. The DNA were sent to TSINGKE Biological Technology Corporation (Shandong, China) for purification and bi-directionally sequencing. Then the obtained 5.8S rDNA sequences were uploaded to the National Center for Biotechnology Information (NCBI) database.

Identification and phylogenetic analysis of the intestinal fungi

As previously reported, the affiliations of all resultant sequences returned from TSINGKE Biological Technology Corporation were identified by valid data in BLAST from NCBI database. Sequence alignment and Neighbor-joining Phylogenetic Analysis were carried out using MEGA software version 6.0. Bootstrap analysis of tree construction built on 1000 replicates of sequence intensities to estimate neighbor-joining information [28].

Preparation of extracts of fermentation broth of intestinal fungi

Each fungus was transferred to PDA medium and incubated at 28℃ for 3–4 days. Then, fresh mycelia of each fungus were transferred to a conical flask containing ME liquid medium and incubated in a constant temperature culture shaker rotating at 180 rpm for 7 days at 28℃. For large-scale fermentation, the above fermentation broth was used as the seed culture. The seed culture was inoculated into 1 L conical flasks containing 400 mL of ME liquid medium at a ratio of 1:20. After incubation, the culture was filtered through four layers of cotton gauze to obtain the fermentation broth. Then the fermentation broth was extracted three times with ethyl acetate (EtOAc, 1:1, v/v). The crude fungal extracts were obtained by concentrating the ethyl acetate phase in vacuo.

Isolation of compounds from target strains

The ethyl acetate extracts of the target strains were analyzed using TLC (thin-layer chromatography) with petroleum ether-ethyl acetate and dichloromethane-methanol systems as developing solvents to choose a suitable elution solvent. In this study, the dichloromethane-methanol solvent system was selected for the separation and purification of the fungal extract. The crude fungal extract was separated by column chromatography (CC) using silica gel (SiO2: 200–300 mesh) and eluted with a stepwise gradient of CH2Cl2/MeOH (100:0-100:32, v/v) to provide seven primary fractions (Fr1 to Fr7). Further separation of the primary fractions was conducted using the same method. Additionally, for further separation, LH-20 Sephadex gel chromatography was employed, using methanol as the mobile phase for column chromatography to separate the metabolites. Different fractions were analyzed using TLC and were visualized by various methods such as 254 and 365 nm UV light, iodine vapor, and 25% sulfuric acid-ethanol, to combine similar fractions.

Structural elucidation of metabolites

The structures of all compounds were initially analyzed by 1H/13C Nuclear Magnetic Resonance (NMR) spectroscopy and High-Resolution Mass Spectrometry (HR-ESI-MS). 1H/13C NMR data were acquired using an Agilent DD2 600 Hz spectrometer (Agilent, USA), and chemical shifts were reported as parts per million (δ) by referring to tetramethylsilane (TMS) as an internal standard. HR-ESI-MS spectral data were collected on a TripeTOF 4600 mass analyzer (Bruker, USA).

Antibacterial activity

The antibacterial activity of fungal crude extracts and compounds from intestinal fungi of E. bimaculata were assessed using the filter paper disk method. Four tested bacteria (E. coli, M. tetragenus, S. aureus, and P. syringae pv. actinidiae) were used. Three of these bacteria (E. coli, M. tetragenus, and S. aureus) were cultured on TSBA medium at 37 °C, while P. syringae pv. actinidiae was cultured on LB solid medium at 28 °C. All tested crude extracts, metabolites and the positive control (gentamicin sulfate) were prepared as solutions at a concentration of 6 mg/mL. The crude extracts and compounds were dissolved in acetone, with acetone as the negative control. The positive control was dissolved in sterile water. All tested crude extracts, compounds, negative controls, and positive controls were filtered for sterilization using 0.22 µm sterile filter membrane. Next, sterile filter paper discs (6 mm in diameter) were loaded with 5 µL of the tested samples and placed on the pre-prepared agar medium. Three replicates were performed for each test. The petri dishes were incubated in a constant-temperature incubator for 24–36 h. The antibacterial activity was assessed by measuring the diameter of the inhibition zones (in mm) using the crossover method.

Phytotoxic assay

According to the methods described in previous literature [29], the phytotoxic activity of gut fungi was evaluated their effects on the radicle growth of Echinochloa crusgalli (monocot plant) and Abutilon theophrasti (dicot plant). The fungi were fermented in 150 mL of ME liquid medium at 28℃ for 7 days, and the resulting fermentation broth was filtered to remove the mycelia. The seeds of A. theophrasti were pretreated by soaking in water at 60 °C for 30 min, followed by immersion in a 40 mmol/L CaCl2 solution for 12 h to enhance germination. The seeds of E. crusgalli and A. theophrasti were surface disinfected by soaking them in 5% sodium hypochlorite for 20 min. Then, the seeds were washed several times with deionized water. The seeds were cultured in an illuminating incubator at 28℃ until germination. Then, 30 pregerminated seeds were placed in 9 cm diameter Petri dishes on filter paper disks soaked with 5.0 mL of fungal fermentation broth. Radicle length was measured after 2–3 days, and distilled water was used as the negative control.

The compounds were dissolved in acetone and diluted to a concentration of 100 µg/mL using 0.1% aqueous Tween-80. The phytotoxic activity of the compounds was assessed using the same procedure as for the fermentation broth. 2,4-Dichlorophenoxyacetic acid (2,4-D) was used as the positive control.

Statistical analysis

Statistical differences were evaluated using one-way ANOVA followed by post-hoc LSD tests and t-tests. A P-value of less than 0.05 was considered statistically significant.

Results

Identification and diversity analysis of intestinal fungi

A total of 54 strains (Table 1) of intestinal fungi were isolated from the gut of E. bimaculata. All fungi were identified using ITS sequence amplification. These fungi were distributed across three major phyla (Ascomycota, Basidiomycota, and Zygomycota) and seven classes (Agaricomycetes, Cystobasidiomycetes, Eurotiomycetes, Dothideomycetes, Sordariomycetes, Saccharomycetes, and Zygomycetes) in 17 genera (Fig. 1). The predominant genera were Irpex, Cladosporium, Penicillium, Mucor, Talaromyces, Pestalotiopsis, Bjerkandera, and Aspergillus, with isolation frequencies of 14.81%, 12.96%, 12.96%, 11.11%, 9.25%, 5.55%, 5.55%, and 5.55%, respectively.

Table 1 Phylogenetic analysis of cultivable fungi associated with gut of E. bimaculata
Full size table
Fig. 1
figure 1

Neighbor-joining phylogenetic tree of 54 fungi isolated from E. bimaculata

Full size image

Antibacterial activity

The filter paper disk method was used to assess the antibacterial activity of 54 fungal ethyl acetate extracts from E. bimaculata (Table S2). The results showed that six strains extracts exhibited inhibitory activity against at least one of the tested bacteria (S. aureus, M. tetragenus, E. coli, and P. syringae pv. actinidiae) at a concentration of 30 µg/6 mm filter paper disc. Notably, the extract from strain QTU-25 exhibited strong antibacterial activity against M. tetragenus, S. aureus, and P. syringae pv. actinidiae, with the inhibition zone diameters (IZD) of 16.0, 16.0, and 23.6 mm, which were slightly weaker than those of the positive gentamicin sulfate with the IZD of 25.3, 17.6, and 26.0 mm, respectively. Additionally, some fungal extracts exhibited potent inhibitory effects against single pathogenic bacteria, such as the extracts from strains QTU-27 and QTU-72, which showed inhibitory activity against P. syringae pv. actinidiae with the IZD of 11.0 and 13.0 mm, respectively.

Phytotoxic assay

The phytotoxic activity of fermentation broths from 54 strains of intestinal fungi isolated from E. bimaculata was evaluated against two major crop weeds, E. crusgalli and A. theophrasti, using the petri dish bioassay method. The results (Table 2) showed that 50 strains (92.5%) exhibited potent phytotoxic activity against E. crusgalli, and 25 strains (46.2%) of intestinal fungi exhibited potent phytotoxic activity against A. theophrasti, with the inhibition rates exceeding 50%. Among them, strains QTU-39, QTU-22, and QTU-9 showed the highest phytotoxic activity against E. crusgalli with the inhibition rates of 100%. Other six strains, including QTU-25, QTU-41, QTU-27, QTU-37, QTU-66, and QTU-28, also showed strong phytotoxic activity against E. crusgalli, with the inhibition rates of 98.7%, 97.9%, 96.5%, 95.6%, 94.4%, and 93.5%, respectively. Additionally, ten strains, including QTU-7, QTU-33, QTU-25, QTU-35, QTU-25, QTU-29, QTU-38, QTU-18, QTU-52, and QTU-21, exhibited significant phytotoxic activity against A. theophrasti, with the inhibition rates of 79.1%, 74.2%, 73.4%, 69.1%, 66.8%, 66.2%, 65.2%, 64.3%, 63.8%, and 62.1%, respectively.

Table 2 Inhibitory activity of the fermentation broth of 54 fungi of E. bimaculata on the radicle growth of E. crusgalli and A. theophrasti
Full size table

Identification of the metabolites isolated from target strains

In the phytotoxic assay of gut fungi, strain QTU-25 exhibited significant herbicidal activity against E. crusgalli and A. theophrasti, with the inhibition rate of 98.7% and 73.4%, respectively. Additionally, strain QTU-25 also showed strong antibacterial activity against various pathogenic bacteria. in the antibacterial activity test. Strain QTU-28 exhibited significant herbicidal effects against E. crusgalli and A. theophrasti, with the inhibition of 93.5% and 66.8%, respectively. Consequently, strains QTU-25 and QTU-28 were selected for further research on them active secondary metabolites.

Nine monomer compounds were isolated from the crude extract of strains QTU-25 and QTU-28. These compounds were identified through spectroscopic analyses, including HR–ESI-MS, NMR, and comparisons with data from previous literature (Fig. 2). Among them, citrinin (1), emodin (2), citreorosein (3), 8-hydroxy-6-methyl-9-oxo-9 H-xanthene-1-carboxylic acid methyl ester (4), ergosterol (5), rubratoxin B (6), and erythrol (7) were isolated from QTU-25, while flufuran (8) and 4-N-butylpyridine-2-carboxylic acid (9) were isolated from QTU-28.

Fig. 2
figure 2

The structure of compounds 1–9

Full size image

Citrinin (1) (Figure S1-3): yellow crystal; HR-ESI-MS: m/z: 251.0912 [M + H]+, calculated for C13H15O5+ 251.0905. 1H NMR (600 MHz, CDCl3) δ: 8.23(s, 1H, H-1), 4.77(dd, J = 12.7, 6.1 Hz, 1H, H-3), 2.98(dd, J = 13.8, 6.7 Hz, 1H, H-4), 2.02(s, 3H, H-11), 1.34(d, J = 6.6 Hz, 3H, H-9), 1.23(d, J = 7.1 Hz, 3H, H-10). 13C NMR (150 MHz, CDCl3) δ: 184.1 (C-6), 177.8 (C-8), 174.9 (C-12), 163.1 (C-1), 139.1 (C-4a), 123.5 (C-5), 107.9 (C-8a), 100.7 (C-7), 81.8 (C-3), 35.0 (C-4), 18.9 (C-9), 18.6 (C-10), 9.8 (C-11). Due to the chemical shifts and relative molecular masses in agreement with reported in the literature [30], the structure of the compound was determined to be citrinin.

Emodin (2) (Figure S4-6) [31]: yellow crystal; HR-ESI-MS: m/z: 269.0455 [M-H]−, calculated for C15H9O5− 269.0450. 1H NMR (600 MHz, Acetone-d6) δ: 7.57(s, 1H, H-4), 7.26(s, 1H, H-5), 7.14(s, 1H, H-2), 6.65(s, 1H, H-7), 2.47(s, 3H, CH3-3). 13C NMR (150 MHz, Acetone-d6) δ: 191.9 (C-9), 182.5 (C-10), 166.9 (C-6), 166.3 (C-8), 163.3 (C-1), 149.7 (C-3), 125.1 (C-2), 121.7 (C-4), 110.0 (C-5), 109.0 (C-7), 22.2 (CH3-3); nodal atoms: 136.9, 134.6, 114.8, 110.6.

Citreorosein (3) (Figure S7-8) [32]: yellow crystal; HR-ESI-MS: m/z: 285.0405 [M-H]−, calculated for C15H9O6− 285.0413. 1H NMR (600 MHz, Acetone-d6) δ: 7.76(s, 1H, H-5), 7.32 (s, 1H, H-7), 7.27 (s, 1H, H-4), 6.63(s, 1H, H-2), 4.77(s, 2H, CH2-3).

8-Hydroxy-6-methyl-9-oxo-9 H-xanthene-1-carboxylic acid methyl ester (4) (Figure S9-11) [33]: yellow needles; HR-ESI-MS: m/z: 307.0586 [M + Na]+, calculated for C16H12O5Na+ 307.0582. 1H NMR (600 MHz, CDCl3) δ: 12.13 (s, 1H, OH-8), 7.73 (t, J = 7.9 Hz, 1H, H-3), 7.51 (d, J = 8.5 Hz, 1H, H-4), 7.29 (d, J = 7.3 Hz, 1H, H-2), 6.73 (s, 1H, H-5), 6.62 (s, 1H, H-7), 4.03 (s, 3H, CH3O-11), 2.42 (s, 3H, H-12). 13C NMR (150 MHz, CDCl3) δ: 180.5 (C-9), 169.9 (C-11), 161.5 (C-8), 156.1 (C-4a), 155.8 (C-10a), 149.5 (C-6), 134.9 (C-3), 133.7 (C-1), 122.7 (C-2), 119.6 (C-4), 117.7 (C-9a), 112.1 (C-7), 111.5, 107.8 (C-5), 107.2 (C-8a), 53.3 (CH3O-11), 22.8 (C-12).

Ergosterol (5) (Figure S12-13) [34]: colorless crystal; 1H NMR (600 MHz, CDCl3) δ: 5.57(s, 1H), 5.38(s, 1H), 5.20(dd, J = 13.7, 7.7 Hz, 2H), 3.64(s, 1H), 2.47(d, J = 14.0 Hz, 1H), 2.29(d, J = 12.1 Hz, 1H), 2.06(d, J = 11.5 Hz, 2H), 1.97(s, 1H), 1.88(t, J = 13.5 Hz, 4H), 1.81–1.70(m, 2H), 1.69–1.63(m, 1H), 1.52–1.43(m, 2H), 1.38(dd, J = 11.6, 5.4 Hz, 1H), 1.35–1.22(m, 4H), 1.04(d, J = 5.9 Hz, 3H), 0.95(s, 3H), 0.92(d, J = 5.9 Hz, 3H), 0.88–0.79(m, 5H), 0.63(s, 3H). 13C NMR (150 MHz, CDCl3) δ: 141.3, 141.3, 139.8, 139.8, 135.6, 135.5, 132.0, 132.0, 119.6, 119.6, 116.3, 116.3, 55.8, 55.8, 54.6, 54.6, 46.3, 46.3, 42.8, 42.8, 40.9, 40.8, 40.3, 40.3, 39.1, 39.1, 38.4, 38.4, 37.1, 37.0, 33.1, 33.1, 32.0, 32.0, 28.2, 28.2, 23.0, 23.0, 21.2, 21.1, 21.1, 19.9, 19.9, 19.6, 19.6, 17.6, 17.6, 16.3, 16.3, 12.1, 12.0.

Rubratoxin B (6) (Figure S14-16) [35]: white solid; HR-ESI-MS: m/z: 541.1683 [M + Na]+, calculated for C26H30O11Na+ 541.1686. 1H NMR (600 MHz, Acetone-d6) δ: 7.13–7.02 (m, 1H, H-3), 5.96 (d, J = 9.8 Hz, 1H, H-2), 5.68 (d, J = 11.0 Hz, 1H, H-11), 4.73 (d, J = 8.1 Hz, 1H, H-5), 4.45 (s, 1H, H-20), 3.84 (s, 1H, H-6), 3.46 (d, J = 11.0 Hz, 1H, H-21), 3.26–3.15 (m, 1H, H-24), 2.92 (d, J = 13.4 Hz, 1H, H-8), 2.79 (d, J = 14.8 Hz, 1H, H-24), 2.70 (t, J = 12.9 Hz, 1H, H-8), 2.50 (m, 2H, H-4), 2.08 (d, J = 8.9 Hz, 1H, H-7), 1.54–1.39 (m, 4H, H-18, H-19), 1.27 (m, 6H, H-15, H-16, H-17), 0.87 (t, J = 7.0 Hz, 3H, H-14). 13C NMR (150 MHz, Acetone-d6) δ: 167.5 (C-26), 167.3 (C-25), 166.7 (C-13), 163.9 (C-1), 163.9 (C-12), 148.3 (C-22), 146.5 (C-3), 144.5 (C-9), 144.0 (C-10), 140.2 (C-23), 121.3 (C-2), 79.8 (C-5), 77.5 (C-6), 70.5 (C-20), 65.1 (C-11), 48.7 (C-21), 36.9 (C-19), 36.9 (C-7), 32.5 (C-24), 32.5 (C-16), 29.8 (C-17), 27.0 (C-18), 26.4 (C-4), 25.3 (C-8), 23.2 (C-15).

Erythrol (7) (Figure S17-19) [36]: white solid; HR-ESI-MS: m/z: 145.0476 [M + Na]+, calculated for C4H10O4Na+ 145.0477. 1H NMR (600 MHz, DMSO) δ: 4.45 (s, 2H), 4.32 (s, 2H), 3.53 (d, J = 8.9 Hz, 2H), 3.36 (d, J = 21.0 Hz, 4H). 13C NMR (150 MHz, DMSO) δ: 72.6, 63.4.

Flufuran (8) (Figure S20-22) [37]: yellow needle crystal; HR-ESI-MS: m/z: 143.0340 [M + H]+, calculated for C6H7O4+ 143.0344, 1H NMR (600 MHz, Methanol-d4) δ: 8.01(s, 1H, H-2), 6.56(s, 1H, H-4), 4.47(s, 2H, H-7). 13C NMR (150 MHz, Methanol-d4) δ: 176.8 (C-6), 170.4 (C-5), 147.4 (C-3), 141.0 (C-2), 110.8 (C-4), 61.2 (C-7).

4-N-Butylpyridine-2-carboxylic acid (9) (Figure S23-24) [38]: white powder; HR-ESI-MS: m/z: 180.1016 [M + H]+, calculated for C10H14NO2+ 180.1025. 1H NMR (600 MHz, Methanol-d4) δ: 8.57 (s, 1H), 7.88 (s, 1H), 7.62 (s, 1H), 2.50 (s, 2H), 1.42 (s, 2H), 1.17 (s, 2H), 0.82 (s, 3H).

Antibacterial activities of metabolites isolated from target strains

The antibacterial activity of the metabolites was tested using the disc diffusion method. The results (Table 3) showed that compound 1 exhibited strong antibacterial activity against four pathogenic bacteria (S. aureus, M. tetragenus, E. coli, and P. syringae pv. actinidiae), with the IZD of 20.0, 18.0, 22.3, 24.1 mm at a concentration of 30 µg/disc, which were comparable to those of positive gentamicin sulfate with the IZD of 25.7, 22.7, 27.6, 24.6 mm, respectively. Compound 9 also exhibited great antibacterial activity against four pathogenic bacteria (S. aureus, M. tetragenus, E. coli, and P. syringae pv. actinidiae), with the IZD of 14.3, 17.3, 13.3, 21.1 mm, respectively.

Table 3 IZD (mm) of compounds 1–9 against the tested bacteria
Full size table

Phytotoxic assay of metabolites

Phytotoxic activity tests (Table 4) showed that compound 1 exhibited strong phytotoxic activity against the roots of E. crusgalli, with an inhibition rate of 97.4% at a concentration of 100 µg/mL, which was comparable to the positive control 2,4-D with an inhibition rate of 100%. Additionally, compound 6 exhibited significant phytotoxic activity against the A. theophrasti, with an inhibition rate of 87.4%. Compounds 6 and 9 also displayed potent phytotoxic activity against the roots of E. crusgalli, with the inhibition rate of 50.4% and 78.4%, respectively (Figure S25).

Table 4 Inhibition rate (%) of compounds 1–9 on the radicle growth of E. crusgalli and A. theophrasti
Full size table

Discussion

The insect gut hosts a rich diversity of microorganisms, with symbiotic microbial communities and their metabolites playing essential roles in the host insect’s survival and microecology. This unique environment not only supports various biological activities but also offers the potential for discovering novel microbial species with unique bioactive properties [39, 40]. In this study, a total of 54 strains of intestinal fungi were isolated and identified from the gut of E. bimaculata. These fungi were distributed across three major phyla (Ascomycota, Basidiomycota, and Zygomycota) and seven classes (Agaricomycetes, Cystobasidiomycetes, Eurotiomycetes, Dothideomycetes, Sordariomycetes, Saccharomycetes, and Zygomycetes). The results are similar to the those of intestinal fungi from other insects [41, 42]. To our knowledge, this is the first report on the diversity of fungi in the gut of the E. bimaculata.

Antibiotics are a class of compounds widely used to treat microbial infections in both human and animal clinical settings, as well as in agriculture [43]. However, the long-term overuse of antimicrobial drugs has led to increasingly serious resistance issues [44], highlighting the urgent need for new antimicrobial compounds. Natural products, with their unique chemical structures and diverse activities, are considered a valuable resource for developing new antibacterial drugs [45]. In our study, strain QTU-25 exhibited strong antibacterial activity against M. tetragenus, S. aureus, and P. syringae pv. actinidiae, with the IZD of 16.0, 16.0, and 23.6 mm, which were slightly weaker than those of the positive gentamicin sulfate. In this study, compounds 1 and 9 exhibited strong antibacterial activity against various pathogenic bacteria, including S. aureus, M. tetragenus, E. coli, and P. syringae pv. actinidiae. Among them, literature reports have shown that compound 1 also demonstrates excellent antibacterial activity against drug-resistant E. coli and S. aureus, which is similar with the findings of this study [46, 47]. Although compound 6 did not exhibit antibacterial activity in this experiment, literature reports indicate that this compound possesses notable antibacterial (Bacillus subtilis) and antitumor activities [35, 48]. The above results indicate that the secondary metabolites of gut fungi from E. bimaculata possess significant antibacterial potential, highlighting their value for further development.

Currently, the damage caused by field weeds to crops is a significant challenge in modern agricultural production, resulting in substantial economic losses and reduced crop yields [19]. However, the extensive and prolonged use of chemical herbicides has led to widespread herbicide resistance among weeds, which is now a major global issue affecting crop production [49]. This has created an urgent need for new herbicides to combat resistant weeds and ensure the sustainable development of agriculture. In this study, 50 (92.5%) and 25 (46.2%) strains of intestinal fungi exhibited potent phytotoxic activity against E. crusgalli and A. theophrasti respectively, with the inhibition rates exceeding 50%. Additionally, compounds 1 and 9 exhibited strong phytotoxic activity against the roots of E. crusgalli, with the inhibition rate of 97.4% and 78.4%, respectively. Compound 6 also showed strong phytotoxic activity against the A. theophrasti, with an inhibition rate of 87.4%. Additionally, the compound has been shown to exhibit phytotoxicity in other plant species as well [50]. In addition to their direct phytotoxic effects, allelopathic compounds (commonly referred to as allelochemicals) are naturally occurring secondary metabolites that can interfere with various physiological processes in other plants [51]. Thus, the compounds identified in this study may possess allelopathic properties that inhibit plant growth, meriting further investigation in future research. These results suggest that gut fungi from E. bimaculata are promising candidates for the development of new bioherbicides.

Conclusions

A total of 54 strains of gut fungi were isolated and purified from the gut of E. bimaculata using 12 different isolation media. These fungal strains were identified as belonging to seven classes within 17 genera. The dominant genera included Penicillium, Talaromyces, Irpex, Mucor, and Cladosporium, with isolation frequencies of 14.81%, 12.96%, 11.11%, 11.11%, and 9.25%, respectively. Antibacterial activity tests showed that six strains extracts exhibited inhibitory activity against at least one of the tested bacteria (S. aureus, M. tetragenus, E. coli, and P. syringae pv. actinidiae). Notably, strain Penicillium sp. QTU-25 showed strong antibacterial activities against S. aureus, M. tetragenus, and P. syringae pv. actinidiae, with the IZD of 16.0, 16.0, and 23.6 mm, respectively. Herbicidal activity tests revealed that seven strains, QTU-39, QTU-22, QTU-9, QTU-41, QTU-37, QTU-28, and QTU-25, exhibited strong phytotoxic activity against E. crusgalli with the inhibition rate of more than 93.5%. Nine monomer compounds were isolated from the crude extracts of strains Penicillium sp. QTU-25 and Pestalotiopsis sp. QTU-28, including citrinin (1), emodin (2), citreorosein (3), 8-hydroxy-6-methyl-9-oxo-9 H-xanthene-1-carboxylic acid methyl ester (4), ergosterol (5), rubratoxin B (6), and erythrol (7) from strain QTU-25, and flufuran (8) and 4-N-butylpyridine-2-carboxylic acid (9) from strain QTU-28. Compound 1 exhibited strong antibacterial activity against four pathogenic bacteria (S. aureus, M. tetragenus, E. coli, and P. syringae pv. actinidiae), with the IZD of 20.0, 18.0, 22.3, 24.1 mm, which were equal to those of positive gentamicin sulfate with the IZD of 25.7, 22.7, 27.6, 24.6 mm, respectively. Compound 9 also exhibited strong antibacterial activity against S. aureus, M. tetragenus, E. coli, and P. syringae pv. actinidiae, with the IZD of 14.3, 17.3, 13.3, and 21.1 mm, respectively. Furthermore, compounds 1 and 6 exhibited strong phytotoxic activity against E. crusgalli and A. theophrasti with an inhibition rate of 97.4% and 87.4% at a concentration of 100 µg/mL, respectively. These results suggest that the fungi isolated from the gut of E. bimaculata exhibited significant microbial diversity and represented a promising natural source of antibacterial and herbicidal compounds.

Data availability

The datasets generated and/or analysed during the current study are available in the NCBI repository, PQ268869-PQ268922.

References

  1. Misof B, Liu S, Meusemann K, Peters RS, Donath A, Mayer C, et al. Phylogenomics resolves the timing and pattern of insect evolution. Science. 2014;346(6210):763–7. https://doiorg.publicaciones.saludcastillayleon.es/10.1126/science.1257570.

    Article  CAS  PubMed  Google Scholar 

  2. Poveda J. Insect frass in the development of sustainable agriculture. A review. Agron Sustain Dev. 2021;41(1):5. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s13593-020-00656-x.

    Article  Google Scholar 

  3. Outhwaite CL, McCann P, Newbold T. Agriculture and climate change are reshaping insect biodiversity worldwide. Nature. 2022;605(7908):97–102. https://doiorg.publicaciones.saludcastillayleon.es/10.1038/s41586-022-04644-x.

    Article  CAS  PubMed  Google Scholar 

  4. Martínez-Solís M, Collado MC, Herrero S. Influence of diet, sex, and viral infections on the gut microbiota composition of Spodoptera exigua caterpillars. Front Microbiol. 2020;11. https://doiorg.publicaciones.saludcastillayleon.es/10.3389/fmicb.2020.00753.

  5. Anderson KE, Russell JA, Moreau CS, Kautz S, Sullam KE, Hu YI, et al. Highly similar microbial communities are shared among related and trophically similar ant species. Mol Ecol. 2012;21(9):2282–96. https://doiorg.publicaciones.saludcastillayleon.es/10.1111/j.1365-294X.2011.05464.x.

    Article  PubMed  Google Scholar 

  6. Wang Z, Wang T, Zhu H, Pan H, Yu X. Diversity and dynamics of microbial communities in brown planthopper at different developmental stages revealed by high-throughput amplicon sequencing. Insect Sci. 2020;27(5):883–94. https://doiorg.publicaciones.saludcastillayleon.es/10.1111/1744-7917.12729.

    Article  CAS  PubMed  Google Scholar 

  7. Nguyen TTT, Kwan Noh KJ, Lee HB. New species and eight undescribed species belonging to the families Aspergillaceae and Trichocomaceae in Korea. Mycobiology. 2021;49(6):534–50. https://doiorg.publicaciones.saludcastillayleon.es/10.1080/12298093.2021.1997461.

    Article  PubMed  PubMed Central  Google Scholar 

  8. Čadež N, Fülöp L, Dlauchy D, Péter G. Zygosaccharomyces favi sp. nov., an obligate osmophilic yeast species from bee bread and honey. Antonie Van Leeuwenhoek. 2015;107(3):645–54. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s10482-014-0359-1.

    Article  CAS  PubMed  Google Scholar 

  9. Jadhav R, Tiwari S, Avchar R, Groenewald M, Baghela A. Suhomyces drosophilae sp. nov., isolated from Drosophila flies feeding on a stinkhorn mushroom. Int J Syst Evol MicroBiol. 2020;70(9):4908–13. https://doiorg.publicaciones.saludcastillayleon.es/10.1099/ijsem.0.004358.

    Article  CAS  PubMed  Google Scholar 

  10. Dimitrov R, Gouliamova D, Guéorguiev B, Smith M, Groenewald M, Boekhout T. First DNA barcoding survey in Bulgaria unveiled huge diversity of yeasts in insects. Insects. 2024;15(8):566.

    Article  PubMed  PubMed Central  Google Scholar 

  11. Cornwallis CK, van ’t Padje A, Ellers J, Klein M, Jackson R, Kiers ET, et al. Symbioses shape feeding niches and diversification across insects. Nat Ecol Evol. 2023;7(7):1022–44. https://doiorg.publicaciones.saludcastillayleon.es/10.1038/s41559-023-02058-0.

    Article  PubMed  PubMed Central  Google Scholar 

  12. Menegatti C, Fukuda TTH, Pupo MT. Chemical Ecology in Insect-microbe interactions in the Neotropics. Planta Med. 2021;87(01/02):38–48. https://doiorg.publicaciones.saludcastillayleon.es/10.1055/a-1229-9435.

    Article  CAS  PubMed  Google Scholar 

  13. Kandasamy D, Gershenzon J, Andersson MN, Hammerbacher A. Volatile organic compounds influence the interaction of the eurasian spruce bark beetle (Ips typographus) with its fungal symbionts. ISME J. 2019;13(7):1788–800. https://doiorg.publicaciones.saludcastillayleon.es/10.1038/s41396-019-0390-3.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  14. Cui P, Liu L, Huang Z, Shi S, Kong K, Zhang Y. Diversity, antibacterial activity and chemical analyses of gut-associated fungi isolated from the Crocothemis servilia. Front Microbiol. 2022;13. https://doiorg.publicaciones.saludcastillayleon.es/10.3389/fmicb.2022.970990.

  15. Kornsakulkarn J, Saepua S, Laksanacharoen P, Rachtawee P, Thongpanchang C. Xanthone and anthraquinone-type mycotoxins from the scale insect fungus Aschersonia marginata BCC 28721. Tetrahedron Lett. 2013;54(29):3813–5. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.tetlet.2013.05.036.

    Article  CAS  Google Scholar 

  16. Kornsakulkarn J, Saepua S, Srichomthong K, Supothina S, Thongpanchang C. New mycotoxins from the scale insect fungus Aschersonia coffeae Henn. BCC 28712. Tetrahedron. 2012;68(40):8480–6. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.tet.2012.07.059.

    Article  CAS  Google Scholar 

  17. Lv J-H, Yao L, Li S-Y, Ye M-Y, Li D, Li C-T, et al. Three new griseofulvin derivatives from Aureobasidium pullulans. Nat Prod Res. 2024;1–6. https://doiorg.publicaciones.saludcastillayleon.es/10.1080/14786419.2024.2312428.

  18. Zhong R, Shi C, Wu X, Zou Y, Li J, Liang Y. A new isocoumarin from sponge endophytic fungus Aspergillus ochraceopetaliformis with cytotoxic activity. Nat Prod Res. 2024;1–6. https://doiorg.publicaciones.saludcastillayleon.es/10.1080/14786419.2024.2411373.

  19. Quareshy M, Prusinska J, Li J, Napier R. A cheminformatics review of auxins as herbicides. J Exp Bot. 2018;69(2):265–75. https://doiorg.publicaciones.saludcastillayleon.es/10.1093/jxb/erx258.

    Article  CAS  PubMed  Google Scholar 

  20. Savary S, Willocquet L, Pethybridge SJ, Esker P, McRoberts N, Nelson A. The global burden of pathogens and pests on major food crops. Nat Ecol Evol. 2019;3(3):430–9. https://doiorg.publicaciones.saludcastillayleon.es/10.1038/s41559-018-0793-y.

    Article  PubMed  Google Scholar 

  21. Zhang YL, Ge HM, Li F, Song YC, Tan RX. New phytotoxic metabolites from Pestalotiopsis sp. HC02, a fungus residing in Chondracris Rosee gut. Chem Biodivers. 2008;5(11):2402–7. https://doiorg.publicaciones.saludcastillayleon.es/10.1002/cbdv.200890204.

    Article  CAS  PubMed  Google Scholar 

  22. Biedermann PHW, Vega FE. Ecology and evolution of insect–fungus mutualisms. Ann Rev Entomol. 2020;65:431–55. https://doiorg.publicaciones.saludcastillayleon.es/10.1146/annurev-ento-011019-024910.

    Article  CAS  Google Scholar 

  23. Yang N, Ren D, Béthoux O. Little bits of dragonfly history repeating exemplified by a new Pennsylvanian family. Royal Soc Open Sci. 2023;10(10):230904. https://doiorg.publicaciones.saludcastillayleon.es/10.1098/rsos.230904.

    Article  Google Scholar 

  24. Nobles S, Jackson CR. Effects of life stage, site, and species on the dragonfly gut microbiome. Microorganisms. 2020;8(2). https://doiorg.publicaciones.saludcastillayleon.es/10.3390/microorganisms8020183.

  25. Deb R, Nair A, Agashe D. Host dietary specialization and neutral assembly shape gut bacterial communities of wild dragonflies. PeerJ. 2019;7:e8058. https://doiorg.publicaciones.saludcastillayleon.es/10.7717/peerj.8058.

    Article  PubMed  PubMed Central  Google Scholar 

  26. Xu X, Shao M, Yin C, Mao Z, Shi J, Yu X, et al. Diversity, bacterial symbionts, and antimicrobial potential of termite-associated fungi. Front Microbiol. 2020;11. https://doiorg.publicaciones.saludcastillayleon.es/10.3389/fmicb.2020.00300.

  27. AlAgha R, Chew Ka L, Tay Wan J, Lum L. Answer to photo quiz: phaeohyphomycosis caused by Exophiala Oligosperma. J Clin Microbiol. 2021;59(7):10.1128/jcm.02195-02120; doi: 10.1128/jcm.02195-20.

  28. Tang Z, Qin Y, Chen W, Zhao Z, Lin W, Xiao Y, et al. Diversity, chemical constituents, and biological activities of endophytic fungi isolated from Ligusticum Chuanxiong Hort. Front Microbiol. 2021;12. https://doiorg.publicaciones.saludcastillayleon.es/10.3389/fmicb.2021.771000.

  29. Lu YH, Jin LP, Kong LC, Zhang YL. Phytotoxic, antifungal and immunosuppressive metabolites from Aspergillus terreus QT122 isolated from the gut of dragonfly. Curr Microbiol. 2017;74(1):84–9. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s00284-016-1157-y.

    Article  CAS  PubMed  Google Scholar 

  30. do Rosário Marinho AM, Rodrigues-Fo E. Dicitrinol, a citrinin dimer, produced by Penicillium Janthinellum. Helv Chim Acta. 2011;94(5):835–41. https://doiorg.publicaciones.saludcastillayleon.es/10.1002/hlca.201000309.

    Article  CAS  Google Scholar 

  31. Kharlamova TV. Reaction of frangula-emodin with α-bromoalkylmethylketones. Chem Nat Compd. 2007;43(4):391–4. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s10600-007-0146-6.

    Article  CAS  Google Scholar 

  32. Khalil A, Park W, Akter K, Ahn M-J. Anti-Helicobacter Pylori compounds from Polygonum cuspidatum. Nat Prod Sci. 2016;22:220. https://doiorg.publicaciones.saludcastillayleon.es/10.20307/nps.2016.22.3.220.

    Article  CAS  Google Scholar 

  33. Macı́as M, Gamboa A, Ulloa M, Toscano RA, Mata R. Phytotoxic naphthopyranone derivatives from the coprophilous fungus Guanomyces polythrix. Phytochemistry. 2001;58(5):751–8. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/S0031-9422(01)00278-3.

    Article  PubMed  Google Scholar 

  34. Martinez M, Torrez Alvarez S, Campi MG, Bravo JA, Vila JL. Ergosterol from the mushroom Laetiporus sp.; isolation and structural characterization. Revista Boliviana De Química. 2015;32:90–4.

    CAS  Google Scholar 

  35. Chen R-D, Yan Z, Zou J-H, Wang N, Dai J-G, Rubratoxin C. A new nonadride derivative from an endophytic fungus Penicillium sp. F-14. Chin Chem Lett. 2014;25(9):1308–10. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.cclet.2014.03.040.

    Article  CAS  Google Scholar 

  36. Chang X, Kang W. Antioxidant and α-glucosidase inhibitory compounds from Pimpinella Candolleana Wight et Arn. Med Chem Res. 2012;21(12):4324–9. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s00044-012-9974-4.

    Article  CAS  Google Scholar 

  37. Evidente A, Cristinzio G, Punzo B, Andolfi A, Testa A, Melck D. Flufuran, an antifungal 3,5-disubstituted furan produced by Aspergillus flavus link. Chem Biodivers. 2009;6(3):328–34. https://doiorg.publicaciones.saludcastillayleon.es/10.1002/cbdv.200800292.

    Article  CAS  PubMed  Google Scholar 

  38. Mei G. Fermentation products of endophyte HCCB00167. J Shenyang Pharm Univ. 2007;(04):245–8.

  39. Zhao X, Zhang X, Chen Z, Wang Z, Lu Y, Cheng D. The divergence in bacterial components associated with Bactrocera dorsalis across developmental stages. Front Microbiol. 2018;9. https://doiorg.publicaciones.saludcastillayleon.es/10.3389/fmicb.2018.00114.

  40. Wang X, Sun S, Yang X, Cheng J, Wei H, Li Z, et al. Variability of gut microbiota across the life cycle of Grapholita molesta (Lepidoptera: Tortricidae). Front Microbiol. 2020;11. https://doiorg.publicaciones.saludcastillayleon.es/10.3389/fmicb.2020.01366.

  41. Khan KA, Al-Ghamdi AA, Ghramh HA, Ansari MJ, Ali H, Alamri SA, et al. Structural diversity and functional variability of gut microbial communities associated with honey bees. Microb Pathog. 2020;138:103793. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.micpath.2019.103793.

    Article  PubMed  Google Scholar 

  42. Malassigné S, Minard G, Vallon L, Martin E, Valiente Moro C, Luis P. Diversity and functions of yeast communities associated with insects. Microorganisms. 2021;9(8):1552. https://doiorg.publicaciones.saludcastillayleon.es/10.3390/microorganisms9081552.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. Manzetti S, Ghisi R. The environmental release and fate of antibiotics. Mar Pollut Bull. 2014;79(1):7–15. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.marpolbul.2014.01.005.

    Article  CAS  PubMed  Google Scholar 

  44. Qiao M, Ying G-G, Singer AC, Zhu Y-G. Review of antibiotic resistance in China and its environment. Environ Int. 2018;110:160–72. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.envint.2017.10.016.

    Article  CAS  PubMed  Google Scholar 

  45. Newman DJ, Cragg GM. Natural products as sources of new drugs over the nearly four decades from 01/1981 to 09/2019. J Nat Prod. 2020;83(3):770–803. https://doiorg.publicaciones.saludcastillayleon.es/10.1021/acs.jnatprod.9b01285.

    Article  CAS  PubMed  Google Scholar 

  46. Subramani R, Kumar R, Prasad P, Aalbersberg W. Cytotoxic and antibacterial substances against multi-drug resistant pathogens from marine sponge symbiont: citrinin, a secondary metabolite of Penicillium sp. Asian Pac J Trop Biomed. 2013;3(4):291–6. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/S2221-1691(13)60065-9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  47. Yao G, Chen X, Zheng H, Liao D, Yu Z, Wang Z, et al. Genomic and chemical investigation of bioactive secondary metabolites from a marine-derived fungus Penicillium steckii P2648. Front Microbiol. 2021;12. https://doiorg.publicaciones.saludcastillayleon.es/10.3389/fmicb.2021.600991.

  48. Chen X, Zheng Y, Shen Y. Natural products with maleic anhydride structure: nonadrides, tautomycin, chaetomellic anhydride, and other compounds. Chem Rev. 2007;107(5):1777–830. https://doiorg.publicaciones.saludcastillayleon.es/10.1021/cr050029r.

    Article  CAS  PubMed  Google Scholar 

  49. Li J, Mu J, Bai J, Fu F, Zou T, An F, et al. Paraquat Resistant1, a golgi-localized putative transporter protein, is involved in intracellular transport of paraquat. Plant Physiol. 2013;162(1):470–83. https://doiorg.publicaciones.saludcastillayleon.es/10.1104/pp.113.213892.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  50. Rovetto EI, Luz C, La Spada F, Meca G, Riolo M, Cacciola SO. Diversity of mycotoxins and other secondary metabolites recovered from blood oranges infected by Colletotrichum, Alternaria, and Penicillium species. Toxins. 2023;15(7):407. https://doiorg.publicaciones.saludcastillayleon.es/10.3390/toxins15070407.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  51. Tabaglio V, Fiorini A, Sterling TM, Schulz M. Abutilon theophrasti’s Resilience against allelochemical-based weed management in sustainable agriculture – due to collection of highly advantageous microorganisms? Plants. 2023;12(4):700. https://doiorg.publicaciones.saludcastillayleon.es/10.3390/plants12040700.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

Download references

Funding

This work was financially supported by the the National Natural Science Foundation of China (32270015).

Author information

Author notes

  1. Kun Kong and Zhe Yan contributed equally to this work.

Authors and Affiliations

  1. School of Life Sciences, Anhui Agricultural University, Hefei, 230036, China

    Kun Kong, Zhe Yan, Mengru Liu, Ye Wang, Zilin Xiang, Caiping Yin & Yinglao Zhang

Authors
  1. Kun Kong
    View author publications

    You can also search for this author inPubMed Google Scholar

  2. Zhe Yan
    View author publications

    You can also search for this author inPubMed Google Scholar

  3. Mengru Liu
    View author publications

    You can also search for this author inPubMed Google Scholar

  4. Ye Wang
    View author publications

    You can also search for this author inPubMed Google Scholar

  5. Zilin Xiang
    View author publications

    You can also search for this author inPubMed Google Scholar

  6. Caiping Yin
    View author publications

    You can also search for this author inPubMed Google Scholar

  7. Yinglao Zhang
    View author publications

    You can also search for this author inPubMed Google Scholar

Contributions

YL-Z designed the research and supervised the study. Z-Y, and ZL-X performed the sample collection; K-K, Z-Y, MR-L, Y-W, and CP-Y performed the experiments. K-K, Z-Y, and MR-L carried out the data analyses; K-K, Z-Y were responsible for the original manuscript. All authors contributed to the article and approved the submitted version.

Corresponding author

Correspondence to Yinglao Zhang.

Ethics declarations

Ethics approval and consent to participate

Materials and experiments were conducted in accordance with relevant institutional, national, and international guidelines. Clinical trial number: not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary Material 1

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Kong, K., Yan, Z., Liu, M. et al. Diversity, antibacterial and phytotoxic activities of intestinal fungi from Epitheca bimaculata. BMC Microbiol 25, 249 (2025). https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12866-025-03756-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12866-025-03756-4

Keywords

BMC Microbiology

ISSN: 1471-2180

Contact us